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Explanatory Notes for the ANDRILL Southern McMurdo Sound Project,

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Explanatory Notes for theANDRILL Southern McMurdo Sound Project, Antarctica

F. Florindo1, d. Harwood2,3 & r. levy3 witH contributions From G. acton4, c. FieldinG2, K. Panter5, t. Paulsen6, F. sanGiorGi, F. talarico8, m. taviani9,

v. willmott & tHe andrill-sms science team11

1Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143, Rome - Italy2Dept. of Geosciences, University of Nebraska-Lincoln, 214 Bessey Hall, Lincoln, NE 68588-0340 - USA

3ANDRILL Science Management Office, Univ. Nebraska-Lincoln, 126 Bessey Hall, Lincoln, NE 68588-0341 - USA4Geology Department, University of California-Davis, One Shields Ave., Davis, CA 95616 - USA

5Dept. of Geology, Bowling Green State University, Bowling Green, OH, 43403 – USA6Dept. of Geology, Univ. of Wisconsin at Oshkosh, Oshkosh, WI 54901-8649 - USA

7Laboratory of Palaeobotany and Palynology, Utrecht University, Utrecht - The Netherlands8Dipt. di Scienze della Terra, Università di Siena, Via Laterina 8, 53100, Siena - Italy

9ISMAR-CNR, Via Gobetti 101, 40129, Bologna - Italy10NIOZ Royal Netherlands Institute for Sea Research, Texel - The Netherlands

11http://andrill.org/projects/sms/team.html*Corresponding authors (fabio.florindo@ingv.it, dharwood1@unlnotes.unl.edu)

Abstract - This Explanatory Notes section complements and supports four other documents, which collectively describe the process and procedures of scientific investigations employed during the ANDRILL SMS Project: (1) ANDRILL Southern McMurdo Sound Project - Scientific Prospectus (ANDRILL contribution 5 - Harwood et al., 2005); (2) a Science Plan summary of SMS Project research compiled from research proposals of Science Team menbers (available on the SMS Project ‘Science Drive’ – Harwood et al., 2007); (3) SMS Project Science Logistics Implementation Plan (SLIP) - draft documents developed and distributed to SMS team members prior to deployment; (4) Operations overview – Falconer et al., this volume). These five documents, and information presented (also available on the SMS Project ‘Science Drive’) at McMurdo Station during the initial morning meetings by co-chief scientists, staff scientist, media coordinator, curator and discipline team leaders, represent the essential elements of the full Science Logistics Implementation Plan (SLIP) for the SMS Project. Please also refer to the McMurdo Ice Shelf Project SLIP available at www.andrill.org (ANDRILL contribution 7 – Naish et al., 2005) for additional background information related to SMS science logistics and operations. These explanatory notes provide important background information on the nature of data present on the SMS Project ‘Science Drive’, including the on-ice report, other core characterization data, and documents and data that record the activities of the SMS Project Science Team.

INTRODUCTION

As described in subsequent sections, the MIS and SMS projects included a core characterization phase, which included research conducted during drilling the drilling period and for ~6 months after drilling. Studies occurred at both on-ice and off-ice locations. A core workshop was held several months after the completion of drilling at the Antarctic Marine Geological Research Facility, at Florida State University,

where scientists reviewed new results, examined the core and selected new sample intervals for future studies (Fig. 1). This provided an opportunity for the ‘on-ice’ and ‘off-ice’ science teams to integrate results and develop an expanded science plan, given new knowledge about the AND2-2A drillcore. This workshop defined the end of the core characterization phase and the start of the science documentation phase, which included additional off-ice sampling and analyses, data synthesis, and dissemination of results.

Fig. 1 – The SMS Science Team at the SMS Project Core Workshop May 2008, Antarctic Marine Geology Research Facility, Florida State University. This workshop marked the end of the Core Characterization Phase of the SMS Project.

© Terra Antartica Publication 2008-200922 F. Florindo et al.

Results obtained during the science documentation phase will be integrated during the science integration workshop to be held ~16-24 months after the core sampling workshop. The science integration workshop will be held in Erice, Sicily, from 6 - 11 April 2010 (http://www.ccsem.infn.it/).

All data produced during the core characterization phase have been submitted to ANDRILL’s central database. Access to raw materials and data generated during the ANDRILL SMS Project is restricted to science team members for a moratorium period that began when first core came out of the ground and extends at least 18 months beyond the post-drilling core workshop that was held in April 2008. For the SMS Project, the moratorium period has been extended to June 2010. After this time, samples and data from the SMS Project ‘Science Drive’ will be available to the broader community of geoscientists.

DRILL SITE SCIENCE ACTIVITIES

overview oF data acQuisition and scientiFic obJectives

Several members of the SMS Project Science Team conducted their routine scientific work at the drill site in the purpose-built lab facility. This group of scientists and technicians resided at the drill site camp and ‘commuted’ to the drill site. The 12 hour work-shifts for science members coincided with the operational shift changes. Although data were acquired at the drill site, some analyses and on-ice and data reduction for the on-ice report writing were done at Crary Lab at McMurdo Station (please refer to Naish et al., 2006; MIS Project Science Logistics Operations Plan for background information and figures to support these description of drillsite and McMurdo Station scientific activities).

The drillsite science team included physical properties disciplines - the borehole, multi-sensor track and structure groups (here referred to as the ‘Logging Group’). For operational reasons, the drill-site scientific group also includes microbiology because sampling of fresh and uncontaminated sediments and rocks from the cores had to be performed at the drill site and thus became part of the technical/scientific core-flow procedure in the drill-site laboratory.

All these disciplines perform on-ice and off-ice science activities. While all on-ice scientists continue with data processing and interpretation during the off-ice period of the project, there are additional scientists with off-ice roles only. Overall Discipline Team Leader (DTL) for off-ice science contributions of the Logging Group is Terry Wilson; Tim Paulsen stepped into the role of on-ice Discipline Team Leader for the Physical Properties/Logging Team, in the absence of Terry Wilson in Antarctica.

Four ‘groups’ carried out scientific activities at the drill site lab: (2) core structure measurements group (CSMG), (2) microbiology and pore water geochemistry

(MPWG), (3) multi-sensor track (MSTG), and (4) downhole measurements group (DMG). The scientific objectives of the Geophysics/Structure disciplines (MSTG, DMG, CSMG) with respect to sedimentology and stratigraphy as well as structure and tectonics are summarized as follows:

Stratigraphic objectives• Link between depth (core and borehole) and

regional seismic lines; • Log- and MST-based physical properties proxies

for sequence stratigraphic calibration and cycle stratigraphy. Identification and quantitative characterization of subtle lithologic patterns and affinities (e.g., cluster and factor analysis, fining-upward patterns, particle size proxies);

• Measurement of sedimentary dip patterns; • Understanding compaction relationships, their

patterns and their controls.

Structure and tectonics objectives• Intraplate stress: direction and magnitude; in-situ

stress tensor from induced fractures (borehole hydrofracture experiment);

• fracture pattern and palaeostress history; rift faulting history from core faults and links to regional seismic profiles;

• uplift and tilting history; • history and pattern of regional heat and fluid

flow; • backstripping for subsidence history.

Drill-site measurementsMeasurements In drill-

holeContinu-ous-core

physical properties: velocity, density, mag susc, resistivity

X X

physical properties: natural gamma, neutron porosity, temperature

X

geochemistry: concentrations of some elements, mean atomic number

X X

imaging: dipmeter, televiewer, core scan

X X

structure: fracture pattern X Xvertical seismic profile Xhydrofracture X

STRUCTURAL ANALYSIS, WHOLE-CORE SCANNING, AND CORE ORIENTATION

The on-ice Core Structure Measurements Group (CSMG) consisted of two fracture logging scientists, Tim Paulsen (TP) and Cristina Millan (CM), and two technicians, Simona Pierdominici (SP) and Scott Drew (SD). Cristina Millan (CM) stepped in for Terry Wilson (TW) as the on ice fracture logging scientist; TW will contribute to core fracture characterization as an off-ice scientist. TP and TW shared the primary responsibilities for oversight of on-ice and off-ice core structural measurements, and will make decisions on

© Terra Antartica Publication 2008-200923Explanatory Notes for the ANDRILL SMS Project, Antarctica

scientific priorities jointly. SP and SD provided technical support and contributed to the core fracture studies. TP and CM shared primary responsibilities for core-based structural logging, core fracture photography, and on ice interpretation of structural data. TP and TW will share primary responsibility of off-ice core fracture studies to be conducted post drilling before the core sampling workshop. CM will contribute to the microstructural characterization of core fractures. An undergraduate student (off ice) working with TP will conduct microstructural palaeostrain/stress analyses. TW will provide oversight of the CoreScan® whole-core image acquisition for the ANDRILL project. SP and SD were responsible for Corescan®’s initial unpacking, set up and checkout and for running and troubleshooting the CoreScan® to capture whole-core digital imagery. SP and SD prepared whole-core segments for scanning, made decisions on which core intervals could be scanned, and were responsible for keeping CoreScan® logs and archiving whole-core imagery on DVD. They were the primary links between the CSMG and ANDRILL’s data management system, providing whole-core scan data for incorporation into the Corelyzer data visualization system. Results of this teams efforts on-ice are reported in Paulsen et al. (this volume).

Most of the on-ice CSMG work took place at the drill site science lab. Two-member teams of the CSMG worked on alternate 12-hour shifts throughout drilling operations. Workload for the CSMG was consistent and intensive, consisting of the following steps (note that the following workflow was only carried out on lithified core sections). The drill-site core-processing technicians (not part of the CSMG) fit together core pieces and carefully and accurately drew red and blue ‘scribe-lines’ along the length of each core run. Members of the CSMG supervised the technicians and helped troubleshoot this process. TP and CM defined intact core intervals, within which there had been no internal relative rotation of the core during drilling or coring.

After the core was scribed, TP and CM assigned depths in meters below sea floor (mbsf) to the top and bottom of each fracture. Depths to fracture top and bottom were recorded to the nearest centimeter. The dip and dip direction of each fracture were measured with respect to an arbitrary ‘north’ defined by the red line scribed on the core.

