Formal Ratification of the Subdivision of the Holocene Series/ Epoch
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Climatic Events During the Late Pleistocene and Holocene in the Upper Parana River: Correlation with NE Argentina and South-Central Brazil Joseh C
Quaternary International 72 (2000) 73}85 Climatic events during the Late Pleistocene and Holocene in the Upper Parana River: Correlation with NE Argentina and South-Central Brazil JoseH C. Stevaux* Universidade Federal do Rio Grande do Sul - Instituto de GeocieL ncias - CECO, Universidade Estadual de Maringa& - Geography Department, 87020-900 Maringa& ,PR} Brazil Abstract Most Quaternary studies in Brazil are restricted to the Atlantic Coast and are mainly based on coastal morphology and sea level changes, whereas research on inland areas is largely unexplored. The study area lies along the ParanaH River, state of ParanaH , Brazil, at 223 43S latitude and 533 10W longitude, where the river is as yet undammed. Paleoclimatological data were obtained from 10 vibro cores and 15 motor auger holes. Sedimentological and pollen analyses plus TL and C dating were used to establish the following evolutionary history of Late Pleistocene and Holocene climates: First drier episode ?40,000}8000 BP First wetter episode 8000}3500 BP Second drier episode 3500}1500 BP Second (present) wet episode 1500 BP}Present Climatic intervals are in agreement with prior studies made in southern Brazil and in northeastern Argentina. ( 2000 Elsevier Science Ltd and INQUA. All rights reserved. 1. Introduction the excavation of Sete Quedas Falls on the ParanaH River (today the site of the Itaipu dam). Barthelness (1960, Geomorphological and paleoclimatological studies of 1961) de"ned a regional surface in the Guaira area de- the Upper ParanaH River Basin are scarce and regional in veloped at the end of the Pleistocene (Guaira Surface) nature. King (1956, pp. 157}159) de"ned "ve geomor- and correlated it with the Velhas Cycle. -
Minimal Geological Methane Emissions During the Younger Dryas-Preboreal Abrupt Warming Event
UC San Diego UC San Diego Previously Published Works Title Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event. Permalink https://escholarship.org/uc/item/1j0249ms Journal Nature, 548(7668) ISSN 0028-0836 Authors Petrenko, Vasilii V Smith, Andrew M Schaefer, Hinrich et al. Publication Date 2017-08-01 DOI 10.1038/nature23316 Peer reviewed eScholarship.org Powered by the California Digital Library University of California LETTER doi:10.1038/nature23316 Minimal geological methane emissions during the Younger Dryas–Preboreal abrupt warming event Vasilii V. Petrenko1, Andrew M. Smith2, Hinrich Schaefer3, Katja Riedel3, Edward Brook4, Daniel Baggenstos5,6, Christina Harth5, Quan Hua2, Christo Buizert4, Adrian Schilt4, Xavier Fain7, Logan Mitchell4,8, Thomas Bauska4,9, Anais Orsi5,10, Ray F. Weiss5 & Jeffrey P. Severinghaus5 Methane (CH4) is a powerful greenhouse gas and plays a key part atmosphere can only produce combined estimates of natural geological in global atmospheric chemistry. Natural geological emissions and anthropogenic fossil CH4 emissions (refs 2, 12). (fossil methane vented naturally from marine and terrestrial Polar ice contains samples of the preindustrial atmosphere and seeps and mud volcanoes) are thought to contribute around offers the opportunity to quantify geological CH4 in the absence of 52 teragrams of methane per year to the global methane source, anthropogenic fossil CH4. A recent study used a combination of revised 13 13 about 10 per cent of the total, but both bottom-up methods source δ C isotopic signatures and published ice core δ CH4 data to 1 −1 2 (measuring emissions) and top-down approaches (measuring estimate natural geological CH4 at 51 ± 20 Tg CH4 yr (1σ range) , atmospheric mole fractions and isotopes)2 for constraining these in agreement with the bottom-up assessment of ref. -
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” -
Circum-Indian Ocean Hydroclimate at the Mid to Late Holocene Transition: the Double Drought Hypothesis and Consequences for the Harappan” by Nick Scroxton Et Al
