The most volcanically active regions of our planet are concentrated along the axes of the globe, encircling midocean ridges. These undersea mountain ranges, and most of the oceanic crust, result from the complex interplay between magmatic (i.e., eruptions of lavas on the surface and intrusion of magma at depth) and tectonic (i.e., faulting, thrusting, and rifting of the solid portions of the ou...

High-silica topaz-bearing rhyolites of Cenozoic emplaced as domes, lava flows or shallow intrusions. They age are widely distributed across the western USA and may also contain Fe-Mn garnet, beryl, bixbyite, pseudoMexico. They are characteristically enriched in fluorine brookite, hematite and fluorite in miarolitic cavities or with(>0.2 wt.%) and incompatible lithophile elements (e.g. Li, in th...

CONTENTS Page Introduction .................................................................................................................. 127 Megascopic structures ...................................................................................................... 128 Hand-specimen petrology .....................................................................................................

introduction the study area is located 12km away from the north east of sarbisheh at the eastern border of the lut block (karimpour et al., 2011; richards et al., 2012). the magmatic activity in the lut blockhas begun in the middle jurassic (165-162 ma) and reached its peak in the tertiary age (jung et al., 1983; karimpour et al., 2011). volcanic and subvolcanic rocks in the tertiary age cover ...