Core was then cut into 1 m segments by the drill site core-logging technicians. TP and CM then measured and photographed fracture features. They systematically examined the core surface and, where open, the individual fracture surfaces to constrain fracture mode of origin. They also recorded any bedding offsets, cross-cutting or abutting relations between fractures, type of fracture fill, and type and orientation of any surface fractographic features.

After photography and surface examination, the whole core surface was cleaned by the scanning technicians, and then each 1 m length (or subsection) of whole core was scanned using the CoreScan®

instrument, except where the integrity of the core did not permit handling.

Throughout the scanning process, SP and SD tabulated whole-core scan records of the depths of individual scans and segments that could not be scanned. They also backed up digital imagery as needed. After whole-core scanning, the scanning technicians transported the whole core to the multi-sensor core logger (MSCL) for analysis.

The CSMG also needed to observe the slabbed-core in order to select appropriate samples for thin section study of microstrucures. This viewing occured at CSEC during breaks in drilling, when possible, and at the end of the drilling. Since visiting CSEC was not possible during drilling, TP and CM used imagery of slabbed core images in Corelyzer at the Drill Site Lab (sent to the drill site each day from the core curators at CSEC) to identify oriented core samples to be taken by the core curators at CSEC.

All members of the CSMG were responsible for initial data processing and analysis, and writing contributions to the ‘On-Ice report’. CM, SP and SD supervised transport of the CoreScan® and structural measurement equipment from the drill site to McMurdo Station, where they prepared the equipment for shipment to the U.S.

MICROBIOLOGY AND PORE-WATER GEOCHEMISTRY

Microbiological and pore-water geochemical studies required intermittent sampling of the whole core and drilling fluids. The samples required different sampling and storage protocol, but in general were kept at stated temperatures prior to and during transport from the drill site to CSEC. Tracy Frank took responsibility for overseeing sample protocol upon her arrival at CSEC.

Once the core was recovered, it was sampled quickly so as to not significantly impact the microbial community and/or alter porewater geochemistry. Core processors cut whole core samples at the designated section in the core. Eight whole core microbiological samples (5 cm in length from PQ and HQ; 10 cm in length from NQ) were taken in different lithologies in monotonous intervals where the stratigraphic sample did not have a unique character (i.e., no lithologic breaks, diverse lithofacies, or obvious contacts).

A core orienting tool was planned to be used every other run during the project. Whole-core samples were not taken from the oriented core, making whole-core sampling every other run at a maximum when the core orienting tool was in use.

Four of the microbiological sample were cut from the core with a sterile/clean blade and placed directly into a sterile 18 oz. (ca. 28 grams) Whirl-Pak bag. The Whirl-Pak bag was placed into a trilaminated plastic bag with oxygen scrubbing packs, and the bag was vacuum- and heat-sealed. The sample was then placed in a cooler with dry-ice at the drill site and transported to CSEC. The remaining four

© Terra Antartica Publication 2008-200924 F. Florindo et al.

microbiological samples were cut from the core at CSEC after the core was cleaned and processed at the drill site. Microbiological studies also required 0.5 L samples of drilling fluid collected in a sterile 0.5 L Nalgene bottle on the same day as the whole core samples and 0.5 L samples collected in a sterile 0.5 L Nalgene bottle every other day. Prior to arrival at the Crary Lab, the drilling fluid samples and pore water samples were stored in dry-ice. At Crary Lab, they were maintained at -80°C in a freezer.

The pore-water whole-core samples were cut and removed from the core. A cylinder of styrofoam or wood marked ‘IW sample’ (interstitial water sample) was placed in the core to take the place of the section that was removed. The outside of the whole-core section was wiped clean, and the sample wrapped tightly in plastic wrap to avoid further exchange with the environment. The sample was clearly labeled in terms of depth and placed in a refrigerator (2 to 4°C). Ideally, the transfer to CSEC had to occur within 12 hours of retrieval, but within 24 hours was acceptable. Initial results of the pore-water geochemistry analyses are presented in Panter et al. (this volume).

MULTI-SENSOR-TRACK MEASUREMENTS

The on-ice multi-sensor track measurements group (MSTG) consisted of one logging scientist, Gavin Dunbar (GD), and two technicians, Cliff Atkins (CA) and Diana Magens (DM). DM maintained scientific involvement in the off-ice phase of the project as part of her Ph.D. program. Members of the MSTG ensured that a continuous (24 hour) whole core logging operation occurred. The work plan included data processing, storage and transfer into the ANDRILL data management system (‘Science Drive’) at the CSEC. Results of these on-ice analyses are presented in Dunbar et al. (this volume).

The on-ice multi-sensor track measurements included gamma attenuation, compressional (P-) wave velocity, and magnetic susceptibility. In order to accurately determine these parameters the instrument also measured core diameter and temperature.

GD was responsible for supervising the MSTG, for proper system calibration and initial data processing to a level that was usable by other groups working on ice. Magnetic susceptibility and wet bulk density (WBD) data were processed so that they could be displayed on the Corelyzer data visualization system. During the drilling phase, high-resolution measurements of p-wave velocities were converted into a cumulative 2-way travel-time log for the entire core combined with an acoustic impedance record calculated from velocity and density data. This log could be directly compared with the seismic profiles from the SMS drill site and with previously generated profile from the MIS AND-1B hole. Daily updates of the travel-time log provided useful information to the co-chiefs on whether or not an important drilling target (reflector) was reached.

DM was responsible for the technical supervision of the MST system, set-up of drill-site laboratory data network, logging and data acquisition during the night shift, and overall MST data storage and backups.

CA assisted GD during the day shift with logging, data acquisition and initial data processing. CA also assisted DM with assembling and dismantling of the MST at the beginning and end of the drilling phase.

In addition, G. Kuhn of the XRF-Scanner team at CSEC sampled the core (one sample per meter) for XRF calibration. These samples will undergo chemical analysis at AWI and University of Göttingen (Hilmar von Eynatten). Prior to this, the MSTG will use the samples to determine water content and grain density, in order to calculate dry bulk density in samples and fractional porosity from MST wet-bulk density.

Workload for the MSTG was relatively constant. Depending on the drilling operation there were the following phases: • between arrival on-ice and the first core available

for logging, the MSTG assembled, calibrate and test the logging equipment;

• during the drilling phases (PQ, HQ, NQ) the team worked 24 hours in two shifts of 12 hours to log core and process data;

• during the drilling pauses (borehole logging phases), any required maintenance on the MST was carried out at the drill site, combined with re-adjustments of the system to smaller core diameter and different state of consolidation of the core material, followed by system re-calibration;

• after the drilling phase and until departure from the ice, the two technicians were responsible for packing the MST and final data storage. GD joined the Crary Lab team for final preparation of the MST data for inclusion in the ‘On-Ice Science Report’;

• After drilling, Frank Niessen (off-ice scientist) will take the lead on preparing and cleaning the MST data for interpretation and publication. Data were sent off-ice to Frank Niessen during on-ice activities at regular intervals for consultation and data improvement.

DOWNHOLE MEASUREMENTS

The on-ice downhole measurements group (DMG) consisted of two logging scientists, Thomas Wonik (TWo) and David Handwerger (DH), VSP/seismic scientist Marvin Speece (MS), hydrofracture scientist Doug Schmitt (DS), and logging technician Thomas Grelle (TG). Simona Pierdominici (SP), member of the CSMG, assisted with the hydrofracture experiment. There were also four off-ice DMG scientists: Richard Jarrard (RJ), Terry Wilson (TW), Dan Moos (DM) and Paola Montone (PM). Results of these on-ice analyses are reported in Wonik et al. (this volume).

The four on-ice scientists were equal partners, but had a clearly defined division of primary

© Terra Antartica Publication 2008-200925Explanatory Notes for the ANDRILL SMS Project, Antarctica

responsibilities. TWo and DH made decisions on logging-tool scientific priorities jointly.

TWo owns the logging equipment and worked with technician TG for initial equipment unpacking and checkout, logging data acquisition, troubleshooting, and final preparation for return shipping. TWo supervised logging data acquisition (including decisions on which tools could be safely run and over what intervals), and initial data processing. Logging data acquisition was too lengthy, however, for TWo and TG to run all of the tools alone, so DH assisted them.

TWo and DH collaborated in the ‘on-ice’ activities, and will collaborate in the ‘off-ice’ phase of analyses of downhole logging data, concentrating on sedimentological, lithostratigraphic, and multivariate statistical interpretation of the logs. DH will be the main scientific link between the DMG and both the MSTG and sedimentologists, and TWo will be the main scientific link to the geochemists. TWo exported logging data to ANDRILL’s data management system.

MS was the lead scientist for the vertical seismic profile (VSP) study. MS worked with Alex Pyne (AP) to determine overall VSP design and placement of shots. MS tested and ran the downhole hydrophone string and uphole Geometrics data acquisition equipment on the hydrofrac winch; he also worked with TWo and TG in using their clumping geophone. MS had primary scientific responsibility for analysis of these data and for establishing the link between seismic-reflection time and well depth, using not only these data but also the sonic log (with DH and TWo) and multisensor-track velocities (with GD).

Ohio State University (TW) and University Utah (RJ) own the hydrofracture system on behalf of the ANDRILL Program. DS was responsible for the hydrofracture experiment, in collaboration with TP and SP (Core Structure Measurements Group). This responsibility involved initial equipment unpacking and checkout, setup of the winch, identification of optimum hydrofracture locations, operation of the hydrofracture equipment at the rig site, troubleshooting (if any), and final preparation for shipment of equipment back to the U.S. During the hydrofracture experiment, DS was assisted by TG, TWo, DH, MS, and some members (TP and SP) of the Core Structure Measurements Group. MS and DS shared responsibility for setup and operation of the hydrofracture winch. Off-ice scientist TW had overall responsibility for coordination of stress analysis for the SMS borehole and core. Off-ice scientists TW, PM, RJ and collaborating scientist DM, worked with on-ice scientists DS, TP and SP in the stress analysis. RJ, PM and SP collaborated on breakout analysis using dipmeter and BHTV data, and collaborated with the CSMG (TP, TW) to identify active faults based on comparison of breakout analysis and structural data from the core and borehole. TW, TP and DS will model stress regime based on drilling-induced fractures in the core, and will collaborate with RJ, PM and SP on integrated analysis of induced fractures in the borehole walls and core. DS, TW

and DM will have primary responsibility for modeling the in situ stress tensor from the hydrofracture and leak-off experiments. Thomas Wonik will collaborate with Dennis Harry using borehole temperature data to model basin subsidence and flexure.