Clim. Past Discuss., https://doi.org/10.5194/cp-2020-138-RC2, 2021 CPD © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Interactive comment Interactive comment on “Circum-Indian ocean hydroclimate at the mid to late Holocene transition: The Double Drought hypothesis and consequences for the Harappan” by Nick Scroxton et al. Harvey Weiss (Referee) [email protected] Received and published: 4 January 2021 Global KM-A Congruence and the Indus Collapse Harvey Weiss Printer-friendly version Department of Near Eastern Languages and Civilizations, Environmental Studies Pro- gram, and School of Environment, Yale University Discussion paper The IUGS-recognized global boundary stratotype for the 4.2 - 3.9 ka BP event, marking C1 the middle to late Holocene transition to the Meghalayan stage, is the KM-A speleothem δ18O record from Mawmluh Cave, Meghalaya, NW India, that is an Indian Summer CPD Monsoon (ISM) drought record (Berkelhammer et al 2012; Walker et al 2019). The recent analysis of the Indus delta foraminifera record at core 63KA has identified, as well, the Indian Winter Monsoon drought synchronous with the 4.2 ka BP ISM drought Interactive (Giesche et al 2019). The global boundary sub-stratotype is the Mt. Logan Yukon comment glacial core’s δ18O moisture event (Fisher et al 2008). Scroxton et al present a principal components analysis of seven recent δ18O speleothem records from the Indian Ocean region and the Giesche et al 2019 delta foraminifera analyses (line 110) “to investigate the impacts of the 4.2 kyr event on trop- ical Indian Ocean basin monsoonal rainfall” and the late third millennium BC Indus urban collapses. -
Low-Cost Epoch-Based Correlation Prefetching for Commercial Applications Yuan Chou Architecture Technology Group Microelectronics Division
Low-Cost Epoch-Based Correlation Prefetching for Commercial Applications Yuan Chou Architecture Technology Group Microelectronics Division 1 Motivation Performance of many commercial applications limited by processor stalls due to off-chip cache misses Applications characterized by irregular control-flow and complex data access patterns Software prefetching and simple stride-based hardware prefetching ineffective Hardware correlation prefetching more promising - can remember complex recurring data access patterns Current correlation prefetchers have severe drawbacks but we think we can overcome them 2 Talk Outline Traditional Correlation Prefetching Epoch-Based Correlation Prefetching Experimental Results Summary 3 Traditional Correlation Prefetching Basic idea: use current miss address M to predict N future miss addresses F ...F (where N = prefetch depth) 1 N Miss address sequence: A B C D E F G H I assume N=2 Use A to prefetch B C Use D to prefetch E F Use G to prefetch H I Correlations recorded in correlation table Correlation table size proportional to application working set 4 Correlation Prefetching Drawbacks Very large correlation tables needed for commercial apps - impractical to store on-chip No attempt to eliminate all naturally overlapped misses Miss address sequence: A B C D E F G H I time A C F H B D G I E compute off-chip access 5 Correlation Prefetching Drawbacks Very large correlation tables needed for commercial apps - impractical to store on-chip No attempt to eliminate all naturally overlapped misses Miss address sequence: -
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. -
“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. -
R~;: PHYSIOLOGICAL, MIGRATORIAL
....----------- 'r~;: i ! 'r; Pa/eont .. 62(4), 1988, pp. 64~52 Copyright © 1988, The Paleontological Society 0022-3360/88/0062-0640$03.00 PHYSIOLOGICAL, MIGRATORIAL, CLIMATOLOGICAL, GEOPHYSICAL, SURVIVAL, AND EVOLUTIONARY IMPLICATIONS OF CRETACEOUS POLAR DINOSAURS GREGORY S. PAUL 3109 North Calvert Street, Baltimore, Maryland 21218 ABSTRACTT- he presence of Late Cretaceous social dinosaurs in polar regions confronted them with winter conditions of extended dark, coolness, breezes, and precipitation that could best be coped with via an endothermic homeothermic physiology of at least the tenrec level. This is true whether the dinosaurs stayed year round in the polar regime-which in North America extended from Alaska south to Montana-or if they migrated away from polar winters. More reptilian physiologies fail to meet the demands of such winters -in certain