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Provenance and Tectonic Significance of the Lower Paleozoic Douglas Conglomerate, Northern Churchill Mountains, Antarctica" (1997)

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Provenance and Tectonic Significance of the Lower Paleozoic Douglas Conglomerate, Northern Churchill Mountains, Antarctica UNLV Retrospective Theses & Dissertations 1-1-1997 Provenance and tectonic significance of the Lower aleoP zoic Douglas Conglomerate, northern Churchill Mountains, Antarctica Susan Kay Panttaja University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Panttaja, Susan Kay, "Provenance and tectonic significance of the Lower Paleozoic Douglas Conglomerate, northern Churchill Mountains, Antarctica" (1997). UNLV Retrospective Theses & Dissertations. 8. http://dx.doi.org/10.25669/nomd-jo7e This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Retrospective Theses & Dissertations by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. INFORMATION TO USERS The most advanced technology has been used to photo­ graph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. 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University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 313/761-4700 800/521-0600 Order Number 1S35896 Provenance and tectonic significance of the Lower Paleozoic Douglas Conglomerate, northern Churchill Mountains, A n tarctica Panttaja, Susan Kay, M.S. University of Nevada, Las Vegas, 1988 UMI 300 N. Zeeb Rd. Ann Arbor, MI 48106 PROVENANCE AND TECTONIC SIGNIFICANCE OF THE LOWER PALEOZOIC DOUGLAS CONGLOMERATE, NORTHERN CHURCHILL MOUNTAINS, ANTARCTICA by Susan Kay Panttaja A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geoscience Department of Geoscience University of Nevada, Las Vegas August, 1988 i The thesis of Susan Kay Panttaja for the degree of Master of Science in Geology is approved. Examining Committee Member, Eugene I. Smith, Ph.D Examining Committee Member, David L. Weide, Ph.D 1P Graduate Faculty R resentative, Penny S. Amy, Ph. D. Graduate Dean, Ronald W. Smith, Ph.D University of Nevada, Las Vegas August, 1988 ii ABSTRACT The Douglas Conglomerate in the Churchill Mountains of Antarctica is a polymictic, unconformity-bounded stratigraphic unit whose age is poorly constrained between Late Cambrian and Devonian. Its clastic material was derived from nearby outcrops of Lower Cambrian Shackleton Limestone, from the craton of Greater Antarctica, and from terranes which lay outboard of the craton but subsequently were dispersed along transform faults. Framework mode analyses suggest a recycled orogen provenance for the Douglas. Its depositional basin may have formed within a fold-and-thrust belt or along an active transform fault. Subsequent tectonism has dismembered the formation, but its overall compositional homogeneity suggests that in the northern Churchill Mountains the Douglas represents a single basin within which numerous depositional systems were simultaneously active. The basin had fault-controlled margins walled with Shackleton Limestone as suggested by significant variation in the percentage of detrital carbonate among the outcrops. Although the Douglas crops out within the trend of granitic batholiths emplaced during the Cambro-Ordovician Ross Orogeny, it does not record the unroofing of these plutons. Therefore, it is probably older than the intrusives and was deposited in a foreland setting related to an earlier tectonic event. iii TABLE OF CONTENTS Abstract ill List of Figures v List of Tables vi Acknowledgements vii Introduction 1 Stratigraphy and Depositional Setting of the Douglas Conglomerate 2 Geologic History 13 Methodology 19 Provenance of the Douglas Conglomerate 25 Sandstone Description 25 Conglomerate Description 34 Provenance 37 Results of Statistical Analyses 48 Multiple Correlation 49 Principal Component Analyses 53 Discriminant Analysis 57 Distribution of Potential Source Areas 60 Tectonic Setting 65 Depositional Basin 65 Tectonic Models 70 Conclusions 73 References Cited 75 iv LIST QF FIGURES Figure Page 1 Location of field area in the northern Churchill Mountains, central TranBantarctic Mountains, Antarctica. 3 2 Geologic map of the field area in the northern Churchill Mountains. 4 3 Index map of locations discussed in the text. 5 4 Areal view of the southern part of the field area. 7 5 Lithofacies of the Douglas Conglomerate. 9 6 Diagrammatic representation of the formations exposed in the Churchill Mountains and their inferred stratigraphy. 11 7 Relative positions along the ridges of samples collected for analyses. 21 8 Photomicrographs of sandstone framework grains. 29 9 Photomicrographs of sandstone framework grains. 33 10 QFL diagram. 40 11 QmFLt diagram. 41 12 QpLvLs diagram. 42 13 ChLvLsc diagram. 45 14 LcLiLs diagram. 48 15 QmPK diagram. 47 18 Simple correlation matrices constructed using raw data from sandstone and conglomerate units. 51 17 Sorted rotated factor loadings for the first three principal components derived from principal component analysis. 55 18 Histogram of the canonical variable derived by discriminant analysis of sandstone framework modes. 58 v LIST OF TABLES Table 1 Sandstone framework mode percentages. 2 Clast count data for fourteen conglomerate samples. 3 Normalized point count data plotted on framework mode diagrams (QFL and QmFLt). 4 Normalized clast count data plotted on ternary diagrams. ACKNOWLEDGEMENTS This research was supported by the National Science Foundation, grants no. DPP 85-18157 and no. DPP 87-44459 awarded to University of Nevada, Las Vegas. Research support was also provided by a grant awarded to the author by the Graduate Student Association Research and Scholarship Council, University of Nevada, Las Vegas. Funding for the second year of graduate work was provided by a Barrick Fellowship awarded by University of Nevada, Las Vegas. Many people have had a hand in this research, and I am grateful to them all. Specifically I want to thank my professor, Margaret N. Rees, for her constant encouragement and support and for giving me the opportunity to go to Antarctica. It has been a privilege and a joy to work with her. I would also like to thank the members of my examining committee, E. I. Smith and D. L. Weide for their thoughtful and often entertaining comments on this manuscript; G. H. Girty for geological insights on this project and help in the early phases of point counting; to E. F. Thomas for encouragement and for and patiently developing film with me; to C. Jeffrey for drafting several of the figures herein; and to P. Braddock for looking after me on the ice and putting up with my singing. I am indebted to my family for their constant support vii throughout my life and to my wonderful Las Vegas "family" who have listened to and loved me for the last two years. I am especially grateful for my wonderful friends Rene Crow, who studied with me when I needed it most, and Taryn Archer, who constantly reminded me it was already done. Finally I wish to acknowledge all the miracles that have gotten me here and all those who have shared the path with me. It has been a wonderful journey. viii INTRODUCTION The Douglas Conglomerate of the central Transantarctlc Mountains (Skinner, 1964; Laird, 1981) originated in response to tectonic uplift along the paleo-Pacific margin of Gondvanaland during early Paleozoic time. This margin had a complex and long-lived tectonic history, much of which has been obscured by more recent deformation including significant transcurrent faulting. The Douglas Conglomerate is an unconformity-bounded stratigraphic sequence, and is the only remaining record of deposition during a 150 Ma period. Moreover, some of its clasts are the only evidence of lithologies no longer exposed in the area. Compositional data from the polymictic conglomerate
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