DOCSLIB.ORG

Microfossil Paleontology and Biostratigraphy of The

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Microfossil Paleontology and Biostratigraphy of The MICROFOSSIL PALEONTOLOGY AND BIOSTRATIGRAPHY OF THE EARLY MESOPROTEROZOIC BELT SUPERGROUP, MONTANA by Zachary Robert Adam A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Earth Sciences MONTANA STATE UNIVERSITY Bozeman, Montana November 2014 ©COPYRIGHT by Zachary Robert Adam 2014 All Rights Reserved ii DEDICATION I would like to dedicate this work to my wife, our family in the US and Turkey, and my friends for all that they have given over the years so that I may have the comfort, care and peace of mind to focus so intently on so many tiny pieces of formerly animate matter. I also wish to dedicate this work to all eukaryotes (and complexity-equivalent organisms elsewhere in the universe) that have ever risen above the selective forces that would otherwise constrain us to an existence lacking an appreciation for the Infinite. iii ACKNOWLEDGMENTS This dissertation was made possible by the kindness and generosity of many individuals and organizations. David Mogk and Mark Skidmore guided the genesis and conclusion of the entire project with aplomb. James Schmitt and Nicholas Atwood provided insightful field interpretations of sedimentology. David Lageson illuminated many nuances of the Belt Supergroup structural environment. Nicholas Butterfield of the University of Cambridge provided invaluable micropaleontological guidance in the field and laboratory, and helpful feedback regarding the content and organization of this dissertation. Don Winston of the University of Montana introduced me to the sedimentary cycles and mysteries of the Belt Supergroup. Gerald Zieg of Tintina Resources oriented me within the Helena Embayment and provided helpful feedback regarding the history of study of the Lower Belt units. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 2011120064. Tuition support was provided by the NSF Integrative Graduate Education and Research Trainee (IGERT) Program. Field activities were supported by awards from the American Philosophical Society and NASA Astrobiology Institute’s Lewis and Clark Fund for Exploration Research, the Tobacco Root Geological Society, the Belt Association, and the Donald L. Smith Memorial Fund. Recep Avci, Muhammedin Deliorman and Laura Kellerman of the Imaging and Chemical Analysis Laboratory at Montana State University assisted with XRD, electron microscope and atomic force microscope data collection. iv VITA Zachary Robert Adam was born May 30th, 1981 in Wenatchee, Washington to Robert and Linda Adam. After graduating from Cashmere High School in 1999, he attended the University of Washington, earning degrees in Earth and Space Sciences and Aeronautics and Astronautics Engineering in 2004. It was during this period that Zach picked up his now-lifelong fascination with Astrobiology, and shortly thereafter he joined the University of Washington’s Astrobiology Program, earning a Master’s degree in Aeronautics and Astronautics Engineering. After volunteering for Americorps at Lewis and Clark Elementary School in Missoula, Montana, Zach worked as a life support systems engineer and launch vehicle inspector for the Office of Commercial Space Transportation at the Federal Aviation Administration, focusing on the SeaLaunch and SpaceX vehicle families. Zach then returned to academia through Montana State University, where he was presented with the opportunity to design and conduct the research project described in this dissertation. v TABLE OF CONTENTS 1. INTRODUCTION ......................................................................................................... 1 2. MICROFOSSILS FROM THE GREYSON FORMATION ....................................... 12 Introduction ................................................................................................................... 12 Geological Setting ......................................................................................................... 19 Sampling and Methods ................................................................................................. 23 Assemblage Summary .................................................................................................. 25 Systematic Paleontology ............................................................................................... 39 Biochronologic Implications ......................................................................................... 47 Conclusions ................................................................................................................... 57 3. MICROFOSSILS FROM THE CHAMBERLAIN FORMATION .............................. 59 Introduction ................................................................................................................... 59 Geological Setting ......................................................................................................... 63 Sampling and Methods ................................................................................................. 68 Assemblage Summary .................................................................................................. 70 Systematic Paleontology ............................................................................................... 79 Discussion ..................................................................................................................... 85 Conclusions ................................................................................................................... 97 4. ONTOGENETIC RECONSTRUCTION OF MICROFOSSILS BASED ON VISIBLE MORPHOLOGICAL CHARACTERS ................................... 