ISSN:
1437-3262
Schlagwort(e):
Key words Pteropods
;
Aragonite preservation
;
South Atlantic
;
Brazilian Continental Slope
;
North Atlantic Deep Water
;
Antarctic Intermediate Water
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
Notizen:
Abstract We present late Quaternary records of aragonite preservation determined for sediment cores recovered on the Brazilian Continental Slope (1790–2585 m water depth) where North Atlantic Deep Water (NADW) dominates at present. We have used various indirect dissolution proxies (carbonate content, aragonite/calcite contents, and sand percentages) as well as gastropodal abundances and fragmentation of Limacina inflata to determine the state of aragonite preservation. In addition, microscopic investigations of the dissolution susceptibility of three Limacina species yielded the Limacina Dissolution Index which correlates well with most of the other proxies. Excellent preservation of aragonite was found in the Holocene section, whereas aragonite dissolution gradually increases downcore. This general pattern is attributed to an overall increase in aragonite corrosiveness of pore waters. Overprinted on this early diagenetic trend are high-frequency fluctuations of aragonite preservation, which may be related to climatically induced variations of intermediate water masses.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s005310050291
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