Dating of the Hiltaba-GRV event and associated mineral...

Dating of the Hiltaba-GRV event and associated mineral systems

11th August 2016, Mineral Systems Drilling Program Open Day

Elizabeth Jagodzinski

Department of State Development

Dating of the Hiltaba-GRV event and associated mineral systems

1. Recent high-precision TIMS dating of the Hiltaba-GRV thermal event

2. Dating of Olympic Dam and other IOCG deposits

3. Dating of Hiltaba-associated mineral systems on the southern margin of the Gawler Range Volcanics

4. Dating of the MSDP holes and future directions.


estimated volume ~ 100 000 km3

~ 70 000 km3 GRV, ~ 30 000 km3 Hiltaba

+ BVS in Curnamona Province

Gawler Range Volcanics & Benagerie Volcanic Suite SLIP


4

• 25 000 km2 of GRV exposed in the central Gawler Craton.

• Evolution of the GRV is separated into two main stages:

• lower GRV 1591 ± 3 Ma • upper GRV 1592 ± 3 Ma

• BVS correlated with the upper GRV 1584–1587 ± 6 Ma

• Hiltaba Suite ~ 1595–1575 Ma with some indication of spatial-temporal variation, with the oldest Hiltaba Suite occurring in the OD region

Fanning et al. Precambrian Research 40-41 (1988) 363 – 386 Wade et al. Precambrian Res. 206–207 (2014) 17-35 Jagodzinski (2014 AESC)

Gawler Range Volcanics & Benagerie Volcanic Suite SLIP


5

Glyde Hill >1km

Chitanilga

~ 3km

lower GRV

Agangi (2011) PhD Thesis CODES S.R. Allen et al. JVGR 172 (2008) 132–147 McAvaney & Wade (2015) DSD RB 2015/00021 Menninnie Dam

~ 200 m

Lavas from 1 km3

to 150–200 km3

Roopena ~ 500 m

Myall Creek ~ 2.4 Km


6

S.R. Allen et al. Australian Journal of Earth Sciences 50:1 (2003) 97-112

Lavas are an order of magnitude bigger than lower GRV units 200-300 m thick 600–2400 km3 upper GRV


Ca-TIMS Results

7

Benagerie Volcanic Suite Age Ma error 2σ

2049213 Finlay Dam Rhyolite 1587.3 0.5

2049215 Finlay Dam Rhyolite 1588.2 0.6

Upper Gawler Range Volcanics

1998160 Moonaree Dacite Member 1587.2 0.5

1998158 Eucarro Rhyolite 1587.5 0.6

Lower Gawler Range Volcanics, central Gawler Craton

1998163 Mangaroongah Dacite 1587.7 0.6

2018616 Bittali Rhyolite 1589.3 0.5

2016125 Ealbara Rhyolite 1591.2 0.5

Gawler Range Volcanics, Stuart Shelf

2000366166 Felsic dyke Olympic Dam 1593.0 0.5

2131365 undifferentiated, Red Dam 1593.6 0.4

2131354 undifferentiated, SAE 11 1595.4 0.6

Concordia diagrams


8 Department of State Development

Ranked date plot

Ca-TIMS Results


The duration of volcanism in the GRV-BVS SLIP was ~ 8 Myr

The extensive upper GRV lavas erupted instantaneously, in ≤ 1 Myr, possibly from large fissures.

The BVS in the Curnamona is temporally equivalent to the upper GRV

There is significant age variance in the lower GRV, indicating each small volcanic centre represents a discrete temporal event

The oldest zircons are from the Olympic Dam region, where the GRV extends below the Stuart Shelf to the east (Olympic Domain)

The Mangaroonah Dacite from the lower GRV (Glyde Hill Volcanic Complex) is the same age as the upper GRV lavas, suggesting ‘lower GRV- style’ volcanic centres continued erupting into upper GRV time

Ca-TIMS Results


CFBPs: a modern analogue

3 eruptive phases 1. Initial phase: low volume eruptions from spatially scattered

volcanic centres. Location controlled by pre-existing crustal weaknesses ≡ lower GRV ~ 8 Myr

2. Main phase: repeated large volume eruptions of extensive tabular tholeiitic flows, and in some cases silicic magma, from a number of spatially restricted eruption sites and fissures ≡ upper GRV ~ 1 Myr

3. Waning phase: usually more protracted, decrease in eruption volume, longer hiatuses between eruptions, increasing silica content and explosive eruptions, more widely distributed or shifts in locus of magmatism ? ≡ ongoing Hiltaba intrusion* ~ 10 Myr

10


1 Myr

* The Hiltaba granites intruded co-evilly with GRV, and continued intruding post-eruption, until ~ 1575 Ma

The time span, eruptive history and volcanic facies of GRV are analogous with CFBPs

5–10 Myr


CFBPs Initial phase 5–10 Myr

Main phase ~ 1 Myr Waning phase

GRV ≡ lower GRV ~ 8 Myr ≡ upper GRV ~ 1 Myr ≡ ? Hiltaba ?10 Myr


CFBPs: a modern analogue

Future directions

Wheepool Rhyolite, Glyde Hill

Chitanilga Volcanic Complex

Angle Dam Volcanics at Roopena

MSDP holes, southern Gawler Ranges

Relationship between Roxby Downs Granite/Hiltaba and GRV at Olympic Dam: intrusive? unconformity?