99 Introduction ................................................................................................................... 99 Geological Setting ....................................................................................................... 101 Methods ...................................................................................................................... 103 Results ......................................................................................................................... 104 Discussion ................................................................................................................... 114 Conclusions ................................................................................................................. 124 5. CONCLUSIONS AND FUTURE WORK ................................................................. 126 APPENDICES ................................................................................................................ 131 APPENDIX A: Image and Actual Size Measurement Calibrations ........................... 132 APPENDIX B: Rock Pyrolysis Data .......................................................................... 140 APPENDIX C: Clay Mineralogy XRD Data .............................................................. 142 vi TABLE OF CONTENTS - CONTINUED APPENDIX D: Individual Microfossil Location Notes ............................................. 149 APPENDIX E: Major Element Analyses ................................................................... 161 REFERENCES CITED…………………………………………………………………163 vii LIST OF TABLES Table Page 1. Comparison of fossil taxa occurring in the SCC-34 (Chamberlain Formation) and Newlan Creek (Greyson Formation) assemblages .................................................................... 86 2. Cross-comparison of interpreted host rock paleoenvironments (top row) and fossil assemblage composition (left column) from units of the Bylot Supergroup, Belt Supergroup and Roper Group. .............................................................................................. 90 viii LIST OF FIGURES Figure Page 1. Locations of outcrops sampled for microfossil content from throughout the Belt Supergroup .......................................................................... 6 2. Map of northern margins of the Helena Embayment (inset) and fossiliferous rocks ..................................................................................... 15 3. Unit stratigraphy and geochronological constraints of the lower Belt Supergroup ..................................................................................... 16 4. WP-133 fossiliferous outcrop (Greyson Formation) unoriented and oriented clay sample spectra ...................................................................... 24 5. Summary and occurrence of microfossil taxa identified from the Newlan Creek locality, Greyson Formation, Belt Supergroup, Montana ....................................................................................... 26 6. Leiosphaeridia specimens from the Newlan Creek locality, Greyson Formation ........................................................................................... 27 7. Caudosphaera winstonii specimens from the Newlan Creek locality, Greyson Formation ............................................................................. 28 8. Pluricellular aggregations from the Newlan Creek locality, Greyson Formation ........................................................................................... 29 9. Valeria lophostriata from the Newlan Creek locality, Greyson Formation ........................................................................................... 31 10. Dictyosphaera delicata from the Newlan Creek locality, Greyson Formation ........................................................................................
Load more

Recommended publications
  • Plant Macrofossil Evidence for an Early Onset of the Holocene Summer Thermal Maximum in Northernmost Europe
    ARTICLE Received 19 Aug 2014 | Accepted 27 Feb 2015 | Published 10 Apr 2015 DOI: 10.1038/ncomms7809 OPEN Plant macrofossil evidence for an early onset of the Holocene summer thermal maximum in northernmost Europe M. Va¨liranta1, J.S. Salonen2, M. Heikkila¨1, L. Amon3, K. Helmens4, A. Klimaschewski5, P. Kuhry4, S. Kultti2, A. Poska3,6, S. Shala4, S. Veski3 & H.H. Birks7 Holocene summer temperature reconstructions from northern Europe based on sedimentary pollen records suggest an onset of peak summer warmth around 9,000 years ago. However, pollen-based temperature reconstructions are largely driven by changes in the proportions of tree taxa, and thus the early-Holocene warming signal may be delayed due to the geographical disequilibrium between climate and tree populations. Here we show that quantitative summer-temperature estimates in northern Europe based on macrofossils of aquatic plants are in many cases ca.2°C warmer in the early Holocene (11,700–7,500 years ago) than reconstructions based on pollen data. When the lag in potential tree establishment becomes imperceptible in the mid-Holocene (7,500 years ago), the reconstructed temperatures converge at all study sites. We demonstrate that aquatic plant macrofossil records can provide additional and informative insights into early-Holocene temperature evolution in northernmost Europe and suggest further validation of early post-glacial climate development based on multi-proxy data syntheses. 1 Department of Environmental Sciences, ECRU, University of Helsinki, P.O. Box 65, Helsinki FI-00014, Finland. 2 Department of Geosciences and Geography, University of Helsinki, P.O. Box 65, Helsinki FI-00014, Finland.
