DOCSLIB.ORG

Stratigraphic Nomenclature and Description STRATIGRAPHIC NOMENCLATURE and DESCRIPTION

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Stratigraphic Nomenclature and Description STRATIGRAPHIC NOMENCLATURE and DESCRIPTION 42 Stratigraphic nomenclature and description STRATIGRAPHIC NOMENCLATURE AND DESCRIPTION HE ROCKS OF THE UNITED STATES are stratigraphic rank, and (3) is mappable. The unit may Tclassified for mapping purposes by a complex be formal: that is, it may be defined by standards of scheme of named material and temporal or geologic the presently (1983) accepted code, or may have been time terms. Most of the time terms (for example, defined under a previously accepted (1933, 1961, Cretaceous) were defined and first used by European 1970) code, or it may have been named and found! geologists and have since been accepted by geologists useful before the writing of any code and has gained in most other parts of the world. As parts of the acceptance through common usage. United States were mapped geologically, local Formal geologic names are those that have been divisions of rocks were recognized and named in defined according to the standards of the time in individual study areas. Lithology, rather than faunal which they were introduced. Units named and found assemblages, is the basis of this local classification, useful before 1983, the publication date of the most principally to aid in recognizing and mapping the recent code, are not discarded just because they were units so as to summarize the geologic history of each not defined according to current standards. Map wits area and evaluate the geologic resources. may also be informal and not defined by any stand- The stratigraphic units discussed in this chapter are ard. Any author using informal names should clearly classified into categories and ranks. The first category distinguish them from formal names. includes "material units" that are called lithostrati- graphic, lithodemic, allostratigraphic, magnetopolar- ity, or pedostratigraphic units in the North American GEOLOGICNAMES UNITS AND THE Stratigraphic Code (NASC) by the North American Commission on Stratigraphic Nomenclature (1983, p. 852). Lithostratigraphic unit is a term much used out- Because the Geological Survey examines various side the United States (International Subcommission aspects of geology throughout the United States, all on Stratigraphic Classification). Some lithostrati- its publications adhere to broadly uniform procedures graphic units may have faunal boundaries that coin- in dealing with the nomenclature and classification of cide with lithologic ones. Uncertainties in interpreting rock masses. The responsibility for this conformity is original definitions of lithologic units, or in correlating delegated to a group of Survey geologists assigned to them with units near or far, have led to many local one of the Geologic Names Unit (GNU) staffs in geologic names and to increasing numbers of units Reston, Va., Denver, Colo., and Menlo Park, Calif., each year. The second category is the "temporal under the technical guidance of the Geologic Names units" which are chronostratigraphic, geochronologic, Committee (GNC). geochronometric, polarity-chronostratigraphic, The Geologic Names Committee was organized in polarity-chronologic, and diachronic units. 1899 to consider all names of geologic formations and The term "geologic name" has evolved in its appli- other divisions of rock classifications, to determine cation by the Survey since the late 19th century. At whether the names comply with nomenclature used in that time the Geologic Names Committee (or GNC) previously published Survey reports, and to reconn- not only considered names for lithologic units and the mend policy on stratigraphic nomenclature. Members geologic age terms applied to them but also adjudi- of the committee are appointed by the Chief Geologist cated (1) the correct use of petrologic terms and and are responsible to him through authority dele- structural terms and their symbols, and (2) the apt- gated by the Director. The members of the GNC are ness of colors, patterns, and all other symbols used on chosen for their experience and knowledge in the geologic maps and reports published by the Survey. science. In addition to the chairman, the committee The term "geologic name" as used in STA is the currently consists of geologists chosen from the three name of a defined rock body, or the local name ap- centers (Reston, Va., Denver, Colo., and Menlo Park, plied to a mapped rock unit. The map unit is recog- Calif .). nized by its lithologic content (homogeneous or The Geologic Names Committee defines and heterogeneous) and its boundaries. It (1) is assigned a recommends policy and rules governing stratigralphic place within the geologic age sequence, (2) has a nomenclature and classification in all manuscript$;and Stratigraphic nomenclature and description 43 maps originating in the U.S. Geological Survey and names of the United States as they are used in concerning the geology of the United States. The publications. These records are available for reference actions of GNC apply whether these reports and maps at all times to all geologists inside and outside the are to be published by the Survey or by an outside Survey. A geologist who plans to name a forinal organization, and whether they result wholly or partly stratigraphic unit may reserve the geographic name from the work of Geological Survey employees. with one of the GNU staffs in Denver, Menlo Park, Except for papers intended as abstracts for talks or or Reston so that other geologists who may inquire for some papers in the Open-File Report series, every about the name can be informed of