نتایج جستجو برای: adakite
تعداد نتایج: 69 فیلتر نتایج به سال:
Abstract Geochemical similarities between the continental crust and arc magmas have led to inference that subduction zones may be primary sites of crustal growth. Thus, it is necessary unravel petrogenetic mechanism(s) granitoid generation in subduction-related settings understand growth through magmatic differentiation processes. In this study, we focused on oceanic-continental zones. We analy...
Kashmar subvolcanic and plutonic bodies have compositional ranges from quartz gabbro to alkali granite. With exception of several small stock with alkaline Tholeiitic basalts characteristic (minimum amounts of SiO2 and CaO; maximum amount of MgO; high amounts of Na2O and K2O and LOI and high meta-luminous to peraluminous (1.33-2.32)), all rocks have high-k calc-alkaline to shoshonitic, meta-lu...
فعالیت آتشفشانی کواترنر در دره الموت در سه مرحله انجام پذیرفته است که گدازههای آن روی رسوبات سرخ نئوژن گسترده شده است. این سنگهای آتشفشانی با ترکیب حدواسط و با میزان SiO2 48/55 تا 88/61 درصد از نوع هورنبلند تراکیآندزیت هستند. نمودار عناصر خاکی کمیاب این سنگها دارای شیب تند در بخش LREE و MREE [(N(La/Ho)] در حدود 85 و شیب به نسبت کم در بخش HREE [N(Ho/Lu)] در ...
Eocene intermediate to felsic subvolcanic rocks of the Torud-Ahmad Abad magmatic belt (TAMB), in northern part Central Iran zone, are exposed between Torud and Ahmad regions South-Southeast Shahrood. These igneous include hypabyssal dacite, trachyte, andesite, trachy-andesite, basaltic andesite; they mainly composed phenocrysts microcrystalline groundmass pyroxene, amphibole, plagioclase, with ...
Abstract The process of continental growth and closure the Paleo‐Asian Ocean are controversial. To address this problem, we report new geochemical geochronological data granitic rocks along a N‐S corridor Dananhu arc. These yield 401–270 Ma U‐Pb zircon ages. arc‐related granites enriched in light rare earth elements (LREE), Rb, Ba, Th, Sr Pb, but depleted Nb Ta, have high zircons values ε Hf (t...
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