DOCSLIB.ORG

Quiz 12 Bonus 2 (9:30-9:35 AM) UNIVERSITY of SOUTH ALABAMA

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Quiz 12 Bonus 2 (9:30-9:35 AM) UNIVERSITY of SOUTH ALABAMA Quiz 12 Bonus 2 (9:30-9:35 AM) UNIVERSITY OF SOUTH ALABAMA GY 112: Earth History Lectures 32 and 33: Mesozoic Sedimentation Instructor: Dr. Douglas W. Haywick Last Time Mesozoic Tectonics A) The Triassic B) The Jurassic C) The Cretaceous (web notes 31) Mesozoic Tectonics Tectonics in North America during the Mesozoic was dominated by docking events involving terranes. Ultimately, continents grow bigger by scooping up geo-crap in their drift direction (Accretionary tectonics) Sonoman Orogeny Mesozoic Tectonics Into the Triassic, many more “terranes” (mostly island arcs) began to be scooped up by North America as it drifted WNW •Brooke Range Terrane (Alaska) •Stikine Terrane (British Columbia) •Sonoma Terrane (Nevada) Mesozoic Tectonics In the Jurassic, we start to see terranes with mixed lithologies docking with North America (e.g., Klamath Terrane) •Major (felsic) intrusions begin Mesozoic Tectonics In the Cretaceous, more hits and more intrusions. More uplift •Wrangellia Terrane docks What’s the Point? The Appalachians and Cordilleran Mountains were both formed via compressional tectonic events. Appalachians formed through collisions with other continents Cordilleran Mts. formed via accretionary tectonics Today’s Agenda Mesozoic Sedimentation A) Triassic Sedimentation (Breakup of Pangaea) B) Jurassic Sedimentation (Birth of the Atlantic Ocean) C) Cretaceous Sedimentation (Creation of the Coastal Plain Province) D) Mesozoic-Cenozoic climate (Greenhouse-Icehouse Earth Transition) (web notes 32) Mesozoic Paleogeography Mesozoic Sedimentation Triassic •Initial opening of Gulf of Mexico Mesozoic Sedimentation Triassic •Initial opening of Gulf of Mexico Mesozoic Sedimentation Triassic •Initial opening of Gulf of Mexico Mesozoic Sedimentation Triassic Mesozoic Paleogeography Mesozoic Sedimentation Early Jurassic •Initial flooding of Gulf of Mexico and Northern Atlantic Ocean Mesozoic Sedimentation Early Jurassic •Initial flooding of Gulf of Mexico and Northern Atlantic Ocean Mesozoic Sedimentation Late-Triassic/Early Jurassic Mesozoic Sedimentation Late-Triassic/Early Jurassic Alabama Mesozoic Stratigraphy Alabama Mesozoic Stratigraphy Halite (evaporite basin) Great Salt Lake (evaporite basin) http://www.americansouthwest.net/utah/photographs700/salt.jpg Alabama Mesozoic Stratigraphy Quartz Arenite (beach/desert) Sand dunes in the Gobi Desert Alabama Mesozoic Stratigraphy Fossil. Limestone & Dolostone (shallow marine with stromatolitic reefs) The Great Barrier Reef http://www.anntorrence.com/blog/at-images/gbr_02.jpg Mesozoic Sedimentation Mid-Late Jurassic •More widespread flooding of Gulf of Mexico and Atlantic Ocean and… Mesozoic Sedimentation Late Jurassic …major transgression and flooding of the craton begins •Sundance Sea Mesozoic Sedimentation Late Jurassic …major transgression and flooding of the craton begins •Sundance Sea •Clastic wedges Mesozoic Sedimentation Late Jurassic …major transgression and flooding of the Sundance Sea craton begins •Sundance Sea •Clastic wedges Mesozoic Paleogeography Mesozoic Sedimentation Cretaceous •Southern rifting in the Atlantic Ocean •Gulf of Mexico stops opening Mesozoic Sedimentation Cretaceous •Southern rifting in the Atlantic Ocean •Gulf of Mexico stops opening •AL Coastal Plain sedimentation Mesozoic Sedimentation North South Only key formations are labeled (those discussed in GY 112) Mesozoic Sedimentation North South Only key formations are labeled (those discussed in GY 112) Mesozoic Climate • High latitudes were warm – 50°F / 10°C – Dinosaurs near south pole Mesozoic Climate • Period of high sea level – Associated with rapid sea floor spreading – Long period without reversal Long Cretaceous Normal Chron Mesozoic Climate • Oceans stagnated – Epicontinental black muds when seas spilled over – Normally thin oxygen poor zone expanded This will change in the early Cenozoic (Late Eocene) Cenozoic Climate • Oxygen isotopes – Late Eocene cooling • Deep sea foraminifera Cenozoic Climate • Temperature inferred from leaf margins Cenozoic Climate Paleocene-Middle Eocene: •No circumpolar current Late Eocene-today: •Circumpolar current –Permitted development of glaciers on Antarctica Cenozoic Climate Today’s Homework 1. Time Chart 3 due Thursday April 28th 2. Study. Lab Final April 26th 3. Study. Lecture Final May 4th 4. Online class evaluation bonus opportunity soon Next Time 1. Cenozoic overview/tectonics GY 112: Earth History Lectures 32, 33: Mesozoic Sedimentation Instructor: Dr. Doug Haywick [email protected] This is a free open access lecture, but not for commercial purposes. For personal use only. .
Load more

Recommended publications
  • Evidence of Pachyostosis in the Cryptocleidoid Plesiosaur Tatenectes Laramiensis from the Sundance Formation of Wyoming Hallie P
    Marshall University Marshall Digital Scholar Biological Sciences Faculty Research Biological Sciences 2010 Evidence of pachyostosis in the cryptocleidoid plesiosaur Tatenectes laramiensis from the Sundance Formation of Wyoming Hallie P. Street Marshall University F. Robin O’Keefe Marshall University, [email protected] Follow this and additional works at: http://mds.marshall.edu/bio_sciences_faculty Part of the Animal Sciences Commons, and the Ecology and Evolutionary Biology Commons Recommended Citation Street, H. P., and F. R. O’Keefe. 2010. Evidence of pachyostosis in the cryptocleidoid plesiosaur Tatenectes laramiensis from the Sundance Formation of Wyoming. Journal of Vertebrate Paleontology 30(4):1279–1282. This Article is brought to you for free and open access by the Biological Sciences at Marshall Digital Scholar. It has been accepted for inclusion in Biological Sciences Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected], [email protected]. EVIDENCE OF PACHYOSTOSIS IN THE CRYPTOCLEIDOID PLESIOSAUR TATENECTES LARAMIENSIS FROM THE SUNDANCE FORMATION OF WYOMING HALLIE P. STREET and F. ROBIN O'KEEFE; Department of Biological Sciences, Marshall University, One John Marshall Drive, Huntington, West Virginia 25755, U.S.A., [email protected], [email protected] INTRODUCTION In this paper we present evidence for pachyostosis in the cryptocleidoid plesiosaur Tatenectes laramiensis Knight, 1900 (O'Keefe and Wahl, 2003a). Pachyostosis is not common in plesio- saurs and is particularly rare in non-pliosaurian plesiosaurs, although enlarged gastralia were first recognized in Tatenectes by Wahl (1999). This study aims to investigate the nature of the dispro- portionately large gastralia of Tatenectes m greater depth, based on new material.
