Since the acceptance of plate tectonics, presence calc-alkaline magmatic rocks has been recognized as evidence subduction. But under specific geodynamic circumstances, subduction may occur without generating magmas. Here, we investigate Cenozoic northern Lesser Antilles arc where, from sparsely exposed records, Eocene?Oligocene and Pliocene flare-ups a Miocene lull were postulated. Nevertheless...

Thermal history and apatite fission-track ages were determined for the Kaleybar, Razgah and Bozqush alkaline intrusions which display Eocene-Oligocene stratigraphic age. These subduction-related intrusions are located in the Alborz-Azarbaijan magmatic belt which is characterized by a Paleogene magmatic flare-up associated with extensional/transtensional tectonism. The mean of Uranium content an...

The airborne geophysical data gamma-spectrometric and magnetic from Itatira Project (1977) was carried out, in the central region of the State of the Ceará, Brazil. Their processing produced products useful to indirectly identify regional geologic features. The verification and applicability of this approach was tested in a pilot-area whose limits are within the Umirim and Canindé topographic s...

We investigated calcite veins in two spinel-garnet peridotite xenoliths from the sub-Sierra Nevada mantle. These peridotites represent samples of the lithospheric mantle wedge beneath the Mesozoic California magmatic arc, as indicated by radiogenic isotopic ratios measured on clinopyroxenes separates (Sr/Sr8 Ma= 0.7058-0.7061, Nd/Nd8 Ma= 0.512538-0.512601). Mineral chemistry of the peridotite m...

The Open University's repository of research publications and other research outputs Late Cretaceous (81Ma) high-temperature metamorphism in the southeastern Lhasa terrane: implication for the Neo-Tethys ocean ridge subduction. (2013). Late Cretaceous (81Ma) high-temperature metamorphism in the southeastern Lhasa terrane: implication for the Neo-Tethys ocean ridge subduction. Tectonophysics, 60...

introduction volcanic rocks with a porphyritic texture have experienced two crystallization stages. the first is slow, resulting in phenocrysts, and the second, which took place at, or near the surface, or during intrusion into a cooler body of rock, result in a groundmass of glass, or fine crystals. the pressure and temperature history of a magma during crystallization is recorded in the chemi...

[1] The Hoggar swell in Algeria is one of the significant massifs of northwest Africa. The paucity of high‐ resolution geophysical studies of the crust and mantle beneath the massifs is mostly responsible for the heated debates about the depth of the source region of the Cenozoic volcanism and the closely related uncertainty about the mechanism that formed and maintains the high elevation of th...