DOCSLIB.ORG

A Formal Model for the Geologic Time Scale and Global Stratotype Section and Point, Compatible with Geospatial Information Transfer Standards

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Formal Model for the Geologic Time Scale and Global Stratotype Section and Point, Compatible with Geospatial Information Transfer Standards A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards Simon J.D. Cox* CSIRO Exploration and Mining, P.O. Box 1130, Bentley, 6102 WA, Australia Stephen M. Richard* Arizona Geological Survey, 416 W. Congress St., #100, Tucson, Arizona 85701, USA ABSTRACT A formal notation is used so as to provide a Structure of the Paper rigorous description of the various elements The geologic time scale is a complex data required to describe the structure and cali- This paper is structured as follows. An in- structure composed of abstract elements bration of the time scale in a manner that troduction and summary of key aspects of that represent time intervals and instants allows the logical consistency of the model stratigraphic methodology is provided in the and their relationships with speci®c con- to be evaluated. This is important, since al- ®rst section. Next, we brie¯y introduce infor- crete representations in the geologic record though stratigraphic methodology is one of mation standardization activities that provide as well as the observations made of those the most rigorously studied aspects of geo- the modeling framework and notation used in concrete representations. The International logical practice, it has evolved throughout this study. We then describe a general frame- Union of Geological Sciences' International the era of historical geology. There have been work for temporal reference systems and de- Commission on Stratigraphy guidelines signi®cant changes in best practice, in partic- velop a formal model for the geologic time recommends a very precise usage of the re- scale and its calibration within that frame- lationships between these components in ular in the shift from characterizing units to de®ning the boundaries between them. Nev- work. This conceptual model is used as the order to establish a standard time scale for basis for an XML implementation of the mod- use in global correlations. However, this ertheless, the time scale itself remains based on named units and eras. Other residues of el, presented using example documents de- has been primarily described in text. Here, scribing the International Union of Geological earlier practice remain visible in the descrip- we present a formal representation of the Sciences (IUGS)'s International Commission tion of the time scale, particularly where model using the Uni®ed Modeling Lan- on Stratigraphy (ICS) time scale with global agreement on the application of current prac- guage (UML). The model builds on existing stratotype section and point (GSSP) referenc- tices is incomplete. In this context, a rigorous components from standardization of geo- es. Some theoretical issues arising from the characterization of the relationships between spatial information systems. The use of a models are discussed. A summary of UML formal notation enforces precise de®nition the elements of the time scale, the evidence notation is given in Appendix 1. of the relationships between the compo- in the geologic record, and the application of nents. The UML platform also supports a speci®c procedures to effect numeric calibra- THE GEOLOGIC TIME SCALE direct mapping to an eXtensible Markup tion of the scale is essential. Language (XML)±based ®le format, which A secondary goal is to develop a machine- Units, Boundaries, and Stratotypes may be used for the exchange of strati- processable format for the exchange of in- graphic information using Web-service formation related to the time scale. The mod- The conventional geologic time scale is a interfaces. eling notation selected (Uni®ed Modeling reference system de®ned by a contiguous se- Language [UML]) is a commonly used soft- Keywords: time scale, stratigraphy, infor- quence of time intervals, each identi®ed with ware engineering standard, so the model can mation model, XML, UML. a name. These are recursively subdivided, re- be implemented easily on various standard sulting in a hierarchy composed of intervals INTRODUCTION platforms. In particular, an eXtensible Mark- of various ranks. The units in the scale are up Language (XML) document schema can ordered, so the relative temporal positions of Goals be derived directly from the model. The geologic objects and events may be recorded XML implementation supports lossless data or asserted, denoted by the names of units The goal of this paper is to provide an in- transfer using standard Web protocols, and it from the scale. formation model for the geologic time scale. provides a basis for formal encoding and As originally conceived, units of the geo- *E-mails: [email protected]; steve.richard@ computer processing of information that is logic time scale identify intervals, each cor- azgs.az.gov. the basis for de®ning geologic time scales. responding to the time during which a partic- Geosphere; December 2005; v. 1; no. 3; p. 119±137; doi: 10.1130/GES00022.1; 6 ®gures; 1 table. For permission to copy, contact [email protected] q 2005 Geological Society of America 119 Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/1/3/119/3332362/i1553-040X-1-3-119.pdf by guest on 26 September 2021 S.J.D. COX and S.M. RICHARD ular sequence of rocks (stratigraphic unit) was plete time scale. However, a complete com- called global standard stratigraphic ages deposited. Historically, the units were chosen pilation is possible only based on sections that (GSSA). because, within the region where they were explicitly include boundaries. Implicitly, the Ages recorded using named units from the de®ned, they could be recognized through uni- shift from unit stratotypes to boundary stra- geologic time scale allow ordering without re- form lithological and biostratigraphic charac- totypes recognizes that, although the time quiring numeric values. However, while the teristics, which correlated with a relatively scale is based on time intervals covering the assignment of numeric values is not necessary consistent geological environment in a single domain, its logical consistency is contingent for use of the time scale, it is convenient to period. The representative object or prototype on a globally recognizable, unambiguously or- calibrate the time scale against a time line. For in a stratigraphy de®ned in this way is a type dered sequence of events. those boundaries de®ned by a stratotype, it section for the geologic unit of interest, for- provides a locality from which specimens may mally called a unit stratotype. This approach Governance and Calibration be collected, the age of which may then be supports stratigraphic practice in which as- measured using quantitative techniques. When signment of strata to a unit is based on the the material in the stratotype is unsuitable or The guidelines of the ICS formalize this presence of characteristics that match the stra- insuf®cient for estimating the numerical age, practice (Remane et al., 1996). These are used ta to the type section for the unit. The basis then specimens from locations that can be cor- for the matching, or correlation, may be lith- by the GSSP project. The GSSP provides a related with the stratotype may be used in- ologic, paleontologic, or geochronologic, de- forum for the speci®cation of boundary stra- stead. The experimentally determined dates ®ning lithostratigraphic, biostratigraphic, and totypes used for correlation on a global scale. from such specimens provide an estimate of chronostratigraphic units. Local stratigraphic de®nitions will still be the chronologic position (numeric coordinate Construction of a consistent time scale us- used for local stratigraphic correlations, but on a time line) of the boundary. ing the unit stratotype approach depends crit- global stratotypes provide the ultimate refer- ically on stratigraphic completeness and the ence for inter-regional correlation. Local Formalization ability to geochronologically correlate bodies stratigraphic schemes must be related to the of rock globally. However, the corollary of a GSSP stratotypes through a coherent chain of This overview of the construction and cal- model based on continuity within units is that correlations in order to be connected to the ibration of the geologic time scale refers to a the boundaries between units correspond with global time scale. Alternatively, geochrono- variety of concepts, instances of which are re- changes in the geological environment and metric methods may be used for objects with- lated to each other in various ways. Effective discontinuities in the stratigraphic record. in those parts of the time scale where chro- use of the time scale for stratigraphic corre- Such discontinuities, and the incongruity of nometric values for the boundaries have been lation requires that these concepts and their lithostratigraphic and biostratigraphic units accepted. interrelationships be precisely understood. with chronostratigraphic units, result in incon- Physical changes in the rock record ob- There is a signi®cant body of literature that sistent and ambiguous correlation in the vicin- served at the boundary horizon are inferred to describes the system, an introduction to which ity of chronostratigraphic unit boundaries. result from a geologic event or events. Ideally, is provided by Walsh et al. (2004) and refer- For these reasons, the complementary ap- these are manifested globally by similar or re- ences therein, in the ICS guidelines (Remane proach to speci®cation of the time scale is lated physical changes in sediment deposited et al., 1996), and in the overview to the In- now preferred, focusing on the boundaries at the same time. Correlation of the boundary ternational Stratigraphic Chart (International rather than the intervals. Within this model, horizons by correlation of physical changes in Commission on Stratigraphy, 2004). the focus is on a representative point within other stratigraphic sections is the basis for es- However, the model for the construction the geologic horizon corresponding to the tablishing the relative age of strata throughout and calibration of the geologic time scale has boundary of interest, formally called a bound- Earth.
