A Fundamental Precambrian–Phanerozoic Shift in Earth's Glacial
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Cryogenian Glaciation and the Onset of Carbon-Isotope Decoupling” by N
CORRECTED 21 MAY 2010; SEE LAST PAGE REPORTS 13. J. Helbert, A. Maturilli, N. Mueller, in Venus Eds. (U.S. Geological Society Open-File Report 2005- M. F. Coffin, Eds. (Monograph 100, American Geophysical Geochemistry: Progress, Prospects, and New Missions 1271, Abstracts of the Annual Meeting of Planetary Union, Washington, DC, 1997), pp. 1–28. (Lunar and Planetary Institute, Houston, TX, 2009), abstr. Geologic Mappers, Washington, DC, 2005), pp. 20–21. 44. M. A. Bullock, D. H. Grinspoon, Icarus 150, 19 (2001). 2010. 25. E. R. Stofan, S. E. Smrekar, J. Helbert, P. Martin, 45. R. G. Strom, G. G. Schaber, D. D. Dawson, J. Geophys. 14. J. Helbert, A. Maturilli, Earth Planet. Sci. Lett. 285, 347 N. Mueller, Lunar Planet. Sci. XXXIX, abstr. 1033 Res. 99, 10,899 (1994). (2009). (2009). 46. K. M. Roberts, J. E. Guest, J. W. Head, M. G. Lancaster, 15. Coronae are circular volcano-tectonic features that are 26. B. D. Campbell et al., J. Geophys. Res. 97, 16,249 J. Geophys. Res. 97, 15,991 (1992). unique to Venus and have an average diameter of (1992). 47. C. R. K. Kilburn, in Encyclopedia of Volcanoes, ~250 km (5). They are defined by their circular and often 27. R. J. Phillips, N. R. Izenberg, Geophys. Res. Lett. 22, 1617 H. Sigurdsson, Ed. (Academic Press, San Diego, CA, radial fractures and always produce some form of volcanism. (1995). 2000), pp. 291–306. 16. G. E. McGill, S. J. Steenstrup, C. Barton, P. G. Ford, 28. C. M. Pieters et al., Science 234, 1379 (1986). 48. -
Geologic Time Scale Cards
PreCambrian SuperEon (4.6 BYA – 541 MYA) Hadean Eon (4.6 BYA - 4 BYA) Slide # 1 46 feet Earth Forms • Earth is formed from a mass of dust and gas that gravity pulled together. • The process causes a huge amount of radioactive decay and Earth is a boiling ball of lava. • At 4.5 BYA a protoplanet named Theia collides with Earth and a debris ring forms which later becomes our moon. • Earth cools and forms the layers – core, mantel, and outer crust. • Meteors bombard earth bringing frozen droplets of water that later become our oceans. • Volcanic activity continues and Earth’s earliest continental crust forms before 4.03 BYA. The Acasta gneiss is one of the oldest rocks on Earth dating 4.03 billion years.. PreCambrian SuperEon (4.6 BYA – 541 MYA) Archaean Eon (4 BYA – 2.5 BYA) Slide # 2 40 feet Primitive, Simple Life Forms • Earth’s crust cools and plate tectonics forms. • Ancient rock formations form from 4 to 2.5 BYA. • The Primordial soup theory suggests early minerals and compounds from meteors made the perfect recipe for primitive, simple life to form at the thermal vents of the ocean. • Single cell life formed the ocean and over time stromatolites, photosynthesizing colonial bacteria, formed in shallow water and released oxygen. • The oxygen attached to trace iron in the oceans and formed sedimentary layers of banded iron formations (BIFS) that are presently mined for iron ore. Banded iron formations from the late Archaean and early Proterozoic eons Stromatolite fossil image PreCambrian SuperEon (4.6 BYA – 541 MYA) Proterozoic Eon (2.5 BYA – 541 MYA) Slide # 3 25 feet Early life • Photosynthesizing life further establishes and releases oxygen throughout the ocean. -
Decoupled Evolution of Soft and Hard Substrate Communities During the Cambrian Explosion and Great Ordovician Biodiversification Event
Decoupled evolution of soft and hard substrate communities during the Cambrian Explosion and Great Ordovician Biodiversification Event Luis A. Buatoisa,1, Maria G. Mánganoa, Ricardo A. Oleab, and Mark A. Wilsonc aDepartment of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E2; bEastern Energy Resources Science Center, US Geological Survey, Reston, VA 20192; and cDepartment of Geology, The College of Wooster, Wooster, OH 44691 Edited by Steven M. Holland, University of Georgia, Athens, GA, and accepted by Editorial Board Member David Jablonski May 6, 2016 (received for review November 21, 2015) Contrasts between the Cambrian Explosion (CE) and the Great shed light on the natures of both radiations. Because there is still Ordovician Biodiversification Event (GOBE) have long been recog- controversy regarding Sepkoski’s nonstandardized curves of