DOCSLIB.ORG

Bulletin of the Geological Society of America Vol. 71. Pp. 1729-1754, 7 Figs. December 1960 Bermuda: a Partially Drowned, Late M

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Bulletin of the Geological Society of America Vol. 71. Pp. 1729-1754, 7 Figs. December 1960 Bermuda: a Partially Drowned, Late M BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 71. PP. 1729-1754, 7 FIGS. DECEMBER 1960 BERMUDA: A PARTIALLY DROWNED, LATE MATURE, PLEISTOCENE KARST BY J HARLEN BRETZ ABSTRACT During Pleistocene time, the Bermuda Islands repeatedly underwent partial inundation and re-emergence. The land areas were continuously attacked and reduced by rain and ground water but repeatedly renewed, during times of submergence, by deposition of marine limestone and by contemporaneous additions of shore-born and wind-transported carbonate sand, now eolianite. Soils formed under subaerial conditions are now buried be- neath later deposits and constitute important stratigraphic markers. The igneous founda- tion rock appears to have been exposed during some low marine stands, and the former shore lines seem to be recorded by submerged terraces. The major karst features are largely below sea level, and they must date from times of continental glaciations. Previous writers have assigned eolian accumulation to times of Pleistocene low sea level and soil-making to times of interglacial high sea. Both conclusions are held to be er- roneous. CONTENTS TEXT Figure Page Page Navy and Air Force modifications of the Introduction 1729 shore line 1730 Acknowledgments 1732 2. Bermuda Islands with the adjacent Dunes and eolianites 1732 banks 1733 Paleosols 1736 3. Diagram of section at Whalebone Bay, Ber- Caves 1741 muda Islands 1735 Origin of the interior basins 1744 4. Diagram to show contrast in soil record on Correlation of soil-making and dune-building uplands and lowlands, Bermuda with Pleistocene eustatism 1746 Islands 1736 Conclusion 1752 5. Diagram of Shore Hills type section, References cited 1754 Bermuda Islands 1737 6. Diagram of section north of Biological Sta- ILLUSTRATIONS tion, Bermuda Islands 1740 Figure Page 7. Diagram of section in Black Watch Pass, 1. Outline map of the Bermuda Islands before Bermuda Islands 1749 INTRODUCTION pletely submerged in the cavern-contained salt water. The curvilinear fingers constituting the Figure 1 suggests that reefs may enclose the Bermuda Islands enclose or nearly enclose larger tidewater-filled areas; however the almost 60 square miles of sounds, reaches, geological evidence indicates (1) that Bermuda harbors, and bays, approximately three times of today is only a skeleton of a once-continuous the total land area. Bermuda's land rock is carbonate land area, (2) that evisceration on a nearly 100 per cent calcium carbonate and so remarkable scale by rain and circulating ground permeable that the surface of every land-locked water has occurred, and (3) that during epochs swamp and pond is at sea level, and the con- of growth interrupting the solutional attack, tained water is salt or brackish. There is no the coastal margins of the island tract have running water except in gutters and on con- been built up. creted catchment areas, and almost no fresh Most of Bermuda's above-tide rock is calcium ground water. Ten enterable caves have sea- carbonate eolian sand, sufficiently indurated to water pools (maximum depth 80 feet) whose serve as building stone and to constitute the levels vary with the tide. Large, apparently sea cliffs which dominate the shore lines. Rows unaltered stalagmites and stalactites are com- of hills of this eolianite characterize all the 1729 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/71/12/1729/3441833/i0016-7606-71-12-1729.pdf by guest on 25 September 2021 1730 J H. BRETZ—BERMUDA, A PLEISTOCENE KARST 'rape Bay 'Elbow Bay FIGURE 1.