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...

 Igneous Rocks form from the solidification of molten rock. Intrusive igneous rocks are composed of crystals that are large enough to be seen with the naked eye because these rocks cooled slowly, deep within the Earth thereby allowing time for the crystals to grow. In contrast, extrusive (volcanic) igneous rocks cool very quickly after they erupt from a volcano, and so are composed of microsco...

Major systems of northwesterly, northerly, and northeasterly trending recurrilig fractures or faults controlled emplacement of various units of the Iron Mask batholith. The batholith was emplaced in a high level volcanic to subvolcanic environment, comagmatic with Nicola volcanic rocks and coeval with part of the upper Nicola succession. The batholith intruded volcanic and sedimentary rocks of ...

Hydrothermal precipitates associated with active vents in the eastern Manus back-arc basin, Papua New Guinea, are among the most gold rich yet discovered on the modern sea floor. The volcanic rocks associated with this mineralization were investigated to determine if they are sufficiently enriched in gold to account for the gold content of the sulfides by simple leaching and to determine whethe...

available online at http://meteoritics.org 1495 © Meteoritical Society, 2004. Printed in USA. Shocked rocks and impact glasses from the El’gygytgyn impact structure, Russia Eugene P. GUROV1 and Christian KOEBERL2* 1Institute of Geological Sciences, National Academy of Sciences of the Ukraine, 55b Oles Gontchar Street, Kiev 01054, Ukraine 2Department of Geological Sciences, University of Vienna,...

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)...

Western Turkey has been dominated by N–S extension since the Early Miocene. The timing and cause of this N–S extension and related basin formation have been the subject of much debate, but new data from the Bigadiç borate basin provide insights that may solve this controversy. The basin is located in the Bornova Flysch Zone, which is thought to have formed as a major NEtrending transform zone d...