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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 Evolution and Distribution of Life in the Precambrian Eon-Global Perspective and the Indian Record 765
The evolution and distribution of life in the Precambrian eon-Global perspective and the Indian record 765 The evolution and distribution of life in the Precambrian eon-Global perspective and the Indian record M SHARMA* and Y SHUKLA Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226 007, India *Corresponding author (Email, [email protected]) The discovery of Precambrian microfossils in 1954 opened a new vista of investigations in the fi eld of evolution of life. Although the Precambrian encompasses 87% of the earth’s history, the pace of organismal evolution was quite slow. The life forms as categorised today in the three principal domains viz. the Bacteria, the Archaea and the Eucarya evolved during this period. In this paper, we review the advancements made in the Precambrian palaeontology and its contribution in understanding the evolution of life forms on earth. These studies have enriched the data base on the Precambrian life. Most of the direct evidence includes fossil prokaryotes, protists, advanced algal fossils, acritarchs, and the indirect evidence is represented by the stromatolites, trace fossils and geochemical fossils signatures. The Precambrian fossils are preserved in the form of compressions, impressions, and permineralized and biomineralized remains. [Sharma M and Shukla Y 2009 The evolution and distribution of life in the Precambrian eon-Global perspective and the Indian record; J. Biosci. 34 765–776] DOI 10.1007/s12038-009-0065-8 1. Introduction suggested that all the living forms can be grouped into three principal domains viz. the Bacteria, the Archaea, and The sudden appearance and radiation of both skeletal and the Eucarya (Woese 1987, 2002; Woese et al. -
Geologic History of the Earth 1 the Precambrian
Geologic History of the Earth 1 algae = very simple plants that Geologists are scientists who study the structure grow in or near the water of rocks and the history of the Earth. By looking at first = in the beginning at and examining layers of rocks and the fossils basic = main, important they contain they are able to tell us what the beginning = start Earth looked like at a certain time in history and billion = a thousand million what kind of plants and animals lived at that breathe = to take air into your lungs and push it out again time. carbon dioxide = gas that is produced when you breathe Scientists think that the Earth was probably formed at the same time as the rest out of our solar system, about 4.6 billion years ago. The solar system may have be- certain = special gun as a cloud of dust, from which the sun and the planets evolved. Small par- complex = something that has ticles crashed into each other to create bigger objects, which then turned into many different parts smaller or larger planets. Our Earth is made up of three basic layers. The cen- consist of = to be made up of tre has a core made of iron and nickel. Around it is a thick layer of rock called contain = have in them the mantle and around that is a thin layer of rock called the crust. core = the hard centre of an object Over 4 billion years ago the Earth was totally different from the planet we live create = make on today. -
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. -
The Cambrian Explosion: a Big Bang in the Evolution of Animals
The Cambrian Explosion A Big Bang in the Evolution of Animals Very suddenly, and at about the same horizon the world over, life showed up in the rocks with a bang. For most of Earth’s early history, there simply was no fossil record. Only recently have we come to discover otherwise: Life is virtually as old as the planet itself, and even the most ancient sedimentary rocks have yielded fossilized remains of primitive forms of life. NILES ELDREDGE, LIFE PULSE, EPISODES FROM THE STORY OF THE FOSSIL RECORD The Cambrian Explosion: A Big Bang in the Evolution of Animals Our home planet coalesced into a sphere about four-and-a-half-billion years ago, acquired water and carbon about four billion years ago, and less than a billion years