—OUTLINE MAP OF THE BERMUDA ISLANDS BEFORE large islands of the group and consistently Solutional reduction occurred uninterrup- parallel the coasts. Dune forms still survive tedly as the land area increased from Pleisto- among the younger hills, although somewhat cene eustatic lowering of sea level and as the reduced by rainwater solution. Calcium carbon- coastal regions thus were shifted into presently ate, carried down into the dune sand, has submerged areas. It was during such times of caused the induration. prominent emergence that the soils formed Despite the widespread cementation, the terra rossa regoliths which, because of later high indurated eolianite contains many pockety sea level, were buried under eolian accumula- masses of friable, even loose, sand which have tions to constitute the conspicuous red paleo- been protected from downward-infiltrating sols. The paleosols thus largely record con- calcium carbonate by densified overlying tinental glaciation, whereas the eolianites material that appears originally to have been a record interglacial high sea levels. surface crust, although now deeply buried. The solutional caves of Bermuda, products of Prompt cementation at the very surface of former ground water and now partially drowned an accumulating body of eolian sand is further in sea water, date from times of widespread evidenced by palmetto-leaf impressions in lee- emergence, as do the huge solutional depressions slope dune bedding. Also the lack of blow-out presently flooded to constitute most of the concavities is evidence that local anchoring by sounds, harbors, bays, and reaches of the little dune vegetation did not give rise to associated archipelago. Cavern collapse accompanying local erosional concavities on windward slopes solutional reduction of these areas, plus and further supports the argument for prompt marginal eolian upbuilding, explains the nearly cementation of Bermuda dune sand. or quite enclosed marine water bodies. The Bermuda dunes are coastal dunes which Differentiation of the stratigraphic elements did not migrate from their feeding grounds, the of Bermuda has been based on paleosols, shore lines. Therefore eolian accretion as disconformities with basal conglomerates, recorded on the present islands occurred only at mineral content, topography, and invertebrate times of high sea level. fossils. No one criterion ranges through the Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/71/12/1729/3441833/i0016-7606-71-12-1729.pdf by guest on 25 September 2021 INTRODUCTION 1731 ISLAND NAVY AND AIR FORCE MODIFICATIONS OP THE SHORE LINE entire column, and that "column" is about as H. A. Lowenstam and I, who worked together far from a conventional "layer cake" succession in the area, are unable to accept Sayles' forma- as are Pleistocene sections in the northern tional ranking of the three uppermost eolianites United States. separated by two accretionary soils. We accept Sayles (1931) has made the outstanding only the Harrington as a record of an interval contribution to Bermuda's geological history of soil-making under conditions of repeated, to date. Sayles' stratigraphy contained four but minor, carbonate-sand contributions.1 eolianites separated from each other by three Both physically and chemically, accretionary soils and from an underlying marine limestone and residual soils are very different products of by a fourth soil. Beneath this limestone was a subaerial exposure. Accretionary soils in section fifth soil, then another marine limestone, and are simply iron- and/or carbon-stained short below that a fifth eolianite. Some of the names linear portions of an eolian carbonate sand and he used were redefined from earlier authors, commonly contain more land-snail shells than most of them were new. The list is as follows: does contiguous unstained eolianite. They record limited vegetated tracts in protected Present soil places which received occasional additions of Southampton eolianite wind-blown sand. Residual soils2 are deep-red McGall's soil (accretionary) Somerset eolianite 1 Lowenstam has stated orally, without specific Signal Hill soil (accretionary) details, that in 1957 he found a marine member Warwick eolianite above Pembroke eolianite and beneath a St. St. George's soil (residual) George's soil in Spencer's Point cliff. This item will Pembroke eolianite be commented on later. 