| _version_ | 1867169498811858944 |
|---|---|
| author | Seyfried, W E Shanks, Wayne C Dibble, W E |
| author_facet | Seyfried, W E Shanks, Wayne C Dibble, W E |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | A blue-green smectite (iron-rich saponite) and green mica (celadonite) are the dominant sheet silicates in veins within the 10.5 m of basalt cored during DSDP Leg 34, Site 32l, in the Nazca plate. Oxygen isotopic analyses of these clays, and associated calcite, indicate a formation temperature of <25°C. Celadonite contains appreciable Fe2O3, K2O and SiO2, intermediate MgO, and very little Al2O3. Celadonite is commonly associated with goethite and hematite, which suggests that this phase formed by precipitation within a dominantly oxygenated environment of components leached from basalt and provided by seawater. A mass balance estimate indicates that celadonite formation can remove no more than 15% of the K annually transported to the oceans by rivers. In contrast, iron-rich saponite containing significant Al2O3 appears to have precipitated from a nonoxidizing, distinctly alkaline fluid containing a high Na/K ratio relative to unmodified seawater. Seawater-basalt interaction at low temperatures, resulting in the formation of celadonite and smectite may explain chemical gradients observed in interstitial waters of sediments overlying basalts. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_714253 |
| institution | PANGAEA |
| language | en |
| publishDate | 1978 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Chemical and isotopical analsyes of DSDP Hole 34-321 basalts Seyfried, W E Shanks, Wayne C Dibble, W E 34-321; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg34; South Pacific/BASIN A blue-green smectite (iron-rich saponite) and green mica (celadonite) are the dominant sheet silicates in veins within the 10.5 m of basalt cored during DSDP Leg 34, Site 32l, in the Nazca plate. Oxygen isotopic analyses of these clays, and associated calcite, indicate a formation temperature of <25°C. Celadonite contains appreciable Fe2O3, K2O and SiO2, intermediate MgO, and very little Al2O3. Celadonite is commonly associated with goethite and hematite, which suggests that this phase formed by precipitation within a dominantly oxygenated environment of components leached from basalt and provided by seawater. A mass balance estimate indicates that celadonite formation can remove no more than 15% of the K annually transported to the oceans by rivers. In contrast, iron-rich saponite containing significant Al2O3 appears to have precipitated from a nonoxidizing, distinctly alkaline fluid containing a high Na/K ratio relative to unmodified seawater. Seawater-basalt interaction at low temperatures, resulting in the formation of celadonite and smectite may explain chemical gradients observed in interstitial waters of sediments overlying basalts. |
| title | Chemical and isotopical analsyes of DSDP Hole 34-321 basalts |
| topic | 34-321; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg34; South Pacific/BASIN |
| url | https://doi.org/10.1594/PANGAEA.714253 |