the first author's manuscript that is written by a Survey author and intention. If that geographic name is already reserved, that contains stratigraphic names is read and an author then has an opportunity to select another approved by a member of a GNU staff before its suitable name. Proposals for new nomenclature and publication is authorized by the Director. Technical revisions of existing nomenclature are made in problems, such as differences of opinion among reports that are published in recognized scientific Survey authors or nonconformance to Survey policy mediums as defined by the 1983 code. Proposals will or to the North American Stratigraphic Code, are be more quickly accepted if they are discussed with referred to the committee for recommended solution. peers who work for State surveys, academia, and The basis of the committee's action is the North industry as well as with those who work for the American Stratigraphic Code (the code) and its Survey during the preparation of a report. predecessors. The North American Commission on In reviewing manuscripts, GNU staff members Stratigraphic Nomenclature currently has more than depend on a file of annotated records, on the frame- 20 members chosen from 8 geological societies and work of policy and objectives as set forth by the GNC State and Federal surveys in North America: and its chairman, and on the North American Strati- American Association of Petroleum Geologists, graphic Code. Each staff member is expected to bring Geological Society of America, Geological Survey of significant departures from these guides to the atten- Canada, Geological Association of Canada, Canadian tion of the local committee members or to the chair- Society of Petroleum Geologists, U.S. Geological man of the committee so that problems may be Survey, Association of American State Geologists, resolved expeditiously at a local level. The full com- Asociaci6n MBxicana de Ge6logos Petroleros, Sociedad mittee formulates general policy and advises on Ge6logica Mexicans, and Instituto de Geologia de la specific nomenclatural problems. Universidad NacionAl Autdnoma de MBxico. Several editions of the code have been printed since the first TO THE one was prepared in 1933; the most recent edition, CONFORMANCE CODE published in 1983, is for sale by the American Asso- AND MODIFICATIONTO ciation of Petroleum Geologists, Box 979, Tulsa, OK 74101. Survey authors can get copies from one of the STRATIGRAPHIC UNITS GNU offices. Amendments and additions to the code Four codes (Ashley and others, 1933; American are proposed from time to time. They are published Commission on Stratigraphic Nomenclature, 1.961, as Notes or Reports, usually in the American Associa- 1970; North American Commission on Stratigraphic tion of Petroleum Geologists Bulletin. Before pro- Nomenclature, 1983) have been written to provide posed changes are adopted by the commission for guidance to scientists using stratigraphic terminology inclusion in the code, comments and discussions are and to provide the profession with standards for invited from the geologic profession. naming, defining, and classifying "rock units and their The classification and nomenclature of rock units in spatial and temporal relations" (North American Com- manuscripts resulting from cooperative investigations mission on Stratigraphic Nomenclature, 1983, p. 847). with State geological surveys, or other outside organ- Each code reflects advances in scientific knowledge izations or individuals, may follow the scheme of the and technology at the time of its preparation. Some cooperating organization, with an appropriate state- recommendations in the 1983 code are similar to ment of explanation. Any classification scheme used those drawn up in 1903 and published in the :24th must have been described in a published report or the Annual Report of the Director. Parts of the 1983 description must be included in the proposed report. code serve researchers who work with discontinuity- Although the Geologic Names Units do not judge bounded sequences
Load more

Recommended publications
  • Cyclicity, Dune Migration, and Wind Velocity in Lower Permian Eolian Strata, Manitou Springs, CO
    Cyclicity, Dune Migration, and Wind Velocity in Lower Permian Eolian Strata, Manitou Springs, CO by James Daniel Pike, B.S. A Thesis In Geology Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCES Approved Dustin E. Sweet Chair of Committee Tom M. Lehman Jeffery A. Lee Mark Sheridan Dean of the Graduate School August, 2017 Copyright 2017, James D. Pike Texas Tech University, James Daniel Pike, August 2017 ACKNOWLEDGMENTS I would like to extend my greatest thanks to my advisor Dr. Dustin Sweet, who was an excellent advisor during this research. Dr. Sweet was vital throughout the whole process, be it answering questions, giving feedback on figures, and imparting his extensive knowledge of the ancestral Rocky Mountains on me; for this I am extremely grateful. Dr. Sweet allowed me to conduct my own research without looking over my shoulder, but was always available when needed. When I needed a push, Dr. Sweet provided it. I would like to thank my committee memebers, Dr. Lee and Dr. Lehman for providing feedback and for their unique perspectives. I would like to thank Jenna Hessert, Trent Jackson, and Khaled Chowdhury for acting as my field assistants. Their help in taking measurements, collecting samples, recording GPS coordinates, and providing unique perspectives was invaluable. Thank you to Melanie Barnes for allowing me to use her lab, and putting up with the mess I made. This research was made possible by a grant provided by the Colorado Scientific Society, and a scholarship provided by East Texas Geological Society.