Load more

Recommended publications
  • Do Gssps Render Dual Time-Rock/Time Classification and Nomenclature Redundant?
    Do GSSPs render dual time-rock/time classification and nomenclature redundant? Ismael Ferrusquía-Villafranca1 Robert M. Easton2 and Donald E. Owen3 1Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, México, DF, MEX, 45100, e-mail: [email protected] 2Ontario Geological Survey, Precambrian Geoscience Section, 933 Ramsey Lake Road, B7064 Sudbury, Ontario P3E 6B5, e-mail: [email protected] 3Department of Geology, Lamar University, Beaumont, Texas 77710, e-mail: [email protected] ABSTRACT: The Geological Society of London Proposal for “…ending the distinction between the dual stratigraphic terminology of time-rock units (of chronostratigraphy) and geologic time units (of geochronology). The long held, but widely misunderstood distinc- tion between these two essentially parallel time scales has been rendered unnecessary by the adoption of the global stratotype sections and points (GSSP-golden spike) principle in defining intervals of geologic time within rock strata.” Our review of stratigraphic princi- ples, concepts, models and paradigms through history clearly shows that the GSL Proposal is flawed and if adopted will be of disservice to the stratigraphic community. We recommend the continued use of the dual stratigraphic terminology of chronostratigraphy and geochronology for the following reasons: (1) time-rock (chronostratigraphic) and geologic time (geochronologic) units are conceptually different; (2) the subtended time-rock’s unit space between its “golden spiked-marked”
    [Show full text]
  • “Anthropocene” Epoch: Scientific Decision Or Political Statement?
    The “Anthropocene” epoch: Scientific decision or political statement? Stanley C. Finney*, Dept. of Geological Sciences, California Official recognition of the concept would invite State University at Long Beach, Long Beach, California 90277, cross-disciplinary science. And it would encourage a mindset USA; and Lucy E. Edwards**, U.S. Geological Survey, Reston, that will be important not only to fully understand the Virginia 20192, USA transformation now occurring but to take action to control it. … Humans may yet ensure that these early years of the ABSTRACT Anthropocene are a geological glitch and not just a prelude The proposal for the “Anthropocene” epoch as a formal unit of to a far more severe disruption. But the first step is to recognize, the geologic time scale has received extensive attention in scien- as the term Anthropocene invites us to do, that we are tific and public media. However, most articles on the in the driver’s seat. (Nature, 2011, p. 254) Anthropocene misrepresent the nature of the units of the International Chronostratigraphic Chart, which is produced by That editorial, as with most articles on the Anthropocene, did the International Commission on Stratigraphy (ICS) and serves as not consider the mission of the International Commission on the basis for the geologic time scale. The stratigraphic record of Stratigraphy (ICS), nor did it present an understanding of the the Anthropocene is minimal, especially with its recently nature of the units of the International Chronostratigraphic Chart proposed beginning in 1945; it is that of a human lifespan, and on which the units of the geologic time scale are based.
