Sodic-calcic amphiboles found from dolerite in the Nedamo Terrane, Northeast Japan

خصوصیات نوری، ترکیب شیمیایی و نحوه تشکیل آمفیبول‌های سدیک و سدیک – کلسیک بی رنگ در پیه مونتیت – کوارتز شیست‌های بخش مرکزی شیکوکو از نوار دگرگونی فشار بالا – دمای پائین سانباگاوا واقع در جنوب غربی ژاپن

Colorless sodic and sodic-calcic amphiboles occur in piemontite-quartz schists in the Asemi-gawa (garnet zone) and Besshi (albite-biotite zone) areas of high P-low T Sanbagawa metamorphic belt in central Shikoku, Japan. Colorless sodic amphiboles in the Asemi-gawa area are glaucophane while colorless sodic-calcic amphiboles from the Besshi area are barroisite and magnesiokatophorite. Colorless ...

The compositional variation of synthetic sodic amphiboles at high and ultra-high pressures

Sodic amphiboles in high pressure and ultrahigh pressure (UHP) metamorphic rocks are complex solid solutions in the system Na2O±MgO±Al2O3±SiO2± H2O (NMASH) whose compositions vary with pressure and temperature. We conducted piston-cylinder experiments at 20±30 kbar and 700±800 °C to investigate the stability and compositional variations of sodic amphiboles, based on the reaction glaucophane ˆ 2...

Polymetamorphic Amphibole Veins in Metabasalts from the Betic Ophiolitic Association at Cóbdar, Southeastern Spain: Relics of Ocean-floor Metamorphism Preserved through the Alpine Orogeny

Our aim in this work is (1) to characterize mineralogically and geochemically the brown amphibole and other minerals filling millimetric veins in the Cóbdar metabasalts of the Betic ophiolites in southern Spain, and (2) to deduce their genetic conditions, mainly with the aid of the optical microscopy and analytical electron-microprobe analysis, complemented by transmission and analytical electr...

ترکیب شیمیایی آمفیبولها در سنگ‌های دگرگون مجموعه افیولیتی شرق بیرجند و تأیید سیر تکاملی فشار و دمای این سنگها

Eastern Birjand ophiolitic complex consist of different rock types of a complete ophiolitic sequence. Three groups of amphiboles which exist in metabasites of this ophiolitic complex are of: calcic amphiboles, such as actinolite-tremolite and magnesio-hornblende; calcic-sodic amphiboles, e.g. vinchite and barroisite; and sodic-amphiboles, e.g., glaucophane, magnesio-riebeckite and ferro-glaucop...

Quaternary Volcanism Along the Volcanic Front in Northeast Japan