    [Show full text]
  • Cambrian Phytoplankton of the Brunovistulicum – Taxonomy and Biostratigraphy
    MONIKA JACHOWICZ-ZDANOWSKA Cambrian phytoplankton of the Brunovistulicum – taxonomy and biostratigraphy Polish Geological Institute Special Papers,28 WARSZAWA 2013 CONTENTS Introduction...........................................................6 Geological setting and lithostratigraphy.............................................8 Summary of Cambrian chronostratigraphy and acritarch biostratigraphy ...........................13 Review of previous palynological studies ...........................................17 Applied techniques and material studied............................................18 Biostratigraphy ........................................................23 BAMA I – Pulvinosphaeridium antiquum–Pseudotasmanites Assemblage Zone ....................25 BAMA II – Asteridium tornatum–Comasphaeridium velvetum Assemblage Zone ...................27 BAMA III – Ichnosphaera flexuosa–Comasphaeridium molliculum Assemblage Zone – Acme Zone .........30 BAMA IV – Skiagia–Eklundia campanula Assemblage Zone ..............................39 BAMA V – Skiagia–Eklundia varia Assemblage Zone .................................39 BAMA VI – Volkovia dentifera–Liepaina plana Assemblage Zone (Moczyd³owska, 1991) ..............40 BAMA VII – Ammonidium bellulum–Ammonidium notatum Assemblage Zone ....................40 BAMA VIII – Turrisphaeridium semireticulatum Assemblage Zone – Acme Zone...................41 BAMA IX – Adara alea–Multiplicisphaeridium llynense Assemblage Zone – Acme Zone...............42 Regional significance of the biostratigraphic
    [Show full text]
  • Standard Procedures for the Assessment and Mitigation of Adverse Impacts to Paleontological Resources
    Standard Procedures for the Assessment and Mitigation of Adverse Impacts to Paleontological Resources Society of Vertebrate Paleontology Impact Mitigation Guidelines Revision Committee Abstract Fossils are nonrenewable paleontological resources that are subject to impacts from land development. Procedures are presented for evaluating the potential for impacts of a proposed action on paleontological resources and for mitigating those impacts. Impact mitigation includes pre-project survey and salvage, monitoring and screen washing during excavation to salvage fossils, conservation and inventory, and final reports and specimen curation. The objective of these procedures is to offer standard methods for assessing potential impacts to fossils and mitigating these impacts. Introduction Fossils are nonrenewable paleontological resources that are afforded protection by federal, state, and local environmental laws and regulations. The Paleontological Resources Preservation Act (PRPA) of 2009 calls for uniform policies and standards that apply to fossils on all federal public lands. All federal land management agencies are required to develop regulations that satisfy the stipulations of the PRPA. Section 6302 of the PRPA mandates that federal agencies "shall manage and protect paleontological resources on Federal land using scientific principles and expertise." Thus, federal agencies need the help of the professional paleontological community in the formulation and implementation of these PRPA- mandated policies and regulations. The potential for destruction or degradation of paleontological resources on both public and private lands selected for development under the jurisdiction of various governmental planning agencies is recognized. The standard procedures below are intended to be applicable to both private and public lands under the jurisdiction of local, city, county, regional, state, and federal agencies.
