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...

Cristobalite is a common mineral in volcanic ash produced from dome-forming eruptions. Assessment of the respiratory hazard posed by volcanic ash requires understanding the nature of the cristobalite it contains. Volcanic cristobalite contains coupled substitutions of Al3+ and Na+ for Si4+; similar co-substitutions in synthetic cristobalite are known to modify the crystal structure, affecting t...

The 18-km-diameter El’gygytgyn crater is located on the Chukotka peninsula, northeastern Russia. It represents the only currently known impact structure formed in siliceous volcanics, including tuffs. The impact melt rocks and target rocks provide an excellent opportunity to study shock metamorphism of volcanic rocks. The shockinduced changes observed in porphyritic volcanic rocks from El’gygyt...

voluminous quaternary extrusive rocks, associated with widespread volcanic activities, occur in the northwestern iran and across the turkish-iranian plateau. field and petrographic studies reveal that these volcanic rocks, consisting of basalt to trachyandesite, occur as lava flows, columnar basalts, and cinder cones in three distinct areas of northern (bazergan-maku-burlan), middle (chalderan)...

Optical depth records indicate that volcanic aerosols from major eruptions often produce clouds that have greater surface area than typical Arctic polar stratospheric clouds (PSCs). A trajectory cloud-chemistry model is used to study how volcanic aerosols could affect springtime Arctic ozone loss processes, such as chlorine activation and denitrification, in a cold winter within the current ran...

Mapping of volcanic activities or events during eruptions such as lava flow, pyroclastic flow, mudflow and etc. at real time basis is very important to monitor and predict movement of these events, and prevent calamity. These events are usually dynamic and occur in short time duration. In this study, a real time volcanic activity mapping system, using single ground fixed digital camera, is deve...

[1] Volcanoes confront Earth scientists with new fundamental questions: Can airborne volcanic ash release nutrients on contact with seawater, thereby excite the marine primary productivity (MPP); and, most notably, can volcanoes through oceanic fertilization affect the global climate in a way that is so far poorly understood? Here we present results from biogeochemical experiments showing that ...

The Volcanic Island Clastic Apron Project (VICAP) entails a case history study of a coupled system, "oceanic island volcaniclastic apron". The source area has a long-term record of chemically distinct rocks/deposits with physically datable mineral phases, so that the submarine and subaerial growth and destruction is reflected in sufficient detail in the volcaniclastic apron. The seamount/island...

This paper presents an experimental and theoretical study of the thermal-runaway instability induced by localized microwaves in basalt stones. This effect leads to the inner melting of the basalt core, and further to its eruption similarly to a volcanic burst. The experiments are conducted in a single-mode cavity at 2.45 GHz, 0.9 kW. The microwave-induced miniature volcano exhibits hotspots, bu...

Oceanic archipelagos of volcanic origin have been important in the study of evolution because they provide repeated natural experiments allowing rigorous tests of evolutionary hypotheses. Ongoing volcanism on these islands may, however, affect the evolutionary diversification of species. Analysis of population structure and phylogeographic patterns in island populations can provide insight into...