Cor nel l Col lege

The Beta Pi Chapter of the Earth Science honor society Sigma Gamma Epsilon (SGE) was reactivated by the Department of Geology during an initiation ceremony in May 2009. SGE was established in 1915 to recognize scholarship and professionalism in the Earth Sciences. The Beta Pi Chapter was installed initially at Cornell College in 1957, becoming the first chapter of the honor society in the state of Iowa. By 1967, the chapter had become inactive, largely due to the lack of male students qualified to be-come members. The barring of women members was listed as a concern of the Cornell chapter in a series of letters written to the national secretary in 1967 and 1968. Wom-en were allowed membership beginning in late 1967.

To qualify for membership, students must maintain at least a 3.0 GPA in all of their geology coursework, have taken a minimum of three geology courses, and maintained a 2.67 overall GPA. Our top majors organized an initiation ceremony following guidelines provided by the national secretary. The ceremony is held at the Pal and is officiated by the current SGE president. New SGE members are each holding a white carnation, the official flower of the society. The Geology Department at Cornell is fortunate to have a cadre of bright, motivated, enthusiastic and smart young scientists currently in the program.

2011-2013

H O N O R S O C I E T Y R E T U R N S T O G E O L O GY DE PA R T M E N T

Newslet ter

SPARKS FROM THE ROCKPILE

D E P A R T M E N T O F G E O L O G Y We’re on the Web!

http://cornellcollege.edu/geology

ASSEMBLED AND EDITED BY MICHAEL BARTHELMES

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Dear Geology Alumni,

The past two years have seen some significant changes in the geology department, not the least of which was Ben’s appointment to a three-year term as Associate Dean of the College. Last year (his first year in the Dean position), Ben taught three classes for the department, but for the next two years he will only teach one (the Bahamas course). While we are thrilled for Ben and for the col-lege, it left us scrambling to figure out how to replace 1/3rd of our department. Fortunately, we were able to solve the dilemma. Last year, we were delighted to welcome a recent alumna, Kelsey Feser, back to teach Invertebrate Paleontology and Historical Geology. Kelsey is working on her Ph.D. in invertebrate paleontology at the University of Cincinnati. After a successful national search this year, we are pleased to announce that we will be joined for the next two years by John Orcutt, a vertebrate paleontologist interested in paleoecology. John will join us as a Post-Doctoral Fellow, meaning that he will teach 4 blocks each year and will also be available to mentor students in research.

We are relieved to have hired John, because the number of geology majors keeps growing. Most of our majors courses for next year are over-enrolled, and as of the end of this academic year, we had 26 declared majors. Our graduating class this year was small (4 geology majors and 1 geology teaching major), which means that our rising senior and junior classes are exceptional. In fact, the number of geology majors is greater than the number of most other 3-faculty department majors on campus. We are hoping that Facilities will be able to make some simple changes in our upper-level classroom (Norton 108) this summer to allow us to accommodate the greater number of students. At present, the classroom seats 12 comfortably (15 uncomfortably); we hope the chang-es will allow for at least 16 students to be comfortable. I am actually teaching two sections of Igneous Petrology next year, because 25 students signed up for the course (and 22 of them need to take it next year, since it is required and only offered every-other year).

Not only is the major growing, but the majors are becoming more actively involved in research and summer geology experiences. Geology students continue to be an impressive force at the annual Student Symposium, with 10 students presenting last year and 7 presenting this year. Two stu-dents completed honors theses last year, and three juniors worked on their honors thesis research this year (to be completed next year). Last summer two majors were selected for highly competitive NSF-funded summer research experiences, four majors pursued research with department faculty, and two others earned government geological positions at the Iowa DNR and with the GeoCorps Geologist-in-the-Parks program. This summer, three students received NSF-REU positions, four are working with department faculty, one was awarded a Cornell Fellows research internship, one is headed to Alaska with GeoCorps, and two others are interning at the Iowa DNR and the Field Muse-um in Chicago. Needless to say, we are very proud of their achievements.

We enjoy hearing from you all, and we hope you will keep in touch—send an email, drop us a note, or stop by to visit.

Wishing you the best,

Emily

FROM THE CHAIR

Sparks From The Rockpi le

Page 3 2011-2013

The Geology Department serves students desiring a major or minor in geology. We offer a basic curriculum of upper-level courses which, along with supporting coursework in other scienc-es and mathematics, prepare our graduates for entry-level occu-pations in government and industry, or for graduate-level educa-tion in Geology or Environmental Science at institutions across the country. Our curriculum also prepares students who choose ca-reers in Earth Science teaching. The department offers several block-long field courses in diverse areas around the world. We especially encourage and support independent research projects by our students. In concert with several departments across sev-eral divisions of the college, we lead Cornell's Environmental Stud-ies Program. Many students have taken advantage of environ-mental-related research and internship opportunities funded though Geology Department research funds or the Cornell Fellows program.

