Zinc and Cadmium in Benthic Foraminifera as Tracers of Ocean Paleochemistry

• Main Author: Marchitto, Thomas M., Jr.
• Other Authors: MASSACHUSETTS INST OF TECH CAMBRIDGE
• Format: Text
• Language: English
• Published: 2000
• Subjects: Physical and Dynamic Oceanography; *OCEAN CURRENTS; *ZINC; *CADMIUM; *BENTHONIC ZONES; *FORAMINIFERA; MEASUREMENT; THESES; NUTRIENTS; AIR WATER INTERACTIONS; NORTH ATLANTIC OCEAN; GLACIERS; TRACER STUDIES; CHEMICAL OCEANOGRAPHY; PALEONTOLOGY; *PALEOCHEMISTRY; BAHAMA BANKS; HOEGLUNDINA ELEGANS; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA380183; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA380183

Benthic foraminiferal delta 13-C, Cd/Ca, and Ba/Ca are important tools for reconstructing nutrient distributions, and thus ocean circulation, on glacial-interglacial timescales. However, each tracer has its own "artifacts" that can complicate paleoceanographic interpretations. It is therefore advantageous to measure multiple nutrient proxies with the aim of separating the various complicating effects. Zn/Ca is introduced as an important aid toward this goal. Benthic (Hoeglundina elegans) Cd/Ca ratios from the Bahama Banks indicate that the North Atlantic subtropical gyre was greatly depleted in nutrients during the last glacial maximum (LGM). A high-resolution Cd/Ca record from 965 m water depth suggests that Glacial North Atlantic Intermediate Water formation was strong during the LGM, weakened during the deglaciation, and strengthened again during the Younger Dryas cold period. Comparison of Cd/Ca and delta C-13 data reveals apparent short-term changes in carbon isotopic air-sea signatures. Prepared in cooperation with Woods Hole Oceanographic Institution, Woods Hole, Massachusetts.