Chemical composition and isotope ratios of basalts from DSDP Sites 417 and 418, West Atlantic Ocean
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| Formato: | Dataset Open Access |
| Lenguaje: | en |
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PANGAEA
1979
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| _version_ | 1867169496466194432 |
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| author | Staudigel, Hubert Frey, Frederick A Hart, Stanley R |
| author_facet | Staudigel, Hubert Frey, Frederick A Hart, Stanley R |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Basalts from Sites 417 and 418 are relatively depleted in light REE compared to a chondritic REE distribution. In the least altered samples, K, Rb, Cs, and Sr and Ba concentrations are lower than in average mid-ocean ridge basalt (MORB). Thus, the source rock for these basalts must have been highly depleted in incompatible elements. However, 87/86Sr ratios in these basalts, even in microscopically fresh glass, are high (> 0.7030). These ratios, compared to normal MORB, are largely an effect of low-temperature alteration. Sr isotope exchange with sea water is postulated for basaltic glass (87/86Sr = 0.70301) with low incompatible-element abundances, but we cannot eliminate the possibility that these relatively high 87/86Sr ratios are primary. By studying closely associated glass-palagonite-crystalline rock samples, we can identify two types of alteration processes: (1) palagonite formation which causes loss of REE elements, without changing their distribution, and decreasing K/Rb and K/Cs with increasing K content; and (2) glass-sea water exchange which is apparently a diffusioncontrolled process, causing increasing K/Rb and K/Cs with increasing K content but not affecting REE. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_667438 |
| institution | PANGAEA |
| language | en |
| publishDate | 1979 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Chemical composition and isotope ratios of basalts from DSDP Sites 417 and 418, West Atlantic Ocean Staudigel, Hubert Frey, Frederick A Hart, Stanley R 51-417D; 52-417D; 52-418A; 53-418A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg51; Leg52; Leg53; North Atlantic/CONT RISE Basalts from Sites 417 and 418 are relatively depleted in light REE compared to a chondritic REE distribution. In the least altered samples, K, Rb, Cs, and Sr and Ba concentrations are lower than in average mid-ocean ridge basalt (MORB). Thus, the source rock for these basalts must have been highly depleted in incompatible elements. However, 87/86Sr ratios in these basalts, even in microscopically fresh glass, are high (> 0.7030). These ratios, compared to normal MORB, are largely an effect of low-temperature alteration. Sr isotope exchange with sea water is postulated for basaltic glass (87/86Sr = 0.70301) with low incompatible-element abundances, but we cannot eliminate the possibility that these relatively high 87/86Sr ratios are primary. By studying closely associated glass-palagonite-crystalline rock samples, we can identify two types of alteration processes: (1) palagonite formation which causes loss of REE elements, without changing their distribution, and decreasing K/Rb and K/Cs with increasing K content; and (2) glass-sea water exchange which is apparently a diffusioncontrolled process, causing increasing K/Rb and K/Cs with increasing K content but not affecting REE. |
| title | Chemical composition and isotope ratios of basalts from DSDP Sites 417 and 418, West Atlantic Ocean |
| topic | 51-417D; 52-417D; 52-418A; 53-418A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg51; Leg52; Leg53; North Atlantic/CONT RISE |
| url | https://doi.org/10.1594/PANGAEA.667438 |