CORNELL COLLEGE DEPARTMENT OF GEOLOGY

Sparks From The Rockpi le

Ask any Cornell College geology major what their favorite building on campus is and the inevitable answer is Norton Geology Center. The unique features of the building—from the submarine-esque spiral stair-case leading to the computer lab and the “bat-cave” rock-saw room, to the well-worn couch in the student lounge and the Anderson Geology Museum that encompasses the entire building—make Norton Geology as much a home to geology students as any dorm room. However, with growing class sizes and technological demands, the need to make modern improvements to Norton has been realized in several key renovations these past two years. Perhaps most importantly for the aesthetic qualities of the building, the lighting for the museum has been entirely updated. Stan Crocker, renowned lighting designer who has worked with Sting, Santana, Stephen Colbert and Ozzy Osbourne, among many others, was involved in choosing the best lighting options and placement. This has made a huge difference in highlighting the displays and brightening the entire building. Additionally, the main lobbies on the 2nd and 3rd floors have been opened up by removing some of the outdated hanging pictures and displays, allowing visitors to better appreciate the architecture of the building. The moldy brown carpet has been removed and replaced with a faux-wood flooring and much of the paint has been touched up, giving a building a much needed breath of fresh air. Finally, several map and specimen cases from the upstairs class-rooms have been removed, allowing more desk space and allowing both lab and lecture of Physical Geology classes to be taught in the same classroom. In Room 108 seating is being increased to 16 (from 12), and the purchase of new polarizing and stereozoom microscopes will allow for larger major classes to be housed more comfortably.

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N O R T O N G E O L O G Y R E N O V A T I O N S

Page 5

NEW PALEONTOLOGY PROFESSOR DR. JOHN ORCUTT

2011-2013

Greetings,

My name is John Orcutt, and I’m excited to be joining the Department of Geology at Cornell as a Post-Doctoral Teacher-Scholar starting this August. I am a paleoecologist, with a particular interest in studying how mammals have interacted with their environment over the course of the Cenozoic and in using my results to help predict how living mammals will respond to future climate change. Many of the biggest uncertainties regarding the effects of climate change can be addressed by looking at what happened the last time Earth underwent a major period of warming: the increase in temperature that brought about the retreat of glaciers around the world following the Last Glacial Maximum, roughly 19,000 years ago. Working in Iowa, near the edge of what was once the North American ice sheet, will give me a chance to pursue the answers to several questions raised by my previous research. Did mammal body size change as the result of warming climate at the end of the last Ice Age? If not, what does account for the geographic variation in body size seen in most modern mammals? Why don’t ranges of small mammals shift as signif-icantly during glacial advances as ecological models suggest they should? Is it because these animals are more adaptable than their modern ranges might suggest, or is it because the conditions near the edge of the ice sheets were less harsh than had been previously thought? It may seem like I’m tackling some questions that will be too big to answer over the course of a two-year job, but I will have the benefit of not only being located near several important fossil localities and museum collec-tions, but of working with Cornell students, for whom there will be several opportunities to begin projects of their own within my research program.

I’m not only looking forward to working at Cornell, but to exploring Iowa as well. I’ve visited the state several times, but always briefly, and it will be great to have the chance to spend much more time getting to know an area that happens to be particularly rich in my family history. Midwest winters might seem like anathema to someone who enjoys getting outdoors and is accustomed to the mild rain and fog of the Northwest, but I have big plans to get back into cross-country ski-ing, an activity that I enjoyed as a child and that seems ideally suited to the Iowa land-scape and climate. I’m also a big baseball fan, and was delighted to see that one of the minor league affiliates of my beloved Seattle Mariners plays just over an hour’s drive from Mt. Vernon, which should make for some nice summer day trips. I can’t wait to get settled in this August and to start my life in Iowa and my work at Cornell!

Sparks From The Rockpi le

Greetings geology alumni,

Much has happened in the two years since you received the department’s last newsletter. The pro-jects in Curaçao and with the literature database I mentioned in my last report have come to fruition. I presented the results of the Curaçao work at the national GSA meeting in Minneapolis in October 2011. We learned that coral communities in reef crest and back reef environments did not show ecological succession even though the water depth in which they were living decreased 2-4 m over the interval the reefs were alive during Late Pleistocene time.

There was an excellent turn out of former Cornell paleontology students at the meeting – all of whom are in graduate school and all of whom gave talks at the GSA meeting. I have included a photo of the “Cornell College Paleontology Research Group” in this issue of Sparks.