nized. Whereas the vast majority of body plans were established Phanerozoic taxonomic diversity (13–15), a rarefaction analysis as a result of the CE, taxonomic increases during the GOBE were was performed in an attempt to standardize diversity data. The manifested at lower taxonomic levels. Assessing changes of ichno- aims of this paper are to document the contrasting ichnodiversity diversity and ichnodisparity as a result of these two evolutionary and ichnodisparity trajectories in soft and hard substrate com- events may shed light on the dynamics of both radiations. The early munities during these two evolutionary events and to discuss the Cambrian (series 1 and 2) displayed a dramatic increase in ichnodi- possible underlying causes of this decoupled evolution. versity and ichnodisparity in softground communities. In contrast to this evolutionary explosion in bioturbation structures, only a few Results Cambrian bioerosion structures are known. -
The Geology of the Enosburg Area, Vermont
THE GEOLOGY OF THE ENOSBURG AREA, VERMONT By JOlIN G. DENNIS VERMONT GEOLOGICAL SURVEY CHARLES G. DOLL, State Geologist Published by VERMONT DEVELOPMENT DEPARTMENT MONTPELIER, VERMONT BULLETIN No. 23 1964 TABLE OF CONTENTS PAGE ABSTRACT 7 INTRODUCTION ...................... 7 Location ........................ 7 Geologic Setting .................... 9 Previous Work ..................... 10 Method of Study .................... 10 Acknowledgments .................... 10 Physiography ...................... 11 STRATIGRAPHY ...................... 12 Introduction ...................... 12 Pinnacle Formation ................... 14 Name and Distribution ................ 14 Graywacke ...................... 14 Underhill Facics ................... 16 Tibbit Hill Volcanics ................. 16 Age......................... 19 Underhill Formation ................... 19 Name and Distribution ................ 19 Fairfield Pond Member ................ 20 White Brook Member ................. 21 West Sutton Slate ................... 22 Bonsecours Facies ................... 23 Greenstones ..................... 24 Stratigraphic Relations of the Greenstones ........ 25 Cheshire Formation ................... 26 Name and Distribution ................ 26 Lithology ...................... 26 Age......................... 27 Bridgeman Hill Formation ................ 28 Name and Distribution ................ 28 Dunham Dolomite .................. 28 Rice Hill Member ................... 29 Oak Hill Slate (Parker Slate) .............. 29 Rugg Brook Dolomite (Scottsmore -
PERMIAN BASIN PROVINCE (044) by Mahlon M
PERMIAN BASIN PROVINCE (044) By Mahlon M. Ball INTRODUCTION The Permian Basin is one of the largest structural basins in North America. It encompasses a surface area in excess of 86,000 sq mi and includes all or parts of 52 counties located in West Texas and southeast New Mexico. Structurally, the Permian Basin is bounded on the south by the Marathon-Ouachita Fold Belt, on the west by the Diablo Platform and Pedernal Uplift, on the north by the Matador Arch, and on the east by the Eastern Shelf of the Permian (Midland) Basin and west flank of the Bend Arch. The basin is about 260 mi by 300 mi in area and is separated into eastern and western halves by a north-south trending Central Basin Platform. In cross section, the basin is an asymmetrical feature; the western half contains a thicker and more structurally deformed sequence of sedimentary rock. The Permian Basin has been characterized as a large structural depression formed as a result of downwarp in the Precambrian basement surface located at the southern margin of the North American craton. The basin was filled with Paleozoic and, to a much lesser extent, younger sediments. It acquired its present structural form by Early Permian time. The overall basin is divisible into several distinct structural and tectonic elements. They are the Central Basin Platform and the Ozona Arch, which separate the Delaware and Val Verde Basins on the south and west from the Midland Basin on the north and east, the Northwestern Shelf on the southern extremity of the Pedernal Uplift and Matador Arch, and the Eastern Shelf on the western periphery of the Bend Arch. -
Chapter 2 Paleozoic Stratigraphy of the Grand Canyon
