The central Oregon section of the Cascade Range volcanic arc is characterized byrelatively high Quaternary volcanic extrusion rates and hot-spring discharge rates, and by high conductive h at flow. However, a large area of near-zero near-surface onductive h at flow occurs in the younger volcanic rocks, due to downward and lateral flow of cold groundwater. Alternate models for the high heat flow...

The El'gygytgyn impact structure in Chukutka, Arctic Russia, is the only impact crater currently known on Earth that was formed in mostly acid volcanic rocks (mainly of rhyolitic, with some andesitic and dacitic, compositions). In addition, because of its depth, it has provided an excellent sediment trap that records paleoclimatic information for the 3.6 Myr since its formation. For these two m...

The Ethiopian Rift System consists of basins that are in different stages of evolution. Some of the rift-related basins in southwestern Ethiopia are half-grabens that have not evolved to symmetrical rifts since the initiation of rifting here in the middle Miocene. These basins contain fossiliferous Pliocene–Pleistocene volcaniclastic sediments and volcanic rocks and have been occupied by early ...

The Razei region in the northwest of Ardabil is considered a part of West Alborz-Azerbaijan. Rocks in this area were created by Eocene volcanic activities. These rocks range from andesite to olivine basalt. The common texture of these rocks is Porphyritic with microlithic matrix. The phenocrysts of these rocks are often clinopyroxene, plagioclase, and olivine. The texture is made of microlithic...

[1] Abstract: We propose that across-arc differences in the geochemistry of Izu-Bonin arc magmas are controlled by the addition of fertile-slab fluids to depleted mantle at the volcanic front, and residual-slab fluids to fertile mantle in the back arc without slab melting or contemporaneous back arc spreading. The arc consists of a volcanic front, an extensional zone, and seamount chains (the W...