Primary alteration of uranpyrochlore from granitic pegmatites is characterized by the substitutions ADYD-+ ACaYO, ANaYF -+ ACaYO, and ANaYOI-I --+ ACaYO. Alteration occurred at ""450-650 °C and 2-4 kbar with fluid-phase compositions characterized by relatively low aNa+,high aeaH, and high pH. In contrast, primary alteration of pyrochlore from nepheline syenites and carbonatites follows a differ...

The Eocene-Oligocene Sarbisheh volcanic complex is a part of the Lut-Sistan Zone that outcrops in eastern Iran. In the east of this complex, three groups of volcanic rocks (i.e., andesite, dacite, and rhyolite) exist. Plagioclase as the main mineral of these rocks is found with varying micro-textures. Based on a changing trend in the concentration of anorthite, the developed micro-textures (coa...

Abstract Bubble and crystal textures evolve during magma ascent, altering properties that control ascent such as permeability viscosity. Eruption style results from feedbacks between bubble nucleation growth, microlite crystallization, gas loss, all processes recorded in pyroclasts. We show pyroclasts of the mafic Curacautín ignimbrite Llaima volcano, Chile, record a history repeated autobrecci...

Abstract Ringwoodite and wadsleyite are the high-pressure polymorphs of olivine, which common in shocked meteorites. They major constituent minerals terrestrial mantle. NWA 8705, an olivine-phyric shergottite, was heavily shocked, producing shock-induced melt veins pockets associated with four occurrences ringwoodite: (1) lamellae intergrown host olivine adjacent to a pocket; (2) polycrystallin...

Abstract The occurrence of groundmass crystals reveals the shallow conduit process magmas, which affects behavior eruptions. Here, we analyzed microtextures ash samples from 2018 eruption Shinmoedake volcano, Japan, to evaluate change magma ascent conditions during sequence. eruptive activity changed venting (Phase 1: March 1–6) lava effusion with continuous ash-laden plumes 2: 6–9) and then sh...

Abstract Microlite crystallization in erupting basalt can occur the conduit, flight, or situ after deposition. Distinguishing products of primary versus secondary (post-fragmentation) be challenging near-vent environments, but is vital for interpreting shallow conduit conditions from pyroclast textures. Here, we examine pyroclasts 1886 basaltic Plinian eruption Tarawera volcano, New Zealand, to...

volcanic rocks of interest are situated in the middle part of the urumieh-dokhtar magmatic arc (udma). they are parts of a vast magmatic province located in the north of bitlis-zagros suture zone. having a prevailing porphyritic texture, these rocks include phenocrysts of plagioclase, amphibole and biotite in a matrix composed of feldspar, quartz, opaque, glass and microlite and mineralogically...

Abstract Volcanic rocks commonly display complex textures acquired both in the magma reservoir and during ascent to surface. While variations mineral compositions, sizes number densities are routinely analysed reconstruct pre-eruptive magmatic histories, crystal shapes often assumed be constant, despite experimental evidence for sensitivity of habit conditions. Here, we develop a new program ( ...