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Evidence For A Northern Transitional Continental Margin Flora In The Cretaceous (Campanian To Maastrichtian) Matanuska Formation, Talkeetna Mountains, Southcentral Alaska Item Type Thesis Authors Reid, Sabra Louise Download date 09/10/2021 10:03:13 Link to Item http://hdl.handle.net/11122/8942 INFORMATION TO USERS This manuscript has been reproduced 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. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. ProQuest Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. EVIDENCE FOR A NORTHERN TRANSITIONAL CONTINENTAL MARGIN FLORA IN THE CRETACEOUS (CAMPANIAN TO MAASTRICHTIAN) MATANUSKA FORMATION, TALKEETNA MOUNTAINS, SOUTHCENTRAL ALASKA A DISSERTATION Presented to the Faculty of the University of Alaska Fairbanks in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY by Sabra Louise Reid, B.S., M.L.A. Fairbanks, Alaska December 2007 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 3302510 Copyright 2008 by Reid, Sabra Louise All rights reserved. UMI___ ® UMI Microform 3302510 Copyright 2008 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. EVIDENCE FOR A NORTHERN TRANSITIONAL CONTINENTAL MARGIN FLORA IN THE CRETACEOUS (CAMPANIAN TO MAASTRICHTIAN) MATANUSKA FORMATION, TALKEETNA MOUNTAINS, SOUTHCENTRAL ALASKA By Sabra Louise Reid RECOMMENDED: ftp A* Advisoryory Committeeee Chair n Chair, Department of Geology and Geophysics APPROVED: h YH4Uiif^ Deanin, College of NaturalNati Science and Mathematics A? Dean of Graduate Sch Date Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Abstract The Late Cretaceous Matanuska Formation contains shallow and deep marine sediments and nonmarine sediment derived from the Talkeetna volcanic island arc. The sediment accumulated in the Matanuska Seaway, a tectonically active basin on the southern margin of southcentral Alaska. The Matanuska Seaway was contemporaneous with the Cretaceous Western Interior Seaway (CWIS) of North America. Angiosperm pollen taxa from the CWIS have been used to date units and reconstruct both paleolatitude and paleoclimate (Nichols and Sweet, 1993). Comparison of pollen taxa from the CWIS to assemblages from the Matanuska Formation reveals that outcrops at Mazuma Creek, Granite Creek, Syncline Mountain, and Slide Mountain are Late Maastrichtian, while Hicks Creek outcrops are Campanian. During the Late Maastrichtian, the Matanuska Seaway was located south of 75° N latitude. The presence of ash layers overlain by low-diversity palynofloras with relatively high proportions of spores indicates the presence of volcanic recovery floras within the Matanuska Formation. Palynofloral composition and diversity of the climax vegetation suggest that the Matanuska paleoflora is a northern, transitional, continental margin flora that shares taxa with Late Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Cretaceous Pacific Rim floras of the Russian Far East and Japan and continental margin floras of western North America. When combined with coeval assemblages from the Alaska Peninsula, southcentral Alaskan palynofloras of the Late Cretaceous contain the most diverse assemblages of Aquilapollenites group taxa known from the North Pacific Rim. The Matanuska Seaway thus represents a coastal dispersal corridor where floras of the North Pacific Rim and western North American mingled. Within Alaska, the diversity of Late Cretaceous Aquilapollenites group taxa increases from north to south. Comparison of the Matanuska Formation palynoflora with assemblages from the interior Lower Cantwell Formation and the Arctic Prince Creek Formation reveals the presence of a north-south paleoecological and paleoclimatic gradient during the Campanian-Maastrichtian. The Matanuska Formation paleoflora suggests that the paleoclimate of southcentral Alaska was warm and humid. Assemblages from the interior Lower Cantwell Formation paleoflora are indicative of a warm, dry paleoclimate, while palynofloras from the Arctic Prince Creek Formation paleoflora record a cooler, more temperate paleoclimate on the North Slope. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. V Table of Contents Page Signature Page ....................................... i Title Page ........................................... ii Abstract ............................................. iii Table of Contents .................................... v List of Figures ...................................... xiii List of Tables ....................................... xvii List of Appendices ................................... xxi Acknowledgements ..................................... xxii I. Introduction .................................... 1 Global paleofloral provinces .................... 1 Geographic locations and geologic environments of Late Cretaceous paleofloras of Alaska ........... 5 Reconstructing paleoclimate, paleolatitude and geologic age .................................... 17 Comparison of the three Alaskan Campanian- Maastrichtian paleofloras.. ..................... 21 Sedimentary facies of the Matanuska Formation ... 25 Two important problems .......................... 31 Purposes of this study .......................... 32 Methods ......................................... 33 Conclusions ..................................... 34 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. vi Page II. Review of the Literature ........................ 37 Introduction to the Late Cretaceous paleofloras of Alaska ....................................... 37 Early research on Late Cretaceous paleofloras, paleoclimate and paleogeography of Alaska and the north Pacific Rim ............................... 4 5 Description of the Matanuska Formation ......... 4 9 Tectonic history............................ 58 Reduction of the Matanuska Seaway.......... 63 Outcrop locations of the Matanuska Formation................................... 64 Coal and volcanic ash deposits........... 67 Lateral equivalents of the Matanuska Formation .. 68 Chignik Formation........................... 69 Hoodoo Formation............................ 71 Kaguyak Formation........................... 72 Geology of the Alaska Peninsula ................ 73 Paleofloras of the Matanuska Formation equivalents on the Alaska Peninsula ............ 7 8 Chignik Paleoflora.......................... 78 Kaguyak Paleoflora.......................... 83 Description and importance of interior Alaska formations coeval with the Matanuska Formation .. 84 Geologic units of the Cantwell Basin....... 84 Lower Yukon River Basin units.............. 87 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. v ii Page Yukon Tanana Uplands units.................. 34 Description and importance of two northern Alaska units in the Colville Basin, Arctic Alaska Terrane, coeval or partially coeval with the Matanuska Formation ............................. 95 Nanushuk Formation.......................... 97 Prince Creek Formation...................... 101 Paleoclimate reconstructions based on the Late Cretaceous floras from Arctic Alaska ........... 102 General description of the Campanian- Maastrichtian North Pacific Rim continental margin paleofloras .............................. Ill Western North America....................... Ill Navarin Basin units......................... 113 Russian Far East............................ 116 Hokkaido, Japan............................. 122 Geologic history and paleofloras of the Cretaceous Western Interior Seaway ............. 128 Relationship of the CWIS to Campanian- Maastrichtian age formations in Alaska..... 128 Geologic history............................ 128 First occurrence data of age-diagnostic pollen taxa................................. 130 Geographically endemic pollen taxa......... 131 Paleolatitude reconstructions based on leaf margin analyses ................................. 134 Reproduced with permission of the copyright