2 Because they contain small quantities of calcium Harrington soil (accretionary) carbonate blown in during soil development and Devonshire marine limestone also a small fraction of material not derived from Shore Hills soil (residual) limestone, they are not wholly a residuum of Belmont marine limestone weathering. R. V. Ruhe prefers not to use the term Walsingham eolianite "residual" for them. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/71/12/1729/3441833/i0016-7606-71-12-1729.pdf by guest on 25 September 2021 1732 J H. BRETZ—BERMUDA, A PLEISTOCENE KARST to chocolate-brown clays and loams with no that summer on such problems. R. V. Ruhe snail shells and little lime other than "rootlets" was persuaded to give a few weeks in 1957 to a made by later infiltrations. They commonly study of Bermuda's pedologic problems which rest on a surface of solution-made pinnacles and Lowenstam and Bretz were not competent to pockets (soil lapies) whose relief may be several handle. Funds for Lowenstam's work were feet. provided by the California Institute of Tech- The Bermuda Islands constitute less than 10 nology; Bretz had a National Science Founda- per cent of the carbonate-covered summit of a tion grant; Ruhe had a grant from the Penrose truncated volcanic cone whose rock has been Bequest of The Geological Society of America. reached in several drill holes. This calcareous Rune's pedologic study of Bermuda's paleosols platform is highest along its southeastern was done in collaboration with his colleagues margin where it is rudely outlined by the J. G. Cady and R. S. Gomez of the Soil Survey islands. The northern margin of the elliptical Laboratory, Soil Conservation Service. Ruhe's platform has but one tiny land mass, North manuscript is being prepared for publication. Rock (Fig. 2). Lowenstam's contributions on stratigraphy, Today, the submerged platform is a great paleontology, and submarine topography should shoal or lagoon nowhere more than 60 feet deep see publication before long. and averaging much less. During glacial times, it undoubtedly became emergent, just as DUNES AND EOLIANITES undoubtedly the marine limestones, now as Sayles' happy invention of the term "eoli- high as 100 feet A.
Load more

Recommended publications
  • Locational Factors Determining the Distribution of Nesting Sites for A
    Edith Cowan University Research Online Theses : Honours Theses 1998 Locational factors determining the distribution of nesting sites for a colony of wedge-tailed shearwaters, puffinus pacificus, onest W Wallabi Island, Houtman Abrolhos, Western Australia Julie Davis Edith Cowan University Follow this and additional works at: https://ro.ecu.edu.au/theses_hons Part of the Ecology and Evolutionary Biology Commons, and the Ornithology Commons Recommended Citation Davis, J. (1998). Locational factors determining the distribution of nesting sites for a colony of wedge- tailed shearwaters, puffinus pacificus, onest W Wallabi Island, Houtman Abrolhos, Western Australia. https://ro.ecu.edu.au/theses_hons/473 This Thesis is posted at Research Online. https://ro.ecu.edu.au/theses_hons/473 Edith Cowan University Copyright Warning You may print or download ONE copy of this document for the purpose of your own research or study. The University does not authorize you to copy, communicate or otherwise make available electronically to any other person any copyright material contained on this site. You are reminded of the following: Copyright owners are entitled to take legal action against persons who infringe their copyright. A reproduction of material that is protected by copyright may be a copyright infringement. Where the reproduction of such material is done without attribution of authorship, with false attribution of authorship or the authorship is treated in a derogatory manner, this may be a breach of the author’s moral rights contained in Part IX of the Copyright Act 1968 (Cth). Courts have the power to impose a wide range of civil and criminal sanctions for infringement of copyright, infringement of moral rights and other offences under the Copyright Act 1968 (Cth).