The literature database yielded some interesting results related to the timing of the decline of the two important species of Acropora in the Caribbean region. I crafted a couple of motion charts using my data – and you are welcome to play with them at http://cornellcollege.edu/geology/greenstein/personal/Res.shtml. You can choose either reef crest or mid-slope environments and them pick from a list of corals (try A. palmata vs. M. complanata in the reef crest, or A. cervicornis vs. M. annularis from the reef slope) and then watch their relative abundances change over time within different countries. I presented these results at the 12th International Coral Reef Symposium in Cairns, Aus-tralia, in early July last year. The data have been incorporated into a 300 page report entitled Status and Trends of Caribbean Coral Reefs: 1969-2012, published by the Global Coral Reef Monitoring Network and a few other NGOs. An additional (much shorter) report is scheduled to be published in Science later this year.

I joined colleague Karl-Heinz Wyrwoll from the University of Western Australia for two weeks of field work in coastal W. Australia in June last year. We are working on the timing and extent of a double peak in sea level during Late Pleistocene time. Coastal Australia is a great place to do fieldwork if one can avoid be eaten by large fish, bitten by large snakes, or stung by a variety of arthropods. Two trips to Australia (for the fieldwork and then the meeting in Cairns) within a five-week interval left me jet-lagged for a month.

It was thus not surprising that attending the Noel-Levitz National Conference on Student Recruit-ment, Marketing and Retention in Chicago shortly after the trip to Cairns was a surreal experience – the otherworldly nature of the meeting amplified by the fact I was attending it in my new role as Associate Dean of the College. The three-year appointment, which began on July 1 last year, allows me to learn a great deal as I lead first year programming, faculty development and off-campus stud-ies at the college. I head to Harvard on 1st June to participate in a Management Development Program offered through their Institute of Higher Education. I am looking forward to learning more about leadership in an academic setting, and also being able to say that I was a student at Harvard.

Tomorrow Janet and I leave for NYC, where we will celebrate Jonah’s graduation from NYU at an intimate commencement ceremony held in Yankee Stadium. Radio City Music Hall is the venue for festivities related to his graduation from the Tisch School of the Arts – I am expecting a hot dog at one event and the Rockettes at the other. Janet and I are housing (and feeding) a dozen or so film crewmembers that are traveling to Mt. Vernon from NYC to shoot Jonah’s senior thesis film during the last two weeks of June. Elijah just completed his first year in a Ph.D. program in East Asian Histo-ry at Princeton after spending the last two years in Japan. Janet and I continue to marvel at our sons’ experiences and bemoan our advancing age.

Best to all of you and don’t hesitate to stop by if you’re in town (you’ll find me in Old Sem).

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N O T E F R O M B E N G R E E N S T E I N

Greetings to all!

The past two years have been productive years for me at Cornell. I received tenure at the end of academic year 2010-11 and took my sabbatical during the fall semester of 2011-12. Wow, sabbatical was fantastic. I did not travel but rather stayed right in town and worked on writing up some of my ongoing research projects. While I enjoy teaching on the block plan, it can be hard to find time during busy blocks to keep the research going steadily. The result for me is a backlog of research projects that need to be finalized and turned into manuscripts. Currently, I am working on revisions for one of the manuscripts regarding the cooling and uplift that took place during the final stages of the Norwegian Caledonide orogeny. Last year two of my research students wrote honors theses on the pressure-temperature histories of eclogites from the ultra-high-pressure North Qaidam mountains in western China. That project is ongoing. This past summer I began a new project with a colleague from Oberlin college on Santa Catalina Island, CA. We received a grant from the Keck Geological Consortium and took 6 undergraduate students from across the country with us to examine the Creta-ceous subduction zone exposed on the island. This project, too, is ongoing.

This year I took over as department chair and joined the Review, Tenure & Promotion Committee of the college—two service positions that required quite a lot of time. I continue in both positions next year, but I can see that having one year of experience under my belt will help me become more efficient in both. In addition, I taught a brand new course, Metamorphic Petrology (which used to be combined with Igneous Petrolo-gy), and a new version of my upper-level elective, Origin of Mountains. Students worked hard in Metamorphic Petrology, making their own thin sections and analyzing a “pet rock” from the department’s extensive rock collections. The results were quite impressive. I was also immensely impressed with the students in Origins who wrote mini-NSF proposals for research projects of their own creation in a mountain belt they had just learned about that block (the Urals).

Jonathan and I are having a wonderful time watching Franklin grow and change—he will turn 3 this summer and every day is a new adventure. Both of them joined me on Santa Catalina Island last summer, camping with the bison and playing at the beach-es. Hard to beat that!

Let us hear from you!

Best wishes to all,

Emily

Page 7

N O T E F R O M E M I L Y W A L S H

2011-2013 Page 8

Dear Cornell Alumni,

Greetings! Life in the department is as busy as always. As for my research, a long-simmering project that I began in 2004 in Portugal is now taking off, and I have a couple of students joining me in fieldwork, as well as time in the labs at Iowa State and the University of New Mexico. By analyzing stalagmites, we are finding that during the last glacial period (the last 100,000 years or so), rainfall in Portugal was ramped up and then clamped down by temperature shifts in the North Atlantic that are recorded in the Green-land ice cap. The research in northern Australia is funded by an NSF grant which I re-ceived a year-and-a-half ago. There, my students and I have reconstructed the behavior of the Australian summer monsoon over the past 40,000 years and have found that it varied in concert with Greenland, just like Portugal does, although when Portugal got wetter, Australia got drier. Despite this work, there is still a lot to do. I am heading back to Portugal this summer for more fieldwork, and I hope to get back to Australia next sum-mer. I have a suite of excellent and extremely hard working research students who keep me on the ball and excited.