CRARY LAB SCIENCE ACTIVITIES

CORE SAMPLING AND CURATION

Core from the drill site was transported to McMurdo Station by helicopter and picked up by the curatorial staff at the helo pad. Whole-round cores were delivered in aluminum boxes holding three PQ, four HQ, or five NQ meter-long sections. Bagged pore water and microbiology samples were received in temperature regulated vessels. All were collected at the helicopter pad and loaded within a Ford F-350 Hardback, and driven up to the Core Storage Facility.

On Tuesday through Friday, the core flight was scheduled between 2130-2200. On Saturdays the core flight was scheduled around 1800. No flights occurred on Sunday. Two flights were scheduled on Monday; at 0900-1000 delivery in addition to 2130-2200. Weather would delay or cancel flights, and other deviations from the regular schedule happened when Helo Ops needed to shuffle flight schedules to catch up on delays.

Core processing took place at four locations at McMurdo Station: (1) Core Storage Facility (CSF); (2) Mobile Laboratory Van (MLV); (3) RAC-Tent Scanning Facility (RTSF); and (4) Crary Science and Engineering Center (CSEC) (please refer to Naish et al., 2006; MIS Project Science Logistics Operations Plan for background information and figures to support these description of drillsite and McMurdo Station scientific activities).

Full core boxes from the drill site were unloaded to the CSF and cores were shelved for splitting. To avoid freezing and to retard desiccation of the core, the temperature in the CSF was maintained at 2-5°C, while an elevated humidity was achieved using a humidifier. The aluminum core boxes were washed and stacked in the CSF vestibule for transport back to the helo pad on the following afternoon.

MLV: CORE SPLITTING PROCEDUREFirm whole-round core sections came covered by

PVC splits from the drill site, with the exception of the last 100 m of HQ core. For these, only one side of the core section was covered at the drill site, while ODP liners were used to cover the other side in the MLV. A blue scribe-line on the core surface indicated the working half, while a red line marked the archive half. The PVC split covering the working half was labelled with project, hole, run number, top and bottom depths, as well as the ‘up’ direction. In the MLV, this procedure was checked by the curatorial staff and the archive

© Terra Antartica Publication 2008-200926 F. Florindo et al.

half was marked in a similar fashion.Each 1 m section of core was placed on the saw

track and aligned so the blade of the rotary diamond saw would cut between the PVC splits, perpendicular to a plane between the red and blue scribe lines. Due to the dense nature of the sediment, the abundance of hard minerals, coarse quartz-rich sands and abundance of hard-rock clasts, the saw blades rarely lasted longer than 100 m. As the core became richer in soft mud-rocks near the end of HQ drilling, the blades lasted longer. The HQ and NQ sections were significantly faster to split compared to the PQ.

The split section half-rounds were assigned blue plastic labels with core identification including run numbers, meter interval represented in the section, ‘top’ and whether the section is the ‘working’ or ‘archive’ half. The blue colour of the labels did not get overexposed during the following imaging, while a lighter colour label would.

Archive and working halves were sorted into separate waxed cardboard boxes holding 2 PQ, 3 HQ or 4 NQ half-round sections. Approximately 800 waxed cardboard boxes were used during the project. The ends of the boxes and associated lids were scraped clean of wax, and marked with box number, top and bottom depth represented in each box (in meters below seafloor), and ‘archive’ or ‘working’. Archive boxes were labelled in red, working boxes in blue.

The saw would be cleaned and lubricated at the end of each shift as deemed necessary.

tHe rac tent: multi-sensor core loGGinG (mscl) and XrF scanninG

• Full core boxes containing archive and working halves were carried to the RTSF for non-destructive imaging and scanning;

• the archive halves were imaged at low resolution, then scanned with an AVAATCH XRF scanner, and finally point-scanned with a Minolta photo-spectrometer;

• after scanning, the archive halves were wrapped for final transport by the curatorial staff and carried back to the CSF;

• the working halves were unwrapped and imaged using the Geotek MSCL imaging system, including a Nikon line scan camera and a Cosina 100 mm F3.5 macro lens. Aperture was set at 1/11. Down-core, the resolution was set at 200 dots/cm, while cross-core resolution depended on core width (app. 180 dots/cm for PQ, 160 for HQ, and 140 for NQ. This procedure took approximately 8 minutes, including preparation and core change;

• after imaging, the working halves were rewrapped and subjected to scanning with a Bartington MS2E magnetic susceptibility point sensor.

Tab. 1 - Samples collected on-ice, per investigator.

Investigator Samples requested Sample type Samples takenFielding 330 Normal 382Pekar 330 Normal 365Passchier 330 Normal 365Bassett 1 100 Thin section 137Bassett 2 100 Normal 17Cornamusini 200 Thin section 42Erhmann 200 Normal 159Fasano 5 Whole round 3Sedimentology total 1595 1470Taviani 250 Normal, TS 598Hannah 180 Normal 235Ishman 250 Normal 211Olney 500 Normal 246Riesselman 100 Normal 41Di Stefano 250 Normal, SS 281Lenczewski 8 Microbio 13Wise 250 Normal, SS 286Palaeontology total 1788 1911Millan Thin section 87Paulsen 200 Thin section 2Wonik (Phys. Prop) 180 Drill plug 135Log/phys prop total 380 224Corrado 100 Normal 107Del Carlo 200 Normal, TS 121Frank 1 50 Thin section 35Frank 2 100 Pore Water 27Kuhn 1000 Normal 972Rocchi 100 Normal 34Sandroni 150 Thin section 193Sprovieri 500 Normal 204Geochem/petro total 2200 1693Acton 1100 818Di Vincenzo 30 22Chrono total 1130 840Total 7093 6138** Difference between “samples taken” here and the 5758 total samples presented in the text is due to the

presence of smear slide samples in the requests for Di Stefano and Wise.

© Terra Antartica Publication 2008-200927Explanatory Notes for the ANDRILL SMS Project, Antarctica

Scanning resolution was set at 2 cm, with a 1 second measuring time. This procedure took approximately 11 minutes per core section;

• after scanning and imaging, the core boxes were transported back to the CSF and shelved before logging;

• at the end of the day shift, 30-39 meters of scanned and imaged core sections were transported to the CSEC for the night shift sedimentology-stratigraphy core logging team. To facilitate transport, the core boxes were stacked in red vinyl insulated bags, loaded onto a pick-up truck and driven to the loading bay of CSEC Room 201 (please refer to Naish et al., 2006; MIS Project Science Logistics Operations Plan for background information and figures to support these description of drillsite and McMurdo Station scientific activities).

CORE SAMPLING

High-priority sampling: Whole-round samples were taken for microbiology and interstitial pore water (IW) studies at the drill site. These samples arrived at McMurdo Station with the core boxes, but placed within insulated white cardboard boxes. The IW samples were kept chilled but not frozen, while the microbiology samples were cooled to -70 to -80°C with dry ice. The IW samples were taken to the refrigerator in CSEC Room 219, while the microbiology samples went into a deep freezer in the CSEC staging area.

In addition, intervals with high density diamictite were suggested for sampling at the drill site based on physical properties. These intervals were then evaluated for whole-round sampling by the sedimentology group in CSEC. If an interval was useful for sampling, it was described before a curator cut out the 8-10 cm whole-round and the core section was taken back to the MLV for splitting.

Another type of high-priority sampling was sections of the core singled out by the co-chiefs or curators as possibly useful for chronological determinations. These “fast-track” samples, usually aimed at the palaeontological group, were taken before the cores were split or during the splitting process.

Standard sampling: Immediately following the morning SMS Project Science Team meetings in the CSEC seminar room, core tours were conducted in CSEC 201. The science team members examined the cores and flagged intervals for sampling with flags made of toothpicks and labels. A total of 5758 samples were taken on-ice, including 618 thin-section samples prepared. In addition, 1206 smear slides for micropalaeontological work, as well as 1138 smear slides for sedimentology, were prepared by the respective discipline teams. See table 1 for a breakdown of samples per investigator and discipline team. In advance of sampling, a mock distribution of samples for the Science Team was generated for the PQ, HQ (Fig. 2) and NQ core sizes to guide sampling

Fig. 2 - Sampling plan to illustrate overall sampling density for the HQ core size. Similar figures were designed for the PQ and NQ cores, to assess the impact of Science Team sample requests in advance of core recovery. This process led to an overall reduction of samples requested, and greater coordination of shared sample sets. This figure reflects generic sample requests, to help guide curatorial team in sampling.

© Terra Antartica Publication 2008-200928 F. Florindo et al.

protocol and to evaluate and monitor sample density during the on-ice Core Characterization sampling phase.

Sampling was generally done on the right side of the split core, if up-core is considered the front side. Samples for clasts, structures and macrofossils were allowed to deviate from this. The curatorial team dealt with disputed sample intervals by discussion between the sampling committee (co-chiefs, staff scientist and head curator) and the science team members involved.

Sampling for palaeomagnetic studies and palaeontological smear-slide analysis were done following the initial core tour and flagging. For smear slide analyses, members of the palaeontological science team scraped minute amounts of sediment from the core surface and prepared smear slides on a slide warmer in CSEC room 201. For palaeomagnetic studies, orientated core sections were carried to the palaeomagnetic sampling lab on the loading dock of CSEC room 201, and drilled using a thin-kerf diamond drill. The remaining material was then replaced in the core liners.

SAMPLING PROCEDUREScience team members placed flags, identified with

their science team logo or letter code, in the upper right corner of the interval of interest. Curatorial team members outlined the requested interval with color crayons, determining the size of the sample from the initial sample requests submitted by science team members for core characterization. After outlining was completed, one curator team member stated aloud the information for each sample. Another curator would enter this information in a spreadsheet. The sample information includes box and run numbers, depth interval, sample volume, investigator name and institution, date of sampling, as well as type of analysis. This information went on the printed labels for the sample bags.