CHAPTER 2 PALEOZOIC STRATIGRAPHY OF THE GRAND CANYON PAIGE KERCHER INTRODUCTION The Paleozoic Era of the Phanerozoic Eon is defined as the time between 542 and 251 million years before the present (ICS 2010). The Paleozoic Era began with the evolution of most major animal phyla present today, sparked by the novel adaptation of skeletal hard parts. Organisms continued to diversify throughout the Paleozoic into increasingly adaptive and complex life forms, including the first vertebrates, terrestrial plants and animals, forests and seed plants, reptiles, and flying insects. Vast coal swamps covered much of mid- to low-latitude continental environments in the late Paleozoic as the supercontinent Pangaea began to amalgamate. The hardiest taxa survived the multiple global glaciations and mass extinctions that have come to define major time boundaries of this era. Paleozoic North America existed primarily at mid to low latitudes and experienced multiple major orogenies and continental collisions. For much of the Paleozoic, North America’s southwestern margin ran through Nevada and Arizona – California did not yet exist (Appendix B). The flat-lying Paleozoic rocks of the Grand Canyon, though incomplete, form a record of a continental margin repeatedly inundated and vacated by shallow seas (Appendix A). IMPORTANT STRATIGRAPHIC PRINCIPLES AND CONCEPTS • Principle of Original Horizontality – In most cases, depositional processes produce flat-lying sedimentary layers. Notable exceptions include blanketing ash sheets, and cross-stratification developed on sloped surfaces. • Principle of Superposition – In an undisturbed sequence, older strata lie below younger strata; a package of sedimentary layers youngs upward. • Principle of Lateral Continuity – A layer of sediment extends laterally in all directions until it naturally pinches out or abuts the walls of its confining basin. -
UC Riverside UC Riverside Electronic Theses and Dissertations
UC Riverside UC Riverside Electronic Theses and Dissertations Title Exploring the Texture of Ocean-Atmosphere Redox Evolution on the Early Earth Permalink https://escholarship.org/uc/item/9v96g1j5 Author Reinhard, Christopher Thomas Publication Date 2012 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE Exploring the Texture of Ocean-Atmosphere Redox Evolution on the Early Earth A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Geological Sciences by Christopher Thomas Reinhard September 2012 Dissertation Committee: Dr. Timothy W. Lyons, Chairperson Dr. Gordon D. Love Dr. Nigel C. Hughes ! Copyright by Christopher Thomas Reinhard 2012 ! ! The Dissertation of Christopher Thomas Reinhard is approved: ________________________________________________ ________________________________________________ ________________________________________________ Committee Chairperson University of California, Riverside ! ! ACKNOWLEDGEMENTS It goes without saying (but I’ll say it anyway…) that things like this are never done in a vacuum. Not that I’ve invented cold fusion here, but it was quite a bit of work nonetheless and to say that my zest for the enterprise waned at times would be to put it euphemistically. As it happens, though, I’ve been fortunate enough to be surrounded these last years by an incredible group of people. To those that I consider scientific and professional mentors that have kept me interested, grounded, and challenged – most notably Tim Lyons, Rob Raiswell, Gordon Love, and Nigel Hughes – thank you for all that you do. I also owe Nigel and Mary Droser a particular debt of graditude for letting me flounder a bit my first year at UCR, being understanding and supportive, and encouraging me to start down the road to where I’ve ended up (for better or worse). -
Neoproterozoic Glaciations in a Revised Global Palaeogeography from the Breakup of Rodinia to the Assembly of Gondwanaland
