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Detrital Zircon Analysis of Permian Victoria Group Sandstones, Transantarctic Mountains, Antarctica

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Detrital Zircon Analysis of Permian Victoria Group Sandstones, Transantarctic Mountains, Antarctica Detrital Zircon Analysis of Permian Victoria Group Sandstones, Transantarctic Mountains, Antarctica THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Samuel Hulett Graduate Program in Geological Sciences The Ohio State University 2012 Master's Examination Committee: David Elliot, Advisor Matt Saltzman Larry Krissek Copyright by Samuel Hulett 2012 Abstract The Beacon Supergroup in the central Transantarctic Mountains, the Gondwana sequence of Antarctica, comprises Devonian (inferred) and Permian-Triassic strata. The latter were deposited in an intracratonic basin which evolved into a foreland basin in mid Permian time. Sedimentary petrology and paleocurrent data indicate that this basin had two major detrital sources, a cratonic source and a volcaniclastic source that characterizes the upper Buckley Formation and younger Triassic beds. In order to investigate the sedimentary provenance further, detrital zircons have been examined from both flanks of the basin. At Clarkson Peak, samples were collected from the lower (quartzose) and upper (volcaniclastic) Buckley Formation. At Mt. Bowers the complete Permian section, from pre-glacial to upper Buckley strata, was collected. Results show varied zircon age provenance, reflecting multiple source regions. In all pre-upper Buckley samples the major zircon provenance is in the 650-480 Ma age range, corresponding to overlapping Ross and Pan African orogenic events, with a subsidiary province of “Grenville age”, ~1000 Ma. These age range variations reflect the influence of multiple sub-provinces. There are also minor contributions from older Proterozoic sources, including a ~1500 Ma source that waned in Fairchild time and is nearly absent in the Buckley Formation. These older Proterozoic zircons were likely sourced from the coast of East Antarctica. A major shift in paleoflow directions between the lower and upper Buckley at both localities is accompanied by a significant input of Permian-age igneous zircons, documenting contemporaneous magmatism and flooding of the basin with detritus from an active magmatic arc. There is also a minor input of ~370 Ma grains which were most likely sourced from Devonian granitoids in West Antarctica. ii Dedication This document is dedicated to my parents, for all their help and encouragement when I needed it most. iii Acknowledgments I would like to extend a special thanks to: David Elliot, for his patience and help; the pilots of Petroleum Helicopters Incorporated for their invaluable assistance in getting to field sites and the National Science Foundation for funding this project. iv Vita May 2006 .......................................................Licking Valley High School May 2010……………………………………B.S Earth Sciences, Ohio State University September 2010 to present…………Graduate Research Assistant, Ohio State Univeristy Fields of Study Major Field: Geological Sciences v Table of Contents Copyright ............................................................................................................................. i Abstract ............................................................................................................................... ii Dedication .......................................................................................................................... iii Acknowledgments.............................................................................................................. iv Vita ...................................................................................................................................... v Table of Contents ............................................................................................................... vi List Of Figures ................................................................................................................. viii List of Tables ................................................................................................................... xiii Chapter 1: Introduction ....................................................................................................... 1 Exposures in East Antarctica ....................................................................................... 3 Exposures in West Antarctica...................................................................................... 6 1.2 Geologic History ....................................................................................................... 7 Geologic History of East Antarctica ............................................................................ 7 Geologic History of West Antarctica ........................................................................ 11 1.3 The Transantarctic Mountains ................................................................................. 13 Stratigraphy of the Transantarctic Mountains ........................................................... 13 Previous Provenance Studies in the TAM ................................................................. 19 Previous Detrital Zircon Studies in the TAM ............................................................ 19 Chapter 2: The Central Transantarctic Mountains ............................................................ 22 2.1 Stratigraphy in the Central Transantarctic Mountains ............................................ 22 The Alexandra Formation .......................................................................................... 22 The Pagoda Formation............................................................................................... 27 The Mackellar Formation .......................................................................................... 27 The Fairchild Formation ............................................................................................ 28 The lower Buckley Formation ................................................................................... 28 The upper Buckley Formation ................................................................................... 29 vi Triassic strata ............................................................................................................. 29 2.2 Areas Specific to This Study ................................................................................... 30 Bunker Cwm (Lat: 83.17°S Long: 164.00°E) ........................................................... 30 Clarkson Peak (Lat: 83°19’S Long: 164°34’E) ......................................................... 31 Tillite Glacier ( Lat: 83°51’S Long: 166° 0’E) ......................................................... 31 Mt. Weeks (Lat: 83°33’S Long: 160°54’E) .............................................................. 33 Mt. Bowers (Lat: 85° 0’S Long: 164° 5’E) ............................................................... 34 Mt. Achernar (Lat: 84°12’S Long: 160°56’E) .......................................................... 37 Chapter 3: Methods ........................................................................................................... 39 3.1 Field Methods .......................................................................................................... 39 3.2 Laboratory methods................................................................................................. 39 Chapter 4: Petrography ..................................................................................................... 41 Chapter 5: Results ............................................................................................................. 42 11-4-3 (lower Buckley Formation, Clarkson Peak) ...................................................... 42 11-4-10 (upper Buckley Formation, Clarkson Peak) .................................................... 44 11-5-2 (Pre-Pagoda Sandstone, Mt Bowers) ................................................................. 44 11-9-2 (Pagoda Formation, Mt Weeks)......................................................................... 49 11-5-8 (Fairchild Formation, Mt Bowers)..................................................................... 49 11-5-15 (lower Buckley Formation, Mt Bowers).......................................................... 52 11-5-22 (upper Buckley Formation, Mt Bowers).......................................................... 52 Chapter 5: Discussion ....................................................................................................... 59 5.1: >2500 Ma (Archean) .............................................................................................. 59 5.2: 1300-2500 Ma ( Early Mesoproterozoic and Paleoproterozoic) ............................ 61 5.3: 1000-1300 Ma (late Mesoproterozoic)................................................................... 64 5.4: 480-650 Ma (Cambro-Ordovician to Neoproterozoic) .......................................... 66 5.5: 460 Ma (Ordovician) .............................................................................................. 69 5.6: 260 Ma (Late Permian) .......................................................................................... 70 Chapter 6: Conclusions ..................................................................................................... 74 References ......................................................................................................................... 78 Appendix A: Raw Data and Concordia Plots ..................................................................
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