Firm sediment usually had to be cut using table saws with diamond blades for rock cutting. The blades were wetted for lithified samples and clasts, but kept as dry as possible for muddy sediments, which would otherwise swell up and be ruined if exposed to water. Cut samples were initially set back in the core, to be picked up and bagged when label printing was complete. Sample bags were finally collected in boxes marked with investigator names and shipped off-ice upon request. Thin section samples were collected separately and delivered to the thin section technician for further processing. The voids left after sampling, as well as any voids from fracturing or loss during drilling, were filled with pieces of foam to help stabilize the core.

tHin section Procedure

Samples requiring thin sections were received from the curatorial staff in one of four sizes requested by the principal investigator. These samples were then

trimmed if needed, one side of the sample surfaces were smoothed, dried in an oven at 60°C and then bonded to a microscope slide. Friable, poorly consolidated, and clay-rich samples required vacuum impregnation with epoxy to prepare them for bonding. Samples were bonded to the slide using a two-part epoxy, placed in a pressure jig and then put on a hot plate at 60°C to accelerate the curing process. Once curing was complete, bonded samples were then scribed with orientation marks and identification numbers, cut to a rough thickness of 600-700 µm, and lapped on an automatic lapping machine to the desired thickness of 30-35 µm. When lapping was finished, the thickness was verified with a polarizing microscope and, if needed, the thin section was hand polished to the correct thickness.

SAMPLE DATA ENTRY

All data were entered into an Excel spreadsheet, including investigator’s name, core type, box number, run number, top and bottom sample interval in meters below seafloor (mbsf), sample volume in cubic centimetre (cc), date, and comments. The comments included type of sample and science discipline group receiving it. This information will be available through the web site of the AMGRF (http://www.arf.fsu.edu).

CORE STORAGE

Upon completion of sampling, each 1 m section of core was misted with deionised water and twice wrapped in plastic film to retard desiccation. The cores were then replaced in the appropriate cardboard box, which were then taped closed. The boxes were loaded into vinyl carrying cases and transported back to the CSF via pickup truck for storage, until final crating and shipping to the AMGRF.

MAILING SAMPLES OFF-ICE DURING CRARY OPERATIONS

All samples were mailed off-ice during and after the core processing using the McMurdo Operations Cargo Application database (MOCA). During core processing, samples were shipped to off-ice scientists participating in core characterization. At the end of the season, all remaining samples taken for both on- and off-ice scientists were shipped. A total of 1693 samples were shipped to off-ice participants (29% of total samples).

PREPARATION FOR CORE SHIPMENT TO THE AMGRF

For final shipment, the loaded cardboard core boxes were placed into wooden crates with skids, each containing nine separate compartments that held four core boxes each. These crates were marked with “keep upright” signs, as well as markings indicating correct temperature for transport (4°C/40°F). The

© Terra Antartica Publication 2008-200929Explanatory Notes for the ANDRILL SMS Project, Antarctica

crates were fork-lifted into two refrigerated ISO shipping containers. These will be transferred to a cargo ship for transport to the AMGRF at Florida State University via Lyttleton, New Zealand and Port Hueneme, California. The final overland transport to Florida will be facilitated by truck.

SEDIMENTOLOGY/STRATIGRAPHY

INTRODUCTION

The primary role of the sedimentology/stratigraphy team during the drilling phase of the SMS project was description of the core and compilation of core logs, which served as the official record of the drillcore. Sedimentological/stratigraphic investigations were divided among: (a) a night shift (22:00-10:00 hours) team, which constructed the primary core log, and (b) a day shift (08:00-20:00 hours) team, which (i) reconfirmed the core description, (ii) developed summary logs and initial interpretations, (iii) communicated additions and modifications to the core log to the night shift and the rest of the science party, and (iv) provided information summaries at daily meetings to scientists from other discipline groups prior to core inspection sessions. Initial on-ice results reported by this team are presented in Fielding et al. (this volume).

Because the commitment to core description consumed all the time and effort of the night shift sedimentologists (Brad Field, Chris Fielding, Larry Krissek, Kurt Panter, Sandra Passchier), the day-shift sedimentologists (Kari Bassett, Greg Browne, Stephen Pekar) assumed primary responsibility for the more interpretive and integrative tasks. These tasks included: (1) defining and describing Lithostratigraphic Units (LSUs); (2) developing the lithofacies scheme; and (3) gathering information that would be of value in establishing a sequence stratigraphic interpretation. Following completion of the core-description phase, the night-shift sedimentologists contributed to these efforts by reviewing the existing classifications and interpretations, and by providing additional descriptions, discussions, and interpretations. At this time, summary graphic logs were developed (with significant input from Josh Reed, SMO’s IT support), general interpretations of glacial proximity and depositional environment developed, and a preliminary sequence stratigraphic interpretation formulated, all as a group effort by the Sedimentology/Stratigraphy team. During the core description phase, Joanna Hubbard and Rainer Lehmann, ARISE (ANDRILL Research Immersion for Science Educators) participants, worked with the day-shift sedimentologists. Their primary responsibility was the capture of representative digital images of lithofacies, bed and unit contacts, and other features of significance, from the Corelyzer system.

Franco Talarico (FT) and Sonia Sandroni (SS) also joined the night-shift for quantitative assessment of

clast composition. The aims of the sed/strat core characterization effort were twofold: (1) to provide a detailed and comprehensive description of the core that can be interpreted in terms of the palaeoenvironmental history of the area, and (2) to provide a summary description of the core that can used by the rest of the science team. The primary mechanism for recording this description was the graphic core logs developed digitally in PSICAT. These logs included a graphic representation of lithology (with particle-size as the main determinant, since particulate sedimentary and volcanic rocks are anticipated to be the likely principal drilling targets). Other rock types, such as igneous flows and intrusions, were recorded on the graphic log. The log also included symbols that provided details of lithology, physical sedimentary structures, deformational structures, biogenic structures, fossils, color, extent of bioturbation, and strata contacts over a given interval. Additional information could be added as textual comments. The detailed core logs were used to develop sedimentological and stratigraphic interpretations of the core for inclusion in the On-Ice Report and Initial Report. Generalized versions of the core logs, which summarize major stratigraphic trends and the locations of important marker beds (such as volcanic ash layers), were served as the template upon which other scientific groups will present and interpret their results.

ARISE Participants Rainer Lehmann and Joanna Hubbard each spent one month working with members of this Discipline Team. They participated in the activities of the day shift team, and were specifically involved in acquiring, describing and imaging the archive collection of smear slides that were compiled by the day shift throughout the core description period.

CORE DESCRIPTION AND CONSTRUCTION OF CORE LOGS

The night-shift sedimentologists carried out the core description and logging in a series of nightly increments, typically ~30 m per shift. Sandra Passchier and Chris Fielding simultaneously made observations on the core: Passchier compiled a draft version of the official core log on paper forms, while Fielding recorded information separately in a notebook. Once a logging form was completed, it was passed to Larry Krissek to be drafted using PSICAT (Palaeontological Stratigraphic Interval Construction and Analysis Tool), a software package PSICAT, developed by Josh Reed (while with CHRONOS - Iowa State University). Lithologies and fill patterns are based on recommendations by the USGS, with minor modifications and additions from ODP/IODP schemes; all lithologies and fill patterns used are defined within the pull-down menus of PSICAT. Symbols for physical and biogenic sedimentary structures, deformational structures, contained fossils, and bed contacts were derived from those used during the CRP, were modified based on the experience of ANDRILL Science Team

© Terra Antartica Publication 2008-200930 F. Florindo et al.

members. Concurrent with these operations, Kurt Panter

made observations on any components within the core that might be of volcanic origin and potentially suitable for radiogenic isotope dating. Also concurrent with these operations, Brad Field prepared and examined smear slides, typically at 1 m spacing throughout the core, and recorded semi-quantitative estimates of composition for each smear slide. Smear slide compositional data are presented in Petrology and Geochemistry: Smear Slides of the On-Ice Report (‘SMS Science Drive’) and Initial Report (this volume). Tracy Frank assisted in the preparation of smear slides during the second half of the core description phase. Sonia Sandroni and Franco Talarico logged the occurrence, position, composition, dimensions and other features of both intraformational and extraformational clasts throughout the core.

litHoloGic classiFication scHemes

Lithologic names for granular sediments and rocks were assigned using the scheme used during the MIS Project (Naish et al., 2007) and combines aspects of the classification systems used during the Cape Roberts Project (Cape Roberts Science Team, 1998, 1999) and Ocean Drilling Program ODP Legs 185 and 188, Explanatory Notes: 1) Principal name - The principal lithologic name is

assigned on the basis of the relative abundances of pelagic biogenic, volcanic, and terrigenous clastic grains, as follows: (a) The principal name of a sediment/rock with

<50% pelagic biogenic grains and a terrigenous clastic/volcanic ratio >1:1 is based on the grain size characteristics of the terrigenous clastic fraction. i) If the sediment/rock contains no gravel,

then the principal name is determined by the relative abundances of sand, silt, and clay (after Mazzullo and Graham, 1988).

ii) If the sediment/rock contains terrigenous clastic gravel, then the principal name is determined by the abundance of gravel and the sand/mud ratio of the terrigenous clastic matrix (after Moncrieff, 1989).

(b) The principal name of a sediment/rock with <50% pelagic biogenic grains and a terrigenous clastic/volcanic ratio <1:1 is based on the grain size characteristics of the volcanic fraction. Volcanic dominance of a specific interval is recognized by the abundance of volcanic glass or altered volcanic glass, pumice or pumiceous grains, or euhedral mineral grains. i) The principal name of a volcanic sediment/

rock is based on texture, using a terminology similar to that applied to terrigenous clastic rocks but preceded by the modifier ‘volcanic’ (after White and Houghton, 2006). The term volcanic is non-genetic and simply describes the rock composition rather than the mode

of origin. In cases where the volcanic rock/sediment origin can be determined, genetic terms (e.g. fine hyaloclastite) can be used as modifiers instead of volcanic, following the conventions described by Fisher (1961), Schmid (1981), and McPhie et al. (1993). Additional discussion and descriptions of volcanic terminology can be found in Gillespie and Styles (1999).

ii) In cases where pyroclastic material forms 75-100% of the sediment/rock, the principal name will be assigned.