Jen and the girls are doing well. Anna is now in 7th grade and really seems to like it despite her occasional claims to the contrary. She has become a huge fan of Sherlock Holmes – both the Arthur Conan Doyle stories and the BBC series “Sherlock”. Harper is a rapidly sprouting 4th grader who, as I write, is covered from head to toe in mud as she and a friend do something slightly geological/archeological/agricultural in our back yard. Harper and two friends have formed a band “Night Owls” (consisting of electric piano, vocals, and drums – Harper is the drummer) and so far have two original songs to their credit, one of which reminisces about those early days (prior to 4th grade, I guess) when life was so carefree. Hmmm.

I love hearing from your news, so please send me an email if you have the time (RDenniston@CornellCollege.edu).

Best,

Rhawn

N O T E F R O M R H A W N D E N N I S T O N

Sparks From The Rockpi le

Page 9 2011-2013

Geology Field Trips 2011-2013

GEOMORPHOLOGY IN

SOUTH DAKOTA 2011

GEOLOGY OF A REGION:

NEW ZEALAND 2012

BAHAMAS 2012 & 2013

“The whole world is, to me, very much ‘alive’ - all the little growing things,

even the rocks...The same goes for a mountain, or a

bit of the ocean, or a magnificent piece of old wood.” -Ansel Adams

Sparks From The Rockpi le Page 10

NEW ZEALAND 2012

In February of 2012, a class of 12 students, Prof. Rhawn Denniston and three of his friends, including economics professor Todd Knoop and Biology professor Lenny Gannes, left the Iowa winter and embarked on the long trip to reach the South Island of New Zealand. Once we finally reached Nelson, we began the long drive to the field station near Takaka where we spent a week and a half exploring a detailed mapping project of Farwell Spit. We grew to love the field station and the beautiful coast around Takaka; as well as The Mussle, the great tavern down the road. We then spent a few days in Hokitika and completed a mapping project of the Alpine fault. After this we moved even farther southward, work-ing our way toward Franz Josef. Along the way we stopped and hiked down into a gulley full of beautiful garnet schist and actually put our hand on the contact of the Alpine Fault! It was a fantastic experience to actually touch a geologic feature that stretches across the entire country. We then moved on to Franz Josef where we hiked on the Franz Josef Glacier in pouring rain; one of the highlights of the trip despite how cold we were. The trip concluded with the long scenic drive back to Nelson where we spent the last couple of days enjoying the beautiful city and going on a 9-hour hike to the top of Dun Mountain, the name locality of dunite. Although we were sad to let New Zea-land go, we left with a better understanding of geology and returned to cam-pus feeling invigorated. The class grew extremely close on that trip and will forever hold those memories and the knowledge gained.

Daniel Pawlak ‘13

Page 11

BAHAMAS 2013

2011-2013

Cornell College is known for offering “one extraordinary opportunity at a time” with their unique academic block program. The Modern and Ancient Car-bonate Systems of the Bahamas class is a prime example of why students at Cornell benefit so much from the block program. Only at Cornell are students given the opportunity to travel to a tropical island for an entire month, during the middle of the academic school year. As a geology major I was required to take a field course, but what better way to meet this requirement then to study corals in San Salvador, Bahamas, while escaping the harsh Iowa win-ter? For a month, we were given the opportunity to snorkel numerous coral reefs, climb through flank margin caves, and of course bask on the various beaches. However, it wasn’t all fun in the sun. Cornell College is also known for its academic rigor, and this course was no exception. While enjoying our-selves on a topical island, we were also educated on the dynamic systems that create the island’s stratigraphy, how to recognize specific fossils in the rock record, and other important skills that every geologist will need after graduation. It was a true test of knowledge and endurance, but it was also one of the most fulfilling and exciting classes I’ve taken during my college career.

Stephanie Wheeler ‘14

STUDENT RESARCH: KECK CATALINA 2012-13

Sparks From The Rockpi le Page 12

Being accepted and funded for a year-long Keck Geology Consortium project studying metamorphic rocks on Santa Catalina Island, California, was an ex-traordinary opportunity. Myself, Dr. Walsh and five other undergraduates from colleges across the nation, as well as Dr. Zeb Page of Oberlin College spent three weeks exploring and collecting samples (and playing with bison, island foxes and hacky-sacks) on Santa Catalina Island. Because each undergrad was working on an individualized project, our experience of the island’s geology was extremely in-depth and varied. Additionally, the connections I formed with the other students are long-lasting friendships that I value to this day.