    [Show full text]
  • Museum's Brochure Here
    Your Self Guided Tour To The Fossil Displays and More We hope this brochure makes it easier for LOOK CAREFULLY, at each dinosaur, you to see and enjoy all the exhibits provided but please, by the museum. Included is a map to assist in DO NOT TOUCH! locating all the exhibits and a brief description of what is on display. The dinosaurs are a Museum Hours: major focus of the museum’s exhibits. Everyday 9:00 a.m. - 10:00 p.m. Summer Hours (May-August) Please find the Map on the back 7:00 a.m. - 9:30 p.m. Tours available. cover to locate various displays. For further information about Western or the Natural History Museum please call 307-382-1600 Cenozoic Era Paleozoic Present to 66 million years ago 245 to 570 million years ago Yellowstone has had 3 major Sea deposits phosphates in explosive eruptions. west, red sand deposits in the east. Global extinction of 2 mill. yrs. Uplift of the western U.S. many marine invertebrates. Buffalo, Bull Lake, Pinedale glaciations. 286 mill. yrs. Wind blown sand forms the Mammals dominate the land. Tensleep, Weber, Casper, Minnelusa formations 24 mill. yrs. Sediments from the Miocene (all oil and gas producers). and Pliocene (2 to 24 mill. yrs.) is preserved in central 360 mill. yrs. Shallow sea covers the entire Wyoming Sweetwater Hills state forming the fossil rich area. End of the Laramide Madison Limestone. mountain building episode. 408 mill. yrs. Uplift in southwest 37 mill. yrs. Time of major deposites of Wyoming, diamond bearing coal, oil shale, and trona.
    [Show full text]
  • Sequence Stratigraphy of the Marginal Marine Facies of the Jurassic
    Sequence Stratigraphy of the Marginal Marine Facies of the Jurassic Sundance Formation, South Dakota and Wyoming: Implications for Controls of Higher-order Cyclicity in a Greenhouse World Karen Elaine Bossenbroek A thesis submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Master of Science in the Department of Geological Sciences. Chapel Hill 2011 Approved By: Dr. Louis R. Bartek III Dr. Kevin G. Stewart Dr. Brian W. Horn ©2011 Karen Elaine Bossenbroek ALL RIGHTS RESERVED ii ABSTRACT Karen Elaine Bossenbroek: Sequence Stratigraphy of the Marginal Marine Facies of the Jurassic Sundance Formation, South Dakota and Wyoming: Implications for Controls of Higher-order Cyclicity in a Greenhouse World (under the direction of Dr. Louis R. Bartek III) The Sundance Formation was produced by three marine inundations of the Western Interior during the Mesozoic, and the passive margin sediments are exposed in the Black Hills region of Wyoming and South Dakota. This study applies sequence-stratigraphic principles in correlation of geophysical well-log data and measured outcrops to establish a chronostratigraphic framework, in order to identify possible processes that govern stratigraphic architecture. The Sundance is part of a higher-order trend of marine inundations on the Western Interior governed by 3rd order cyclicity. The stratigraphy of the Lower Sundance displays a long-term trend of transgression and regression, punctuated by multiple parasequences. High-frequency variation in stratal architecture observed was likely shaped by cyclic variation in sediment supply governed by climate change. This study supports the current view that eustacy during greenhouse intervals is governed by low-frequency slow variations, and higher-frequency short-order cyclicity in sedimentation may also be superimposed during these long-term intervals.
    [Show full text]
  • Stratigraphy, Paleotectonics and Paleoenvironments of the Morrison Formation in the Bighorn Basin of Wyoming and Montana Dibakar Goswami Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1993 Stratigraphy, paleotectonics and paleoenvironments of the Morrison Formation in the Bighorn Basin of Wyoming and Montana Dibakar Goswami Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Geology Commons Recommended Citation Goswami, Dibakar, "Stratigraphy, paleotectonics and paleoenvironments of the Morrison Formation in the Bighorn Basin of Wyoming and Montana " (1993). Retrospective Theses and Dissertations. 10434. https://lib.dr.iastate.edu/rtd/10434 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. 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 afiect 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.
