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Title: Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments

Abstract

Evidence for precipitation of authigenic carbonate fluorapatite (CFA) in Long Island Sound and Mississippi Delta sediments suggests that formation of CFA is not restricted to environments of active coastal upwelling. The authors present porewater data suggestive of CFA formation in both these areas. Application of a sequential leaching procedure, designed specifically to separate authigenic carbonate fluorapatite from other phosphorus-containing phases, including detrital apatite of igneous or metamorphic origin, provides strong supporting evidence for authigenic apatite formation in these sediments. The size of the authigenic apatite reservoir increases with depth, indicating continued formation of CFA during early diagenesis. This depth increase is mirrored by a decrease in solid-phase organic P at both sites, suggesting that CFA is forming at the expense of organic P. Mass balance considerations, application of diagenetic models to intersitital water nutrient data, and the saturation state of the interstitial water are consistent with this interpretation. Diagenetic redistribution of phosphorus among the different solid-phase reservoirs is observed at both sites, and results in near perfect retention of P by these sediments over the depth intervals sampled. Formation of CFA in continental margins which do not conform to the classically defined regions of phosphorite formation renders CFA a quantitativelymore » more important sink than has previously been recognized. Including this reservoir as a newly identified sink for reactive P in the ocean, the residence time of P in the modern ocean must be revised downward. The implication for ancient oceans of CFA formation in continental margin sediments other than phosphorites is that phosphorite formation may be less a representation of episodicity in removal of reactive P from the oceans than of localized concentration of CFA in phosphatic sediments by secondary physical processes. 90 refs., 5 figs., 2 tabs.« less

Authors:
;  [1]
  1. Yale Univ., New Haven, CT (United States)
Publication Date:
OSTI Identifier:
6573533
Resource Type:
Journal Article
Journal Name:
Geochimica et Cosmochimica Acta; (United States)
Additional Journal Information:
Journal Volume: 57:5; Journal ID: ISSN 0016-7037
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; APATITES; ORIGIN; COASTAL WATERS; SEDIMENTS; CONTINENTAL MARGIN; DEPTH; DIAGENESIS; INTERSTITIAL WATER; LEACHING; LONG ISLAND SOUND; MASS BALANCE; MISSISSIPPI; PHOSPHORITES; PHOSPHORUS; REMOVAL; RETENTION; SATURATION; UPWELLING; WATER; ATLANTIC OCEAN; DEVELOPED COUNTRIES; DIMENSIONS; DISSOLUTION; ELEMENTS; ESTUARIES; GROUND WATER; HYDROGEN COMPOUNDS; MINERALS; NONMETALS; NORTH AMERICA; OXYGEN COMPOUNDS; PHOSPHATE MINERALS; PHOSPHATE ROCKS; ROCKS; SEAS; SEDIMENTARY ROCKS; SEPARATION PROCESSES; SURFACE WATERS; USA; 540310* - Environment, Aquatic- Basic Studies- (1990-)

Citation Formats

Ruttenberg, K C, and Berner, R A. Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments. United States: N. p., 1993. Web. doi:10.1016/0016-7037(93)90035-U.
Ruttenberg, K C, & Berner, R A. Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments. United States. https://doi.org/10.1016/0016-7037(93)90035-U
Ruttenberg, K C, and Berner, R A. 1993. "Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments". United States. https://doi.org/10.1016/0016-7037(93)90035-U.
@article{osti_6573533,
title = {Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments},
author = {Ruttenberg, K C and Berner, R A},
abstractNote = {Evidence for precipitation of authigenic carbonate fluorapatite (CFA) in Long Island Sound and Mississippi Delta sediments suggests that formation of CFA is not restricted to environments of active coastal upwelling. The authors present porewater data suggestive of CFA formation in both these areas. Application of a sequential leaching procedure, designed specifically to separate authigenic carbonate fluorapatite from other phosphorus-containing phases, including detrital apatite of igneous or metamorphic origin, provides strong supporting evidence for authigenic apatite formation in these sediments. The size of the authigenic apatite reservoir increases with depth, indicating continued formation of CFA during early diagenesis. This depth increase is mirrored by a decrease in solid-phase organic P at both sites, suggesting that CFA is forming at the expense of organic P. Mass balance considerations, application of diagenetic models to intersitital water nutrient data, and the saturation state of the interstitial water are consistent with this interpretation. Diagenetic redistribution of phosphorus among the different solid-phase reservoirs is observed at both sites, and results in near perfect retention of P by these sediments over the depth intervals sampled. Formation of CFA in continental margins which do not conform to the classically defined regions of phosphorite formation renders CFA a quantitatively more important sink than has previously been recognized. Including this reservoir as a newly identified sink for reactive P in the ocean, the residence time of P in the modern ocean must be revised downward. The implication for ancient oceans of CFA formation in continental margin sediments other than phosphorites is that phosphorite formation may be less a representation of episodicity in removal of reactive P from the oceans than of localized concentration of CFA in phosphatic sediments by secondary physical processes. 90 refs., 5 figs., 2 tabs.},
doi = {10.1016/0016-7037(93)90035-U},
url = {https://www.osti.gov/biblio/6573533}, journal = {Geochimica et Cosmochimica Acta; (United States)},
issn = {0016-7037},
number = ,
volume = 57:5,
place = {United States},
year = {Mon Mar 01 00:00:00 EST 1993},
month = {Mon Mar 01 00:00:00 EST 1993}
}