The basement rocks encountered in exploratory boreholes drilled for exploration and evaluation of coal deposits in Thar Parkar district, Sindh Pakistan have formed the basis for present studies. The basement complex was penetrated through eighteen boreholes at drill depth range from 112 to 279 meters. These rocks were identified in field as Pink and Grey Granites.. The basement rocks are of Ign...

Abstract We report a new zircon U–Pb age of 1257 ± 6 Ma for the Punugodu granite (PG) pluton in Eastern Dharwar Craton (EDC), Southern India. The Mesoproterozoic PG is alkali feldspar hypersolvus emplaced at shallow crustal level, as evident from presence rhyodacite xenoliths and hornfelsic texture developed metavolcanic country rocks Neoarchaean Nellore Schist Belt (NSB). Geochemically, metalu...

Zircon ages and trace element compositions from recent silicic eruptions in the Lassen Volcanic Center (LVC) allow for an evaluation of the timing and conditions of rejuvenation (reheating and mobilization of crystals) within the LVC magmatic system. The LVC is the southernmost active Cascade volcano and, prior to the 1980 eruption of Mount St. Helens, was the site of the only eruption in the C...

Abstract The Olds Ferry terrane is the more inboard of two accreted volcanic arc terranes in late Paleozoic–early Mesozoic Blue Mountains province northern U.S. Cordillera. We present geologic, geochronologic, and geochemical data from volcano-sedimentary Huntington Formation that place within a firm temporal tectonomagmatic context, establish its identity as fringing along Triassic to Early Ju...

introduction the study area is a small part of the urumieh-dokhtar structural zone in the markazi province, located in the northeastern part of the farmahin, north of arak (hajian, 1970). the volcanic rocks studied from the area include andesite, dacite, rhyodacite, ignimbrite and tuff of middle to late eocene age (middle lutetian to upper lutetian) (ameri et al., 2009). it seems that folding a...

Laboratory experiments investigating syn-eruptive crystallization are fundamental for interpreting crystal and vesicle textures in pyroclasts. Previous have advanced our understanding by varying decompression cooling pathways, volatile components, melt composition. However, they largely failed to produce the high number densities seen many cryptodome dome samples. This is feasibly due relativel...

Crater Lake was surveyed nearly to its shoreline by high-resolution multibeam echo sounding in order to define its geologic history and provide an accurate base map for research and monitoring surveys. The bathymetry and acoustic backscatter reveal the character of landforms and lead to a chronology for the concurrent filling of the lake and volcanism within the ca. 7700 calibrated yr B.P. cald...