    [Show full text]
  • Sedimentology of the Sundance Formation, Northern Wyoming David Mason Uhlir Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1987 Sedimentology of the Sundance Formation, northern Wyoming David Mason Uhlir Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Geology Commons Recommended Citation Uhlir, David Mason, "Sedimentology of the Sundance Formation, northern Wyoming " (1987). Retrospective Theses and Dissertations. 11654. https://lib.dr.iastate.edu/rtd/11654 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS While the most advanced technology has been used to photograph and reproduce this manuscript, the quality of the reproduction is heavily dependent upon the quality of the material submitted. For example: • Manuscript pages may have indistinct print. In such cases, the best available copy has been filmed. • Manuscripts may not always be complete. In such cases, a note will indicate that it is not possible to obtain missing pages. • Copyrighted material may have been removed from the manuscript. In such cases, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, and charts) are photographed by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each oversize page is also filmed as one exposure and is available, for an additional charge, as a standard 35mm slide or as a 17"x 23" black and white photographic print.
    [Show full text]
  • The Geology of Sheep Canyon Quadrangle: Wyoming Robert Edward Ladd Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1979 The geology of Sheep Canyon Quadrangle: Wyoming Robert Edward Ladd Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Geology Commons Recommended Citation Ladd, Robert Edward, "The eg ology of Sheep Canyon Quadrangle: Wyoming" (1979). Retrospective Theses and Dissertations. 16864. https://lib.dr.iastate.edu/rtd/16864 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. The geology of Sheep Canyon Quadrangle: Wyoming by Robert Edward Ladd A Thesis Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of MASTER OF SCIENCE Department: Earth Sciences Hajor: Geology Signatures have been redacted for privacy Iowa State University Ames, Iowa 1979 ii TABLE OF CONTENTS Page INTRODUCTION 1 Methods of Study 1 Physiography and Location 2 Previous Work 6 MAP CORRELATION BETWEEN SHEEP CANYON AND GREYBULL NORTH QUADRANGLES 10 GEOLOGIC SETTING 15 STRATIGRAPHY 21 Mississippian. 24 Madison Formation 24 Mississippian-Pennsylvanian 26 Amsden Formation 26 Pennsylvanian 30 Tensleep Formation 30 Permian 32 Phosphoria Formation 32 Triassic 35 Dinwoody Formation
    [Show full text]
  • Asteroid Fossils from the Upper Jurassic of South-Central Montana
    Asteroid Fossils from the Upper Jurassic of South-Central Montana MBMG Open-File Report 660 Jay A. Gunderson Cover image: Photo of sea star by Jay Gunderson, MBMG Contents Abstract ...................................................................................................................................................... 1 Introduction ................................................................................................................................................ 1 Occurrence ................................................................................................................................................. 1 Discussion ................................................................................................................................................... 2 Acknowledgments ...................................................................................................................................... 7 References .................................................................................................................................................. 7 Figures Fig. 1 Location map ...................................................................................................................................iv Fig. 2. Sea star fossils occur along a single bedding plane of the Swift Formation .................................... 3 Fig. 3. Site 1 bedding face showing locations of individual sea star specimens within fractured coquinoid sandstone .....................................................................................................................
