نتایج جستجو برای: post collision volcanism
تعداد نتایج: 453614 فیلتر نتایج به سال:
Pleistocene basaltic lava flows, consisting of trachybasalt and basaltic trachyandesite, cover an area north-northwest of Shahre-Babak in southeastern Iran. The whole rock chemistry indicates that the lavas are dominantly alkaline and mildly calc-alkaline. Variation diagrams of SiO2 with major and trace elements are consistent with fractional crystallization processes involving olivine, pyroxen...
The contribution of the Deccan Traps (west-central India) volcanism in the CretaceousPaleogene (KPg) crisis is still a matter of debate. Recent U-Pb dating of zircons interbedded within the Deccan lava flows indicate that the main eruptive phase (>1.1 × 106 km3 of basalts) initiated ~250 k.y. before and ended ~500 k.y. after the KPg boundary. However, the global geochemical effects of Deccan vo...
[1] We report Hf isotope compositions of 79 lavas that record the early ( 5–95 Ma) history of the Galápagos plume volcanism. These include lavas from the Caribbean Large Igneous Province (CLIP; 95–70 Ma), the accreted Galápagos paleo-hot spot track terranes (54–65 Ma) of Costa Rica (Quepos, Osa and Burica igneous complexes), and the Galápagos hot spot tracks (<20 Ma) located on the Pacific seaf...
Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition wit...
[1] We report Hf isotope compositions of 79 lavas that record the early ( 5–95 Ma) history of the Galápagos plume volcanism. These include lavas from the Caribbean Large Igneous Province (CLIP; 95–70 Ma), the accreted Galápagos paleo-hot spot track terranes (54–65 Ma) of Costa Rica (Quepos, Osa and Burica igneous complexes), and the Galápagos hot spot tracks (<20 Ma) located on the Pacific seaf...
The details of stratigraphic units and structures making up six coronae and their regional surroundings on Venus were examined using full resolution Magellan images and stereoscopic coverage. Altimetry and stereoscopic coverage were essential in establishing the local stratigraphic relationships and the timing of corona-related topography. The degree of preservation of signatures of earlier cor...
The respective tectonic effects of back arc spreading and continental collision in Asia are considered either as two independent processes or as closely interrelated. Extrusion tectonics assumes that the opening of the South China Sea and the left-lateral motion along the Red River fault are geometrically linked in a pull-apart manner. This model is not accepted by several workers because the s...
Abstract The SHRIMP U–Pb dating of zircons from felsic subvolcanic rocks in the Carboniferous formations Intra-Sudetic Basin SW Poland verifies previous views on timing Late Palaeozoic magmatic activity this area and constrains links between regional tectonics intra-basinal volcanism mid-European Variscides. Two main stages magmatism are identified: late orogenic stage, Early Permian post-oroge...
[1] The seafloor is characterized by numerous seamounts and oceanic islands which are mainly volcanic in origin. Relatively few of these features (< 0.1%), however, have been dated, and so little is known about their tectonic setting. One parameter that is sensitive to whether a seamount formed on, near, or far from a mid-ocean ridge is the elastic thickness, Te, which is a proxy for the long-t...
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