    [Show full text]
  • 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]
  • Geological Processes and Evolution
    GEOLOGICAL PROCESSES AND EVOLUTION J.W. HEAD1, R. GREELEY2, M.P. GOLOMBEK3, W.K. HARTMANN4, E. HAUBER5, R. JAUMANN5, P. MASSON6, G. NEUKUM5, L.E. NYQUIST7 and M.H. CARR8 1Department of Geological Sciences, Brown University, Providence, RI 02912 USA 2Department of Geology, Arizona State University, Tempe, AZ 85287 USA 3Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 USA 4Planetary Science Institute, Tucson, AZ 85705 USA 5DLR Institute of Space Sensor Technology and Planetary Exploration, Rutherfordstrasse 2, 12484 Berlin-Aldershof, Germany 6University of Paris-Sud, 91405, Orsay Cedex France 7Johnson Space Center, Houston TX 77058 USA 8US Geological Survey, Branch of Astrogeological Studies, 345 Middlefield Road, Menlo Park, CA 94025 USA Received:14 February 2001; accepted:12 March 2001 Abstract. Geological mapping and establishment of stratigraphic relationships provides an overview of geological processes operating on Mars and how they have varied in time and space. Impact craters and basins shaped the crust in earliest history and as their importance declined, evidence of extensive regional volcanism emerged during the Late Noachian. Regional volcanism characterized the Early Hesperian and subsequent to that time, volcanism was largely centered at Tharsis and Elysium, con- tinuing until the recent geological past. The Tharsis region appears to have been largely constructed by the Late Noachian, and represents a series of tectonic and volcanic centers. Globally distributed structural features representing contraction characterize the middle Hesperian. Water-related pro- cesses involve the formation of valley networks in the Late Noachian and into the Hesperian, an ice sheet at the south pole in the middle Hesperian, and outflow channels and possible standing bodies of water in the northern lowlands in the Late Hesperian and into the Amazonian.
    [Show full text]
  • The Contact of the Upper Neoproterozoic with the Lower
    Ugidos, J.M., Barba, P., Valladares, M.I., Suarez, M., and Ellam, R.M. (2016) The Ediacaran-Cambrian transition in the Cantabrian Zone 1 (North Spain): sub-Cambrian weathering, K-metasomatism and provenance of detrital series. Journal of the Geological Society, 173(4), pp. 603-615. (doi:10.1144/jgs2016-004) This is the author’s final accepted version. There may be differences between this version and the published version. You are advised to consult the publisher’s version if you wish to cite from it. http://eprints.gla.ac.uk/115950/ Deposited on: 1 February 2016 Enlighten – Research publications by members of the University of Glasgow http://eprints.gla.ac.uk 1 1 The Ediacaran-Cambrian transition in the Cantabrian Zone (North Spain): sub- 2 Cambrian weathering, K-metasomatism and provenance of detrital series 3 4 J.M. Ugidos,a* P. Barba,a M.I. Valladares,a M. Suárez,a R.M. Ellam, b 5 a Departamento de Geología, Facultad de Ciencias, Universidad de Salamanca, 37008 6 Salamanca, Spain b Scottish Universities Environmental Research Centre, East Kilbride G75 OQF, UK 7 8 9 Abstract: The Upper Ediacaran detrital succession in the Cantabrian Zone shows 10 geochemical and mineralogical changes resulting from sub-Cambrian weathering during 11 the Late Ediacaran worldwide sea-level fall. Relative to the unaltered rocks the altered 12 ones show crosscutting rubefaction of varying thickness a remarkable increase in illite, 13 K2O, Rb and Cs indicating K-metasomatism, and also depletion in MgO, CaO, Na2O, 14 Be and Sr, but not in Zr, Nb, Y, Sc.