key ways, a· point tentatively confirmed by the apparent failure of giant Late Cretaceous phobosuchid crocodilians to dwell north of Montana. Low metabolisms were also insufficient for extended annual migrations away from and towards the poles. It is shown that even high metabolic rate dinosaurs probably remained in their polar habitats year-round. The possibility that dinosaurs had avian-mammalian metabolic systems, and may have borne insulation at least seasonally, severely limits their use as polar paleoclimatic and Earth axial tilt indicators. Polar dinosaurs may have been a center of dinosaur evolution. The possible ability of polar dinosaurs to cope with conditions of cool and dark challenges theories that a gradual temperature decline, or a sudden, meteoritic or volcanic induced collapse in temperature and sunlight, destroyed the dinosaurs. INTRODUCTION America suggests that dinosaurs were regularly crossing, and NCREASINGNUMBERSof remains show that dinosaurs lived living upon, the Bering Land Bridge within a few degrees of the I near the North and South Poles during the Cretaceous. -
Holocene Environmental Changes and Climate Development in Greenland
R-10-65 Holocene environmental changes and climate development in Greenland Stefan Engels, Karin Helmens Stockholm University December 2010 Svensk Kärnbränslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 250, SE-101 24 Stockholm Phone +46 8 459 84 00 CM Gruppen AB, Bromma, 2010 CM Gruppen ISSN 1402-3091 Tänd ett lager: SKB R-10-65 P, R eller TR. Holocene environmental changes and climate development in Greenland Stefan Engels, Karin Helmens Stockholm University December 2010 This report concerns a study which was conducted for SKB. The conclusions and viewpoints presented in the report are those of the authors. SKB may draw modified conclusions, based on additional literature sources and/or expert opinions. A pdf version of this document can be downloaded from www.skb.se. Contents 1 Introduction 5 1.1 Aims and framework 5 1.2 Present-day climatical and biogeographical trends in Greenland 5 1.3 Geology of Greenland 7 2 Late Pleistocene and Early Holocene deglaciation in Greenland 9 2.1 Deglaciation in East Greenland 9 2.2 Deglaciation in West Greenland 11 2.3 Deglaciation in South Greenland 13 2.4 Holocene ice sheet variability 13 3 Holocene climate variability and vegetation development in Greenland 15 3.1 Terrestrial records from East Greenland 15 3.2 Terrestrial records from West Greenland 18 3.3 Terrestrial records from South Greenland 23 3.4 Terrestrial records from North Greenland 25 3.5 Ice-core records 25 3.6 Records from the marine realm 28 4 Training sets and the transfer-function approach 29 4.1 General 29 4.2 Training set development in Greenland 30 5 The period directly after deglaciation 33 5.1 Terrestrial plants and animals 33 5.2 Aquatic plants and animals (lacustrine) 33 6 Summary and concluding remarks 35 References 37 R-10-65 3 1 Introduction 1.1 Aims and framework The primary aim of this report is to give an overview of the Holocene environmental and climatic changes in Greenland and to describe the development of the periglacial environment during the Holocene. -
Climate Updates What Have We Learnt Since the IPCC 5Th Assessment Report?
Climate updates What have we learnt since the IPCC 5th Assessment Report? REFERENCES REFERENCES Contents Introduction 3 How sensitive is global temperature to increasing greenhouse gases? 4 How are methane concentrations changing and what does this mean for the climate? 7 Was there a “pause” in global warming? 9 How high could sea level rise because of anthropogenic climate change? 12 Decreasing Arctic sea ice – is there any influence on the weather in middle latitudes? 16 Have temperature and rainfall extremes changed, and how will they change in the future? 19 Are there thresholds beyond which particularly dangerous or irreversible changes may occur? 22 Is the land taking up carbon dioxide because of faster plant growth? 26 How do increasing carbon dioxide concentrations impact ocean life and fisheries? 30 How will climate change affect food production on land? 35 What is the influence of climate change on water availability across the globe? 