Boron and chlorine contents of upper oceanic crust; basement samples from IODP Hole 1256D

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doi: 10.1029/2008GC002182
Author(s): Sano, Takashi; Miyoshi, Masaya; Ingle, Stephanie; Banerjee, Neil R.; Ishimoto, Mitsunori; Fukuoka, Takaaki
Author Affiliation(s): Primary:
National Museum of Nature and Science, Department of Geology and Paleontology, Tokyo, Japan
Kumamoto University, Japan
University of Southampton, United Kingdom
University of Western Ontario, Canada
University of Tokyo, Japan
Risso University, Japan
Volume Title: Geochemistry, Geophysics, Geosystems - G<sup>3</sup>
Source: Geochemistry, Geophysics, Geosystems - G>3`, 9(12). Publisher: American Geophysical Union and The Geochemical Society, United States. ISSN: 1525-2027
Note: In English. 78 refs.; illus., incl. 2 tables
Summary: Boron, Cl, Ti, K, Sm, and Gd concentrations of oceanic crust samples were determined by prompt gamma neutron activation analysis. The samples include 63 basalts and 5 gabbros obtained at various depths (369-1503 m below seafloor) from Hole 1256D during Ocean Drilling Program Leg 206 and Integrated Ocean Drilling Program Expedition 309 and 312. The results show stepwise downhole variations, B content and B/K decrease, and Cl content and Cl/K increase with increasing depth. High B content (>1.5 ppm) in shallower rocks (extrusive lavas) is probably achieved by low-temperature seawater alteration, and high Cl contents (up to 1400 ppm) in the deeper rocks (plutonic section) would show result of high-temperature hydrothermal alteration. Average B and Cl values for the upper oceanic crust in Hole 1256D are 1.5 ppm and 334 ppm, respectively.
Year of Publication: 2008
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; Alteration; Basalts; Boron; Chlorine; Crust; East Pacific; Equatorial Pacific; Expeditions 309/312; Gabbros; Geophysical methods; Guatemala Basin; Halogens; Hydrothermal alteration; Igneous rocks; Integrated Ocean Drilling Program; Leg 206; Major elements; Metasomatism; Mineral composition; Neutron-gamma methods; North Pacific; Northeast Pacific; ODP Site 1256; Ocean Drilling Program; Oceanic crust; Pacific Ocean; Plutonic rocks; Sea water; Trace elements; Upper crust; Volcanic rocks; Water-rock interaction; Weathering
Coordinates: N064400 N064400 W0915600 W0915600
Record ID: 2009080498
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