After a summer of field work on the island, and a week of preliminary lab work at Oberlin College, OH, each student worked on their project throughout the year. Some of the projects became honors theses, others senior theses; but after a year of research we returned to California, to Pomona College, to present at the annual Keck Geology Symposium. Seeing everyone’s hard work pay off, and learning what other Keck students had been working on was a highlight of the year for me. It was also very exciting to be on a flight where everyone is holding a poster tube, and the word “subduction” can actually be overheard in casual conversation…

Michael Barthelmes ‘13

Page 13 2011-2013

STUDENT RESEARCH: NEW MEXICO 2012

Conducting research at the University of New Mexico provided me with an amazing experi-ence. While I was there, I learned how to date stalagmites using U-Th dating techniques and how to work with others in a lab setting. Basi-cally, the process of dating stalagmites in-volves drilling samples from interesting areas of the stalagmite, processing them through various chemical procedures, and then run-ning them on a mass spectrometer. Though the days could be long, and I spent a lot of time in the lab waiting for samples to go through various chemical processes, I gained lab skills and confidence. However, I was not stuck in the lab the entire time in New Mexi-co. During days off my peers and I visited a few places of geological interest, such as Tent Rocks National Monument, Ghost Ranch, and the Valles Caldera National Preserve. Overall, this research experience has allowed me to work on a thesis and has provided me with the skills needed to conduct research this summer at the University of Texas.

Angelique Gonzales ‘14

During the summer of 2012, I went to the University of New Mexico with Professor Rhawn Denniston and assisted his research for two months with two other students. While there, we polished slabs of stalagmites using a handheld sander and milled them with a computer-guided drill bit. We processed the more than 100 samples in the clean lab with wet chemistry procedures to measure the amount of thorium and uranium within each sample. Finally, we assisted Professor Denniston in running a Neptune mass spectrometer to obtain uranium and thorium isotopic ratios to get accu-rate dates for each sample. In addition to the lab-work during the weekdays, we hiked in the nearby mountains to learn about the local geology on the weekends. This experience allowed me to obtain essential skills such as polishing, drilling, and uranium/thorium dating, which are all very useful skills in the art of paleoclimate re-construction. The experience taught me physical and mental endurance, and helped prepare me for a life of field-work.

Ni An ‘14

Sparks From The Rockpi le Page 14

STUDENT RESEARCH: PORTUGAL 2012

In the summer of 2012 I had the privilege of accompanying my advisor, Rhawn Denniston, to Portugal to help collect stalagmites from two caves. We joined a colleague of his, Jonathan Haws, an anthropology professor at the University of Louisville. The first cave we sampled involved a twenty-foot descent down a steel cable ladder. It was not a very deep cave, ~150m long, but it was well decorated. We were able to collect several samples from this cave, all of which had already been broken off. The next cave, fondly known as Buraca Gloriosa or “Glory Hole”, required a tight squeeze through a hole, feet first, and then a climb down a root to get into the body of the cave. This cave was bigger and deeper than the previous cave, but not as well decorated. We collected two stalagmites, one of which was a three-foot long piece, weighing 90 lbs, that continues a sample Rhawn had collected in 2006. It is this sample that I decided to work on for my honors thesis. After shipping all the samples back to the USA, I met Rhawn at the University of New Mexico in Albuquerque during late summer, and we per-formed U-Th series dating on the samples using the Inductively-Coupled Plasma Mass Spectrometer. Then in the fall, I took my sample to Iowa State where, under the direction of Al Wannamaker, I drilled for and analyzed carbon and oxygen isotopes. This allowed me to begin reconstructing cli-mate in Portugal for the last glacial cycle, the topic of my honors thesis.

Amanda Houts ‘14

Page 15 2011-2013

C O R N E L L C O L L E G E G E O L O G Y

2012 Graduating Majors: Luke Anderson, Matt Ash, Robin Drucker, Chelsea Nissen, Elizabeth Greaves, Wilson Keys, James Ostrander, Julian Peota, Andrew Roers, Bill Rood, Ellen Shank, Nic Slater

2013 Graduating Majors: Mike Barthelmes, Dan Pawlak, Daniel Cleary, David Al-

len, Shannon Carty (Geology Teaching major)

Student Awards and Honors

Herbert Hendriks Award (to the top senior geology major)

2012. Chelsea Nissen

William H. Norton Geology Prize (to the top junior geology major)

2012. Michael Barthelmes

2013. Ni An, Angelique Gonzales

Gene Hinman Geology Prize (for excellence in field research)

2012. Angelique Gonzales

2013. Amanda Houts

Paul Garvin Geology Prize (to the top sophomore geology major)

2012. Ni An, Amanda Houts

2013. Setsen Altan-Ochir

Student Symposium A full list of Symposium contributions and abstracts can be found on the college web-site at this address:

http://symposium.cornellcollege.edu/category/geology/ Following is a selection of abstracts of the varied topics that have been featured at recent symposiums.