    [Show full text]
  • The Origin and Paleoclimatic Significance of Carbonate Sand Dunes Deposited on the California Channel Islands During the Last Glacial Period
    Pages 3–14 in Damiani, C.C. and D.K. Garcelon (eds.). 2009. Proceedings of 3 the 7th California Islands Symposium. Institute for Wildlife Studies, Arcata, CA. THE ORIGIN AND PALEOCLIMATIC SIGNIFICANCE OF CARBONATE SAND DUNES DEPOSITED ON THE CALIFORNIA CHANNEL ISLANDS DURING THE LAST GLACIAL PERIOD DANIEL R. MUHS,1 GARY SKIPP,1 R. RANDALL SCHUMANN,1 DONALD L. JOHNSON,2 JOHN P. MCGEEHIN,3 JOSSH BEANN,1 JOSHUA FREEMAN,1 TIMOTHY A. PEARCE,4 1 AND ZACHARY MUHS ROWLAND 1U.S. Geological Survey, MS 980, Box 25046, Federal Center, Denver, CO 80225; [email protected] 2Department of Geography, University of Illinois, Urbana, IL 61801 3U.S. Geological Survey, MS 926A, National Center, Reston, VA 20192 4Section of Mollusks, Carnegie Museum of Natural History, 4400 Forbes Ave., Pittsburgh, PA 15213 Abstract—Most coastal sand dunes, including those on mainland California, have a mineralogy dominated by silicates (quartz and feldspar), delivered to beach sources from rivers. However, carbonate minerals (aragonite and calcite) from marine invertebrates dominate dunes on many tropical and subtropical islands. The Channel Islands of California are the northernmost localities in North America where carbonate-rich coastal dunes occur. Unlike the mainland, a lack of major river inputs of silicates to the island shelves and beaches keeps the carbonate mineral content high. The resulting distinctive white dunes are extensive on San Miguel, Santa Rosa, San Nicolas, and San Clemente islands. Beaches have limited extent on all four of these islands at present, and some dunes abut rocky shores with no sand sources at all. Thus, the origin of many of the dunes is related to the lowering of sea level to ~120 m below present during the last glacial period (~25,000 to 10,000 years ago), when broad insular shelves were subaerially exposed.
    [Show full text]
  • Holocene Growth History of a Reef Complex on a Cool-Water Carbonate Margin: Easter Group of the Houtman Abrolhos, Eastern Indian Ocean
    Marine Geology, 115 (1993) 29-46 29 Elsevier Science Publishers B.V., Amsterdam Holocene growth history of a reef complex on a cool-water carbonate margin: Easter Group of the Houtman Abrolhos, Eastern Indian Ocean L.B. Collins a, Z.R. Zhu a, K.-H. Wyrwoll b, B.G. Hatcher c, P.E. Playford d, A. Eisenhauer e'l , J.H. Chen e, G.J. Wasserburg e and G. Bonani f aSchool of Applied Geology, Curtin University of Technology, Perth, WA 6102, Australia bUniversity of Western Australia, Nedlands, WA 6009, Australia CDepartment of Oceanography, Dalhousie University, Halifax, N.S. B3H 4Jl, Canada dGeological Survey of Western Australia, East Perth, WA 6004, Australia eDivision of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA f lnstitut fiir Mittelenergiephysik der ETH Ziirich, ETH-Hoenggerberg, CH-8093 Zurich, Switzerland (Received March 5, 1993; revision accepted August 18, 1993) ABSTRACT Collins, L.B., Zhu, Z.R., Wyrwoll, K.-H., Hatcher, B.G., Playford, P.E., Eisenhauer, A., Chen, J.H., Wasserburg, G.J. and Bonani, G., 1993. Holocene growth history of a reef complex on a cool-water carbonate margin: Easter Group of the Houtman Abrolhos, Eastern Indian Ocean. Mar. Geol., 115: 29-46. The Houtman Abrolhos reefs, situated on the western continental margin of Australia, occupy a transitional position between cool-water shelf carbonate sediments to the south and more tropical environments to the north. Their existence at the outer limits of the geographical range for coral reef growth is a result of the warm, poleward-flowing Leeuwin Current. Though the modern reefs differ ecologically from tropical reefs, their geological characteristics have been little known until recently.