    [Show full text]
  • A Fan Delta Complex of Dinantian/Namurian Age
    The Orustdalen Formation of Braggerhalvaya, Svalbard: A fan delta complex of Dinantian/Namurian age By Ian J. Fairchildl Abstract The Orustdalen Formation of Broggerhalvnya is well exposed on two coastal sections and is 200-250 m thick. It consists dominantly of siliceous conglomerates anid sandstones with subordinate shales and impure coal. One horizoin low in the sequence yielded spores of upper- most Dinantian/lowermost Namurian agc. Three sedimentary facies have been recognised The fluvial channel facies (interbedded conglomerates and cross-stratified sandstones) are interpreted as braided sitream deposits with flow directions to south and west A shale facies, sometimes with dri\fted plant remains, is interpreted as ovrrbank ia origin. Highly quartzose, medium-to-coarse-grained, cross-stratified sandstones make up the reworked facies wheie palaeocurrents are bimodal or indicate movement to the NE The Formation is thought to represent semdiments shed from an early Carboniferuus fault scarp erod,ing a siliceous Lower Palaeozoic source terramin The proximity of a nearby coastline led to the construction of fan deltas where fluvial deposits were reworked by waves and/or tides Early diagenetic events include the local development of pyrite, kaoIinite and calcite cements Reddening probably occurred during Middle Carboniferous times beneath an exposed land surface. Following burial, pressure solution and quartz cementation eliminated porosity at depths greater than 1000 m. Introduction The association of conglomerates with coal is unusual (Heward 1978), but is found in a number of Upper Devonian and Lower Carboniferous sequences in Svalbard (Dineley 1958; Birkenmajer 1964; Worsley and Edwards 1976; Gjelberg 1978; Gjelberg and Steel 1979). A discussion of the Br~ggerhalveya Lower Carboniferous, conglomerates and sandstones with subordinate shales and coals, is thus of interest in contributing to an understanding of this facies association.
    [Show full text]
  • Distribution of Elements in Sedimentary Rocks of the Colorado Plateau a Preliminary Report
    Distribution of Elements in Sedimentary Rocks of the Colorado Plateau A Preliminary Report GEOLOGICAL SURVEY BULLETIN 1107-F Prepared on behalf of the U.S. Atomic Energy Commission Distribution of Elements in Sedimentary Rocks of the Colorado Plateau A Preliminary Report By WILLIAM L. NEWMAN CONTRIBUTIONS TO THE GEOLOGY OF URANIUM GEOLOGICAL SURVEY BULLETIN 1107-F Prepared on behalf of the U.S. Atomic Energy Commission UNITED STATES GOVERNMENT PRINTING OFFICE. WASHINGTON : 1962 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.G. CONTENTS Page Abstract____________________________-__-__-_---_-___-___ 337 Introduction ______________________________________________________ 339 Physical features of sedimentary rocks------_--__----_------------__- 339 Precambrian sedimentary rocks.________________________________ 341 Cambrian system____________________________________________ 342 Ordovician system..___________________________________________ 344 Devonian system._____________________________________________ 344 Mississippian system.._________________________________________ 346 Pennsylvanian system________________________________________ 346 Permian system _______________________________________________ 349 Triassic system______________________________________________ 352 Moenkopi formation _______________________________________ 352 Chinle formation..._______________________________________
    [Show full text]
  • Golden Spikes, Transitions, Boundary Objects, and Anthropogenic Seascapes
    sustainability Article A Meaningful Anthropocene?: Golden Spikes, Transitions, Boundary Objects, and Anthropogenic Seascapes Todd J. Braje * and Matthew Lauer Department of Anthropology, San Diego State University, San Diego, CA 92182, USA; [email protected] * Correspondence: [email protected] Received: 27 June 2020; Accepted: 7 August 2020; Published: 11 August 2020 Abstract: As the number of academic manuscripts explicitly referencing the Anthropocene increases, a theme that seems to tie them all together is the general lack of continuity on how we should define the Anthropocene. In an attempt to formalize the concept, the Anthropocene Working Group (AWG) is working to identify, in the stratigraphic record, a Global Stratigraphic Section and Point (GSSP) or golden spike for a mid-twentieth century Anthropocene starting point. Rather than clarifying our understanding of the Anthropocene, we argue that the AWG’s effort to provide an authoritative definition undermines the original intent of the concept, as a call-to-arms for future sustainable management of local, regional, and global environments, and weakens the concept’s capacity to fundamentally reconfigure the established boundaries between the social and natural sciences. To sustain the creative and productive power of the Anthropocene concept, we argue that it is best understood as a “boundary object,” where it can be adaptable enough to incorporate multiple viewpoints, but robust enough to be meaningful within different disciplines. Here, we provide two examples from our work on the deep history of anthropogenic seascapes, which demonstrate the power of the Anthropocene to stimulate new thinking about the entanglement of humans and non-humans, and for building interdisciplinary solutions to modern environmental issues.
