| _version_ | 1867170458084835328 |
|---|---|
| author | Hagedorn, Birgit Gersonde, Rainer Gohl, Karsten Hubberten, Hans-Wolfgang |
| author_facet | Hagedorn, Birgit Gersonde, Rainer Gohl, Karsten Hubberten, Hans-Wolfgang |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The De Gerlache Seamounts are two topographic highs in the Bellingshausen Sea, southeastern Pacific. Petrological and geochemical studies together with K-Ar age determinations were carried out on four dredged basalt samples collected during a RV Polarstern expedition (ANT-XII/4) in 1995. Minor and trace element composition suggest alkaline basalt compositions. Compared to alkaline basalts of adjacent West Antarctica (the Jones Mountains) and of Peter I Island, the samples have lower mg-numbers, lower Ni and Cr contents and lower high field-strength elements (HFSE)/Nb and large-ion lithophile elements (LILE)/HFSE ratios. Three of the four samples have low K, Rb, and Cs concentrations relative to alkaline basalts. The K-depletion and other elemental concentrations may be explained by 1.1% melting of amphibole bearing mantle material. Additionally, low Rb and Ba values suggest low concentrations of these elements in the mantle source. K-Ar age determinations yield Miocene ages (20-23 Ma) that are similar in age to other alkaline basalts of West Antarctica (Thurston Island, the Jones Mountains, Antarctic Peninsula) and the suggested timing of onset of Peter I Island volcanism (~10-20 Ma). The occurrence of the DGS and Peter I Island volcanism along an older but reactivated tectonic lineation suggests that the extrusions exploited a zone of pre-existing lithospheric weakness. The alkaline nature and age of the DGS basalts support the assumption of plume activity in the Bellingshausen Sea. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_743234 |
| institution | PANGAEA |
| language | en |
| publishDate | 2007 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Petrology, geochemistry and K-Ar Age determination of De Gerlache Seamount basalts Hagedorn, Birgit Gersonde, Rainer Gohl, Karsten Hubberten, Hans-Wolfgang ANT-XII/4; AWI_Paleo; Dredge; DRG; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Polarstern; PS2693-1; PS35/155; PS35 06AQANTXII_4; Southeast Pacific The De Gerlache Seamounts are two topographic highs in the Bellingshausen Sea, southeastern Pacific. Petrological and geochemical studies together with K-Ar age determinations were carried out on four dredged basalt samples collected during a RV Polarstern expedition (ANT-XII/4) in 1995. Minor and trace element composition suggest alkaline basalt compositions. Compared to alkaline basalts of adjacent West Antarctica (the Jones Mountains) and of Peter I Island, the samples have lower mg-numbers, lower Ni and Cr contents and lower high field-strength elements (HFSE)/Nb and large-ion lithophile elements (LILE)/HFSE ratios. Three of the four samples have low K, Rb, and Cs concentrations relative to alkaline basalts. The K-depletion and other elemental concentrations may be explained by 1.1% melting of amphibole bearing mantle material. Additionally, low Rb and Ba values suggest low concentrations of these elements in the mantle source. K-Ar age determinations yield Miocene ages (20-23 Ma) that are similar in age to other alkaline basalts of West Antarctica (Thurston Island, the Jones Mountains, Antarctic Peninsula) and the suggested timing of onset of Peter I Island volcanism (~10-20 Ma). The occurrence of the DGS and Peter I Island volcanism along an older but reactivated tectonic lineation suggests that the extrusions exploited a zone of pre-existing lithospheric weakness. The alkaline nature and age of the DGS basalts support the assumption of plume activity in the Bellingshausen Sea. |
| title | Petrology, geochemistry and K-Ar Age determination of De Gerlache Seamount basalts |
| topic | ANT-XII/4; AWI_Paleo; Dredge; DRG; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Polarstern; PS2693-1; PS35/155; PS35 06AQANTXII_4; Southeast Pacific |
| url | https://doi.org/10.1594/PANGAEA.743234 |