TY - JOUR
T1 - Neoproterozoic basalts of the Paleo-Asian Ocean (Kurai accretionary zone, Gorny Altai, Russia)
T2 - geochemistry, petrogenesis, and geodynamics
AU - Safonova, I. Yu
AU - Simonov, V. A.
AU - Buslov, M. M.
AU - Ota, T.
AU - Maruyama, Sh
PY - 2008/4
Y1 - 2008/4
N2 - Late Neoproterozoic (Late Vendian) basalts of the Paleo-Asian Ocean are found as fragments incorporated in the Kurai accretionary zone, Gorny Altai, Russia. Detailed study of their geochemistry and relationships with associated sedimentary rocks allowed us to recognize three types of basalts: (1) lavas depleted in REE, Nb and Ti, compositionally similar to N-MORB and associated with thin-bedded oceanic siliceous sediments; (2) basalts of transitional compositions, and (3) basalts enriched in the above elements; basalts of types 2 and 3 are similar to Pacific intraplate basalts and are associated with carbonate "cap" sediments. The N-MORB-type basalts generated from a depleted upper-mantle source, whereas the transitional and enriched ones from a heterogeneous mantle source. Their crystallization temperatures were estimated from the experiments on homogenization of melt microinclusions hosted by clinopyroxene phenocrysts (1160-1190 °C) and from the composition of the latter (1100-1295 °C). The geological, lithological, petrological, and geochemical data show that the Kurai basalts were formed in the geodynamic settings of mid-oceanic ridges and oceanic seamounts/islands.
AB - Late Neoproterozoic (Late Vendian) basalts of the Paleo-Asian Ocean are found as fragments incorporated in the Kurai accretionary zone, Gorny Altai, Russia. Detailed study of their geochemistry and relationships with associated sedimentary rocks allowed us to recognize three types of basalts: (1) lavas depleted in REE, Nb and Ti, compositionally similar to N-MORB and associated with thin-bedded oceanic siliceous sediments; (2) basalts of transitional compositions, and (3) basalts enriched in the above elements; basalts of types 2 and 3 are similar to Pacific intraplate basalts and are associated with carbonate "cap" sediments. The N-MORB-type basalts generated from a depleted upper-mantle source, whereas the transitional and enriched ones from a heterogeneous mantle source. Their crystallization temperatures were estimated from the experiments on homogenization of melt microinclusions hosted by clinopyroxene phenocrysts (1160-1190 °C) and from the composition of the latter (1100-1295 °C). The geological, lithological, petrological, and geochemical data show that the Kurai basalts were formed in the geodynamic settings of mid-oceanic ridges and oceanic seamounts/islands.
KW - Gorny Altai
KW - MORB
KW - OIB
KW - Paleo-Asian Ocean
KW - basalts
KW - crystallization temperature
KW - major and trace-element geochemistry
KW - melt microinclusions
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U2 - 10.1016/j.rgg.2007.09.011
DO - 10.1016/j.rgg.2007.09.011
M3 - Article
AN - SCOPUS:40949114190
VL - 49
SP - 254
EP - 271
JO - Russian Geology and Geophysics
JF - Russian Geology and Geophysics
SN - 1068-7971
IS - 4
ER -