    [Show full text]
  • Chapter 1: Sequence Stratigraphy of the Glenshaw Formation
    Martino, R. L., 2004, Sequence stratigraphy of the Glenshaw Formation (middle–late Pennsylvanian) in the central Appalachian basin, in J. C. Pashin and R. A. Gastaldo, eds., Sequence stratigraphy, paleoclimate, and tectonics of coal-bearing strata: AAPG Studies 1 in Geology 51, p. 1–28. Sequence Stratigraphy of the Glenshaw Formation (Middle–Late Pennsylvanian) in the Central Appalachian Basin Ronald L. Martino Department of Geology, Marshall University, Huntington, West Virginia, U.S.A. ABSTRACT he Glenshaw Formation consists predominantly of sandstones and mud- rocks with thin limestones and coals, which are thought to have accumu- T lated in alluvial, deltaic, and shallow-marine environments. Analysis of 87 Glenshaw outcrops from southern Ohio, eastern Kentucky, and southern West Vir- ginia has revealed widespread, well-developed paleosols. These paleosols are used, along with marine units and erosional disconformities, to develop a high-resolution sequence-statigraphic framework. The tops of the paleosols constitute boundaries for nine allocycles, which are interpreted as fifth-order depositional sequences. Allocycles in this framework correlate with similar allocycles described from the northern Appalachian basin. A sequence-stratigraphic model is proposed that provides a framework for in- terpreting facies architecture in terms of base-level dynamics linked to relative sea level changes. Lowered base level caused valley incision along drainage lines and sediment bypassing of interfluves, which led to development of well-drained paleo- sols. Rising base level produced valley filling by fluvioestuarine systems (lowstand systems tract/transgressive systems tract), whereas pedogenesis continued on inter- fluves. As drainage systems aggraded, the coastal plain water table rose, and in- terfluvial paleosols were onlapped by paludal and lacustrine deposits.
    [Show full text]
  • Soils in the Geologic Record
    in the Geologic Record 2021 Soils Planner Natural Resources Conservation Service Words From the Deputy Chief Soils are essential for life on Earth. They are the source of nutrients for plants, the medium that stores and releases water to plants, and the material in which plants anchor to the Earth’s surface. Soils filter pollutants and thereby purify water, store atmospheric carbon and thereby reduce greenhouse gasses, and support structures and thereby provide the foundation on which civilization erects buildings and constructs roads. Given the vast On February 2, 2020, the USDA, Natural importance of soil, it’s no wonder that the U.S. Government has Resources Conservation Service (NRCS) an agency, NRCS, devoted to preserving this essential resource. welcomed Dr. Luis “Louie” Tupas as the NRCS Deputy Chief for Soil Science and Resource Less widely recognized than the value of soil in maintaining Assessment. Dr. Tupas brings knowledge and experience of global change and climate impacts life is the importance of the knowledge gained from soils in the on agriculture, forestry, and other landscapes to the geologic record. Fossil soils, or “paleosols,” help us understand NRCS. He has been with USDA since 2004. the history of the Earth. This planner focuses on these soils in the geologic record. It provides examples of how paleosols can retain Dr. Tupas, a career member of the Senior Executive Service since 2014, served as the Deputy Director information about climates and ecosystems of the prehistoric for Bioenergy, Climate, and Environment, the Acting past. By understanding this deep history, we can obtain a better Deputy Director for Food Science and Nutrition, and understanding of modern climate, current biodiversity, and the Director for International Programs at USDA, ongoing soil formation and destruction.
