The Indian Peak volcanic field is representative of the more than 50,000 km3 of ashflow tuff and tens of calderas in the Great Basin that formed during the Oligocene-early Miocene "ignimbrite flareup" in southwestern North America. The field formed about 32 to 27 Ma in the southeastern Great Basin and consists of the centrally positioned I n d i Peak caldera complex and a surrounding blanket of...

Two fundamentally different types of silicic volcanic rocks formed during the Cenozoic of the western Cordillera of the United States. Large volumes of dacite and rhyolite, mostly ignimbrites, erupted in the Oligocene in what is now the Great Basin and contrast with rhyolites erupted along the Snake River Plain during the Late Cenozoic. The Great Basin dacites and rhyolites are generally calc-a...

Abu Hamamid (AH) Neoproterozoic (Sm/Nd model age of 770 ± 20 Ma) mafic–ultramafic intrusion lies along a NE–SW fracture zone in the Shadli Metavolcanic Belt, south Eastern Desert, Egypt. AH intrusion is concentrically zoned with cumulate clinopyroxenebearing dunite core mantled by olivine clinopyroxenite, hornblende clinopyroxenite and hornblende gabbroic rim. The observed crystallization seque...

Introduction: It has been widely accepted that the lunar anorthosite crust formed by floatation of anorthite in the magma ocean at the time of a giant impact of the Earth-Moon system formation. The positive Eu-anomaly in lunar anothosites and the absence of mafic components in the lunar crust that contain complementary negative Eu-anomalies can also be the evidence of formation of the anorthosi...

Cretaceous mafic dykes in the Moyar Shear Zone (MSZ) area, north Kerala, India, provide signatures to probe into the nature of their source and thereby the evolution of the Mesozoic lithospheric mantle beneath the South Indian Granulite Terrain (SIGT). Bulk of the dykes in northern parts of Kerala is broadly in spatial association with the shear system. Mafic dykes striking NE-SW, NWSE, NNW-SSE...

Abstract Petrological and geochemical features of gabbros fine-grained mafic rocks (mafic microgranular enclaves; MMEs) in the Inagawa Granite Ryoke Plutonic Complex were investigated to assess interactions between coexisting silicic magmas, petrogenetic relationships MMEs surrounding gabbros. The exhibit mingling textures that imply coexistence magmas did not undergo complete mixing, but compo...