quaternary environments marine sediments and corals
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Quaternary Environments Marine Sediments and Corals. Marine Environments. Cover more than 70% of the Earth’s surface Between 6-11 billion metric tons of sediment accumulate in the ocean basins annually. Definitions. - PowerPoint PPT PresentationTRANSCRIPT
Quaternary EnvironmentsQuaternary EnvironmentsMarine Sediments and CoralsMarine Sediments and Corals
Marine EnvironmentsMarine Environments Cover more than 70% of the Earth’s Cover more than 70% of the Earth’s
surfacesurface Between 6-11 billion metric tons of Between 6-11 billion metric tons of
sediment accumulate in the ocean basins sediment accumulate in the ocean basins annuallyannually
DefinitionsDefinitionsPlanktic – Passively floating organisms Planktic – Passively floating organisms
living near the surface (0-200m depth)living near the surface (0-200m depth)Benthic – Bottom-dwelling organismsBenthic – Bottom-dwelling organismsTest – Protective coveringTest – Protective covering
CLIMAPCLIMAP The CLIMAP Research GroupThe CLIMAP Research Group
Climate: Long-range Investigation, Mapping, and Climate: Long-range Investigation, Mapping, and prediction (CLIMAP)prediction (CLIMAP)
SST and Ocean Surface ConditionsSST and Ocean Surface Conditions From 635 ocean sediment coresFrom 635 ocean sediment cores Data from faunal counts of diatoms, planktonic Data from faunal counts of diatoms, planktonic
foraminifera, coccoliths, and radiolariaforaminifera, coccoliths, and radiolaria Stratigraphy - percent fine, coarse, total carbonate, Stratigraphy - percent fine, coarse, total carbonate,
1818O and O and 1313CC Geochemistry - percent opal, quartz, and organic Geochemistry - percent opal, quartz, and organic
carboncarbon
SPECMAPSPECMAP Spectral Mapping ProjectSpectral Mapping Project
Determining the spectral characteristics of ocean Determining the spectral characteristics of ocean sediment-based paleoclimatic recordssediment-based paleoclimatic records
Establishing a basic timeframe for past climatic Establishing a basic timeframe for past climatic eventsevents
Climate times series of the past 400,000 yearsClimate times series of the past 400,000 years Based on 17 sediment cores from the Atlantic Ocean. Based on 17 sediment cores from the Atlantic Ocean. Quantitative data on planktonic species and Quantitative data on planktonic species and
assemblages which reflect conditions in the surface assemblages which reflect conditions in the surface waters of the Atlantic Oceanwaters of the Atlantic Ocean
1818O, O, 1313C difference (planktic and benthic), and Cd/Ca. C difference (planktic and benthic), and Cd/Ca.
Sedimentation in the OceanSedimentation in the Ocean
Problems With Marine SedimentsProblems With Marine Sediments
Selective dissolution of thin-walled Selective dissolution of thin-walled specimensspecimens
Transportation by ocean currentsTransportation by ocean currents Removal of easily transported speciesRemoval of easily transported species Introduction of exoticsIntroduction of exotics
These problems may make some ocean These problems may make some ocean floor sediments unsuitable for paleoclimatic floor sediments unsuitable for paleoclimatic reconstructionsreconstructions
Regions Usable for Foram StudiesRegions Usable for Foram Studies
Important OrganismsImportant Organisms Foraminifera - ZooplanktonForaminifera - Zooplankton Coccolithophores (coccoliths) – Unicellular Coccolithophores (coccoliths) – Unicellular
algaealgae Dinoflagellate – Organic walledDinoflagellate – Organic walled Radiolarians – Siliceous zooplankton Radiolarians – Siliceous zooplankton Silicoflagallates – Siliceous Silicoflagallates – Siliceous Diatoms – Siliceous algae Diatoms – Siliceous algae
Foraminifera – Neogloboquadrina pachyderma from the North Atlantic
Foraminifera – Globigerina bulloides from the Labrador Sea
Coccolith Dinoflagellate
Centric Diatom Pennate Diatom
Paleoclimatic Inferences Paleoclimatic Inferences Oxygen isotopic composition of CaCOOxygen isotopic composition of CaCO3 3 in foram in foram
teststests Quantitative interpretations of species Quantitative interpretations of species
assemblages and their spatial variations through assemblages and their spatial variations through timetime
Morphological variations in particular species Morphological variations in particular species resulting from environmental factorsresulting from environmental factors
Benthic Benthic 1818O record for equatorial O record for equatorial Atlantic for the past 3.2 MyaAtlantic for the past 3.2 Mya
SST Reconstructions for 18,000 yrs BPSST Reconstructions for 18,000 yrs BP
Coral Records of Past ClimateCoral Records of Past Climate Reef-Building Massive Corals that have a Reef-Building Massive Corals that have a
symbiotic relationship with algaesymbiotic relationship with algae The algae produce carbohydrates through The algae produce carbohydrates through
photosynthesis and are therefore dependent photosynthesis and are therefore dependent upon water depth, turbidity, and cloudinessupon water depth, turbidity, and cloudiness
Sectioned and x-rayed Sectioned and x-rayed High and low density bands can be High and low density bands can be
distinguished with high-density bands relating distinguished with high-density bands relating to high SSTto high SST
http://www.noaanews.noaa.gov/magazine/stories/mag95.htm
Drilling corals for paleoclimatic reconstruction.
http://www-ocean.tamu.edu/Quarterdeck/QD6.2/giese.html
Growth bands in Coral. Arrows indicate "stress bands" revealed in an x-ray of coral skeletal material caused by cold, unfavorable temperatures.
Benefits of Coral AnalysisBenefits of Coral Analysis Tropical records that fill gaps left by other Tropical records that fill gaps left by other
marine paleorecordsmarine paleorecords Annual resolutionAnnual resolution Dating is checked with Dating is checked with 230230ThTh Possible extent back to 130,000 years BPPossible extent back to 130,000 years BP
Problems with Coral AnalysisProblems with Coral Analysis Few records that extend past one centuryFew records that extend past one century Real extreme events may go unrecorded Real extreme events may go unrecorded
do to death of the coral colony for some do to death of the coral colony for some period of timeperiod of time
Long Coral Based Records of Past Long Coral Based Records of Past ClimateClimate