The Indian Plate began drifting northward after the Gondwana breakup and collided with Eurasian during Early Cenozoic, resulting in consequential development of Himalayan–Tibetan Orogeny. Several microcontinents were rifted from amalgamated Plate, magmatism along continental margin. Abor volcanic rocks (AVRs) eastern Himalaya represent one such magmatism, emplacement mechanism, timing which is ...

The Neoproterozoic rocks of the Bir Madi area, south Eastern Desert, comprise a metagabbrodiorite complex (GDC) and a tonalite-granodiorite suite (TGrS). The GDC has a weak tholeiitic to strong calc-alkaline character and is made up of olivine gabbro, hornblende gabbro, diorite and monzodiorite. The olivine gabbro is characterized by abundance of augite and labradorite with pseudomorphic serpen...

[1] The Coast Ridge Belt (CRB, Santa Lucia Mts., central California) comprises mid-crustal rocks (750–800 C and 0.8 GPa) of the California magmatic arc. We estimated the bulk composition of the CRB and converted our results to seismic velocities expected at the observed pressures and temperatures. The bulk composition of this arc section changes abruptly at 25 km depth from a granodiorite to a ...

Bastnaesite, a rare-earth fluocarbonate, was found in the Mountain Pass district in April 1949. Subsequent geologic mapping has shown that rare-earth mineral deposits occur in a belt about 6 miles long and iy2 miles wide. One of the deposits, the Sulphide Queen carbonate body, is the greatest concentration of rare-earth minerals now known in the world. The Mountain Pass district is in a block o...

We present geochronological evidence in the eastern Himalayan syntaxis (Namche Barwa) for high-pressure (HP) granulite-facies metamorphism and explain its importance for understanding both the deep continental subduction of the Indian plate beneath Asia and its subsequent exhumation. The timing of peak and retrograde metamorphism in part constrains these processes but is debated. We present zir...