the eocene volcanic rocks from the southwest of the jandaq (kuh-e-godar-e-siah, central-east iran micro-continent) are andesitic basalt and andesite in composition. these rocks contain xenoliths with granulitic mineralogy. mineral assemblage of these xenoliths is plagioclase + phlogopite + corundum + sillimanite + chlorite + phengite with granublastic, poiklioblastic and foliated textures in th...

Formation of a hydrated superficial layer early in the history Earth and Earth-like planets may occur by extensive serpentinization mantle rocks water, similar to that still active at present-day slow-spreading oceanic plates. We investigated lifetime this buoyant weak “crust” with 2D numerical simulations convection. Three regimes preservation crust exist as function its thickness buoyancy, bo...

sangan magnetite skarn mine is located 300 km southeast of mashhad, along the eastern part of khaf-drouneh volcanic-plutonic belt. granitoids from three areas within the sangan mine a, c-north and dardvay were studied. within the study area, three intrusive rocks including biotite-hornblende monzonite porphyry, biotite syenite and syenogranite were recognized. based on field cross cutting, abse...

Zircon and monazite from three restitic enclaves and one host dacite have been dated by ion microprobe (SHRIMP), with the aim of characterising their Miocene history and defining the timing relationships between crustal melting and eruption in the high-K calc-alkaline volcanics of the Neogene Volcanic Province of SE Spain. The studied samples are from the volcanic edifices of El Joyazo (Cerro d...

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...

Unlike the other terrestrial planets, Earth has a substantial silica-rich continental crust with bulk andesitic composition. A small number of meteorites compositions have been identified that are thought to be products partial melting chondritic protoliths, mode petrogenesis distinct from Earth’s crust. Here we show, using geochemical analyses, unlike known meteorites, Erg Chech 002 strongly f...