Sedimentary Geology 294 (2013) 219–232 Contents lists available at SciVerse ScienceDirect Sedimentary Geology journal homepage: www.elsevier.com/locate/sedgeo Invited review Neoproterozoic glaciations in a revised global palaeogeography from the breakup of Rodinia to the assembly of Gondwanaland Zheng-Xiang Li a,b,⁎, David A.D. Evans b, Galen P. Halverson c,d a ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS) and The Institute for Geoscience Research (TIGeR), Department of Applied Geology, Curtin University, GPO Box U1987, Perth, WA 6845, Australia b Department of Geology and Geophysics, Yale University, New Haven, CT 06520-8109, USA c Earth & Planetary Sciences/GEOTOP, McGill University, 3450 University St., Montreal, Quebec H3A0E8, Canada d Tectonics, Resources and Exploration (TRaX), School of Earth and Environmental Sciences, University of Adelaide, SA 5005, Australia article info abstract Article history: This review paper presents a set of revised global palaeogeographic maps for the 825–540 Ma interval using Received 6 January 2013 the latest palaeomagnetic data, along with lithological information for Neoproterozoic sedimentary basins. Received in revised form 24 May 2013 These maps form the basis for an examination of the relationships between known glacial deposits, Accepted 28 May 2013 palaeolatitude, positions of continental rifting, relative sea-level changes, and major global tectonic events Available online 5 June 2013 such as supercontinent assembly, breakup and superplume events. This analysis reveals several fundamental ’ Editor: J. Knight palaeogeographic features that will help inform and constrain models for Earth s climatic and geodynamic evolution during the Neoproterozoic. First, glacial deposits at or near sea level appear to extend from high Keywords: latitudes into the deep tropics for all three Neoproterozoic ice ages (Sturtian, Marinoan and Gaskiers), al- Neoproterozoic though the Gaskiers interval remains very poorly constrained in both palaeomagnetic data and global Rodinia lithostratigraphic correlations. -
Integrative and Comparative Biology Integrative and Comparative Biology, Volume 58, Number 4, Pp
Integrative and Comparative Biology Integrative and Comparative Biology, volume 58, number 4, pp. 605–622 doi:10.1093/icb/icy088 Society for Integrative and Comparative Biology SYMPOSIUM INTRODUCTION The Temporal and Environmental Context of Early Animal Evolution: Considering All the Ingredients of an “Explosion” Downloaded from https://academic.oup.com/icb/article-abstract/58/4/605/5056706 by Stanford Medical Center user on 15 October 2018 Erik A. Sperling1 and Richard G. Stockey Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305, USA From the symposium “From Small and Squishy to Big and Armored: Genomic, Ecological and Paleontological Insights into the Early Evolution of Animals” presented at the annual meeting of the Society for Integrative and Comparative Biology, January 3–7, 2018 at San Francisco, California. 1E-mail: [email protected] Synopsis Animals originated and evolved during a unique time in Earth history—the Neoproterozoic Era. This paper aims to discuss (1) when landmark events in early animal evolution occurred, and (2) the environmental context of these evolutionary milestones, and how such factors may have affected ecosystems and body plans. With respect to timing, molecular clock studies—utilizing a diversity of methodologies—agree that animal multicellularity had arisen by 800 million years ago (Ma) (Tonian period), the bilaterian body plan by 650 Ma (Cryogenian), and divergences between sister phyla occurred 560–540 Ma (late Ediacaran). Most purported Tonian and Cryogenian animal body fossils are unlikely to be correctly identified, but independent support for the presence of pre-Ediacaran animals is recorded by organic geochemical biomarkers produced by demosponges. -
Late Paleozoic Sea Levels and Depositional Sequences Charles A
Western Washington University Western CEDAR Geology Faculty Publications Geology 1987 Late Paleozoic Sea Levels and Depositional Sequences Charles A. Ross Western Washington University, [email protected] June R. P. Ross Western Washington University Follow this and additional works at: https://cedar.wwu.edu/geology_facpubs Part of the Geology Commons, and the Paleontology Commons Recommended Citation Ross, Charles A. and Ross, June R. P., "Late Paleozoic Sea Levels and Depositional Sequences" (1987). Geology Faculty Publications. 