    [Show full text]
  • Scientific Dating of Pleistocene Sites: Guidelines for Best Practice Contents
    Consultation Draft Scientific Dating of Pleistocene Sites: Guidelines for Best Practice Contents Foreword............................................................................................................................. 3 PART 1 - OVERVIEW .............................................................................................................. 3 1. Introduction .............................................................................................................. 3 The Quaternary stratigraphical framework ........................................................................ 4 Palaeogeography ........................................................................................................... 6 Fitting the archaeological record into this dynamic landscape .............................................. 6 Shorter-timescale division of the Late Pleistocene .............................................................. 7 2. Scientific Dating methods for the Pleistocene ................................................................. 8 Radiometric methods ..................................................................................................... 8 Trapped Charge Methods................................................................................................ 9 Other scientific dating methods ......................................................................................10 Relative dating methods ................................................................................................10
    [Show full text]
  • Zerohack Zer0pwn Youranonnews Yevgeniy Anikin Yes Men
    Zerohack Zer0Pwn YourAnonNews Yevgeniy Anikin Yes Men YamaTough Xtreme x-Leader xenu xen0nymous www.oem.com.mx www.nytimes.com/pages/world/asia/index.html www.informador.com.mx www.futuregov.asia www.cronica.com.mx www.asiapacificsecuritymagazine.com Worm Wolfy Withdrawal* WillyFoReal Wikileaks IRC 88.80.16.13/9999 IRC Channel WikiLeaks WiiSpellWhy whitekidney Wells Fargo weed WallRoad w0rmware Vulnerability Vladislav Khorokhorin Visa Inc. Virus Virgin Islands "Viewpointe Archive Services, LLC" Versability Verizon Venezuela Vegas Vatican City USB US Trust US Bankcorp Uruguay Uran0n unusedcrayon United Kingdom UnicormCr3w unfittoprint unelected.org UndisclosedAnon Ukraine UGNazi ua_musti_1905 U.S. Bankcorp TYLER Turkey trosec113 Trojan Horse Trojan Trivette TriCk Tribalzer0 Transnistria transaction Traitor traffic court Tradecraft Trade Secrets "Total System Services, Inc." Topiary Top Secret Tom Stracener TibitXimer Thumb Drive Thomson Reuters TheWikiBoat thepeoplescause the_infecti0n The Unknowns The UnderTaker The Syrian electronic army The Jokerhack Thailand ThaCosmo th3j35t3r testeux1 TEST Telecomix TehWongZ Teddy Bigglesworth TeaMp0isoN TeamHav0k Team Ghost Shell Team Digi7al tdl4 taxes TARP tango down Tampa Tammy Shapiro Taiwan Tabu T0x1c t0wN T.A.R.P. Syrian Electronic Army syndiv Symantec Corporation Switzerland Swingers Club SWIFT Sweden Swan SwaggSec Swagg Security "SunGard Data Systems, Inc." Stuxnet Stringer Streamroller Stole* Sterlok SteelAnne st0rm SQLi Spyware Spying Spydevilz Spy Camera Sposed Spook Spoofing Splendide
    [Show full text]
  • Formal Ratification of the Subdivision of the Holocene Series/ Epoch
    Article 1 by Mike Walker1*, Martin J. Head 2, Max Berkelhammer3, Svante Björck4, Hai Cheng5, Les Cwynar6, David Fisher7, Vasilios Gkinis8, Antony Long9, John Lowe10, Rewi Newnham11, Sune Olander Rasmussen8, and Harvey Weiss12 Formal ratification of the subdivision of the Holocene Series/ Epoch (Quaternary System/Period): two new Global Boundary Stratotype Sections and Points (GSSPs) and three new stages/ subseries 1 School of Archaeology, History and Anthropology, Trinity Saint David, University of Wales, Lampeter, Wales SA48 7EJ, UK; Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Wales SY23 3DB, UK; *Corresponding author, E-mail: [email protected] 2 Department of Earth Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario LS2 3A1, Canada 3 Department of Earth and Environmental Sciences, University of Illinois, Chicago, Illinois 60607, USA 4 GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sölveg 12, SE-22362, Lund, Sweden 5 Institute of Global Change, Xi’an Jiaotong University, Xian, Shaanxi 710049, China; Department of Earth Sciences, University of Minne- sota, Minneapolis, MN 55455, USA 6 Department of Biology, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada 7 Department of Earth Sciences, University of Ottawa, Ottawa K1N 615, Canada 8 Centre for Ice and Climate, The Niels Bohr Institute, University of Copenhagen, Julian Maries Vej 30, DK-2100, Copenhagen, Denmark 9 Department of Geography, Durham University, Durham DH1 3LE, UK 10
    [Show full text]
  • Anthropocene
    ANTHROPOCENE Perrin Selcer – University of Michigan Suggested Citation: Selcer, Perrin, “Anthropocene,” Encyclopedia of the History of Science (March 2021) doi: 10.34758/be6m-gs41 From the perspective of the history of science, the origin of the Anthropocene appears to be established with unusual precision. In 2000, Nobel laureate geochemist Paul Crutzen proposed that the planet had entered the Anthropocene, a new geologic epoch in which humans had become the primary driver of global environmental change. This definition should be easy to grasp for a generation that came of age during a period when anthropogenic global warming dominated environmental politics. The Anthropocene extends the primacy of anthropogenic change from the climate system to nearly every other planetary process: the cycling of life-sustaining nutrients; the adaptation, distribution, and extinction of species; the chemistry of the oceans; the erosion of mountains; the flow of freshwater; and so on. The human footprint covers the whole Earth. Like a giant balancing on the globe, each step accelerates the rate of change, pushing the planet out of the stable conditions of the Holocene Epoch that characterized the 11,700 years since the last glacial period and into a turbulent unknown with “no analog” in the planet’s 4.5 billion-year history. It is an open question how much longer humanity can keep up. For its advocates, the Anthropocene signifies more than a catastrophic regime shift in planetary history. It also represents a paradigm shift in how we know global change from environmental science to Earth System science. Explaining the rise the Anthropocene, therefore, requires grappling with claims of both ontological and epistemological rupture; that is, we must explore the entangled histories of the Earth and its observers.
