Last Deglaciation in the Bahamas: A Dissolution Record from Variations of Aragonite Content?

  1. E.T. Sundquist and
  2. W.S. Broecker
  1. Andre W. Droxler

Published Online: 18 MAR 2013

DOI: 10.1029/GM032p0195

The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present

The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present

How to Cite

Droxler, A. W. (1985) Last Deglaciation in the Bahamas: A Dissolution Record from Variations of Aragonite Content?, in The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present (eds E.T. Sundquist and W.S. Broecker), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM032p0195

Author Information

  1. Rosenstiel School of Marine and Atmospheric Science, MGG, University of Miami, Miami, Florida 33149

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1985

ISBN Information

Print ISBN: 9780875900605

Online ISBN: 9781118664322

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Keywords:

  • Carbon cycle (Biogeochemistry)—Congresses;
  • Atmospheric carbon dioxide—Congresses;
  • Geological time—Congresses;
  • Paleothermometry—Congresses;
  • Geology, Stratigraphic—Congresses

Summary

Detailed studies of three core tops and corresponding box cores display the last 20,000-year history of the Bahamian basins and the adjacent Atlantic Ocean. The cores are from three different areas, the northern part of Tongue of the Ocean at 1,900 m, NE Providence Channel at 2,390 m, and the crest of Eleuthera Ridge at 4,000 m. Variations of aragonite content are occurring in concert with the variations of carbonate and quartz content, and also parallel the oxygen isotopic record on Globigerinoides rubra known to be related to the glacial rhythm of the earth's climate. The most drastic mineralogical and lithological changes are recorded during the transition interval between the last glacial maximum at 18,000 years B.P. and the hypsithermal at 6,000 years B.P. of the current interglacial. During the deglaciation interval, the mineralogical and lithological variations and oxygen isotopic records seem to have recorded together regression events of 1,000 years duration that can be correlated with established events in ice cores from Greenland and Antarctica, in North Atlantic cores, and in the southwest of France. In addition, the lag time of several thousand years between bank flooding and aragonite content in the basins has been confirmed to exist in several cores from different Bahamian basins and from the adjacent Atlantic Ocean. Based on these observations, the aragonite variations seem to be related to a more climatic, thus oceanic signal than the regional alternate flooding and exposure of the Bahamas Banks. We propose that aragonite dissolution cycles analogous to the calcite dissolution glacial cycles observed in deeper waters are the main cause of the aragonite variations.