Yatabe, Autumn; Vanko, David A.; Ghazi, A. Mohamad (2000): Petrography and chemical compositions of secondary calcite and aragonite in Juan de Fuca Ridge basalts altered at low temperature. Texas A & M University, Ocean Drilling Program, College Station, TX, United States, In: Fisher, Andrew T., Davis, Earl E., Firth, John V., Andersson, Eva M., Aoike, Kan, Becker, Keir, Brown, Kimberly A., Buatier, Martine D., Constantin, Marc, Elderfield, Henry, Goncalves, Carlos A., Grigel, Jens S., Hunter, Arlene G., Inoue, Atsuyuki, Lawrence, Roisin M., Macdonald, Robert D., Marescotti, Pietro, Martin, Jeffrey T., Monnin, Christophe, Mottl, Michael J., Pribnow, Daniel F. C., Stein, Joshua S., Su, Xin, Sun, Yue-Feng, Underwood, Michael B., Vanko, David A., Wheat, C. Geoffrey, Miller, Christine M. (editor), Peters, Lorri L. (editor), Proceedings of the Ocean Drilling Program, scientific results, hydrothermal circulation in the oceanic crust, eastern flank of the Juan de Fuca Ridge; covering Leg 168 of the cruises of the drilling vessel JOIDES Resolution, San Francisco, California, to Victoria, British Columbia, sites 1023-1032, 20 June-15 August 1996, 168, 137-148, georefid:2001-000790

Abstract:
During Leg 168 a transect was drilled across the eastern flank of the Juan de Fuca Ridge in an area where the volcanic basement is covered by sediments of variable thickness. Samples of basement volcanic rocks were recovered from nine locations along the transect, where the basement sediment interface is presently heated to temperatures varying from 15 degrees to 64 degrees C. Altered rocks with secondary calcium carbonate were common at four of the sites, where present-day temperatures range from 38 degrees to 64 degrees C. Fluid inclusions in aragonite suggest that the mineral precipitated from an aqueous fluid of seawater salinity at temperatures well below 100 degrees C. The chemical compositions of secondary calcite and aragonite were determined with both an electron microprobe and a laser-ablation inductively coupled plasma-mass spectroscopy (LA-ICP-MS) microprobe. These two techniques yielded consistent analyses of the same minor elements (Mg and Sr) in the same specimens. The combined results show that secondary aragonites contain very little Mg, Mn, Fe, Co, Ni, Cu, Zn, Rb, La, Ce, Pb, or U, yet they contain significant Sr. In contrast, secondary calcites contain significant Mg, Mn, Fe, Ni, Cu, Zn, and Pb, yet very little Co, Rb, Sr, La, Ce, or U. Secondary calcium carbonates provide subseafloor reservoirs for some minor and trace elements. Replacement of aragonite by calcite should result in a release of Sr, Rb, and Zn to solution, and it provides a sink for Mg, Mn, Ni, Cu, Zn, and Pb.
Coverage:
West: -129.0000 East: -127.3000 North: 48.0000 South: 47.4500
Relations:
Expedition: 168
Supplemental Information:
Includes appendix
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.168.003.2000 (c.f. for more detailed metadata)
Data download: application/pdf
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