later, according to microscopic fossils, organic cells began to show up in that inert matter. Single-celled life had begun. Single cells dominated life on the planet for billions of years before multicellular animals appeared. Fossils from 635,000 million years ago reveal fats that today are only produced by sponges. These biomarkers may be the earliest evidence of multi-cellular animals. Soon after we can see the shadowy impressions of more complex fans and jellies and things with no names that show that animal life was in an experimental phase (called the Ediacran period). Then suddenly, in the relatively short span of about twenty million years (given the usual pace of geologic time), life exploded in a radiation of abundance and diversity that contained the body plans of almost all the animals we know today. -
Trace Fossils and Substrates of the Terminal Proterozoic–Cambrian Transition: Implications for the Record of Early Bilaterians and Sediment Mixing
Trace fossils and substrates of the terminal Proterozoic–Cambrian transition: Implications for the record of early bilaterians and sediment mixing Mary L. Droser*†,So¨ ren Jensen*, and James G. Gehling‡ *Department of Earth Sciences, University of California, Riverside, CA 92521; and ‡South Australian Museum, Division of Natural Sciences, North Terrace, Adelaide 5000, South Australia, Australia Edited by James W. Valentine, University of California, Berkeley, CA, and approved August 16, 2002 (received for review May 29, 2002) The trace fossil record is important in determining the timing of the appearance of bilaterian animals. A conservative estimate puts this time at Ϸ555 million years ago. The preservational potential of traces made close to the sediment–water interface is crucial to detecting early benthic activity. Our studies on earliest Cambrian sediments suggest that shallow tiers were preserved to a greater extent than typical for most of the Phanerozoic, which can be attributed both directly and indirectly to the low levels of sediment mixing. The low levels of sediment mixing meant that thin event beds were preserved. The shallow depth of sediment mixing also meant that muddy sediments were firm close to the sediment–water interface, increasing the likelihood of recording shallow-tier trace fossils in muddy sed- iments. Overall, trace fossils can provide a sound record of the onset of bilaterian benthic activity. he appearance and subsequent diversification of bilaterian Tanimals is a topic of current controversy (refs. 1–7; Fig. 1). Three principal sources of evidence exist: body fossils, trace fossils (trails, tracks, and burrows of animal activity recorded in the sedimentary record), and divergence times calculated by means of a molecular ‘‘clock.’’ The body fossil record indicates a geologically rapid diversification of bilaterian animals not much earlier than the Precambrian–Cambrian boundary, the so-called Cambrian explosion. -
A Fundamental Precambrian–Phanerozoic Shift in Earth's Glacial
Tectonophysics 375 (2003) 353–385 www.elsevier.com/locate/tecto A fundamental Precambrian–Phanerozoic shift in earth’s glacial style? D.A.D. Evans* Department of Geology and Geophysics, Yale University, P.O. Box 208109, 210 Whitney Avenue, New Haven, CT 06520-8109, USA Received 24 May 2002; received in revised form 25 March 2003; accepted 5 June 2003 Abstract It has recently been found that Neoproterozoic glaciogenic sediments were deposited mainly at low paleolatitudes, in marked qualitative contrast to their Pleistocene counterparts. Several competing models vie for explanation of this unusual paleoclimatic record, most notably the high-obliquity hypothesis and varying degrees of the snowball Earth scenario. The present study quantitatively compiles the global distributions of Miocene–Pleistocene glaciogenic deposits and paleomagnetically derived paleolatitudes for Late Devonian–Permian, Ordovician–Silurian, Neoproterozoic, and Paleoproterozoic glaciogenic rocks. Whereas high depositional latitudes dominate all Phanerozoic ice ages, exclusively low paleolatitudes characterize both of the major Precambrian glacial epochs. Transition between these modes occurred within a 100-My interval, precisely coeval with the Neoproterozoic–Cambrian ‘‘explosion’’ of metazoan diversity. Glaciation is much more common since 750 Ma than in the preceding sedimentary record, an observation that cannot be ascribed merely to preservation. These patterns suggest an overall cooling of Earth’s longterm climate, superimposed by developing regulatory feedbacks -
