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Open Earth Systems: An Earth Science Course For Maryland Teacher Professional Development EARTH HISTORY AND THE FOSSIL RECORD DAY 1 - Weds. July 8 AM Instruction: Solar System Origin Activity 1: Period of planetary orbits Activity 2: Planets on your birthday Instruction: Early Earth & Habitability -lunchtime- PM Instruction: Major Events in Earth History Activity 3: Exploring Geologic Time with TS-Creator Instruction: Concepts in Radioisotope-dating Activity 4: Simulating Radioactive Decay DAY 2 - Thurs. July 9 AM Instruction: Climates of the Past Activity 5: JHU Soil Profile Instruction: Fossil Record of Life -lunchtime- PM Instruction: Conversation with Steven Stanley Activity 6: Fossil Identification LINDA HINNOV, Instructor
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OUTLINE Paleoclimate archives and proxies Weathering and soils Icehouse-greenhouse oscillations Inventory of Earth’s major icehouses and greenhouses ICEHOUSE FOCUS: Late Proterozoic snowballs GREENHOUSE FOCUS: Early Cenozoic hyperthermia ICEHOUSE FOCUS: Last Glacial Maximum
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Paleoclimate archives and proxies Earth materials that contain a signature of paleoclimatic conditions Isotopes deuterium, oxygen Plants stomata, leaf margins, tree rings Gas in ice CO 2, CH 4 in gas bubbles Minerals evaporites, glendonites, coal, clays Marine Organisms Faunal assemblages Other Proxies Geomorphology, sedimentary facies archives proxies
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Stanley (2005) https://en.wikipedia.org/wiki/At mospheric_circulation Climate Zones
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Weathering
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Soils
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https://upload.wikimedia.org/wikipedia/commons/e/e5/Global_soils_map_USDA.jpg
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http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_053588/ This URL has clickable panels Soils
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http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_053588/ This URL has clickable panels Soils
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GlacialNon-glacialPan-glacial Icehouse-Greenhouse oscillations
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PRECAMBRIAN: GREENHOUSE: Archean-Proterozoic ICEHOUSE: Archean Witwatersrand glaciation ICEHOUSE: Early Proterozoic Huronian glaciation * ICEHOUSE: Late Proterozoic “snowball earths” PHANEROZOIC: GREENHOUSE: Early Paleozoic greenhouse(s) ICEHOUSE: Late Ordovician glaciation ICEHOUSE: Permo-Carboniferous glaciations GREENHOUSE: Late Permian - Triassic greenhouse and hot spikes ICEHOUSE: Jurassic-Cretaceous “cool” phases GREENHOUSE: Jurassic-Cretaceous greenhouses and OAEs * GREENHOUSE: Early Cenozoic hyperthermia (the PETM) ICEHOUSE: Late Cenozoic glaciation GREENHOUSE: Pliocene Warm interval ICEHOUSE: Pleistocene – Last Glacial Maximum Inventory of Earth’s major icehouses and greenhouses time
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Atmospheric CO 2 * * Greenhouses? Kastings, 1987
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http://www.snowballearth.org Earth’s great icehouses
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ICEHOUSE FOCUS: Late Proterozoic snowballs http://www.snowballearth.org
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The tillite-bearing Ghaub Formation has been mapped for >600 km along the outer arc of the Otavi fold belt. Marinoan Snowball 635 Ma http://www.snowballearth.org
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TODAY: Supraglacial/Ice-margin Environments A dirty-ice zone at a glacier's leading edge. Debris carried in the ice melts out and piles up at the glacier's edge. Till-like mixtures of material with a wide range of particle sizes, called "diamicton", are interspersed with waterlain sediments from lakes and streams. This photo shows a moraine forming at the edge of a glacier in eastern Canada. on top of or along the margin of the glacier http://www.isgs.uiuc.edu/research/glacial-geology/
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Marinoan Snowball 635 Ma http://www.snowballearth.org
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http://www.isgs.uiuc.edu/research/glacial-geology/ TODAY: Proglacial Environments in front of the glacier Proglacial lake sediment in a pit near Chicago.Proglacial lake at the southern margin of Flaajokull, Iceland. http://www.geology.wisc.edu/~qlab/iceland/iceland2000.html Sediments of the proglacial environment include materials sorted by water or wind: river sediment (outwash), lake deposits (rhythmites), and windblown sand and silt (loess).