    [Show full text]
  • Stratigraphic Correlation Chart for Western Colorado and Northwestern New Mexico
    New Mexico Geological Society Guidebook, 32nd Field Conference, Western Slope Colorado, 1981 75 STRATIGRAPHIC CORRELATION CHART FOR WESTERN COLORADO AND NORTHWESTERN NEW MEXICO M. E. MacLACHLAN U.S. Geological Survey Denver, Colorado 80225 INTRODUCTION De Chelly Sandstone (or De Chelly Sandstone Member of the The stratigraphic nomenclature applied in various parts of west- Cutler Formation) of the west side of the basin is thought to ern Colorado, northwestern New Mexico, and a small part of east- correlate with the Glorieta Sandstone of the south side of the central Utah is summarized in the accompanying chart (fig. 1). The basin. locations of the areas, indicated by letters, are shown on the index map (fig. 2). Sources of information used in compiling the chart are Cols. B.-C. shown by numbers in brackets beneath the headings for the col- Age determinations on the Hinsdale Formation in parts of the umns. The numbers are keyed to references in an accompanying volcanic field range from 4.7 to 23.4 m.y. on basalts and 4.8 to list. Ages where known are shown by numbers in parentheses in 22.4 m.y. on rhyolites (Lipman, 1975, p. 6, p. 90-100). millions of years after the rock name or in parentheses on the line The early intermediate-composition volcanics and related rocks separating two chronostratigraphic units. include several named units of limited areal extent, but of simi- No Quaternary rocks nor small igneous bodies, such as dikes, lar age and petrology—the West Elk Breccia at Powderhorn; the have been included on this chart.
    [Show full text]
  • International Chronostratigraphic Chart
    INTERNATIONAL CHRONOSTRATIGRAPHIC CHART www.stratigraphy.org International Commission on Stratigraphy v 2015/01 numerical numerical numerical Eonothem numerical Series / Epoch Stage / Age Series / Epoch Stage / Age Series / Epoch Stage / Age Erathem / Era System / Period GSSP GSSP age (Ma) GSSP GSSA EonothemErathem / Eon System / Era / Period EonothemErathem / Eon System/ Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) / Eon GSSP age (Ma) present ~ 145.0 358.9 ± 0.4 ~ 541.0 ±1.0 Holocene Ediacaran 0.0117 Tithonian Upper 152.1 ±0.9 Famennian ~ 635 0.126 Upper Kimmeridgian Neo- 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 1000 Callovian 166.1 ±1.2 Quaternary 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 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 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 Langhian Sinemurian Proterozoic Neogene 15.97 Orosirian 199.3 ±0.3 Lochkovian Paleo- Hettangian 2050 Burdigalian 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 28.1 Gorstian Oligocene Upper Norian 427.4 ±0.5 2500 Rupelian Wenlock Homerian
    [Show full text]
  • Small-Scale Post-Noachian Volcanism in the Martian Highlands? Insights from Terra Sirenum P
    45th Lunar and Planetary Science Conference (2014) 1104.pdf SMALL-SCALE POST-NOACHIAN VOLCANISM IN THE MARTIAN HIGHLANDS? INSIGHTS FROM TERRA SIRENUM P. Brož1,2 and E. Hauber3 1Institute of Geophysics ASCR, v.v.i., Prague, Czech Republic, [email protected], 2Institute of Petrology and Structural Geology, Charles University, Czech Republic 3Institute of Planetary Research, DLR, Berlin, Germany, [email protected]. Introduction: Volcanism was globally widespread on Mars in the early history of the planet, but focused with ongoing evolution on two main provinces in Tharsis and Elysium [1]. On the other hand, evidence for post-Noachian volcanism in the Martian highlands is rare outside some isolated regions (e.g., Tyrrhena and Hadriaca Montes) and, to our knowledge, few, if any, such volcanic edifices have been reported so far. It is generally thought that highland volcanism oc- curred early in Mars` history and stopped not later than ~1 Ga after planet formation [2, 3]. Several candidate locations were suggested as volcanic centers in western Gorgonum and south-eastern Atlantis basins [4], where extensive accumulations of possible volcanic deposits exist, however, these volcanic centers were not con- firmed by later studies [5, 6]. Based on our observations we report several prom- ising edifices in Terra Sirenum that might change this view. The study area is situated south of Gorgonum Fig. 1: Themis-IR day-time (upper image), night-time (mid- basin and is about 150x50 km wide. It contains two dle), and interpretational map of the study area. The thermal spectacular cones with outgoing flow-like features and contrast between the two upper images suggests the presence 3 dome-like structures (Fig.
    [Show full text]