    [Show full text]
  • North American Stratigraphic Code1
    NORTH AMERICAN STRATIGRAPHIC CODE1 North American Commission on Stratigraphic Nomenclature FOREWORD TO THE REVISED EDITION FOREWORD TO THE 1983 CODE By design, the North American Stratigraphic Code is The 1983 Code of recommended procedures for clas- meant to be an evolving document, one that requires change sifying and naming stratigraphic and related units was pre- as the field of earth science evolves. The revisions to the pared during a four-year period, by and for North American Code that are included in this 2005 edition encompass a earth scientists, under the auspices of the North American broad spectrum of changes, ranging from a complete revision Commission on Stratigraphic Nomenclature. It represents of the section on Biostratigraphic Units (Articles 48 to 54), the thought and work of scores of persons, and thousands of several wording changes to Article 58 and its remarks con- hours of writing and editing. Opportunities to participate in cerning Allostratigraphic Units, updating of Article 4 to in- and review the work have been provided throughout its corporate changes in publishing methods over the last two development, as cited in the Preamble, to a degree unprece- decades, and a variety of minor wording changes to improve dented during preparation of earlier codes. clarity and self-consistency between different sections of the Publication of the International Stratigraphic Guide in Code. In addition, Figures 1, 4, 5, and 6, as well as Tables 1 1976 made evident some insufficiencies of the American and Tables 2 have been modified. Most of the changes Stratigraphic Codes of 1961 and 1970. The Commission adopted in this revision arose from Notes 60, 63, and 64 of considered whether to discard our codes, patch them over, the Commission, all of which were published in the AAPG or rewrite them fully, and chose the last.
    [Show full text]
  • INTERNATIONAL CHRONOSTRATIGRAPHIC CHART International Commission on Stratigraphy V 2020/03
    INTERNATIONAL CHRONOSTRATIGRAPHIC CHART www.stratigraphy.org International Commission on Stratigraphy v 2020/03 numerical numerical numerical numerical Series / Epoch Stage / Age Series / Epoch Stage / Age Series / Epoch Stage / Age GSSP GSSP GSSP GSSP EonothemErathem / Eon System / Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) Eonothem / EonErathem / Era System / Period GSSA age (Ma) present ~ 145.0 358.9 ±0.4 541.0 ±1.0 U/L Meghalayan 0.0042 Holocene M Northgrippian 0.0082 Tithonian Ediacaran L/E Greenlandian 0.0117 152.1 ±0.9 ~ 635 U/L Upper Famennian Neo- 0.129 Upper Kimmeridgian Cryogenian M Chibanian 157.3 ±1.0 Upper proterozoic ~ 720 0.774 372.2 ±1.6 Pleistocene Calabrian Oxfordian Tonian 1.80 163.5 ±1.0 Frasnian 1000 L/E Callovian Quaternary 166.1 ±1.2 Gelasian 2.58 382.7 ±1.6 Stenian Bathonian 168.3 ±1.3 Piacenzian Middle Bajocian Givetian 1200 Pliocene 3.600 170.3 ±1.4 387.7 ±0.8 Meso- Zanclean Aalenian Middle proterozoic Ectasian 5.333 174.1 ±1.0 Eifelian 1400 Messinian Jurassic 393.3 ±1.2 Calymmian 7.246 Toarcian Devonian Tortonian 182.7 ±0.7 Emsian 1600 11.63 Pliensbachian Statherian Lower 407.6 ±2.6 Serravallian 13.82 190.8 ±1.0 Lower 1800 Miocene Pragian 410.8 ±2.8 Proterozoic Neogene Sinemurian Langhian 15.97 Orosirian 199.3 ±0.3 Lochkovian Paleo- Burdigalian Hettangian proterozoic 2050 20.44 201.3 ±0.2 419.2 ±3.2 Rhyacian Aquitanian Rhaetian Pridoli 23.03 ~ 208.5 423.0 ±2.3 2300 Ludfordian 425.6 ±0.9 Siderian Mesozoic Cenozoic Chattian Ludlow
    [Show full text]
  • Are We Now Living in the Anthropocene?