(c) The principal name of a sediment/rock with >50% pelagic biogenic grains is “ooze”, by the most specific biogenic grain type that forms 50% or more of the sediment/rock. (e.g., if diatoms exceed 50%, then the sediment is a “diatom ooze”. However, if diatoms are 40% of the sediment and sponge spicules are 20%, then the sediment is a “siliceous ooze”).

2) Major and minor modifiers – major and minor modifiers can be applied to any of the principal granular sediment/rock names, and are listed before the principal name in order of decreasing abundance. The use of major and minor modifiers follows the scheme of ODP Leg 185, Explanatory Notes: (a) Major modifiers are those components with

abundances >25%, and are indicated by the suffix “rich” (e.g., “diatom-rich”).

(b) Minor modifiers are those components with abundances of 10-25%, and are indicated by the suffix “-bearing” (e.g., “diatom-bearing”).

(c) If possible, modifiers are assigned on the basis of the most specific grain type (e.g., “silt-rich” or “silt-bearing”). If necessary to exceed the 10% or 25% abundance thresholds, however, similar grain types can be grouped together (e.g., combine 5% diatoms and 5% sponge spicules to assign a modifier of “biosiliceous-bearing”).

(d) Authigenic components, if present, can be included as major or minor modifiers (e.g., “pyrite-bearing”), although the abundances of authigenic components do not play a role in determining the principal name of a granular sediment.

Lithologic names for non-pelagic limestones, if present, would have been be assigned using the Dunham classification scheme (from Boggs, 2006).

PALAEONTOLOGY

INTRODUCTION

Fossils are of fundamental importance to the interpretation of Antarctic sediments in terms of environmental reconstruction, sedimentary processes, chronology and climate. Both micro-and macrofossils

© Terra Antartica Publication 2008-200931Explanatory Notes for the ANDRILL SMS Project, Antarctica

occur in diverse lithologies with a wide range in fossil concentration from rich siliceous oozes and bioclastic carbonates to diamictites, ashes, and sandstones virtually devoid of microfossils. Hemipelagic sediments typically contain common or abundant fossil material, whereas most glacial diamictites contain fossils in low abundance. Fossils may be in situ and well-preserved or reworked, diagenetically altered, or mechanically degraded. Fossils occurring in Antarctic sediments include skeletonised groups with predominance among microfossils of siliceous taxa. Results from the on-ice analyses and initial post-drilling studies are presented in Taviani et al. (this volume).

Antarctic marine microfauna and microflora are strongly dominated by diatoms, but also include silicoflagellates, ebridians, radiolarians, sponge spicules, endoskeletal dinoflagellates, and chrysophyte cysts. Calcareous microfossils are far less common in Late Cenozoic Antarctic sediments but may include planktonic and benthic foraminifera, although agglutinated forams generally dominate over calcareous benthic forams. Other calcareous plankton may include thoracosphaera (calcareous dinoflagellates) and rare calcareous nannofossils.

Calcareous macrofossils and traces may be locally abundant and diverse, dominated in order of abundance by benthic molluscs, bryozoans, barnacles, serpulid polychaetes, echinoderms, cnidarians, and other groups.

Organic walled microfossils are relatively uncommon in Late Cenozoic Antarctic sediments but occurrences include dinoflagellates, foram linings, and other groups, including in situ and reworked terrestrial palynomorphs.

Reworked microfossils from older strata may be abundant, especially in association with glacially influenced sediments. These may comprise all of the above groups, most notably diatoms and marine and terrestrial palynomorphs.

Initial study of diatoms and other siliceous microfossils, foraminifera, macrofossils, calcareous nannofossils and organic-walled microfossils were characterized on-ice during drilling, and will continue into the post-drilling phase.

Fossils provide five distinct sets of valuable information on these cores: (a) Biostratigraphic age determination (during and

post-drilling); (b) palaeoenvironmental interpretation based on

ecological constraints of the living organisms (and their ancestors) (during and post-drilling);

(c) assessment of reworking by analysis of stratigraphically mixed fossil assemblages (during and post-drilling);

(d) interpretation of sedimentologic and glacial processes by mechanical degradation by either normal load compaction or by subglacial shearing (during and post-drilling);

(e) fossils as a source of geochemical (stable isotopes, elemental chemistry etc.) (post drilling) and geochronological signals (suitable samples will

be selected and sent to Samuel Mukasa during drilling for Sr dating). Biostratigraphy is the most critical palaeontologic

application for analysis during drilling. Each fossil group has a unique biostratigraphic signature, but diatoms provide, by far, the most detailed and well-calibrated biostratigraphic record for the Antarctic nearshore and shelf zone.

Certain critical analyses, notably selection of fossil material for 87Sr/86Sr dating initiated during the drilling phase. Suitable samples for dating were delivered to off-ice specialists.

Katie Johnson (KJ: on-ice technician) helped with palaeontologic sample preparation, chiefly foram preparations. Two ARISE participants spent one month working with members of this Discipline Team, developing a diatom occurrence index. Peter Webb, Jake Cames, Joan Hamre and several SMS science team members assisted the palaeo team with sample preparation and data collection.

diatoms and otHer siliceous microFossils

Diatoms are ubiquitous unicellular, eukaryotic, microalgae that form a bivalved siliceous frustule. They are abundant in Antarctic waters and preserve well in Antarctic sediments. Diatom taxa are closely constrained by ecological conditions, and many lineages have high rates of evolution. These characteristics make diatoms the most important source of palaeontologic information in Cenozoic aquatic sediments of Antarctica, and will be central to interpreting recovered ANDRILL sediments.

Diatoms are the primary palaeontologic tool for biostratigraphy and palaeoenvironmental reconstruction for the Antarctic. Virtually all sediments from Antarctica’s marine basins include diatoms, though abundance and preservation may vary, respectively, from dominant and excellent, to rare and poor.

Diatoms were analyzed during drilling by Matt Olney (MO), Eva Tuzzi (ET) and Christina Riesselman (CR) in association with David Harwood (DH), to provide (1) real-time biostratigraphic assignments and (2) palaeoenvironmental interpretation. In addition to the overarching biostratigraphic and palaeoenvironmental interpretations, each diatomist was also responsible for directing individual post-drilling research focused on specialized applications. All diatomists participated in sample preparation, with laboratory assistance from MK and ARISE team members.

ARISE educators were responsible for making routine smear slides at regular intervals throughout the core to produce a Diatom Occurrence Index for diatom presence. This basic character is important as a marine or glacial indicator. ARISE members were responsible for determination of abundance as Barren, Trace, Rare, Frequent, Common, Abundant, following a scheme established by Cape Roberts Project diatomists and presented in initial results volumes of that Project.

© Terra Antartica Publication 2008-200932 F. Florindo et al.

Diatom samples were selected from fine-grained sediments wherever possible. Abundant smear slides were prepared coincident with lithostratigraphic description of the core. Small volume toothpick samples were taken for smear-slides. These were rapidly produced and provide an unadulterated observation of microfossils in the sediment, allowing an accurate assessment of total microfossil abundance. The absence of chemical and mechanical degradation of the sample permitted the assessment of absolute and relative abundance and preservation of diatom assemblages. Smear slides also permitted assessment of material to guide interval sampling for diatoms and other microfossil groups, including nannofossils and palynomorphs.

Diatom mounts were prepared at the CSEC using several distinct methods. Interval samples (2 cc to 5 cc volume) were taken at approximately 100 cm intervals down-core, with higher- or lower-frequency sampling employed where indicated by lithology or smear slide investigation. Samples were selected for further analysis based on lithology, diatom abundance, and preservation. Diatom-rich hemipelagic sediments were processed for biostratigraphy following standard methods common for diatom analysis. On-ice, a variety of techniques were utilized dependent on the types of sediments recovered. These include simple disaggregation in distilled water, acid cleaning, settling, and sieving.

Most secondary biosiliceous groups were analyzed routinely with the diatoms, because they utilize the same methodology. When important larger siliceous groups were encountered, subsequent processing was performed in an attempt to concentrate these fossils for further analysis. Radiolarians were sampled by MO and studied by Chris Hollis (CH: off-ice). Furthermore, diatomists plus Davide Persico (DP) and Stacey Blair (SB) from the curatorial team checked for the presence of calcareous nannofossil and thoracosphera, in order to assist with sampling by on-ice curators.

Diatom biostratigraphy followed established schemes developed during previous drilling/coring programs in the nearshore zone (CRP, CIROS, MSSTS, DVDP, piston cores) and the pelagic realm (ODP legs 114, 119, 120, 177, 178, 183, DSDP Leg 28, piston cores, etc.).

Biostratigraphic study on-ice proceeded following methods previously employed during on-ice/shipboard participation in the CRP and Ocean Drilling Program (ODP) legs. Biostratigraphic ages were established based on the most recent and complete datums from neritic and circumpolar pelagic high latitude records. On-ice biostratigraphy was based mostly on qualitative and semi-quantitative data. High sediment accumulation rates of diatom-rich intervals offer the opportunity to study patterns and rates of evolution in diatom lineages, which will further help refine biostratigraphy. This goal will be largely addressed in the post-drilling investigations.

MARINE AND TERRESTRIAL PALYNOLOGY

Marine palynomorphs are acid insoluble microfossils, including cysts of dinoflagellates, phycoma of prasinophyte algae and acritarchs. Dinocyst analysis focused on the characterization of environmental changes in sea-surface conditions, and thus marine-based ice-sheet evolution. Dinocysts and acritarchs are in fact excellent proxies for reconstructing relative sea-surface conditions (sea-surface salinity, temperature, sea ice).

Previous work in the Cape Roberts Project cores established a well-understood succession of marine palynomorphs. Significant shifts in the assemblages, which probably reflect environmental change, have been calibrated using the CRP age models and are therefore available for correlation and dating of the SMS cores, should strata of a similar age be encountered. A provisional biostratigraphy based largely on dinocysts has also been established. Miocene marine palynomorph assemblages have been investigated and used to increase our understanding of glacial advance and retreat in ODP 1165 Prydz Bay. Marine palynomorphs have the potential to date strata where other fossils are absent. Mike Hannah (MH), Barbara Mohr (BM), and Sophie Warny (SW) carried out the study of marine palynomorphs.