    [Show full text]
  • In Pliocene Deposits, Antarctic Continental Margin (ANDRILL 1B Drill Core) Molly F
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln ANDRILL Research and Publications Antarctic Drilling Program 2009 Significance of the Trace Fossil Zoophycos in Pliocene Deposits, Antarctic Continental Margin (ANDRILL 1B Drill Core) Molly F. Miller Vanderbilt University, [email protected] Ellen A. Cowan Appalachian State University, [email protected] Simon H. H. Nielsen Florida State University Follow this and additional works at: http://digitalcommons.unl.edu/andrillrespub Part of the Oceanography Commons, and the Paleobiology Commons Miller, Molly F.; Cowan, Ellen A.; and Nielsen, Simon H. H., "Significance of the Trace Fossil Zoophycos in Pliocene Deposits, Antarctic Continental Margin (ANDRILL 1B Drill Core)" (2009). ANDRILL Research and Publications. 61. http://digitalcommons.unl.edu/andrillrespub/61 This Article is brought to you for free and open access by the Antarctic Drilling Program at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in ANDRILL Research and Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in Antarctic Science 21(6) (2009), & Antarctic Science Ltd (2009), pp. 609–618; doi: 10.1017/ s0954102009002041 Copyright © 2009 Cambridge University Press Submitted July 25, 2008, accepted February 9, 2009 Significance of the trace fossil Zoophycos in Pliocene deposits, Antarctic continental margin (ANDRILL 1B drill core) Molly F. Miller,1 Ellen A. Cowan,2 and Simon H.H. Nielsen3 1. Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37235, USA 2. Department of Geology, Appalachian State University, Boone, NC 28608, USA 3. Antarctic Research Facility, Florida State University, Tallahassee FL 32306-4100, USA Corresponding author — Molly F.
    [Show full text]
  • Ediacaran) of Earth – Nature’S Experiments
    The Early Animals (Ediacaran) of Earth – Nature’s Experiments Donald Baumgartner Medical Entomologist, Biologist, and Fossil Enthusiast Presentation before Chicago Rocks and Mineral Society May 10, 2014 Illinois Famous for Pennsylvanian Fossils 3 In the Beginning: The Big Bang . Earth formed 4.6 billion years ago Fossil Record Order 95% of higher taxa: Random plant divisions domains & kingdoms Cambrian Atdabanian Fauna Vendian Tommotian Fauna Ediacaran Fauna protists Proterozoic algae McConnell (Baptist)College Pre C - Fossil Order Archaean bacteria Source: Truett Kurt Wise The First Cells . 3.8 billion years ago, oxygen levels in atmosphere and seas were low • Early prokaryotic cells probably were anaerobic • Stromatolites . Divergence separated bacteria from ancestors of archaeans and eukaryotes Stromatolites Dominated the Earth Stromatolites of cyanobacteria ruled the Earth from 3.8 b.y. to 600 m. [2.5 b.y.]. Believed that Earth glaciations are correlated with great demise of stromatolites world-wide. 8 The Oxygen Atmosphere . Cyanobacteria evolved an oxygen-releasing, noncyclic pathway of photosynthesis • Changed Earth’s atmosphere . Increased oxygen favored aerobic respiration Early Multi-Cellular Life Was Born Eosphaera & Kakabekia at 2 b.y in Canada Gunflint Chert 11 Earliest Multi-Cellular Metazoan Life (1) Alga Eukaryote Grypania of MI at 1.85 b.y. MI fossil outcrop 12 Earliest Multi-Cellular Metazoan Life (2) Beads Horodyskia of MT and Aust. at 1.5 b.y. thought to be algae 13 Source: Fedonkin et al. 2007 Rise of Animals Tappania Fungus at 1.5 b.y Described now from China, Russia, Canada, India, & Australia 14 Earliest Multi-Cellular Metazoan Animals (3) Worm-like Parmia of N.E.