    Are we now living in the Anthropocene? Jan Zalasiewicz, Mark Williams, Department of Geology, numerical date. Formal adoption of this term in the near future University of Leicester, Leicester LE1 7RH, UK; Alan Smith, will largely depend on its utility, particularly to earth scientists Department of Earth Sciences, University of Cambridge, working on late Holocene successions. This datum, from the Cambridge CB2 3EQ, UK; Tiffany L. Barry, Angela L. Coe, perspective of the far future, will most probably approximate a Department of Earth Sciences, The Open University, Walton distinctive stratigraphic boundary. Hall, Milton Keynes MK7 6AA, UK; Paul R. Bown, Department of Earth Sciences, University College London, Gower Street, INTRODUCTION London, WC1E 6BT, UK; Patrick Brenchley, Department of In 2002, Paul Crutzen, the Nobel Prize–winning chemist, sug- Earth Sciences, University of Liverpool, Liverpool L69 3BX, UK; gested that we had left the Holocene and had entered a new David Cantrill, Royal Botanic Gardens, Birdwood Avenue, Epoch—the Anthropocene—because of the global environ- South Yarra, Melbourne, Victoria, Australia; Andrew Gale, mental effects of increased human population and economic School of Earth and Environmental Sciences, University of development. The term has entered the geological literature Portsmouth, Portsmouth, Hampshire PO1 3QL, UK, and informally (e.g., Steffen et al., 2004; Syvitski et al., 2005; Cross- Department of Palaeontology, Natural History Museum, land, 2005; Andersson et al., 2005) to denote the contemporary London SW7 5BD, UK; Philip Gibbard, Department of global environment dominated by human activity. Here, mem- Geography, University of Cambridge, Downing Place, bers of the Stratigraphy Commission of the Geological Society Cambridge CB2 3EN, UK; F.
    [Show full text]
  • 23. the Holocene Boundary Stratotype: Local and Global Problems
    PLEISTOCENE/HOLOCENE BOUNDARY 281 E. OLAUSSON (ED.) 23. THE HOLOCENE BOUNDARY STRATOTYPE: LOCAL AND GLOBAL PROBLEMS RHODES W. FAIRBRIDGE Department of GeologicaJ Sciences, Columbia University, New York, N.Y. 10027. U.S.A. TNTRODUCTION The late-glacial elirnatic warming began in the tropics around 14 000-13 500 years B.P. I attributed this (1961) to the rising solar radiation predicted by Milankovitch and also at the same time noted the inverse relationship that existed between 14C flux and mean temperature (and eustatic sea level). The warm-up of the southern hemisphere, with its oceanic continuity, was extremely rapid. Not so the northern hemisphere with its high continentality and extensive ice sheets where in the ocean it was around 3 000 years later (Hays et al. 1977, Salinger 1981). lndeed, as one goes farther north, the Postglacial warm maximum is found to be younger and younger, until in the high Arctic it was as late as 6 000 years B.P. a classic "retardation" phenomenon (Fairbridge 1961), due largely to oceanic feed-back (Ruddi­ man and Meintyre 1981). If one selects elirnatic proxies from different parts of the world it becomes all-too evident that one could select anything from 14 000 to 6 000 years B.P. as the most suitable time plane where a stratotype might be established (Fig. 23:1). In the early discussions, the Russian specialists tended to favour a early date, perhaps 12 000 to 12 500 years B.P. On the other hand, some of the Americans, with experience in Alaska, wanted the date closer to 6 000 years B.P.