12.007 Geobiology Spring 2009
MIT OpenCourseWare http://ocw.mit.edu 12.007 Geobiology Spring 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. Geobiology 2009 Lecture 10 The Antiquity of Life on Earth Homework #5 Topics (choose 1): Describe criteria for biogenicity in microscopic fossils. How do the oldest describes fossils compare? Use this to argue one side of the Brasier-Schopf debate OR What are stromatolites; where are they found and how are they formed? Articulate the two sides of the debate on antiquity and biogenicity. Up to 4 pages, including figures. Due 3/31/2009 Need to know • How C and S- isotopic data in rocks are informative about the advent and antiquity of biogeochemical cycles • Morphological remains and the antiquity of life; how do we weigh the evidence? • Indicators of changes in atmospheric pO2 • A general view of the course of oxygenation of the atm-ocean system Readings for this lecture Schopf J.W. et al., (2002) Laser Raman Imagery of Earth’s earliest fossils. Nature 416, 73. Brasier M.D. et al., (2002) Questioning the evidence for Earth’s oldest fossils. Nature 416, 76. Garcia-Ruiz J.M., Hyde S.T., Carnerup A. M. , Christy v, Van Kranendonk M. J. and Welham N. J. (2003) Self-Assembled Silica-Carbonate Structures and Detection of Ancient Microfossils Science 302, 1194-7. Hofmann, H.J., Grey, K., Hickman, A.H., and Thorpe, R. 1999. Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia. Geological Society of America, Bulletin, v. 111 (8), p. -
Trace Fossils
C O N F E R E N C E R E P O R T S T race Fossils, Sm all Shelly Fossils an d th e Precam brian-Cam brian Boundary St. John's, New foundland, C anada, 8 一18 A ugust 1987 The Precam brian-Cam brian boundary m arks a fundam ental stratigraphic ranges of ichnotaxa are needed for m ore change in Ea rth history, the first developm ent of abundant sections, particularly in A ustralia and the R ussian Platform , skeletal and bioturbating orga nism s. A lthough there is to fu rthe r te st the co rrelation s. A c rita rch s ha ve no t be e n general agreem ent w ith the principle of placing the bound- as w idely studied, but presentations by G . Vidal (Sw eden), M . ary "as close as practical to the first appearance of abun- M oczydow ski (Poland) and X ing Y usheng em phasized their dant shelly fossils," m arked provincialism o f the earliest potential biostratigraphic utility in the boundary interval. sk eletal fossils an d the ir virtua l restric tio n to ca rbo na te facies have ham pered g lobal correlation in the boundary In the past, paleontologic studies in the Precam brian- C am brian boundary interval have focused upon the evolution interval (Cowie, 1985, Episo旦es v. 8, p. 93-98). of the biota. A m ajor them e of the conference was the need In A ugust of 1987, fifty geologists from ten countries m et to to reconsider the effects of environm ental and p reserva- consider a possible stratotype site in eastern N ew foundland. -
The Weeks Formation Konservat-Lagerstätte and the Evolutionary Transition of Cambrian Marine Life
Downloaded from http://jgs.lyellcollection.org/ by guest on October 1, 2021 Review focus Journal of the Geological Society Published Online First https://doi.org/10.1144/jgs2018-042 The Weeks Formation Konservat-Lagerstätte and the evolutionary transition of Cambrian marine life Rudy Lerosey-Aubril1*, Robert R. Gaines2, Thomas A. Hegna3, Javier Ortega-Hernández4,5, Peter Van Roy6, Carlo Kier7 & Enrico Bonino7 1 Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia 2 Geology Department, Pomona College, Claremont, CA 91711, USA 3 Department of Geology, Western Illinois University, 113 Tillman Hall, 1 University Circle, Macomb, IL 61455, USA 4 Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK 5 Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA 6 Department of Geology, Ghent University, Krijgslaan 281/S8, B-9000 Ghent, Belgium 7 Back to the Past Museum, Carretera Cancún, Puerto Morelos, Quintana Roo 77580, Mexico R.L.-A., 0000-0003-2256-1872; R.R.G., 0000-0002-3713-5764; T.A.H., 0000-0001-9067-8787; J.O.-H., 0000-0002- 6801-7373 * Correspondence: [email protected] Abstract: The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore margin of a carbonate platform, resembling the setting of the underlying Wheeler and Marjum formations. However, the Weeks fauna differs significantly in composition from the other remarkable biotas of the Cambrian Series 3 of Utah, suggesting a significant Guzhangian faunal restructuring. -
