Characterization of rock-magnetic signature during subaerial exposure in platform carbonates from New Providence, Bahamas
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Date
1996-06
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Publisher
The Ohio State University
Abstract
The marine carbonate Bahamian bank bore hole core BH-5
from New Providence Island was subsampled for paleomagnetic study at The University of Miami, Rosenstiel School of Marine and Atmospheric Science. Susceptibility, magnetic remanence of Natural Remanent Magnetism and Alternating Field intensities, Saturation Isothermal Remanent Magnetism, and coercivity spectral analysis experiments on sixty-four subsamples were conducted. A study of magnetic mineralogy identified conclusive
results for a sea level lowstand and a subaerial exposure surface horizon at a depth of 14.7 meters below core top within the Early to Late Pleistocene Epoch following the Matuyama-Brunhes geomagnetic reversal. This interpretation is based upon one subsample (sample #41) containing the magnetic minerals hematite and coarse-grained magnetite identified by coercivity
spectral analysis. This Bahamian bank marine carbonate
lowstand, the result of a eustatic fall in sea level during a global glacial event is of Pleistocene age and may correspond either to the Early Pleistocene pre-lllinoian G Glaciation or the Middle Pleistocene lllinoian Glaciation.