37 What is the influence of climate change on species extinction? 41 How will aspects of human health be affected by climate change? 45 CLIMATE CHANGE 2 REFERENCES Introduction This document provides information supplementary to the Climate Updates report. Each section is the partner to a ‘question’ in the main report and provides background information to the conclusions reached there as well as a limited bibliography. CLIMATE CHANGE 3 REFERENCES How sensitive is global temperature to increasing greenhouse gases? SUPPLEMenTARY InfORMATION The IPCC quotes used in this section comes from IPCC AR5, WGI, Summary for Policymakers, section D.2, page 14. Note that although climate sensitivity values Climate sensitivities derived from GCMs are defined in terms of carbon dioxide doubling, underestimate the long term effect: Armour these typically (and specifically in the IPCC (2017), Proistosescu and Huybers (2017). -
Schmitz, M. D. 2000. Appendix 2: Radioisotopic Ages Used In
Appendix 2 Radioisotopic ages used in GTS2020 M.D. SCHMITZ 1285 1286 Appendix 2 GTS GTS Sample Locality Lat-Long Lithostratigraphy Age 6 2s 6 2s Age Type 2020 2012 (Ma) analytical total ID ID Period Epoch Age Quaternary À not compiled Neogene À not compiled Pliocene Miocene Paleogene Oligocene Chattian Pg36 biotite-rich layer; PAC- Pieve d’Accinelli section, 43 35040.41vN, Scaglia Cinerea Fm, 42.3 m above base of 26.57 0.02 0.04 206Pb/238U B2 northeastern Apennines, Italy 12 29034.16vE section Rupelian Pg35 Pg20 biotite-rich layer; MCA- Monte Cagnero section (Chattian 43 38047.81vN, Scaglia Cinerea Fm, 145.8 m above base 31.41 0.03 0.04 206Pb/238U 145.8, equivalent to GSSP), northeastern Apennines, Italy 12 28003.83vE of section MCA/84-3 Pg34 biotite-rich layer; MCA- Monte Cagnero section (Chattian 43 38047.81vN, Scaglia Cinerea Fm, 142.8 m above base 31.72 0.02 0.04 206Pb/238U 142.8 GSSP), northeastern Apennines, Italy 12 28003.83vE of section Eocene Priabonian Pg33 Pg19 biotite-rich layer; MASS- Massignano (Oligocene GSSP), near 43.5328 N, Scaglia Cinerea Fm, 14.7 m above base of 34.50 0.04 0.05 206Pb/238U 14.7, equivalent to Ancona, northeastern Apennines, 13.6011 E section MAS/86-14.7 Italy Pg32 biotite-rich layer; MASS- Massignano (Oligocene GSSP), near 43.5328 N, Scaglia Cinerea Fm, 12.9 m above base of 34.68 0.04 0.06 206Pb/238U 12.9 Ancona, northeastern Apennines, 13.6011 E section Italy Pg31 Pg18 biotite-rich layer; MASS- Massignano (Oligocene GSSP), near 43.5328 N, Scaglia Cinerea Fm, 12.7 m above base of 34.72 0.02 0.04 206Pb/238U -
1 TIMESCALE for CLIMATIC EVENTS of SUBBOREAL/SUBATLANTIC TRANSITION RECORDED at the VALAKUPIAI SITE, LITHUANIA Jacek Pawlyta1,2
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by BSU Digital Library RADIOCARBON, Vol 49, Nr 2, 2007, p 1–9 © 2007 by the Arizona Board of Regents on behalf of the University of Arizona TIMESCALE FOR CLIMATIC EVENTS OF SUBBOREAL/SUBATLANTIC TRANSITION RECORDED AT THE VALAKUPIAI SITE, LITHUANIA Jacek Pawlyta1,2 • Algirdas Gaigalas3 • Adam MichczyÒski1 • Anna Pazdur1 • Aleksander Sanko4 ABSTRACT. Oxbow lake deposits of the Neris River at the Valakupiai site in Vilnius (Lithuania) have been studied by dif- ferent methods including radiocarbon dating. A timescale was attained for the development of the oxbow lake and climatic events recorded in the sediments. 14C dates obtained for 24 samples cover the range 990–6500 BP (AD 580 to 5600 BC). Medieval human activity was found in the upper part of the sediments. Mollusk fauna found in the basal part of the terrace indicate contact between people living in the Baltic and the Black Sea basins. Mean rates were calculated for erosion of the river and for accumulation during the formation of the first terrace. INTRODUCTION This work presents the results of radiocarbon dating of samples collected at the Valakupiai site, near Vilnius in eastern Lithuania (54°43′58″N, 25°18′33″E; 98.5 m asl) (Figure 1). Special attention was paid to the remnant oxbow lake in the Neris River valley and to the lake-bog deposits filling it. Detailed study of the deposits delivered specific information that enabled paleoecological recon- struction of the site, as well as a description of the geochronological evolution of the oxbow lake and accompanying climatic events.