Glyde Hill

Chitanilga

Roopena

Chandabooka

Dacite

Lake Gairner Rhyolite

Wheepool

Mangaroongah

Wheepool

Rhyolite

MSDP01

Angle Dam Volcanics



Future directions

pitchbende maximum crystallisation ~1400 Ma, about 200 m.y. younger than the Roxby Downs Granite (Trueman 1986)

ODBC, alteration and mineralisation ~1590 Ma, associated with the GRV-Hiltaba thermal event (Johnson and Cross 1995)

CODES dating of sulphide phases (galenas), preliminary interpretations 1200-1400 Ma (Meffre et al., 2010 GODs conference)

Jagodzinski (2014 AESC)

Host Rocks


OLYMPIC DAM


Timing of mineralization in Olympic Cu-Au Province

Reid et al. Economic Geology 108 (2011) 883–894


Manxman West: 1567 ± 10 Ma (titanate, U-Pb) Prominent Hill: 1585 ± 8 Ma (zircon, U-Pb) Vulcan: 1586 ± 8 Ma (molybdenite, Re-Os) Olympic Dam: 1572 ± 99 Ma (sulphides, Sm-Nd) ~ 1400 Ma (pitchblende, U-Pb) 1258 ± 28 Ma (sulphides, Re-Os) Acropolis: 1604 ± 9 Ma (apatite, U-Pb) Torrens: 1575 ± 11 Ma (muscovite Ar-Ar) Murdie: 1576 ± 5 Ma (titanate, U-Pb) Oak Dam: 1455 ± 20 Ma (monazite, U-Pb) Punt Hill: 1577 ± 5 Ma (garnet-diopside, Sm-Nd) Hillside: 1584 ± 6 Ma (titanite, U-Pb) Moonta-: 1599 ± 6 Ma (molybdenite, Re-Os) Wallaroo 1577 ± 6 Ma (molybdenite, Re-Os) 1574 ± 6 Ma (molybdenite, Re-Os)


hydrothermal zircon ~ 1690 Ma, with Musgravian–Delamerian resetting/remobilisation (Jagodzinski 2014)

hematites 1577 ± 5 Ma, 1590 ± 8 Ma, (Ciobanu et al., 2013)

BHP-Billeton-CODES concur that the mineral system is co-eval with the GRV and associated Hiltaba Suite, and is a multi-stage, prolonged hydrothermal system evolving progressively over ~1.0 Ga, in response to major tectonothermal events

1600 Ma breakup of Columbia Supercontinent

1400 Ma final cratonisation, rebrecciation and incorporation of Pandurra Fm

1.3 -1.1 Ga Rodinia assembly

825 Ma Ga breakup of Rodinia

500 Ma Delamerian Orogeny –Gondwana assembly

OLYMPIC DAM


17


Timing of mineralization in other Hiltaba-GRV-related prospects

18

Mawson • Host rock is c. 1790–1740 Ma Cleve Group : quartz-feldspar-sillimanite gneiss Dmax c. 1740 Ma • Kimban metamorphism (titanite in amphibolite) 1718 ± 6 Ma • Kimban intrusion (leucogranite) c. 1685 Ma • Skarn alteration 1581 ± 9 Ma (Sm-Nd)

1604–1548 Ma (Re-Os) Weednana • Hiltaba granite intruding host gneisses 1584 ± 5 Ma

Telephone Dam base metal Pb-Zn • Host rock is Sleaford Complex:

leucocratic felsic gneiss Dmax 2473 ± 8 Ma

Menninnie Dam Pb-Zn • Basement to metasedimentary host sequence:

Sleaford Complex biotite-rich gneiss 2511 ± 4 Ma

Paris epithermal Ag-Au • Monzogranite porphyry 1593 ± 8 Ma

• Rhyodacite feeder dyke 1597 ± 14 Ma


Timing of mineralization in other Hiltaba-GRV-related prospects

19

Future directions MSDP holes


Future directions MSDP holes

Disclaimer

Our study stands on the shoulders of giants and we have built on the contributions of earlier workers in the GRV, particularly the CODES team at U.Tas and their studies of the physical volcanology. Thanks to Jocelyn McPhie for giving me carte blanche to use diagrams from their many publications. And to Kathy Ehrig, our collaborator at BHP Billiton, for permission to refer to unreleased TIMs dates from Olympic Dam. This study has been submitted to the J.Geol.Soc.Lond. for publication.

The information contained in this presentation has been compiled by the Department of State Development (DSD) and originates from a variety of sources. Although all reasonable care has been taken in the preparation and compilation of the information, it has been provided in good faith for general information only and does not purport to be professional advice. No warranty, express or implied, is given as to the completeness, correctness, accuracy, reliability or currency of the materials. DSD and the Crown in the right of the State of South Australia does not accept responsibility for and will not be held liable to any recipient of the information for any loss or damage however caused (including negligence) which may be directly or indirectly suffered as a consequence of use of these materials. DSD reserves the right to update, amend or supplement the information from time to time at its discretion.

Acknowledgements

Contact

www.statedevelopment.sa.gov.au


Level 4, 11 Waymouth Street Adelaide, South Australia 5000 GPO Box 320 Adelaide, South Australia 5001

T: +61 8 8226 3821 E: [email protected]

check out Research Gate for all your SA dating needs

Dating of the Hiltaba-GRV event and associated mineral...

Documents

Transcript of Dating of the Hiltaba-GRV event and associated mineral...