Terrestrial palynology focuses on pollen and spores suitable to carry out a detailed study on climate evolution, since they provide an excellent insight in the palaeovegetation. In the Ross Sea region, the vegetation record of the Cenozoic is gradually being pieced together from pollen and spores preserved in marine sediments, but many gaps and uncertainties remain. Even though there are always certain difficulties in identifying material recycled from older sediments in these glacigenic sediments, it is possible to determine the remnants of the in situ vegetation. Redeposited palynomorphs, for example from the Beacon Supergroup, also provide information about sediment provenance. Study of the terrestrial palynoflora is a cooperative effort of Rosie Askin (RA), BM and Ian Raine (IR).

Standard sampling requirement is about 10 cc per sample, with initial sampling at 5 m intervals, depending on suitable lithology. The final preparation of the palynological samples for this project will be done off-ice. During drilling, samples were taken by MH and shipped off-ice at regular intervals to be prepared at three laboratories, GNS, LSU, Berlin. Slides were returned from the GNS laboratory to McMurdo for Hannah to examine.

CALCAREOUS NANNOFOSSILS

Previous experience gained through drilling Cenozoic strata in Antarctica has demonstrated the paucity of calcareous nannofossils and thoracosphera. A team of nannofossil specialists, working on the core curatorial staff (Davide Persico (DP) and Stacie Blair

© Terra Antartica Publication 2008-200933Explanatory Notes for the ANDRILL SMS Project, Antarctica

(SB)), routinely checked for the presence of calcareous nannofossils. Samples were taken approximately every two meters and smear slides were prepared. A selected set of samples was sent off-ice to Sherwood Wise (SW) (calcareous nannofossil biostratigraphy, distribution and palaeoecology) and Agata Di Stefano (AD) (nannofossil biostratigraphy and palaeoecology) for more detailed nannofossil hunting during the drilling period. Collaborating scientists working on these samples are SB, DP, Giuliana Villa, and others, as allowed.

FORAMINIFERAL MICROPALAEONTOLOGY

Samples were taken on ice in three sample sets, with one sample set collected from the Pleistocene to the Plio-Pleistocene transition for Alessandra Asioli (AA). The additional 2 sample sets were collected with alternating designation for Scott Ishman/Katherine Johnson (SI/KJ) and Fabrizio Lirer/Mario Sprovieri (FL/MS) (Lirer/Sprovieri). The SI/KJ samples were prepared on-ice, and the FL samples sent to FL for off-ice preparation. Washed residues and picked foraminifera from all preparations will be shared between these individuals.

Fo r a m i n i f e r a l b i o s t r a t i g r a p h i c a n d palaeoenvironmental analyses were carried out on sediments collected at SMS site. Foraminifera (calcareous and agglutinated) are known to occur in the Cenozoic Antarctic record, although in most cases they are a minor component of microfossil assemblages. Although planktonic foraminifera were rarely recovered from prior drilling in the Ross Sea region, Antarctica, their occurrence in the SMS cores may provide useful biostratigraphic information. Benthic foraminifera, in combination with diatom data, have been proven to provide limited biostratigraphic control in the Ross Sea Neogene. Planktonic and benthic foraminifera recovered from the SMS cores will be identified and faunal analyses conducted to statistically differentiate assemblages to define assemblage zones within the cores for biostratigraphic purposes. The foraminiferal zonations will be correlated with diatom, palynological and other biostratigraphic proxies from the cores to develop a robust chronological framework. Besides their use in biostratigraphy, foraminifera are reliable marine palaeoenvironmental indicators and assemblages may be useful to interpret palaeoenvironmental conditions such as bathymetry, salinity, temperature, and productivity, to name a few. Benthic foraminiferal data from the SMS cores will be analyzed to establish biofacies zonations using a variety of statistical techniques.

In collaboration with geochemists (stable isotopic and trace element), the faunal associations and geochemical data will be used to show variations in the extent of ice cover throughout the Neogene, and changes in meltwater input associated with ice volume fluctuations. Foram data will also be used to

tackle the issue of polar biota evolution. Core characterization sediment samples of SI/KJ

were processed at the Crary Lab using standard nondestructive foraminiferal processing techniques. Samples of ~20 cc volume were collected for foraminiferal analyses. M. Taviani provided additional samples of varying volume as residues from samples collected for macrofossil analysis and as ‘Fast Track’ samples.

On-ice processing occurred in phases dependent on the depth and lithification of the sediments. All on-ice samples were first weighed. Loosely consolidated samples were manually disaggregated into pebble size particles or smaller and soaked in a 5% calgon solution for 24 hours. Beginning at 122 mbsf the samples were soaked 24 hrs in 3% H2O2 and boiled for 5 minutes to disaggregate before sieving. Samples from approximately 140 mbsf and below were broken into small pebble-size fragments using a Carver Press followed by gentle breaking with a mortar and pestle. The disaggregated samples from both processes were sieved over nested sieves of 63 μm and 38 μm. The residues from the two size fractions were collected and dried at <50°C. To achieve the goal of core characterization, the on-ice ≥63 μm size fraction was split using a microsplitter to a 1/8th sample size, which was examined for foraminifera to determine the presence/absence of foraminifera.

Based on results of the core characterization phase of the SMS Project supplementary samples will be selected to increase sampling resolution. Since the foraminiferal assemblage analyses are nondestructive, once the census data is tabulated the samples can be used for geochemical analysis of the shells as well.

Depending upon circumstances, calcareous forams may be also targeted as datable material (14C, amino acid, Sr isotopes) depending upon the age of the embedding sediments or as geochemical archives for palaeoceanographic and/or diagenetic issues. Residues will consist of >63 micron size fraction stored in vials and available.

The study of foraminifera will be conducted primarily by SI (foraminiferal biostratigraphy and palaeoecology) and KJ (palaeoceanographic linkages between Antarctic (ANDRILL - Ross Sea) and SW Pacific-Southern Ocean benthic foraminiferal faunas during the latest Cenozoic <6 Ma). Depending upon availability of suitable material, FL will assist Sprovieri in recovery of chiefly planktonic foraminifera; while the palaeoenvironmental analysis of Pleistocene agglutinated forams will be the task of AA.

Sampling and proper storing of samples for agglutinated forams was carried out by SI.

macroFossils

Marine macrofossils occur consistently in the marine record of Cenozoic Antarctica as proven by previous coring in the Ross Sea (CIROS, CRP, ANDRILL MIS). Body calcareous macrofossils and traces may be locally

© Terra Antartica Publication 2008-200934 F. Florindo et al.

abundant and diverse, dominated by benthic mollusks (especially bivalves and gastropods), bryozoans, barnacles, serpulid polychaetes, echinoderms, cnidarians, and other groups. Macropalaeontology may supply a wealth of independent information to assist palaeoenvironmental, palaeoclimatic and chronological reconstructions.

Macrofossils may have a limited stratigraphic significance (especially pectinids) in the Neogene of Antarctica. Their major value stays with palaeoecological and palaeoceanographical analyses in order to reconstruct main attributes of former environments (salinity, temperature, nutrients, bathymetry, food chain, sea-ice, etc.), palaeogeography (space-temporal relationships with other Southern Ocean faunas), palaeoclimatology (also applying sclerochronological/geochemical techniques when necessary), and evolutionary (comparison with the world’s record). They may also serve as material for palaeoclimaticoriented geochemical studies (stable isotopes, elemental chemistry) and unaltered shells offer suitable material for dating (14C, amino acid, 87Sr/86Sr). Macrofossils are also relevant in the study of carbonate diagenesis.

Macrofossils were sampled only as seen, following a procedure adopted during previous drilling projects (CRP). More than 600 horizons were inspected for their potential macrofossil content. Since the standard procedure of picking and cleaning macrofossils is largely non-destructive and mechanical, residues are normally suitable to others, such as micropalaeontologists, geochemists and petrologists.

The activity of macrofauna (feeding, foraging, dwelling, predation, locomotion, etc.) often results in the formation of obvious structures, traditionally grouped under the discipline of ichnology. Although this topic is somewhat bridging between palaeontology and sedimentology, nevertheless the palaeontology team provided information on this aspect. No samples were recommendable because destructive sampling will likely erase or badly compromise more detailed interpretation to be seeking off-ice through various techniques such as tomography, x-rays, and large thin sections.

The study of marine macrofossils was the responsibility of Marco Taviani (MT). Further detailed taxonomic studies requiring specialists will be conducted off-ice and specialists to be individuated and approved case by case. Bryozoans were collected by MT and will be studied by Simon Nielsen off-ice.

PALAEOBOTANY

This research will involve documentation, description and/or identification of the occasional plant macrofossil material recovered from the ANDRILL cores. Samples were taken as seen by MT and other scientists on-ice and post-drilling delivered to Elisabeth Kennedy (EK) off-ice.

GEOCHEMISTRY AND PETROLOGY

INTRODUCTION

During the on-ice activity, the Geochemistry-Petrology team focused mainly on compositional and textural characterization of coarse glacigenic sediments and on the description and characterization of volcaniclastic layers and tephra. Finer sediments (<2 mm size) were described from a textural and lithological point of view by Sedimentology-Stratigraphy team members, with preliminary modal analysis of sandstones provided by Kari Bassett (KB), while the XRF core scanner provided high-resolution relative element concentrations on the split core surface (Gerard Kuhn, Stefan Hoffman, Lucia Reichelt). Further detailed studies by both teams are planned off-ice (e.g., Gianluca Cornamusini and Brian Storey) to implement the investigations on sedimentary clasts, and sand petrology, respectively; Sergio Rocchi and Hilmar von Eynatten for bulk rock geochemistry. Initial results from the petrology, geochemistry and core composition team are presented in Panter et al. (this volume).

clastoloGy, sand PetroloGy and volcanoloGy

An in situ macroscopic analysis and log of all clasts from granule to boulder grain class in the SMS core was carried out by Sonia Sandroni (SS) and Franco Talarico (FT). Compositional, shape and surface features (alteration rings) were described in all clasts, followed by sampling and petrographical examination of thin sections of selected basement clasts (about 10-15 per 100 m). Using thin sections from selected samples Cornamusini will improve the petrographical characterization of sedimentary clasts (intraclasts and clasts derived from the Beacon Supergroup), while Kurt Panter (KP) and Paola Del Carlo (PdC) described the clasts derived from the Ferrar Dolerite and Kirkpatrick Basalt. This helped to discriminate between different lithologies and to improve lithological determinations and attribution. Preliminary processing of clast log data by SS and FT include summaries of size, shape and relative abundances all major lithologies. Sandstone petrography was conducted by KB to support clast composition, to identify finer size fractions, and to distinguish primary versus reworked volcanic lithofacies.