61. https://cedar.wwu.edu/geology_facpubs/61 This Article is brought to you for free and open access by the Geology at Western CEDAR. It has been accepted for inclusion in Geology Faculty Publications by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. Cushman Foundation for Foraminiferal Research, Special Publication 24, 1987. LATE PALEOZOIC SEA LEVELS AND DEPOSITIONAL SEQUENCES CHARLES A. ROSSI AND JUNE R. P. ROSS2 1 Chevron U.S.A., Inc.,P. O. BOX 1635, Houston, TX 77251 2 Department of Biology, Western Washington University, Bellingham, WA 98225 ABSTRACT studies on these changes in sea level and their paleogeographic distribution (Ross, 1979; Ross Cyclic sea level charts for the Lower and Ross, 1979, 1981a, 1981b, 1985a, 1985b) are Carboniferous (Mississippian), Middle and Upper elaborated on in this paper with charts in a Carboniferous (Pennsylvanian), and Permian show similar format to that used for Mesozoic and considerable variability in the duration and Cenozoic sea-level cyclic fluctuations by Haq, magnitude of third-order depositional sequences, Hardenbol, and Vail (1987 and this volume). and also in the position of general sea level as represented by second-order sea level. -
Two Stages of Late Carboniferous to Triassic Magmatism in the Strandja
Geological Magazine Two stages of Late Carboniferous to Triassic www.cambridge.org/geo magmatism in the Strandja Zone of Bulgaria and Turkey ł ń 1,2 3 1 1 Original Article Anna Sa aci ska , Ianko Gerdjikov , Ashley Gumsley , Krzysztof Szopa , David Chew4, Aleksandra Gawęda1 and Izabela Kocjan2 Cite this article: Sałacińska A, Gerdjikov I, Gumsley A, Szopa K, Chew D, Gawęda A, and 1Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia in Katowice, Będzińska 60, 41-200 Kocjan I. Two stages of Late Carboniferous to 2 3 Triassic magmatism in the Strandja Zone of Sosnowiec, Poland; Institute of Geological Sciences, Polish Academy of Sciences, Warsaw, Poland; Faculty of ‘ ’ Bulgaria and Turkey. Geological Magazine Geology and Geography, Sofia University St. Kliment Ohridski , 15 Tzar Osvoboditel Blvd., 1504 Sofia, Bulgaria 4 https://doi.org/10.1017/S0016756821000650 and Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland Received: 9 February 2021 Abstract Revised: 3 June 2021 Accepted: 8 June 2021 Although Variscan terranes have been documented from the Balkans to the Caucasus, the southeastern portion of the Variscan Belt is not well understood. The Strandja Zone along Keywords: the border between Bulgaria and Turkey encompasses one such terrane linking the Strandja Zone; Sakar unit; U–Pb zircon dating; Izvorovo Pluton Balkanides and the Pontides. However, the evolution of this terrane, and the Late Carboniferous to Triassic granitoids within it, is poorly resolved. Here we present laser ablation Author for correspondence: – inductively coupled plasma – mass spectrometry (LA-ICP-MS) U–Pb zircon ages, coupled ł ń Anna Sa aci ska, with petrography and geochemistry from the Izvorovo Pluton within the Sakar Unit Email: [email protected] (Strandja Zone). -
The Geologic Time Scale Is the Eon
Exploring Geologic Time Poster Illustrated Teacher's Guide #35-1145 Paper #35-1146 Laminated Background Geologic Time Scale Basics The history of the Earth covers a vast expanse of time, so scientists divide it into smaller sections that are associ- ated with particular events that have occurred in the past.The approximate time range of each time span is shown on the poster.The largest time span of the geologic time scale is the eon. It is an indefinitely long period of time that contains at least two eras. Geologic time is divided into two eons.The more ancient eon is called the Precambrian, and the more recent is the Phanerozoic. Each eon is subdivided into smaller spans called eras.The Precambrian eon is divided from most ancient into the Hadean era, Archean era, and Proterozoic era. See Figure 1. Precambrian Eon Proterozoic Era 2500 - 550 million years ago Archaean Era 3800 - 2500 million years ago Hadean Era 4600 - 3800 million years ago Figure 1. Eras of the Precambrian Eon Single-celled and simple multicelled organisms first developed during the Precambrian eon. There are many fos- sils from this time because the sea-dwelling creatures were trapped in sediments and preserved. The Phanerozoic eon is subdivided into three eras – the Paleozoic era, Mesozoic era, and Cenozoic era. An era is often divided into several smaller time spans called periods. For example, the Paleozoic era is divided into the Cambrian, Ordovician, Silurian, Devonian, Carboniferous,and Permian periods. Paleozoic Era Permian Period 300 - 250 million years ago Carboniferous Period 350 - 300 million years ago Devonian Period 400 - 350 million years ago Silurian Period 450 - 400 million years ago Ordovician Period 500 - 450 million years ago Cambrian Period 550 - 500 million years ago Figure 2.