Sparks From The Rockpi le

The North Qaidam Mountains on the northeastern edge of the Tibetan plateau contain an ultrahigh-pressure (U)HP metamorphic terrane. The region has been deformed, uplifted and tilted by the Himalayan orogeny, exposing a ~10 km thickness of metamorphosed crust at the surface (Menold et al., 2009). This tilting combined with the desert conditions of the region provides excellent exposure and access to (U)HP rocks, making it the site of many studies on the mechanics of (U)HP metamorphism and exhumation. The area is still not well understood, with large variations in metamorphic dates and peak pressure–temperature estimates throughout the region. We analyzed eclogites from the NW part of the North Qaidam Mountains, the Luliangshan, for pressure-temperature estimates. We found peak pressures of 24.5 ± 4 kbar at 508 ± 90°C from sample CM-5-27-04-7A and 23.9 ± 5 kbar at 650 ± 100°C from sample CM-6-6-04-8A. Our samples indicate late stage heating as well as possible UHP conditions in the region.

Page 16

Using eclogites to decode the pressure–temperature history of an ultrahigh-pressure metamorphic zone, North Qaidam, China

Honors Thesis, Robin Drucker

Page 17 2011-2013

The North Qaidam (ultra)high-pressure metamorphic belt (NQMB) is located on the northeastern corner of the Tibetan Plateau. It is composed of multiple suture zones and terranes that have been tectonically altered. The NQMB is roughly 15 km wide, extends 350 km NW-SE, and contains well-exposed continental collision-type (ultra)high-pressure [(U)HP)] metamorphic rocks. Eclogites in the NQMB occur as blocks, boudins or layers within the host orthogneiss. The eclogites hold pressure indicator minerals in fluid-reduced conditions, resulting in slow reaction rates. This makes them ideal rocks for pressure–temperature (PT) studies. Thermobarometry calculations from eclogites and (U)HP gneisses has been used to decipher PT histories along the NQMB; however, many of the eclogites in the area do not contain an ideal mineral assemblage for conventional thermobarometry. Likewise, eclogite sample E9814B1, from the northwestern end of the NQMB, contains only garnet+clinopyroxene+biotite+quartz. However, the size of the garnets (3-5 mm diameter), the lack of inclusions in garnet, and the overall lack of retrograde metamorphism, makes sample E9814B1 ideal for detailed element diffusion studies. We analyzed major and trace elements in the garnets of sample E9814B1 by electron microprobe (EMP) and laser-ablation inductively coupled plasma mass spectrometry( LA-ICP-MS). Major and trace element patterns reveal three stages of prograde garnet growth, which produced a well-defined core, outer core (mantle) and rim within each garnet. Major elements (Ca, Mg, Mn, Fe), light rare earth elements and middle rare earth elements show bell-shaped distribution profiles, across each grain, indicating element distribution through Rayleigh fractionation, whereas vanadium and scandium exhibit M-shaped profiles, likely designating diffusion-limited distribution (Skora et al., 2006). Major element zoning and diffusion rates allow for estimation of PT conditions of prograde growth of the sample, indicating three distinct stages of growth.

Major and minor elemental analysis of eclogitic garnets from the North Qaidam (U)HP metamorphic belt; implications for thermobarometry

Honors Thesis, Chelsea Nissen

Sparks From The Rockpi le

The last several hundred thousand years have wit-nessed dramatic changes in sea level due to the growth and decay of the Greenland, Antarctic, and now-melted North Ameri-can continental ice sheets. The last time sea level exceeded modern day levels was 120,000 years ago, at which time it was as much as 6-8 m above pre-sent. Given that 10% of the world’s population lives in low lying coastal regions, understanding the causes, mechanisms, and rates of past sea level changes are of critical importance. Several methods have been developed for recon-structing past sea levels, including analysis of the oxygen isotopes of forami-nifera. Radiometric dating

of select species of coral and of submerged flow-stones, stalagmites, and stalactites allows us to correlate a date with the already-determined timing of subaerial exposures. One limitation to sea level studies involves tectonic activity, which raises the land surface, thus altering the evidence of past sea levels. If the tectonic activity is not corrected for, then an incorrect sea level height will be ob-tained. Therefore, one area often studied is The Bahamas Bank, an area that is tectonically stable and that can thus record sea level without the complications of tectonic uplift. This project involves a synthesis and summary of

Page 18

Sea Level Rise and Fall Recorded in The Bahamas Caused by Glacial Events and the Future Impacts of Sea Level on World

Population Daniel Pawlak

sea level reconstructions from The Bahamas over the last 120,000 years, with the goal of under-standing the large scale impact on the world popu-lation of sea level rise above its current day position due to global climate change and the resulting melting of the continental ice sheets in Greenland and Antarctica.

