Oxygen isotopes sediments

However, the Slowey et al. (1995) work on shallower carbonate bank sediments (off of the Bahamas) was successful and led to the dating of a number of important events in the marine oxygen isotope record (including the timing of the Last Interglacial (Slowey et al. 1996), Termination II (Henderson and Slowey 2000) and portions of the Penultimate Interglacial (Slowey et al. 1996, Robinson et al. 2002). The shallower depths obviate the most serious of the initial thorium problems encountered in the Nicaragua Rise work. 

Olley JM, Roberts RG, Murray AS (1997) A novel method for determining residence times of river and lake sediments based on disequilibriiun in the thorium decay series. Water Resom Res 33 1319-1326 Onac BP, Lauritzen S-E (1996) The climate of the last 150,000 years recorded in speleothems preliminary results from north-western Romania. Theor Appl Karstology 9 9-21 O Neil JR., Clayton RN, Mayeda TK (1969) Oxygen isotope fractionation in divalent metal carbonates. J ChemPhys 51 5547-5558... 

Determining the temperature at which ancient sediments were formed entails two successive experimental stages (1) extracting the carbon dioxide from the sediments and (2) determining the relative amounts of the oxygen isotopes in the extracted carbon dioxide. Treating a sediment with a standard acid, such as hydrochloric or sulfuric acid, dissolves the calcium and magnesium carbonates in the sediments and... 

Finally it should be mentioned that sulfate is labeled with two biogeochemical isotope systems, sulfur and oxygen. Coupled isotope fractionations of both sulfur and oxygen isotopes have been observed in experiments (Mizutani and Rafter 1973 Fritz et al. 1989 Bottcher et al. 2001) and in natnrally occurring sediments (Ku et al. 1999 Aharon and Fn 2000 Wortmann et al. 2001). Brunner et al. (2005) argned that characteristic fractionation slopes do not exist, but depend... 

Carbonate sediments deposited in shallow marine environments are often exposed to the influence of meteoric waters during their diagenetic history. Meteoric diagenesis lowers 8 0- and 8 C-values, because meteoric waters have lower 8 0-values than sea water. For example. Hays and Grossman (1991) demonstrated that oxygen isotope compositions of carbonate cements depend on the magnitude of depletion of respective meteoric waters. 5 C-values are lowered because soil bicarbonate is C-depleted relative to ocean water bicarbonate. 

The oxygen isotopes in the water molecules locked up in polar ice sheets tell another version of the planet s climate story. The ice that covers Antarctica is a mile and a half deep at its thickest points, and the snow that became transformed into the deepest ice fell at least 250,000 years ago. So the Antarctic ice sheets, like deep-sea sediments, encode thousands of years of climate history in their isotope compositions. 

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