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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
1992
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| Online Access: | https://doi.org/10.1594/PANGAEA.707686 |
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| _version_ | 1867169008298491904 |
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| author | Ishikawa, Tsuyoshi Nakamura, Eizo |
| author_facet | Ishikawa, Tsuyoshi Nakamura, Eizo |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Boron contents and boron isotopic compositions were determined for the uppermost 1.3 km section of typical 6.2 Ma oceanic crust from DSDP/ODP Hole 504B, Costa Rica Rift, Galapagos Spreading Center. Both the boron content and the d11B value in the oceanic crust are controlled by two types of alteration: 1. (1) low-temperature alteration (0 to 60°C; Zones I and II) and 2. (2) high-temperature hydrothermal alteration (200 to 400°C; Zones III and IV). Basalts subjected to the low-temperature alteration are characterized by their relatively high boron contents (0.69 to 19.3 ppm) and high d11B values (+2.2 to +10.6‰), indicating uptake of boron into secondary phases in equilibrium with seawater or evolved seawater. Hydrothermally altered basalts contain less abundant boron (0.17 to 0.52 ppm) and relatively constant d11B values (?0.1 to +1.0‰). Although basalts from the upper part of these hydrothermal zones (<1300 mbsf) show equilibrated boron content and d11B value with aqueous fluid, effective leaching of boron from basalt is predominant in the lower part (>1300 mbsf). Original boron content and d11B value of the Hole 504B MORB were 0.35 ppm and +0.2‰, respectively. The present data provide fundamental information in understanding of the distribution of boron and boron isotopes in the oceanic crust. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_707686 |
| institution | PANGAEA |
| language | en |
| publishDate | 1992 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) B content, d11B, δ¹⁸O, degree of alteration, and lithology of basalts from ODP Hole 504B Ishikawa, Tsuyoshi Nakamura, Eizo 111-504B; 83-504B; Alteration; Boron; Calculated; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Isotope dilution mass spectrometry; Joides Resolution; Leg111; Leg83; Lithologic unit/sequence; Mass spectrometer Finnigan MAT 261; North Pacific Ocean; Ocean Drilling Program; ODP; Rock type; Sample code/label; δ11B; δ18O Boron contents and boron isotopic compositions were determined for the uppermost 1.3 km section of typical 6.2 Ma oceanic crust from DSDP/ODP Hole 504B, Costa Rica Rift, Galapagos Spreading Center. Both the boron content and the d11B value in the oceanic crust are controlled by two types of alteration: 1. (1) low-temperature alteration (0 to 60°C; Zones I and II) and 2. (2) high-temperature hydrothermal alteration (200 to 400°C; Zones III and IV). Basalts subjected to the low-temperature alteration are characterized by their relatively high boron contents (0.69 to 19.3 ppm) and high d11B values (+2.2 to +10.6‰), indicating uptake of boron into secondary phases in equilibrium with seawater or evolved seawater. Hydrothermally altered basalts contain less abundant boron (0.17 to 0.52 ppm) and relatively constant d11B values (?0.1 to +1.0‰). Although basalts from the upper part of these hydrothermal zones (<1300 mbsf) show equilibrated boron content and d11B value with aqueous fluid, effective leaching of boron from basalt is predominant in the lower part (>1300 mbsf). Original boron content and d11B value of the Hole 504B MORB were 0.35 ppm and +0.2‰, respectively. The present data provide fundamental information in understanding of the distribution of boron and boron isotopes in the oceanic crust. |
| title | (Table 1) B content, d11B, δ¹⁸O, degree of alteration, and lithology of basalts from ODP Hole 504B |
| topic | 111-504B; 83-504B; Alteration; Boron; Calculated; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Isotope dilution mass spectrometry; Joides Resolution; Leg111; Leg83; Lithologic unit/sequence; Mass spectrometer Finnigan MAT 261; North Pacific Ocean; Ocean Drilling Program; ODP; Rock type; Sample code/label; δ11B; δ18O |
| url | https://doi.org/10.1594/PANGAEA.707686 |