On-ice investigations on volcanic sediment/rock was aimed at recovering information on composition, grading, internal sedimentary structures, grain size, internal organization and geometry. These data are crucial for reconstructing the mode of emplacement and post-depositional history of the deposits. Textures of volcanic deposits (McPhie et al., 2003) reflect both processes related to eruption and emplacement and also successive modification by both syn-volcanic and post-volcanic processes. It was important to determine whether volcanic layers

© Terra Antartica Publication 2008-200935Explanatory Notes for the ANDRILL SMS Project, Antarctica

are undisturbed pyroclastic, autoclastic or hyaloclastic deposits (primary volcanoclastic deposits, White and Houghton, 2006), or are related to resedimentation coeval with or independent of eruptions (volcanic sedimentary deposits). The role of weathering, erosion and reworking of primary effusive (lava flows) or volcaniclastic deposits was assessed. This distinction is important for dating and for possible correlation with other volcanic deposits in the area, and for the reconstruction of the magmatic evolution of volcanoes and finally for an assessment of magma production rate.

Preliminary compositional analysis and petrographic and textural characterization of volcanic layers and clasts, was undertaken by PdC and KP in Crary Lab on the basis of thin section and smear-slide examination, microscopic observation of clast morphology and sieving. Any significant volcanic units in the core, and in particular all recognizable primary volcanoclastic deposits, lava flows or subvolcanic bodies was sampled (50 cc) for textural and petrological investigation.

Volcanic rocks are usually classified based on their whole-rock chemical composition because they are often glassy or have fine-grained groundmass, which does not allow the mineralogical composition to be determined. The on-ice classification of volcanic materials was based on the mineral assemblage recognised in thin sections: - Mafic (basaltic) -characterized by phenocrysts

of olivine and clinopyroxene with or without plagioclase in the groundmass.

- Intermediate -phenocrysts of plagioclase ± kaersutite ± clinopyroxene

- Felsic (phonolitic, trachytic) -phenocrysts of K-feldspar ± kaersutite ± sodic clinopyroxene (acmite). Large clasts of volcanic rocks were also sampled

systematically through the core, up to a maximum of about 200 samples between 100-500 grams in size. In case of thick and monotonous tephra succession, a reasonable representative number of samples (e.g., 2-3 per meter) were collected. Samples were also sent to off-ice labs for preliminary analyses for chemistry and chronology of critical volcanic layers (whole-rock, minerals and/or glass). PdC and KP were primarily responsible for the selection of samples for argon dating to be sent to Gianfranco Di Vincenzo’s lab at IGG-CNR in Pisa (Italy). PdC and KP also selected an initial suite of samples for geochemical characterization to be sent to Sergio Rocchi’s lab in Pisa.

GEOCHEMICAL INVESTIGATIONS

INTRODUCTION

In addition to the geochemical characterization of sediments and volcanic rocks, other planned geochemical investigations included: 1) Pore fluid sampling and analysis. This investigation

was performed on-ice by Tracy Frank (TF). TF

also sampled heavily cemented, fractured and/or carbonate-rich intervals to investigate the diagenetic processes, through a multidisciplinary approach including petrographical and stable isotope geochemistry, with a specific focus on carbonate allochems and cements;

2) a combination of stable isotope and trace element analysis that will be performed by Mario Sprovieri on selected species of planktonic and benthic foraminifers (to be picked by Lirer);

3) organic geochemistry proxies such as TEX86 (Tetra Ether IndeX of lipids with 86 carbon atoms), MBT (Methylation of Branched Tetraether lipids) index, and BIT (Branched and Isoprenoid Tetraether lipids) index (by Sangiorgi & Willmott).

XRF-CORE SCANNING, WHOLE ROCK GEOCHEMISTRY, AND CLASTS ALTERATION

The XRF Core Scanner was used for rapid on-ice quantification of the relative proportions of the chemical elements ranging from aluminium to barium, and, hence, the relative proportions of terrigenous fluxes and palaeoproductivity. We added spectrophotometer measurements as high-resolution parameter to the dataset.

Off-ice investigations as outlined above including organic/inorganic carbon, total nitrogen and sulfur, bulk mineral composition with XRD, and biogenic silicate require approximately one sample (20-30 cm3) per meter. On these samples, measurement of water content and density will be made to determine correction factors and to calculate accumulation rates.

The overall multivariate data set will be mainly used to constrain (i) ice-sheet variability, bioproductivity, and the palaeoenvironment (ii) provenance, and (iii) alteration of siliciclastic material at site SMS. These results will be compared to the results from the AND-01 (MIS) core.

High Resolution X-ray Fluorescence (XRF) Core Scanning: X-ray fluorescence core scanning is a low-cost, quick and non-destructive technique for the analysis of chemical elements directly on the split-core sediment surface. Continuous XRF scanning provides a high-resolution geochemical dataset, and has been used in several case studies for rapid palaeoclimate changes in low and high latitudes on various time scales. In order to obtain a high-resolution geochemical dataset to identify rapid changes in the Antarctic cryosphere recorded in the AND-2A sediment core, an Avaatech XRF core scanner (www.avaatech.com) of the 2nd generation was set up directly in McMurdo Station. This core scanner measures the variation in elements of atomic mass range from Al (atomic no. 13) to U (atomic no. 92). The continuous XRF measurements began on 16 October 2007 and ended on 7 December 2007. During the on-ice period the measurements were carried out with the same settings as used in the previous ANDRILL McMurdo Ice Shelf (MIS) Project.

© Terra Antartica Publication 2008-200936 F. Florindo et al.

Immediately after core splitting the continuous XRF scanning was done on the archive half of the core. Depending on the rate of drilling advance, and the available time for core scanning, the measurement point resolution varied over the whole core between 1 and 10 centimetres.

The technical details of the Avaatech XRF Core Scanner are summarised in table 2. Inside the scanner the X-ray-source, the detector and the He-flushed prism are oriented as a triangle over the sediment surface (Fig. 3). The generated radiation from the X-ray source travels through the He-flushed prism and hits the sediment surface under a 45° angle. For background optimization different filters can be moved inside the beam. The detector for the outgoing fluorescence radiation is also oriented in an angle of 45°. To minimize absorption of fluorescence radiation by air, the prism between X-ray source and detector is flushed with helium. During scanning, the surface of the sediment core was covered with a 4 µm thin SPEXCerti Prep Ultralene® foil to avoid contamination of the prism, since the prism touches the surface of the core at every measurement point (Fig. 3). All air bubbles and water beneath the foil were squeezed out and the sediment surface was smoothed if possible.

The measuring spot size (irradiated sample length) was constant at 1 x 1cm over the whole measuring period. This is the highest possible setting on the

XRF core scanner and should be large enough to minimise inhomogeneities. Furthermore, every specific core section was checked by hand to prevent measurements on big clasts, fractures or veins.

The measurements were carried out on the whole core with 10 kV and 50 kV, but some particular sections were measured with 30 kV. To suppress the background radiation a copper filter was put in the beam at 50 kV and a thick lead filter at 30 kV. Only with the 10 kV setting was no filter used. These instrumental settings are recommended to achieve reliable results. A count time of 30 s was used for the 10 kV and 30 kV setting and 40 s for the 50 kV setting. To achieve a dead-time below 40% the count time is respectively prolonged for each measurement point.

The raw spectra of all approx. 22 000 measurement points were saved on a computer connected to the XRF scanner. Before the spectra for every measurement could be processed with the Canberra WinAxil and WinAxilBatch (www.canberra.com) software, a processing model was arranged to obtain counts for each element. On the basis of the processed model, the software calculated the element counts as peak integrals and applied background subtraction. The quality of every single spectra and peak integral can be easily checked with a χ2 value.

Regular instrumental tests during the XRF scanning are essential for accurate measurements with stable conditions downcore: standard material measurements provide an easy way to estimate the instrumental drift. Another useful indicator for the X-ray source stability is the measurement of the target material Rh. During the measuring period of the AND-2A core the Rh counts stay fairly constant over the upper 1 040.28 metres. Below this point the Rh counts drop exactly at the boundary of LSU 13 to 14 of about 30% and stays constant at a lower level until the bottom of the core (see description of LSU 14 below). Repeated measurements indicate that the reason for this drop is probably not related to the source, but rather to the changes in the lithologies and associated rock behaviour of these LSUs.

INTERSTITIAL WATER SAMPLING AND CHEMISTRY

Samples of interstitial water were obtained from 5-to 10-cm-long whole-round sediment sections, which

Tab. 2 - Technical details of the Avaatech XRF core scanner.

Fig. 3 - Geometry of the main components inside the Avaatech XRF core scanner. The X-ray source (left), the detector (right) and the He-flushed prism (middle) are oriented in a triangle to each other. Both the X-ray source and the detector are set an angle of 45° to the sediment surface. To avoid contamination a foil covers the sediment surface.

© Terra Antartica Publication 2008-200937Explanatory Notes for the ANDRILL SMS Project, Antarctica

were cut immediately after each run. To minimize potential chemical alteration due to oxidation and temperature change while the whole-rounds awaited delivery from the drill site to Crary Lab, the samples were wrapped in plastic shrinkwrap and refrigerated at ~4°C.

Upon delivery to the Crary Lab, samples were removed from the plastic wrap and the outside surface of each whole-round section was carefully removed with a spatula to minimize potential contamination. The samples were placed into a titanium and stainless steel squeezing device and squeezed at ambient temperature by applying pressure up to 40,000 lb (~4150 psi) with a Carver press (Manheim and Sayles, 1974). Interstitial water was extruded through a prewashed Whatman no. 1 filter fitted above a titanium screen. All interstitial water samples were filtered through 0.45-mm disposable filters and collected into clean plastic syringes. After collection of up to 30 ml of interstitial water, the syringe was removed, a fresh 0.45-mm filter was attached, and aliquots were dispensed into acid-washed plastic vials for on-ice analyses (alkalinity, pH, chlorinity, and salinity) and into glass vials with poly-seal caps for future off-ice work (stable isotope analysis). Any remaining sample was placed into acid-washed, plastic vials for off-ice measurement of major ions. Samples for off-ice work were kept refrigerated at ~4°C.