    [Show full text]
  • International Chronostratigraphic Chart
    INTERNATIONAL CHRONOSTRATIGRAPHIC CHART www.stratigraphy.org International Commission on Stratigraphy v 2018/07 numerical numerical numerical Eonothem numerical Series / Epoch Stage / Age Series / Epoch Stage / Age Series / Epoch Stage / Age GSSP GSSP GSSP GSSP EonothemErathem / Eon System / Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) / Eon Erathem / Era System / Period GSSA age (Ma) present ~ 145.0 358.9 ± 0.4 541.0 ±1.0 U/L Meghalayan 0.0042 Holocene M Northgrippian 0.0082 Tithonian Ediacaran L/E Greenlandian 152.1 ±0.9 ~ 635 Upper 0.0117 Famennian Neo- 0.126 Upper Kimmeridgian Cryogenian Middle 157.3 ±1.0 Upper proterozoic ~ 720 Pleistocene 0.781 372.2 ±1.6 Calabrian Oxfordian Tonian 1.80 163.5 ±1.0 Frasnian Callovian 1000 Quaternary Gelasian 166.1 ±1.2 2.58 Bathonian 382.7 ±1.6 Stenian Middle 168.3 ±1.3 Piacenzian Bajocian 170.3 ±1.4 Givetian 1200 Pliocene 3.600 Middle 387.7 ±0.8 Meso- Zanclean Aalenian proterozoic Ectasian 5.333 174.1 ±1.0 Eifelian 1400 Messinian Jurassic 393.3 ±1.2 7.246 Toarcian Devonian Calymmian Tortonian 182.7 ±0.7 Emsian 1600 11.63 Pliensbachian Statherian Lower 407.6 ±2.6 Serravallian 13.82 190.8 ±1.0 Lower 1800 Miocene Pragian 410.8 ±2.8 Proterozoic Neogene Sinemurian Langhian 15.97 Orosirian 199.3 ±0.3 Lochkovian Paleo- 2050 Burdigalian Hettangian 201.3 ±0.2 419.2 ±3.2 proterozoic 20.44 Mesozoic Rhaetian Pridoli Rhyacian Aquitanian 423.0 ±2.3 23.03 ~ 208.5 Ludfordian 2300 Cenozoic Chattian Ludlow 425.6 ±0.9 Siderian 27.82 Gorstian
    [Show full text]
  • Geological Classification the Term 'Anthropocene'
    Downloaded from http://sp.lyellcollection.org/ by guest on October 26, 2013 Geological Society, London, Special Publications Online First The term 'Anthropocene' in the context of formal geological classification P. L. Gibbard and M. J. C. Walker Geological Society, London, Special Publications, first published October 25, 2013; doi 10.1144/SP395.1 Email alerting click here to receive free e-mail alerts when service new articles cite this article Permission click here to seek permission to re-use all or request part of this article Subscribe click here to subscribe to Geological Society, London, Special Publications or the Lyell Collection How to cite click here for further information about Online First and how to cite articles Notes © The Geological Society of London 2013 The term ‘Anthropocene’ in the context of formal geological classification P. L. GIBBARD1* & M. J. C. WALKER2 1Department of Geography, Cambridge Quaternary, University of Cambridge, Cambridge CB2 3EN, UK 2School of Archaeology, History and Anthropology, Trinity Saint David, University of Wales, Lampeter SA48 7ED, UK *Corresponding author (e-mail: [email protected]) Abstract: In recent years, ‘Anthropocene’ has been proposed as an informal stratigraphic term to denote the current interval of anthropogenic global environmental change. A case has also been made to formalize it as a series/epoch, based on the recognition of a suitable marker event, such as the start of the Industrial Revolution in northern Europe. For the Anthropocene to merit formal definition, a global signature distinct from that of the Holocene is required that is marked by novel biotic, sedimentary and geochemical change.
    [Show full text]