    [Show full text]
  • Aeolianite, Calcrete/Microbialite and Karst in Southwestern Australia As Indicators of Middle to Late Quaternary Palaeoclimates
    Palaeogeography, Palaeoclimatology, Palaeoecology 470 (2017) 11–29 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Aeolianite, calcrete/microbialite and karst in southwestern Australia as indicators of Middle to Late Quaternary palaeoclimates Matej Lipar a,⁎,JohnA.Webba, Matthew L. Cupper b,NingshengWangc a Environmental Geoscience, Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Bundoora, Victoria, 3086, Australia b School of Earth Sciences, The University of Melbourne, Melbourne, Victoria 3010, Australia c School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington 6140, New Zealand article info abstract Article history: The mid-Late Pleistocene and Holocene aeolianites of the Tamala Limestone on the northern Swan Coastal Plain Received 25 September 2016 in southwestern Western Australia consist of six members that show cyclic deposition of coastal aeolianite, over- Received in revised form 15 December 2016 lain by calcrete/microbialite, karstified surface and palaeosol. Field work, combined with mineralogical, chemical, Accepted 16 December 2016 stable isotope analysis and uranium-thorium (U/Th) and optically stimulated luminescence (OSL) dating, pro- Available online 10 January 2017 vides an insight into the repetitive glacial and interglacial climatic periods over the past 500 kyr. Deposition of the carbonate aeolianites occurred during interglacial episodes (marine isotope stage (MIS) 1, 5, 7, 9, 11, and pos- Keywords: fl Tamala limestone sibly 13), due to migration of coastal dunes under the in uence of strong southerly to southwesterly winds. Rain- Pleistocene fall was insufficient to support vegetation cover on the dunes, and so was probably limited or seasonal. The Holocene transition from interglacial to glacial climates was characterised by higher effective rainfall, accompanied by Calcarenite aeolianite dissolution and karstification.
    [Show full text]
  • Paleontology of the Bears Ears National Monument
    Paleontology of Bears Ears National Monument (Utah, USA): history of exploration, study, and designation 1,2 3 4 5 Jessica Uglesich ,​ Robert J. Gay *,​ M. Allison Stegner ,​ Adam K. Huttenlocker ,​ Randall B. ​ ​ ​ ​ Irmis6 ​ 1 Friends​ of Cedar Mesa, Bluff, Utah 84512 U.S.A. 2 University​ of Texas at San Antonio, Department of Geosciences, San Antonio, Texas 78249 U.S.A. 3 Colorado​ Canyons Association, Grand Junction, Colorado 81501 U.S.A. 4 Department​ of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, 53706 U.S.A. 5 University​ of Southern California, Los Angeles, California 90007 U.S.A. 6 Natural​ History Museum of Utah and Department of Geology & Geophysics, University of Utah, 301 Wakara Way, Salt Lake City, Utah 84108-1214 U.S.A. *Corresponding author: [email protected] or [email protected] ​ ​ ​ Submitted September 2018 PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.3442v2 | CC BY 4.0 Open Access | rec: 23 Sep 2018, publ: 23 Sep 2018 ABSTRACT Bears Ears National Monument (BENM) is a new, landscape-scale national monument jointly administered by the Bureau of Land Management and the Forest Service in southeastern Utah as part of the National Conservation Lands system. As initially designated in 2016, BENM encompassed 1.3 million acres of land with exceptionally fossiliferous rock units. Subsequently, in December 2017, presidential action reduced BENM to two smaller management units (Indian Creek and Shash Jáá). Although the paleontological resources of BENM are extensive and abundant, they have historically been under-studied. Here, we summarize prior paleontological work within the original BENM boundaries in order to provide a complete picture of the paleontological resources, and synthesize the data which were used to support paleontological resource protection.