Cambrian Transition in the Southern Great Basin
The Sedimentary Record 2000; Shen and Schidlowski, 2000). Due to The Precambrian- endemic biotas and facies control, it is diffi- cult to correlate directly between siliciclas- Cambrian Transition in the tic- and carbonate-dominated successions. This is particularly true for the PC-C boundary interval because lowermost Southern Great Basin, USA Cambrian biotas are highly endemic and Frank A. Corsetti James W.Hagadorn individual, globally distributed guide fossils Department of Earth Science Department of Geology are lacking (Landing, 1988; Geyer and University of Southern California Amherst College Shergold, 2000). Los Angeles, CA 90089-0740 Amherst, MA 01002 Determination of a stratigraphic bound- [email protected] [email protected] ary generates a large amount of interest because it provides scientists with an oppor- ABSTRACT:The Precambrian-Cambrian boundary presents an interesting tunity to address a variety of related issues, stratigraphic conundrum: the trace fossil used to mark and correlate the base of the including whether the proposed boundary Cambrian, Treptichnus pedum, is restricted to siliciclastic facies, whereas position marks a major event in Earth histo- biomineralized fossils and chemostratigraphic signals are most commonly obtained ry. Sometimes the larger-scale meaning of from carbonate-dominated sections.Thus, it is difficult to correlate directly between the particular boundary can be lost during many of the Precambrian-Cambrian boundary sections, and to assess details of the the process of characterization. This is timing of evolutionary events that transpired during this interval of time.Thick demonstrated in a plot of PC-C boundary sections in the White-Inyo region of eastern California and western Nevada, USA, papers through time (Fig. -
Bedrock Geology of the Cape St. Mary's Peninsula
BEDROCK GEOLOGY OF THE CAPE ST. MARY’S PENINSULA, SOUTHWEST AVALON PENINSULA, NEWFOUNDLAND (INCLUDES PARTS OF NTS MAP SHEETS 1M/1, 1N/4, 1L/16 and 1K/13) Terence Patrick Fletcher Report 06-02 St. John’s, Newfoundland 2006 Department of Natural Resources Geological Survey COVER The Placentia Bay cliff section on the northern side of Hurricane Brook, south of St. Bride’s, shows the prominent pale limestones of the Smith Point Formation intervening between the mudstones of the Cuslett Member of the lower Bonavista Formation and those of the overlying Redland Cove Member of the Brigus Formation. The top layers of this marker limestone on the southwestern limb of the St. Bride’s Syncline contain the earliest trilobites found in this map area. Department of Natural Resources Geological Survey BEDROCK GEOLOGY OF THE CAPE ST. MARY’S PENINSULA, SOUTHWEST AVALON PENINSULA, NEWFOUNDLAND (INCLUDES PARTS OF NTS MAP SHEETS 1M/1, 1N/4, 1L/16 and 1K/13) Terence P. Fletcher Report 06-02 St. John’s, Newfoundland 2006 EDITING, LAYOUT AND CARTOGRAPHY Senior Geologist S.J. O’BRIEN Editor C.P.G. PEREIRA Graphic design, D. DOWNEY layout and J. ROONEY typesetting B. STRICKLAND Cartography D. LEONARD T. PALTANAVAGE T. SEARS Publications of the Geological Survey are available through the Geoscience Publications and Information Section, Geological Survey, Department of Natural Resources, P.O. Box 8700, St. John’s, NL, Canada, A1B 4J6. This publication is also available through the departmental website. Telephone: (709) 729-3159 Fax: (709) 729-4491 Geoscience Publications and Information Section (709) 729-3493 Geological Survey - Administration (709) 729-4270 Geological Survey E-mail: [email protected] Website: http://www.gov.nl.ca/mines&en/geosurv/ Author’s Address: Dr.