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Marinoan Snowball 635 Ma - post glacial cap carbonate, Namibia http://www.snowballearth.org
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GREENHOUSE FOCUS - Early Cenozoic hyperthermia PETM= Paleocene/Eocene Thermal Maximum The end of the Paleocene (55.5/54.8 Ma) was marked by the Paleocene-Eocene Thermal Maximum (PETM): -rise in atmospheric CO2 and global temp. -Sea surface temperatures rose ~8ºC. -altered ocean/ atmosphere circulation -extinction of 30-40% benthic foraminifera -a major turnover in mammals http://scicom.ucsc.edu/SciNotes/0301/warm/index.html http://www.yale.edu/opa/newsr/06-06-01-03.all.html Sea surface temperatures at the North Pole reached as high as 23ºC (73ºF). Today's mean annual temperature at the N. Pole is around -20ºC (-4ºF).
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During the PETM, the Earth remained warm for about 80,000 to 200,000 years. On land, there was a massive turnover of mammals, with primitive mammals that had developed since the end of the Cretaceous suddenly replaced by ancestors of most of the surviving modern mammal groups, all of them in small versions, adapted to Eocene heat. Plant life was characterized by the boreotropical flora, with extensive high- latitude forests composed of large, fast- growing trees such as Dawn Redwood (Metasequoia) as far north as 80°N. Metasequoia glyptostroboides http://en.wikipedia.org/wiki/Paleocene-Eocene_Thermal_Maximum http://scicom.ucsc.edu/SciNotes/0301/warm/index.html GREENHOUSE FOCUS - Early Cenozoic hyperthermia
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A. Terrestrial paleosol carbonate records from northern Wyoming (dark green) northern Spain (light green), and southern China (olive green). Dashed lines track onset of the PETM event. B. Marine planktonic foraminifera records from the subtropical Pacific (red) and southern Atlantic (blue). Carbon isotope changes during the onset of the PETM (dashed lines) occurred as a series of abrupt (~1 Kyr) steps. Bowen et al., 2006 Summary of environmental records and a 3-phase model of Earth Systems evolution through the (PETM). D. Surface temperature anomaly records for the 2 oceanic sites, with colors as in B. C. Difference of the averaged carbon isotope curves for the 3 terrestrial and 2 surface ocean records. E. Patterns of biotic change: tropical dinoflagellates (Apectodinium) at N. Pole small-bodied mammals extinction of benthic foraminifera GREENHOUSE FOCUS - Early Cenozoic hyperthermia
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Proposed cause of the hyperthermia A sharp decrease in the amount of heavy carbon in 55-million-year-old occurred marine fossils. A gas with very low amounts of heavy 13 C must have flooded the atmosphere: methane gas has enough light carbon to produce this change. The hypothesis: methane escaped from submarine methane hydrates in cold bottom water under great pressures, plentiful and widely distributed in sediments on the outer edges of continental margins. Methane is estimated to be 21 times as effective as carbon dioxide as a greenhouse gas. The methane oxidized to carbon dioxide, raising atmospheric carbon dioxide levels to as high as 3,000 ppm, compared with 400 ppm today. The carbon dioxide increased the acidity of seawater, accelerated dissolution of calcite shells of marine microplankton, leaving behind nonsoluble clays. A documented change in colors of the sediment, from bright white carbonate to deep red clays, marks the PETM. Normal deposition of microscopic carbonate foraminifera did not resume for 50,000 years, and the total recovery time to a "normal state" took ~100,000 years. http://www.palmod.uni-bremen.de/FB5//geochron/Robert/RPSpeb.html Demerara Rise offshore Brazil DEEP SEA CORES RECORD ACIDIFICATION OF OCEAN ODP Leg 207 Scientific Party GREENHOUSE FOCUS - Early Cenozoic hyperthermia
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LAST GLACIAL MAXIMUM 20,000 YEARS AGO Numbers: kiloyears bp Stanley (2005)
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LAST GLACIAL MAXIMUM 20,000 YEARS AGO Stanley (2005)
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