    [Show full text]
  • Stratigraphy and Timing of Eolianite Deposition on Rottnest Island, Western Australia
    Available online at www.sciencedirect.com R Quaternary Research 60 (2003) 211–222 www.elsevier.com/locate/yqres Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia Paul J. Hearty School of Earth Sciences, James Cook University, Townsville, Queensland, 4811 Australia Received 7 May 2002 Abstract Over 100 whole-rock amino acid racemization (AAR) ratios from outcrops around Rottnest Island (32.0° S Latitude near Perth) indicate distinct pulses of eolian deposition during the late Quaternary. Whole-rock D-alloisoleucine/L-isoleucine (A/I) ratios from bioclastic carbonate deposits fall into three distinct modal classes or “aminozones.” The oldest, Aminozone E, averages 0.33 Ϯ 0.04 (n ϭ 21). Red palaeosol and thick calcrete generally cap the Aminozone E deposits. A younger Aminozone C averages 0.22 Ϯ 0.03 (n ϭ 63); comprising two submodes at 0.26 Ϯ 0.01 (n ϭ 14) and 0.21 Ϯ 0.02 (n ϭ 49). Multiple dune sets of this interval are interrupted by relatively weak, brown to tan “protosols.” A dense, dark brown rendzina palaeosol caps the Aminozone C succession. Ratios from Holocene dune and marine deposits (“Aminozone A”) center on 0.11 Ϯ 0.02 (n ϭ 15), comprising submodes of 0.13 Ϯ 0.01 (9) and 0.09 Ϯ 0.01 (6). Calibration of A/I averages from Aminozones E and A are provided by U/Th and 14C radiometric ages of 125,000 yr (marine oxygen isotope stage (MIS) 5e and 2000–6000 14C yr B.P. (MIS 1), respectively. The whole-rock A/I results support periodic deposition initiated during MIS 5e, continuing through MIS 5c, and then peaking at the end of MIS 5a, about 70,000–80,000 yr ago.
    [Show full text]
  • Origin of Bermuda's Clay-Rich Quaternary Paleosols and Their Paleoclimatic Significance
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USGS Staff -- Published Research US Geological Survey 1996 Origin of Bermuda's clay-rich Quaternary paleosols and their paleoclimatic significance Stanley R. Herwitz Clark University Daniel R. Muhs U.S. Geological Survey, [email protected] Joseph M. Prospero University of Miami Shannon Mahan U.S. Geological Survey Bruce Vaughn U.S. Geological Survey Follow this and additional works at: https://digitalcommons.unl.edu/usgsstaffpub Part of the Earth Sciences Commons Herwitz, Stanley R.; Muhs, Daniel R.; Prospero, Joseph M.; Mahan, Shannon; and Vaughn, Bruce, "Origin of Bermuda's clay-rich Quaternary paleosols and their paleoclimatic significance" (1996). USGS Staff -- Published Research. 165. https://digitalcommons.unl.edu/usgsstaffpub/165 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- Published Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 101, NO. D18, PAGES 23,389-23,400, OCTOBER 27, 1996 Origin of Bermuda's clay-rich Quaternary paleosols and their paleoclimatic significance StanleyR. Herwitz,1 Daniel R. Muhs,2 JosephM. Prospero,3 ShannonMahan, 2 and Bruce Vaughn2 Abstract. Red clayeypaleosols that are chieflythe productof aerosolicdust deposition are interbeddedin the Quaternarycarbonate formations of the Bermuda oceanicisland system.These paleosolsprovide a basisfor reconstructingQuaternary atmospheric circulationpatterns in the northwesternAtlantic. Geochemicalanalyses were performed on representativepaleosol samples to identify their parent dust source.Fine-grained fractionswere analyzedby energy-dispersiveX ray fluorescenceto determine trace element (Zr, Y, La, Ti, and Nb) concentrationsand to derive geochemicalsignatures basedon immobile element ratios.