    [Show full text]
  • The Mesozoic
    MESOZOIC ERA Triassic Period 1. Sonoma Orogeny* latest Permian-Early Triassic • complete closure of back-arc basin between Klamath island arc & N. Amer. craton accreted terrance; considerable growth of western margin • deepwater deposits thrust eastward over shallow water carbonates Golgonda Thrust (Nevada) *change in style of Cordilleran tectonics: Paleozoic: "Japan-type" margin subduction zone complex - island arc - back-arc basin Mesozoic-Cenozoic: "Andean type" margin subduction zone complex - forearc basin - magmatic arc - foreland basin 2. Arid/semi-arid climate continues in western N. America • widespread reddish-colored continental deposits sandstones & shales; fluvial, alluvial plain, lacustrine, aeolian • shallow marine deposits restricted to narrow foreland basin 3. low global sea level during Triassic 4. break-up of Pangea began during Triassic • rifting propagated westward first split s. Europe & n. Africa: Tethys Sea • by Late Triassic, discontinuous series of grabens on each side of the future N. Atlantic • rift basins: thick sequences of red clastics, intruded by basalt dikes & sills, also extrusive lava flows alluvial fan, alluvial plain, fluvial, flood plain, lacustrine • some rift basins hooked-up: = proto-North Atlantic ocean basin • others = "failed rifts" Hartford/Deerfield Basins, Newark Basin • basins subsided, periodically invaded by Tethys Sea; thick salts accumulated in proto-N. Atlantic MARINE ENVIRONMENTS "Modern Fauna" replaces "Paleozoic Fauna" • adaptive radiation of bivalve molluscs ecologic replacement
    [Show full text]
  • Vertebrate Paleontology of Montana
    VERTEBRATE PALEONTOLOGY OF MONTANA John R. Horner1 and Dale A. Hanson2 1Chapman University, Orange, California; Montana State University, Bozeman, Montana 2South Dakota School of Mines & Technology, Rapid City, South Dakota (1) INTRODUCTION derived concerning the evolution, behavior, and paleo- Montana is renowned for its rich paleontological ecology of vertebrate fossil taxa from Montana. treasures, particularly those of vertebrate animals All Paleozoic vertebrates from Montana come such as fi shes, dinosaurs, and mammals. For exam- from marine sediments, whereas the Mesozoic as- ple, the most speciose fi sh fauna in the world comes semblages are derived from transgressive–regressive from Fergus County. The fi rst dinosaur remains noted alternating marine and freshwater deposits, and the from the western hemisphere came from an area near Cenozoic faunas are derived strictly from freshwater the mouth of the Judith River in what would become terrestrial environments. Fergus County. The fi rst Tyrannosaurus rex skeleton, (2) PALEOZOIC VERTEBRATES and many more since, have come from Garfi eld and McCone Counties. The fi rst dinosaur recognized to Two vertebrate assemblages are known from the show the relationship between dinosaurs and birds Paleozoic, one of Early Devonian age, and the other of came from Carbon County, and the fi rst dinosaur eggs, Late Mississippian age. embryos, and nests revealing dinosaur social behav- a. Early Devonian (Emsian: 407–397 Ma) iors were found in Teton County. The fi rst dinosaur Beartooth Butte Formation confi rmed to have denned in burrows was found in The oldest vertebrate remains found in Montana Beaverhead County. come from the Beartooth Butte Formation exposed Although Montana is not often thought of for in the Big Belt and Big Snowy Mountains of central mammal fossils, a great diversity of late Mesozoic Montana.
    [Show full text]
  • Geology of Glendo State Park
    For more information visit: INTRODUCTION Glendo State Park is the home of Glendo Reservoir, located along the North Platte River. wyoparks.state.wy.us/index.php/places-to-go/ The geology exposed around the park—representing more than 300 million years of Earth glendo history—is largely visible because the North Platte River cut a canyon through this region, leaving the landscape seen today. These rock exposures allow a better understanding of the geologic history of the region, telling a story of inland flooding, dinosaurs, mountain building, and volcanism. Wyoming State GEOLOGIC HISTORY The oldest rocks exposed in Glendo State Park, along the northwestern edge of the Geological Survey reservoir, are the gray to white limestones and red silty sandstones of the Hartville Formation. These Pennsylvanian- and Permian-age beds were deposited about 300 million P.O. Box 1347 years ago in a shallow subtropical ocean that once covered the region. The Hartville Laramie, WY 82073-1347 Formation also makes up the cliffs above the reservoir at nearby Guernsey State Park. www.wsgs.wyo.gov As this ancient ocean retreated, a broad, flat coastal plain developed. It was in this setting phone: (307) 766-2286 that the middle Permian to Lower Triassic Goose Egg (~250 million years old) and the email: [email protected] Triassic Chugwater (~230 million years old) formations were deposited. The Goose Egg Formation contains interbedded rusty-red shales, limestones, and evaporites (mineral deposits left after water evaporates). The Chugwater Formation is made up of red shales, siltstones, and thin evaporite beds. The distinctive red-colored beds found in both formations are the result of oxidation (rusting) of naturally occurring iron in the rock.
