Neoproterozoic High-K Calc-Alkaline Granitoids from Bapa-Batié, North Equatorial Fold Belt, Central Cameroon: Petrogenesis and Geodynamic Significance

Significance of hornblende in calc-alkaline andesites and basalts

Hornblende occurs in some andesitic and basaltic rocks of calc-alkaline affini1y, where it is commonly associated with olivine. The texture, eruption history, and composition are interpreted to indicate that hornblende commonly forms as a product of reaction between olivine and basaltic and andesitic liquids. The natural hornblendes probably formed within the crust at temperatures between 960o ...

Petrogenesis of High-K Arc Magmas: Evidence from Egmont Volcano, North Island, New Zealand

Egmont Volcano (Mt Taranaki) is located 140 km west of the INTRODUCTION Taupo Volcanic Zone (TVZ), the principal locus of volcanic activity Egmont Volcano is a 2518 m high stratovolcano (Mt in the North Island of New Zealand, and is one of four closely Taranaki) resting on an extensive ring plain of volcanic associated Quaternary andesitic volcanoes in Taranaki province. debris in Taranaki prov...

Pressure, temperature and oxygen fugacity conditions of calc-alkaline granitoids, Eastern Desert of Egypt, and tectonic implications

Five calc-alkaline plutons; Um Tagher, Abu Zawil, Um Gidri, Um Anab and El Ghuzah, in the northern Eastern Desert of Egypt were subjected to petrographic and mineralogical investigations. They are composed of varying proportions of quartz + plagioclase +potash feldspar+ biotite + hornblende± epidote ± calcite + titanite +magnetite + apatite and zircon. Electron microprobe analyses of coexisting...

Transition from Paleogene Normal Calc-Alkaline to Neogene Adakitic-Like Plutonism and

Geochemistry and evolution of the Neoproterozoic granitoid magmatisms in the Wadi El Sheikh-Gabal Saint Katherine area, Southw

Older and younger granitoids are widespread throughout the basement rocks of NE Egypt. Therefore, they are played a significant role in the evolution of the Pan-African crust. The Wadi El Sheikh-Gabal Saint Katherine area comprise three distinctive magmatic granitoid suites, namely: (1) calc-alkaline older quartz monzodiorite-tonalite suite (COG), (2) calcalkaline younger monzogranite suite (CY...