    [Show full text]
  • Last Interglacial Sea-Level Proxies in East Africa and the Western Indian Ocean
    Earth Syst. Sci. Data, 13, 1633–1651, 2021 https://doi.org/10.5194/essd-13-1633-2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Last interglacial sea-level proxies in East Africa and the Western Indian Ocean Patrick Boyden1, Jennifer Weil-Accardo2, Pierre Deschamps2, Davide Oppo3, and Alessio Rovere1 1MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany 2CEREGE, Aix-Marseille Université, CNRS, IRD, Collège de France, Aix-en-Provence, France 3Sedimentary Basins Research Group, School of Geosciences, University of Louisiana at Lafayette, Lafayette, Louisiana, USA Correspondence: Patrick Boyden ([email protected]) Received: 17 November 2020 – Discussion started: 23 November 2020 Revised: 4 March 2021 – Accepted: 12 March 2021 – Published: 20 April 2021 Abstract. In this paper, we describe a sea-level database compiled using published last interglacial, Marine Iso- topic Stage 5 (MIS 5), geological sea-level proxies within East Africa and the Western Indian Ocean (EAWIO). Encompassing vast tropical coastlines and coralline islands, this region has many occurrences of well-preserved last interglacial stratigraphies. Most notably, islands almost entirely composed of Pleistocene reefs (such as Aldabra, the Seychelles) have provided reliable paleo relative sea-level indicators and well-preserved samples for U-series chronology. Other sea-level proxies include uplifted marine terraces in the north of Somalia and Pleistocene eolian deposits notched by the MIS 5 sea level in Mozambique to tidal notches in luminescence- limited eolian deposits in Mozambique. Our database has been compiled using the World Atlas of Last Inter- glacial Shorelines (WALIS) interface and contains 58 sea-level indicators and 2 terrestrial-limiting data points.
    [Show full text]
  • Introduction to Major Environments and Their Deposits, Great Bahama Bank
    Introduction to Major Environments and Their Deposits, Great Bahama Bank Guide to the 2001 Field Workshop in the Bahamas and South Florida, sponsored by the International Association of Sedimentologists and the Ocean Research and Education Foundation Robert N. Ginsburg and Guido L. Bracco Gartner (editors) With contributions by Layaan Al Kharusi Kelly Bergman Matt Buoniconti Christophe Dupraz Kathryn Lamb Tiina Manne Chris Moses Brad Rosenheim Amel Saeid Marie-Eve Scherer Brigitte Vlaswinkel September 2001 Division of Marine Geology and Geophysics Rosenstiel School of Marine and Atmospheric Science 4600 Rickenbacker Cswy Miami, FL 33149 ‘Mud, mud, glorious mud Nothing quite like it for cooling the blood So follow me follow, down to the hollow And there let me wallow in glorious mud’ -Flanders & Swann, 'At the drop of a hat', 1958 Table of Contents Preface _______________________________________________________________ 3 1. The geological history and proposed origin of the Bahamas___________________ 4 1.1. Why the Bahamas? ______________________________________________________ 4 1.2. Physiography ___________________________________________________________ 4 1.3. Origin of the Bahamas____________________________________________________ 5 1.4. Stratigraphy ____________________________________________________________ 7 2. Bank top morphology, surface sediments, and physical processes in the Bahamas 11 2.1. Introduction ___________________________________________________________ 12 2.2. The platform top _______________________________________________________
    [Show full text]
  • Pleistocene), the Bahamas
    PLOS ONE RESEARCH ARTICLE First known trace fossil of a nesting iguana (Pleistocene), The Bahamas 1 2 3 4 Anthony J. MartinID *, Dorothy Stearns , Meredith J. Whitten , Melissa M. Hage , 1,5 5 Michael Page , Arya BasuID 1 Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America, 2 School of Medicine, University of Colorado, Aurora, Colorado, United States of America, 3 North Carolina Division of Marine Fisheries, Morehead City, North Carolina, United States of America, 4 Department of Environmental Sciences, Oxford College of Emory University, Oxford, Georgia, United States of America, a1111111111 5 Center for Digital Scholarship, Emory University, Atlanta, Georgia, United States of America a1111111111 * [email protected] a1111111111 a1111111111 a1111111111 Abstract Most species of modern iguanas (Iguania, Iguanidae) dig burrows for dwelling and nesting, yet neither type of burrow has been interpreted as trace fossils in the geologic record. Here OPEN ACCESS we describe and diagnose the first known fossil example of an iguana nesting burrow, pre- Citation: Martin AJ, Stearns D, Whitten MJ, Hage served in the Grotto Beach Formation (Early Late Pleistocene, ~115 kya) on San Salvador MM, Page M, Basu A (2020) First known trace Island, The Bahamas. The trace fossil, located directly below a protosol, is exposed in a ver- fossil of a nesting iguana (Pleistocene), The tical section of a cross-bedded oolitic eolianite. Abundant root traces, a probable land-crab Bahamas. PLoS ONE 15(12): e0242935. https:// doi.org/10.1371/journal.pone.0242935 burrow, and lack of ghost-crab burrows further indicate a vegetated inland dune as the paleoenvironmental setting.