    [Show full text]
  • Algal Stromatolites in the Willow River Member of the Lower Ordovician Shakopee Formation Near Chatfield, Minnesota, USA
    The Compass: Earth Science Journal of Sigma Gamma Epsilon Volume 84 Issue 1 Article 6 1-6-2012 Algal Stromatolites in the Willow River Member of the Lower Ordovician Shakopee Formation near Chatfield, Minnesota, USA Sophia L. May College of St. Benedict / St. John's University, [email protected] Larry E. Davis College of St. Benedict / St. John's University, [email protected] David G. Brown College of St. Benedict / St. John's University, [email protected] Follow this and additional works at: https://digitalcommons.csbsju.edu/compass Part of the Paleontology Commons Recommended Citation May, Sophia L.; Davis, Larry E.; and Brown, David G. (2012) "Algal Stromatolites in the Willow River Member of the Lower Ordovician Shakopee Formation near Chatfield, Minnesota, USA," The Compass: Earth Science Journal of Sigma Gamma Epsilon: Vol. 84: Iss. 1, Article 6. Available at: https://digitalcommons.csbsju.edu/compass/vol84/iss1/6 This Article is brought to you for free and open access by DigitalCommons@CSB/SJU. It has been accepted for inclusion in The Compass: Earth Science Journal of Sigma Gamma Epsilon by an authorized editor of DigitalCommons@CSB/SJU. For more information, please contact [email protected]. ON THE OUTCROP Algal Stromatolites in the Willow River Member of the Lower Ordovician Shakopee Formation near Chatfield, Minnesota, USA Sophia L. May, Larry E. Davis, and David G. Brown Department of Biology College of Saint Benedict/Saint John’s University Collegeville, Minnesota, 56321 USA [email protected] LOCATION From the intersection of (Olmsted) Co. Hwy 2 and U.S. 52 Rochester I-90 (Main Street) in Chatfield, MN drive N south-southeast on U.S.
    [Show full text]
  • Phytoplankton As Key Mediators of the Biological Carbon Pump: Their Responses to a Changing Climate
    sustainability Review Phytoplankton as Key Mediators of the Biological Carbon Pump: Their Responses to a Changing Climate Samarpita Basu * ID and Katherine R. M. Mackey Earth System Science, University of California Irvine, Irvine, CA 92697, USA; [email protected] * Correspondence: [email protected] Received: 7 January 2018; Accepted: 12 March 2018; Published: 19 March 2018 Abstract: The world’s oceans are a major sink for atmospheric carbon dioxide (CO2). The biological carbon pump plays a vital role in the net transfer of CO2 from the atmosphere to the oceans and then to the sediments, subsequently maintaining atmospheric CO2 at significantly lower levels than would be the case if it did not exist. The efficiency of the biological pump is a function of phytoplankton physiology and community structure, which are in turn governed by the physical and chemical conditions of the ocean. However, only a few studies have focused on the importance of phytoplankton community structure to the biological pump. Because global change is expected to influence carbon and nutrient availability, temperature and light (via stratification), an improved understanding of how phytoplankton community size structure will respond in the future is required to gain insight into the biological pump and the ability of the ocean to act as a long-term sink for atmospheric CO2. This review article aims to explore the potential impacts of predicted changes in global temperature and the carbonate system on phytoplankton cell size, species and elemental composition, so as to shed light on the ability of the biological pump to sequester carbon in the future ocean.
    [Show full text]
  • Evaluating the Biological Pump Efficiency of the Last Glacial Maximum Ocean Using Δ13c Anne L
    Evaluating the Biological Pump Efficiency of the Last Glacial Maximum Ocean using δ13C Anne L. Morée1, Jörg Schwinger2, Ulysses S. Ninnemann3, Aurich Jeltsch-Thömmes4, Ingo Bethke1, Christoph Heinze1 5 1Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research, Bergen, 5007, Norway 2NORCE Norwegian Research Centre and Bjerknes Centre for Climate Research, Bergen, 5838, Norway 3Department of Earth Science, University of Bergen and Bjerknes Centre for Climate Research, Bergen, 5007, Norway 4Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, 10 University of Bern, Bern, Switzerland Correspondence to: Anne L. Morée ([email protected]) Abstract. Although both physical and biological marine changes are required to explain the 100 ppm lower atmospheric pCO2 of the Last Glacial Maximum (LGM, ~21 ka) as compared to pre-industrial (PI) times, their exact contributions are debated. Proxies of past marine carbon cycling (such as δ13C) document these changes, and 15 thus provide constraints for quantifying the drivers of long-term carbon cycle variability. This modelling study explores the relative rolespresents a realization of the of physical and biological changes in the ocean needed to simulate an LGM ocean in satisfactory agreement with proxy data, and here especially δ13C. We prepared a PI and LGM equilibrium simulation using the ocean model state (NorESM-OC) with full biogeochemistry (including the carbon isotopes δ13C and radiocarbon) and dynamic sea ice. The modelled LGM-PI differences are evaluated 20 against a wide range of physical and biogeochemical proxy data, and show agreement for key aspects of the physical ocean state within the data uncertainties.