The analysis of interstitial water samples followed the procedures outlined by Gieskes et al. (1991). Interstitial waters were routinely analyzed for salinity with an optical hand-held refractometer. On samples with higher yields, conductivity was also determined using a YSI 3100 Conductivity Instrument. Salinity was then calculated using the salinity calculator of Thomczak (2000), available at http://gyre.umeoce.maine.edu/physicalocean/Tomczak/Utilities/salcon.html).

The pH was measured on the National Institute of Standards scale using a Beckman pH meter. Alkalinity was measured using a Brinkmann pH electrode and a Metrohm autotitrator. Note that although pH was also measured as part of the alkalinity titration, pH measurements obtained in this fashion are not always reliable because the algorithm employed for pH measurement before the start of the alkalinity titration is strongly influenced by degassing. Dissolved chloride (Cl–) was determined by titration with AgNO3.

ORGANIC GEOCHEMISTRY PROXIES

Introduction: The main target of this pilot study was to test the applicability of organic geochemistry proxies to the Mid-Miocene Climatic Optimum sequence of drillcore AND-2A to provide sea surface temperature (SSTs) and continental temperature (mean annual air temperatures, MAAT). We applied recently developed organic geochemistry proxies such as TEX86 (Tetra Ether IndeX of lipids with 86 carbon atoms), MBT (Methylation of Branched Tetraether lipids) index to derive absolute sea surface and continental air

temperature values, respectively, and BIT (Branched and Isoprenoid Tetraether lipids) index to evaluate the relative contribution of (fluvially transported) soil organic matter versus marine organic matter. The methods followed are described in Schouten et al. (2002), Weijers et al. (2007a, b) and Hopmans et al. (2004).

The TEX86 is based on lipids from archaea, glycerol dialkyl glycerol tetraethers (GDGTs). Culture experiments have shown that the relative distribution of cyclopentane rings in the GDGTs strongly depends on culture temperatures and a significant linear correlation (r2 =0.93) is found between the number of cyclopentane rings in sedimentary membrane lipids derived from marine crenarchaeota and the annual mean sea surface temperatures (SST). Using a calibration equation, the SSTs are derived from the TEX86 (Schouten et al., 2002; Kim et al., 2008).

In soils structurally similar membrane lipids from terrestrial bacteria haven been encountered, i.e. GDGTs with a branched carbon skeleton. These compound are also found in the marine environment near large river outflows and the ratio of these compounds relative to marine derived GDGTs, the so-called the BIT index can be used to trace the relative importance of soil organic matter in marine environments (Hopmans et al., 2004). Furthermore, recent studies (e.g., Weijers et al., 2007a; Schouten et al., 2008) have revealed that the distribution of these branched GDGTs is strongly correlated (r2 =0.82) with continental mean annual air temperatures (MAAT), thereby allowing the reconstruction of continental air temperature in marine sediment cores (see Weijers et al., 2007b).

Materials and Methods: Our pilot study used 15 samples (~10 gram dry weight each) from interval correspondent to the lower and middle Miocene part of core AND-2A according to the age model available. Sediments were processed following the methodologies for TEX86, BIT and MAAT described in Schouten et al. (2002), Hopmans et al. (2004), Schouten et al. (2007), Weijers et al. (2007b) and Kim et al. (2008).

PALAEOMAGNETISMPROCEDURES AND SAMPLING

On-ice sampling and measurements were conducted by Gary Acton, Luigi Jovane, and Eleonora Strada with assistance from the co-chief scientist Fabio Florindo. During SMS drilling, off-ice measurements were conducted by Leonardo Sagnotti, Ken Verosub, Gary Wilson and Christian Ohneiser (Otago University technician). Results from the initial analyses of palaeomagnetism on the SMS core are presented in Acton et al. (this volume).

Oriented standard discrete palaeomagnetic samples (8 cc plastic cubes or 11 cc drilled cylinders depending on core consistency) were collected, where possible, from fine-grained undisturbed horizons at

© Terra Antartica Publication 2008-200938 F. Florindo et al.

~1.0-2.0 m intervals. Samples were collected from the working half of the SMS split core sections and oriented with respect to up-core direction and with respect to the core orientation scribe line. Paired samples (separated by a few cm stratigraphically) were collected from varying lithofacies every 10-20 m down core for a pilot study to assess the most suitable demagnetization technique for routine treatment of the remaining samples.

To collect a sample, we first scribed arrows that pointed uphole on the split-core face of the core with a diamond scribe and then traced over the scribed mark with a colored pencil to increase the visibility. The split-core piece was then flipped over and another arrow pointing uphole was scribed and then traced with color pencil on the periphery of the core near the middle (thickest part) of the core. Mini-cores were cored from the middle of the split-core pieces using a drill press with an assembly for a coring bit that is lubricated with water during coring. Each mini-core collected this way was about 2.3 cm in diameter and about 4.2 cm in length for PQ cores or 3.1 cm in length for HQ cores. Three intervals were too poorly consolidated to allow mini-cores to be collected. For these, we instead used an extruder, which is somewhat like a cookie cutter. The extruder was pressed into the sediment of the split-core face keeping one of the flat sides of the extruder perpendicular to the uphole direction. The extruder was then extracted full of sediment. A plunger on the end of the extruder allows the sediment to be extruded into a plastic sample box (2 cm x 2 cm x 2 cm), which has an arrow embedded in it. The sample was extruded such that the arrow points uphole.

Once collected, samples were put into plastic bags with the core depth/sample label on them. Scrap pieces of samples, such as those cut off the ends of mini-cores, were stored with the primary sample or placed in a separate sample bag that is properly label for use in rock magnetic studies. During all phases of collection and handling, efforts were made to minimize the exposure of the core and samples to strong magnetic fields.

High and low frequency magnetic susceptibility were measured using a Bartington MS2 susceptibility meter. We also measured susceptibility and its frequency dependence on the clast samples being studied by petrologists. For those samples that could fit into the Bartington susceptibility meter, measurements were made either on a thin-section billet, or on a piece of a clast. Owing to the irregular shapes of the clasts, volumes are more difficult to determine and so susceptibilities are mass normalized only.

Samples from different intervals were divided and then shipped to U.S., Italy, or New Zealand. In order to determine the magnetic polarity of each sample, the natural remanent magnetization (NRM) of the samples were measured using 2G cryogenic magnetometers that reside in magnetically shielded rooms in the palaeomagnetism laboratories at University of California, Davis (UCD), at Istituto

Nazionale di Geofisica e Vulcanologia, Rome (INGV), and at Otago University, respectively. Pilot samples were first demagnetized using both thermal and AF methods and the remainder of samples demagnetized using the appropriate method. For samples subjected to AF demagnetization, the remanent magnetization was measured following demagnetization at 0-50 mT using 5 mT increments and then at 50-100 mT using 10 mT increments. For samples subjected to thermal demagnetization, the remanent magnetization was measured after heating at 23°C (room temperature), 120°C, 200°C, and then in 50°C steps up to 650°C. After each thermal demagnetization step, the susceptibility was measured to monitor thermal alteration.

Data were returned to the on-ice palaeomagnetism team as it becomes available for incorporation into the on-ice chronostratigraphy report. Following the drilling season, discrete samples will be shared between the respective palaeomagnetic laboratories at UCD, INGV, and Otago University.

CHRONOSTRATIGRAPHY AND GEOCHRONOLOGY

A robust age model for the core recovered during the SMS Project relies on the integration of magnetostrat igraphy, b iostrat igraphy, cyclostratigraphy, radiometric dating of volcaniclastic sediments and tephras, 87Sr/86Sr dating of macrofossils, and correlation of compositional and physical properties to well-dated global or regional records. While drilling was underway, however, initial age model development relied mainly on diatom biostratigraphy and a preliminary magnetostratigraphy, which was obtained by shipping samples off-ice to palaeomagnetism laboratories for rapid analysis. Additional information was available from the Sedimentology/Stratigraphy Discipline Team through the recognition of disconformities and/or unconformities in the stratigraphic succession. The remainder of the on-ice effort for dating the sediments was the careful selection of specific samples for post-drilling analyses.

immediate on-ice aGe model

As age relevant data became available in collaboration with the Palaeontology, Palaeomagnetism, and Sedimentology Discipline Teams, a working age model was compiled and refined to assist the CCSs in progress and target assessment. The primary task was to identify age ranges for stratigraphic subdivisions of the cored succession. The recognition of breaks in deposition or preservation required combined sedimentologic and chronostratigraphic information with primary emphasis, initially on biostratigraphic occurrence datums and zones and on magnetostratigraphic occurrence of magnetic polarity zones. Results are presented as an age-depth

© Terra Antartica Publication 2008-200939Explanatory Notes for the ANDRILL SMS Project, Antarctica

plot showing constraining datums and geomagnetic reversals along with the range in the possible age and, where possible, error margins. The initial age model for the AND-2A drillcore is presented, along with supporting data tables, in Acton et al. (this volume).

Acknowledgements - The ANDRILL Program is a multinational collaboration between the Antarctic programs of Germany, Italy, New Zealand and the United States. Antarctica New Zealand is the project operator and developed the drilling system in collaboration with Alex Pyne at Victoria University of Wellington and Webster Drilling and Exploration Ltd. Antarctica New Zealand supported the drilling team at Scott Base; Raytheon Polar Services Corporation supported the science team at McMurdo Station and the Crary Science and Engineering Laboratory. The ANDRILL Science Management Office at the University of Nebraska-Lincoln provided science planning and operational support. Scientific studies are jointly supported by the US National Science Foundation (NSF), NZ Foundation for Research, Science and Technology (FRST), the Italian Antarctic Research Program (PNRA), the German Research Foundation (DFG) and the Alfred Wegener Institute for Polar and Marine Research (AWI).

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