    [Show full text]
  • Pleistocene Aeolianites at Cape Spencer, South Australia; Record of a Vanished Inner Neritic Cool- Water Carbonate Factory
    Received Date: 18-Dec-2014 Revised Date: 31-Mar-2015 Accepted Date: 15-May-2015 Article Type: Original Manuscript Pleistocene aeolianites at Cape Spencer, South Australia; record of a vanished inner neritic cool- water carbonate factory NOEL P JAMES* and YVONNE BONE† *Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada (E-mail: [email protected]) †School of Earth and Environmental Sciences, Geology, University of Adelaide, Adelaide, South Australia 5005, Australia Associate Editor – Giovanna Della Porta Short Title – Aeolianites record cool-water marine carbonate factory This is an Accepted Article that has been peer-reviewed and approved for publication in the Sedimentology, but has yet to undergo copy-editing and proof correction. Please cite this article as an “Accepted Article”; doi: 10.1111/sed.12216 ABSTRACT Aeolianites are integral components of many modern and ancient carbonate depositional systems. Southern Australia contains some of the most impressive and extensive late Cenozoic aeolianites in the modern world. Pleistocene aeolianites on Yorke Peninsula are sculpted into imposing seacliffs up to 60 m high and comprise two distinct imposing complexes of the Late Pleistocene Bridgewater Formation. The lower aeolianite complex, which forms the bulk of the cliffs, is a series of stacked palaeodunes and intervening palaeosols. The diagenetic low Mg-calcite sediment particles are mostly bivalves, echinoids, bryozoans and small benthic foraminifera. This association is similar to sediments forming offshore today on the adjacent shelf in a warm-temperate ocean. By contrast, the upper aeolianite complex is a series of mineralogically metastable biofragmental carbonates in a succession of stacked lenticular palaeodunes with impressive interbedded calcretes and palaeosols.
    [Show full text]
  • Coastal Eolian Sands, Paleosols, and Pleistocene Geoarchaeology of the Southwestern Cape, South Africa
    Journal of Archaeological Science 31 (2004) 1743e1781 http://www.elsevier.com/locate/jas Coastal eolian sands, paleosols, and Pleistocene geoarchaeology of the Southwestern Cape, South Africa Karl W. Butzer Department of Geography and the Environment, The University of Texas at Austin, Austin, TX 78712, USA Received 20 November 2003; received in revised form 28 May 2004 Abstract Narratives of Pleistocene prehistory for MIS 4 to 9 are primarily constructed on the basis of what appear to be subcontinuous archaeological records in cave sites, with subsidiary geo- and bioarchaeological research attempting to determine the nature of external environments and biotic resources from the inside, rather than the outside. The present study seeks to establish a detailed chronostratigraphy for faunal and archaeological sites linked with coastal sediments in the Southwestern Cape province. Accelerated shore deflation during glacio-eustatic oscillations of sea level deposited multiple eolianites, and textural changes of such calcified sands identify both transgressive and regressive sea level trends. These provide a proxy for local shore proximity, sometimes directly linked to ‘high’ sea level stands. Such sediments are subdivided into lithostratigraphic sequences by multiple paleosols, that range from ABC-soils to calcretes or plinthite/ferricrete horizons. Repeated intervals of solution or karstic activity created underground cavities that allowed fossil bone to collect in or below hyena lairs. Such fills further connect sedimentary units with pedogenic events, to integrate local stratigraphies into a regional lithostratigraphy that can be readily correlated with global chronostratigraphies (MIS stages and Dansgaard-Oeschger events), derived from polar ice and deep sea cores, as well as long stalagmite and pollen records.
    [Show full text]