“A road cut is to a geologist as

a $20 bill is to a starving man”

John McPhee

Page 19 2011-2013

Sea surface temperature (SST) is one of the most important and fundamental components of Earth’s climate. Tropical SST deter-mines the location of the Intertropical Convergence Zone where the northeast and southeast trade winds meet, and influences global moisture content, the strength of monsoons, and precipitation in the tropics. Therefore, the importance of understanding the changes in SST can help us grasp a better understand-ing of the effects of climate change. Several SST prox-ies have been developed, including oxygen isotope, magnesium-calcium, and strontium-calcium ratios in foraminifera and corals, and alkenones in marine algae and foraminifera, all of which serve as important tools in palaeoceanogra-phy. However, each method offers advantages and disadvantages. For exam-ple, an advantage for the magnesium-calcium meth-od is that it can be meas-ured along with oxygen isotope records found in the same shell of foraminif-era. A drawback to the magnesi-um-calcium method is that partial dissolution of foram-inifera shells can occur after the shells reach the

sea floor. This dissolution can reduce the magnesi-um-calcium ratio, raising the apparent tempera-ture. Our understanding of SST variability decreases as we stretch deeper back in time; but over the last glacial cycle, fluctuations in SST occurred coinci-dent with changes in glacial ice volume, atmos-pheric temperature, and changes in ocean circula-tion. Reconstructed tem-perature estimates of up to 5°C warmer than pre-sent have been calculat-ed for sea surface tem-peratures during this time period. The last time tropical SST was as high or higher than today was during Marine Isotope Stage 5e (120,000 years

ago), which would imply similar climate conditions. This study summarizes data that show how the various proxies indicate fluctuations of SST over the last glacial cycle and how applying these re-sults can give us a better understanding of the effects of climate change.

Tropical Sea Surface Temperatures Over the Last 120,000 Years

David Allen

Fe2+ equilibration. Sam-ples were then measured using near-infrared reflec-tance spectroscopy and Mossbauer spectroscopy to determine the cation ordering. The results show that pyroxenes on Earth are more ordered, having experienced slower cool-ing or metamorphism, while extraterrestrial materials are more disor-dered, due to rapid cool-ing. However, our re-search will need some tweaking before doing final analyses.

Page 20

Pyroxenes are among the most common minerals in the inner solar system. The degree of order/ disorder in their crystal structure re-lates to the cooling history of the mineral. In pyrox-enes, Fe2+ prefers the M2 cation site, and Mg prefers the M1 cation site in the crystallographic structure; the slower the pyroxene cools, the more ordered it will be. Previous work re-vealed that the ordering of Fe2+ and Mg between the M1 and M2 sites affects the relative strengths of absorption bands in the near-infrared. We per-formed a series of heating experiments to help con-strain the relationship between cation ordering

and reflectance spectra for orthopyroxenes. For the experiments, 100 mg of crushed orthopyrox-ene was heated in an alumina capsule sealed inside an evacuated high-purity silica tube. A small piece of iron foil was placed beneath the cap-sule to buffer oxygen fugacity; a small piece of the iron foil outside the seal showed the differ-ence between the atmos-pheres inside and outside of the tube. The samples were heated to four differ-ent temperatures (500°C, 600°C, 700°C and 800°C) and were held at those temperatures for one day to a month to ensure Mg-

Characterizing Pyroxene Cooling Rate Using Reflectance Spectra

Ellen Shank

Sparks From The Rockpi le

Paleoclimate records from Indonesia and the West Pacific Warm Pool (WPWP) reveal that changes in global and regional climate have altered the intensity and location of Indonesian-Australian Summer Mon-soon (IASM) precipitation over glacial/interglacial cycles (Magee & Miller, 2004; Griffiths et al., 2009; Mohtadi et al., 2011). Understanding the magni-tude and timing of mon-soon variability in tropical Western Australia is less well constrained because paleoclimate proxies across the region are sparse and have been limited to alluvial sequenc-es (Muller et al., 2008; Wyrwoll & Miller, 2001)

and shallow marine sedi-ments (Magee & Miller, 2004). Recent stalagmite records developed in the Kimberly region of West-ern Australia provide high resolution records of IASM variability over the past 40,000 years (R. Denniston, personal com-munication), but do not necessarily reflect all aspects of a changing hydrologic cycle. In order to develop a more complete picture of changing precipitation conditions over this time interval, samples of groundwater carbonate (tufa) deposits formed in the Kimberly region were dated using U/Th mass spectrometry tech-

niques. These deposits track changes in climate by marking the timing of groundwater discharge, which is controlled pri-marily by the amount of precipitation that is al-lowed to infiltrate into groundwater reservoirs (Yan et al., 2012). Samples taken from the top half meter of the tufa mound date back approxi-mately 3,000 years, with a maximum age of 4,800 years. This suggests that the entire mound could date back between 35,000 and 57,600 years, providing evidence for a continued, larger study.