    [Show full text]
  • Lower Ellis Group (M. Jurassic), Wyoming and Montana, U.S.A
    Sedimentary Geology 177 (2005) 175–194 www.elsevier.com/locate/sedgeo Mixed sediment deposition in a retro-arc foreland basin: Lower Ellis Group (M. Jurassic), Wyoming and Montana, U.S.A. William C. ParcellT, Monica K. Williams Department of Geology, Wichita State University, 1845 Fairmount, Box 27, Wichita, KS 67260-0027, USA Received 28 January 2004; received in revised form 17 January 2005; accepted 25 February 2005 Abstract The blowerQ Ellis Group (M. Jurassic) of northern Wyoming and southern Montana affords an excellent opportunity to examine the influence of tectonics, sea-level change, and incipient topography on facies dynamics and the evolution of mixed sediment ramp deposits. The Sawtooth, Piper, and Gypsum Spring formations (Bajocian to Callovian) represent sedimentation along the forebulge of a retro-arc foreland basin. The blowerQ Ellis Group records deposition during two transgressive– regressive cycles, (1) a Bajocian-age cycle dominated by evaporites and red shales, and (2) a Bathonian-age cycle characterized by carbonates, evaporites, and red shales. These cycles are capped by a Callovian-age cycle distinguished by carbonates and red shales that is represented by the blowerQ Sundance and Rierdon Formations. Transgressive episodes favored intensified chemical sediment production resulting in thick units deposited in subtidal to peritidal environments. Regressive periods are characterized by supratidal redbed progradation and subsequent shallowing–upward cycles. The depositional cycles in the lower Ellis Group developed due the interplay between sea-level change and tectonic subsidence related to the evolution of a retro-arc foreland basin. Differential subsidence before, during, and after deposition created paleohighs that locally influenced accommodation space and, thereby, complicated depositional and erosional patterns.
    [Show full text]
  • Oxygen Isotopic Analysis of Belemnites: Implications for Water Temperature and Life Habits in the Jurassic Sundance Sea
    Oxygen Isotopic Analysis of Belemnites: Implications for Water Temperature and Life Habits in the Jurassic Sundance Sea By Amanda Adams A thesis submitted in partial fulfillment of the requirements of the degree of Bachelor of Arts (Geology) at Gustavus Adolphus College 2013 Oxygen Isotopic Analysis of Belemnites: Implications for Water Temperature and Life Habits in the Jurassic Sundance Sea By Amanda Adams Under the supervision of Dr. Julie Bartley ABSTRACT Stretching across much of the west-central United States, the Jurassic-aged (164 Ma) Sundance Formation is all that remains of the largest continental seaway in the past 250 million years. Despite its wide extent and excellent exposure, little is known about the temperature or chemistry of this ancient inland sea, making it an ideal choice for studying the geochemistry of the now dry sea. The Sundance Formation preserves a diverse array of well-preserved marine fossils, including belemnites, an extinct relative of today’s squid. Analysis of oxygen isotopic composition of belemnites permits calculation of paleotemperatures for this seaway. In this study, subsamples of 36 well-preserved adult belemnites yielded average paleotemperatures of 13-17˚C for the Sundance Seaway. Comparisons between adult and juvenile belemnites also suggest that these cephalopods occupied distinct habitats during different life stages. 2 ACKNOWLEDGEMENTS I would like to thank my advisor Dr. Julie Bartley as well as Dr. Laura Triplett and Dr. Jim Welsh of the Geology department at Gustavus Adolphus College for their encouragement and guidance. I would also like to thank Bill Wahl (Wyoming Dinosaur Center) for his help in formulating ideas as well as sample collection.
    [Show full text]