    [Show full text]
  • Palaeobiology of the Early Ediacaran Shuurgat Formation, Zavkhan Terrane, South-Western Mongolia
    Journal of Systematic Palaeontology ISSN: 1477-2019 (Print) 1478-0941 (Online) Journal homepage: http://www.tandfonline.com/loi/tjsp20 Palaeobiology of the early Ediacaran Shuurgat Formation, Zavkhan Terrane, south-western Mongolia Ross P. Anderson, Sean McMahon, Uyanga Bold, Francis A. Macdonald & Derek E. G. Briggs To cite this article: Ross P. Anderson, Sean McMahon, Uyanga Bold, Francis A. Macdonald & Derek E. G. Briggs (2016): Palaeobiology of the early Ediacaran Shuurgat Formation, Zavkhan Terrane, south-western Mongolia, Journal of Systematic Palaeontology, DOI: 10.1080/14772019.2016.1259272 To link to this article: http://dx.doi.org/10.1080/14772019.2016.1259272 Published online: 20 Dec 2016. Submit your article to this journal Article views: 48 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tjsp20 Download by: [Harvard Library] Date: 31 January 2017, At: 11:48 Journal of Systematic Palaeontology, 2016 http://dx.doi.org/10.1080/14772019.2016.1259272 Palaeobiology of the early Ediacaran Shuurgat Formation, Zavkhan Terrane, south-western Mongolia Ross P. Anderson a*,SeanMcMahona,UyangaBoldb, Francis A. Macdonaldc and Derek E. G. Briggsa,d aDepartment of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, Connecticut, 06511, USA; bDepartment of Earth Science and Astronomy, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan; cDepartment of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts, 02138, USA; dPeabody Museum of Natural History, Yale University, 170 Whitney Avenue, New Haven, Connecticut, 06511, USA (Received 4 June 2016; accepted 27 September 2016) Early diagenetic chert nodules and small phosphatic clasts in carbonates from the early Ediacaran Shuurgat Formation on the Zavkhan Terrane of south-western Mongolia preserve diverse microfossil communities.
    [Show full text]
  • Silicate Weathering in Anoxic Marine Sediment As a Requirement for Authigenic Carbonate Burial T
    Earth-Science Reviews 200 (2020) 102960 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Silicate weathering in anoxic marine sediment as a requirement for authigenic carbonate burial T Marta E. Torresa,*, Wei-Li Hongb, Evan A. Solomonc, Kitty Millikend, Ji-Hoon Kime, James C. Samplef, Barbara M.A. Teichertg, Klaus Wallmannh a College of Earth, Ocean and Atmospheric Science, Oregon State University, Corvallis OR 97331, USA b Geological Survey of Norway, Trondheim, Norway c School of Oceanography, University of Washington, Seattle, WA 98195, USA d Bureau of Economic Geology, University of Texas at Austin, Austin, TX 78713, USA e Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, South Korea f School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA g Geologisch-Paläontologisches Institut, Wilhelms-Universität Münster, Corrensstr. 24, 48149 Münster, Germany h IFM-GEOMAR Leibniz Institute of Marine Sciences, Wischhofstrasse 1-3, 24148 Kiel, Germany ARTICLE INFO ABSTRACT Keywords: We emphasize the importance of marine silicate weathering (MSiW) reactions in anoxic sediment as funda- Silicate weathering mental in generating alkalinity and cations needed for carbonate precipitation and preservation along con- Authigenic carbonate tinental margins. We use a model that couples thermodynamics with aqueous geochemistry to show that the CO2 Organogenic dolomite released during methanogenesis results in a drop in pH to 6.0; unless these protons are buffered by MSiW, Alkalinity carbonate minerals will dissolve. We present data from two regions: the India passive margin and the active Carbon cycling subduction zone off Japan, where ash and/or rivers supply the reactive silicate phase, as reflected in strontium isotope data.
