| _version_ | 1867169032775401472 |
|---|---|
| author | Clarke, D B |
| author_facet | Clarke, D B |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Basalt samples recovered from the lowermost 37 m of Leg 105 Hole 647A in the Labrador Sea are fine- to medium grained, have microphenocrysts of clinopyroxene, and show little evidence of alteration. Chemically, these rocks are low potassium (0.01-0.09 wt% K20), olivine- to quartz-normative tholeiites that are also depleted in other incompatible elements. In terms of many of the incompatible trace elements, the Labrador Sea samples are similar both to iV-type midocean ridge basalts (MORBs) and to the terrestrial Paleocene volcanic rocks in the Davis Strait region of Baffin Island and West Greenland. However, significant differences are found in their strontium and neodymium isotope systematics. Hole 647A samples are more depleted in epsilon-Nd (+9.3) and are anomalously rich in 87Sr/86Sr (0.7040) relative to the Davis Strait basalts (epsilon-Nd +2.54 to + 8.97; mean 87Sr/86Sr, 0.7034). We conclude that the Hole 647A and Davis Strait basalts may have been derived from a similar depleted mantle source composition. In addition, the Davis Strait magmas were generated from mantle of more than one composition. We also suggest that there is no geochemical evidence from the Hole 647A samples to support or to refute the existence of foundered continental crust in the Labrador Sea. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_745267 |
| institution | PANGAEA |
| language | en |
| publishDate | 1989 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Chemical analyses of ODP Hole 105-647A basalts (Table 2) Clarke, D B 105-647A; Albite; Aluminium oxide; Anorthite; Apatite; Barium; Caesium; Calcium oxide; Cerium; Chromium; Copper; Diopside; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Europium; Gallium; Hafnium; Hypersthene; Illite; Iron oxide, Fe2O3; Iron oxide, FeO; Joides Resolution; Lanthanum; Leg105; Lutetium; Magnesium oxide; Manganese oxide; Montmorillonite; Neodymium; Nickel; North Atlantic Ocean; Ocean Drilling Program; ODP; Olivine; Orthoclase; Phosphorus pentoxide; Potassium oxide; Quartz; Samarium; Sample code/label; Scandium; Silicon dioxide; Sodium oxide; Strontium; Strontium-87/Strontium-86 ratio; Sum; Tantalum; Terbium; Thorium; Titanium dioxide; Uranium; Vanadium; Water in rock; Ytterbium; Yttrium; Zinc; Zirconium; ε-Neodymium Basalt samples recovered from the lowermost 37 m of Leg 105 Hole 647A in the Labrador Sea are fine- to medium grained, have microphenocrysts of clinopyroxene, and show little evidence of alteration. Chemically, these rocks are low potassium (0.01-0.09 wt% K20), olivine- to quartz-normative tholeiites that are also depleted in other incompatible elements. In terms of many of the incompatible trace elements, the Labrador Sea samples are similar both to iV-type midocean ridge basalts (MORBs) and to the terrestrial Paleocene volcanic rocks in the Davis Strait region of Baffin Island and West Greenland. However, significant differences are found in their strontium and neodymium isotope systematics. Hole 647A samples are more depleted in epsilon-Nd (+9.3) and are anomalously rich in 87Sr/86Sr (0.7040) relative to the Davis Strait basalts (epsilon-Nd +2.54 to + 8.97; mean 87Sr/86Sr, 0.7034). We conclude that the Hole 647A and Davis Strait basalts may have been derived from a similar depleted mantle source composition. In addition, the Davis Strait magmas were generated from mantle of more than one composition. We also suggest that there is no geochemical evidence from the Hole 647A samples to support or to refute the existence of foundered continental crust in the Labrador Sea. |
| title | Chemical analyses of ODP Hole 105-647A basalts (Table 2) |
| topic | 105-647A; Albite; Aluminium oxide; Anorthite; Apatite; Barium; Caesium; Calcium oxide; Cerium; Chromium; Copper; Diopside; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Europium; Gallium; Hafnium; Hypersthene; Illite; Iron oxide, Fe2O3; Iron oxide, FeO; Joides Resolution; Lanthanum; Leg105; Lutetium; Magnesium oxide; Manganese oxide; Montmorillonite; Neodymium; Nickel; North Atlantic Ocean; Ocean Drilling Program; ODP; Olivine; Orthoclase; Phosphorus pentoxide; Potassium oxide; Quartz; Samarium; Sample code/label; Scandium; Silicon dioxide; Sodium oxide; Strontium; Strontium-87/Strontium-86 ratio; Sum; Tantalum; Terbium; Thorium; Titanium dioxide; Uranium; Vanadium; Water in rock; Ytterbium; Yttrium; Zinc; Zirconium; ε-Neodymium |
| url | https://doi.org/10.1594/PANGAEA.745267 |