Calcium isotope ratios from marine barite and carbonate over Paleocene-Eocene Boundary (ODP Sites 1212 and 1221)
Cobertura |
MEDIAN LATITUDE: 22.240780 * MEDIAN LONGITUDE: -172.991260 * SOUTH-BOUND LATITUDE: 12.033110 * WEST-BOUND LONGITUDE: 157.711660 * NORTH-BOUND LATITUDE: 32.448450 * EAST-BOUND LONGITUDE: -143.694180 * DATE/TIME START: 2001-09-30T02:55:00 * DATE/TIME END: 2001-12-05T00:00:00 |
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Data(s) |
05/11/2015
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Resumo |
Carbonates are invaluable archives of the past, and have been used extensively to reconstruct paleoclimate and paleoceanographic conditions over geologic time scales. Such archives are susceptible to diagenetic alteration via dissolution, recrystallization and secondary precipitation, particularly during ocean acidification events when intense dissolution can occur. Despite the importance of diagenesis on proxy fidelity, the effects of diagenesis on the calcium isotopic composition (d44Ca) of carbonates are unclear. Accordingly, bulk carbonate d44Ca was measured at high resolution in two Pacific deep sea sediment cores (ODP Sites 1212 and 1221) with considerably different dissolution histories over the Paleocene-Eocene Thermal Maximum (PETM, ~55 Ma). The d44Ca of marine barite was also measured at the deeper Site 1221, which experienced severe carbonate dissolution during the PETM. Large (~0.8 per mil) variations in bulk carbonate d44Ca occur in the deeper site near the peak carbon isotope excursion, and are correlated with a large drop in carbonate weight percent. Such an effect is seen in neither the 1221 barite record nor the bulk carbonate record at the shallower, less dissolved Site 1212. We contend that ocean chemical changes associated with the abrupt and massive carbon release into the ocean-atmosphere system and subsequent ocean acidification at the PETM affected the bulk carbonate d44Ca record via diagenesis in the sedimentary column. Such changes are considerable, and need to be taken into account when interpreting and modeling Ca isotope data over extreme climatic events associated with ocean chemical evolution. |
Formato |
application/zip, 3 datasets |
Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.854737 doi:10.1594/PANGAEA.854737 |
Idioma(s) |
en |
Publicador |
PANGAEA |
Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
Fonte |
Supplement to: Griffith, Elizabeth M; Fantle, Matthew S; Eisenhauer, Anton; Paytan, Adina; Bullen, Thomas D (2015): Effects of ocean acidification on the marine calcium isotope record at the Paleocene-Eocene Thermal Maximum. Earth and Planetary Science Letters, 419, 81-92, doi:10.1016/j.epsl.2015.03.010 |
Palavras-Chave | #87Sr/86Sr; 87Sr/86Sr e; Age model; barite rel sw; base CIE; CaCO3; Calcium carbonate; d13C carb; d18O carb; d44Ca; d44Ca std dev; delta 13C, carbonate; delta 18O, carbonate; delta 44Ca; delta 44Ca, standard deviation; Depth; DEPTH, sediment/rock; Event; Label; Magnesium/Calcium ratio; Mg/Ca; Ocean Drilling Program; ODP; relative to NIST915a; relative to seawater; Repl; Replicates; Sample code/label; seawater rel NIST915a; seawater rel sw; Sr/Ba; Sr/Ca; Strontium/Barium ratio; Strontium/Calcium ratio; Strontium 87/Strontium 86, error; Strontium 87/Strontium 86 ratio |
Tipo |
Dataset |