    [Show full text]
  • A Mesoproterozoic Iron Formation PNAS PLUS
    A Mesoproterozoic iron formation PNAS PLUS Donald E. Canfielda,b,1, Shuichang Zhanga, Huajian Wanga, Xiaomei Wanga, Wenzhi Zhaoa, Jin Sua, Christian J. Bjerrumc, Emma R. Haxenc, and Emma U. Hammarlundb,d aResearch Institute of Petroleum Exploration and Development, China National Petroleum Corporation, 100083 Beijing, China; bInstitute of Biology and Nordcee, University of Southern Denmark, 5230 Odense M, Denmark; cDepartment of Geosciences and Natural Resource Management, Section of Geology, University of Copenhagen, 1350 Copenhagen, Denmark; and dTranslational Cancer Research, Lund University, 223 63 Lund, Sweden Contributed by Donald E. Canfield, February 21, 2018 (sent for review November 27, 2017; reviewed by Andreas Kappler and Kurt O. Konhauser) We describe a 1,400 million-year old (Ma) iron formation (IF) from Understanding the genesis of the Fe minerals in IFs is one step the Xiamaling Formation of the North China Craton. We estimate toward understanding the relationship between IFs and the this IF to have contained at least 520 gigatons of authigenic Fe, chemical and biological environment in which they formed. For comparable in size to many IFs of the Paleoproterozoic Era (2,500– example, the high Fe oxide content of many IFs (e.g., refs. 32, 34, 1,600 Ma). Therefore, substantial IFs formed in the time window and 35) is commonly explained by a reaction between oxygen and between 1,800 and 800 Ma, where they are generally believed to Fe(II) in the upper marine water column, with Fe(II) sourced have been absent. The Xiamaling IF is of exceptionally low thermal from the ocean depths. The oxygen could have come from ex- maturity, allowing the preservation of organic biomarkers and an change equilibrium with oxygen in the atmosphere or from ele- unprecedented view of iron-cycle dynamics during IF emplace- vated oxygen concentrations from cyanobacteria at the water- ment.
    [Show full text]
  • Appendix: Economic Geology: Exploration for Coal, Oil and Minerals
    Downloaded from http://mem.lyellcollection.org/ by guest on October 1, 2021 PART 4 Appendix: Economic geology: exploration for coal, oil and Glossary of stratigraphic names, 463 minerals, 449 References, 477 Index of place names, 455 General Index, 515 Alkahornet, a distinctive landmark on the northwest, entrance to Isfjorden, is formed of early Varanger carbonates. The view is from Trygghamna ('Safe Harbour') with CSE motorboats Salterella and Collenia by the shore, with good anchorage and easy access inland. Photo M. J. Hambrey, CSE (SP. 1561). Routine journeys to the fjords of north Spitsbergen and Nordaustlandet pass by the rocky coastline of northwest Spitsbergen. Here is a view of Smeerenburgbreen from Smeerenburgfjordenwhich affords some shelter being protected by outer islands. On one of these was Smeerenburg, the principal base for early whaling, hence the Dutch name for 'blubber town'. Photo N. I. Cox, CSE 1989. Downloaded from http://mem.lyellcollection.org/ by guest on October 1, 2021 The CSE motorboat Salterella in Liefdefjorden looking north towards Erikbreen with largely Devonian rocks in the background unconformably on metamorphic Proterozoic to the left. Photo P. W. Web, CSE 1989. Access to cliffs and a glacier route (up Hannabreen) often necessitates crossing blocky talus (here Devonian in foreground) and then possibly a pleasanter route up the moraine on to hard glacier ice. Moraine generally affords a useful introduction to the rocks to be traversed along the glacial margin. The dots in the sky are geese training their young to fly in V formation for their migration back to the UK at the end of the summer.
    [Show full text]