Page 21

U/Th Dating of Cold Water Tufa Deposits from Kimberly Region of Australia

Aaron Campbell

2011-2013 Page 22 Sparks From The Rockpi le

The Catalina Schist crops out on Santa Catalina Is-land and underlies the southwestern California borderland, preserving a Cretaceous subduction zone environment. The Catalina Schist consists of amphibolite-facies rocks atop a suite of rocks meta-morphosed at progressively lower temperatures with increasing depth. This inverted metamorphic sequence has been ex-plained to be the result of tectonic juxtaposition of the subduction zone sequence with rocks formed in a slab-parallel thrust in the fore-arc. Subsequent subduc-tion erosion and faulting has juxtaposed the lower grade blueschist-facies rocks with the higher grade units of the Catalina Schist.

The epidote-blueschist unit of the Catalina Schist exists between the high-grade epidote-amphibolite unit and the low-grade lawsonite-blueschist unit and was originally mapped together with the epidote-amphibolite unit as the Catalina greenschist unit. Signifi-cant differences in meta-morphic grade separate these units and bring into question whether the epidote-blueschist facies metamorphism occurred within a slab-parallel megathrust in the forearc region or within the accre-tionary complex of the subduction zone proper. Last summer I collected a series of samples along Cottonwood Canyon, starting from apparent epidote-blueschist at the

bottom to amphibolite at the top. Thin-section anal-ysis of these samples has shown a complete lack of gradation between units, strongly implying unique histories of formation and perhaps the existence of a second metamorphic thrust zone. Pseudosec-tion analysis of XRF data for some samples, as well as electron microprobe data, can refine the tec-tonic model of the Catali-na Schist to include spe-cifics regarding the for-mation of the epidote-blueschist.

Evolution of a Cretaceous Subduction Model: Insights from the Catalina Schist

Michael Barthelmes

“(In geology) we find no vestige of a beginning – no prospect of an end..”

James Hutton

We present U-Th and Sr isotopic data on young (Holocene) lavas from Lassen and Mt Shasta volcanic fields and surrounding areas. Andesitic lavas from Shasta have 232Th/238U ratios of 2.6–2.7 and, similar to those reported previously, have activity ratios (230Th/238U) of 1.01–1.03 close to secular equilibrium. A Holocene rhyodacite flow from Lassen has a 232Th/238U ratio of 2.9 and (230Th/238U) near secular equilibrium (0.99), similar to lavas from Shasta reported here and elsewhere. In contrast, basaltic andesite lavas from the Cinder Cone at Lassen show large U en-richments, 232Th/238U ratios between 1.4 and 1.7 and (230Th/238U) of 0.61–0.74. These are the highest 238U over 230Th enrichments seen in Cascade lavas, similar to many arc lavas. Lavas from Lassen, despite large differences in bulk compo-sition of U/Th and (230Th/238U), have similar 87Sr/86Sr ratios (0.703954 – 0.704137). These Sr isotopic ratios are similar to values from other southern Cas-cade lavas. In contrast, the Shasta lavas have low 87Sr/86Sr ratios (0.702905 -0.703118), within the range of local MORB. The similarity in Sr isotopic composition between the more evolved lavas of Lassen and the Cinder Cone lavas argue against source variation to explain the U enrichment in the latter. The differences in (230Th/238U) are reflected in the 232Th/238U ratio, suggesting inherent U over Th enrichment of the Cinder Cone lavas, most likely due to fluid addition in the mantle.

High-fluid Component in Some Recent Lavas from the Southern Cascades Nic Slater

Page 23 2011-2013

Mud Layers in Stalagmites: A Proxy for Past Cyclone Activity Daniel Cleary

Our current understanding of trends in tropical cyclone activity in the Indo-Pacific is restricted by a limited historical record. Mud layers deposited in stalagmites during flooding events in cave KNI-51 from tropical Western Australia appear to be a proxy for tropical cyclone activity in the region. Aragonite stalagmites were precisely dated using U/Th mass spectrometry techniques, and these high resolution dates were used to construct age models that can, in turn, be used to calculate the age of each mud layer. Stalagmite KNI-51-G is 63 cm tall and cylindrically shaped, and preserves evidence of increased flooding frequency from 1310-1460 AD and decreas-ing flooding frequency from 1460-1640 AD. These data compare well with similar analyses of two other stalagmites collected from KNI-51. West Pacif-ic Warm Pool sea surface temperatures, which exert a first-order control on tropical cyclone activity, track flood layer frequency from 1000-1637 AD suggesting that tropical cyclone-induced flooding increased during periods of warmer sea surface temperatures from 1100-1250 AD.

“Show me a person who throws money into a shifting crack in the ground, and I’ll show you someone who is generous to a fault.” -Unknown

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