TY - JOUR
T1 - The fertilization of the Bahamas by Saharan dust
T2 - A trigger for carbonate precipitation?
AU - Swart, P. K.
AU - Oehlert, A. M.
AU - Mackenzie, G. J.
AU - Eberli, G. P.
AU - Reijmer, J. J.G.
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2014/8
Y1 - 2014/8
N2 - The enigma of the Bahamas is that this highly productive carbonate system has existed for at least 100 m.y., building a vast edifice of carbonates, thousands of meters thick, in an essentially nutrientpoor environment. Based on measurements of the insoluble material, the Fe and Mn in the carbonate fraction, and the δ15N of the sedimentary organic matter, we suggest a paradigm shift in order to explain the formation of the Bahamas and possibly other similar platforms. We propose that the Great Bahama Bank is currently, and may in the past have been, fertilized by atmospheric dust, promoting the fixation of atmospheric N2 by cyanobacteria. These cyanobacteria provided a source of nitrogen to the rest of the community in this nutrient-poor environment. The fixation of N has imparted a characteristic δ15N signal and has been responsible, through the drawdown of CO2, for initiating the precipitation of carbonate in the shallow waters. This phenomenon might be responsible for the formation of vast amounts of sediments in the oceans, not only within recent times, but throughout geological history, particularly in the early history of the Earth prior to the existence of calcium carbonate- secretingorganisms.
AB - The enigma of the Bahamas is that this highly productive carbonate system has existed for at least 100 m.y., building a vast edifice of carbonates, thousands of meters thick, in an essentially nutrientpoor environment. Based on measurements of the insoluble material, the Fe and Mn in the carbonate fraction, and the δ15N of the sedimentary organic matter, we suggest a paradigm shift in order to explain the formation of the Bahamas and possibly other similar platforms. We propose that the Great Bahama Bank is currently, and may in the past have been, fertilized by atmospheric dust, promoting the fixation of atmospheric N2 by cyanobacteria. These cyanobacteria provided a source of nitrogen to the rest of the community in this nutrient-poor environment. The fixation of N has imparted a characteristic δ15N signal and has been responsible, through the drawdown of CO2, for initiating the precipitation of carbonate in the shallow waters. This phenomenon might be responsible for the formation of vast amounts of sediments in the oceans, not only within recent times, but throughout geological history, particularly in the early history of the Earth prior to the existence of calcium carbonate- secretingorganisms.
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U2 - 10.1130/G35744.1
DO - 10.1130/G35744.1
M3 - Article
AN - SCOPUS:84905170126
VL - 42
SP - 671
EP - 674
JO - Geology
JF - Geology
SN - 0091-7613
IS - 8
ER -