Webb6 dec. 2024 · The observed host rocks of VMS deposits in the PVB are rhyolite, rhyodacite, and andesite, with occasional basaltic flows [25,26,28,35]. Thus, sulfur in the ore-fluids of VMS deposits in the PVB must have been partially derived from pre-existing volcanic basement rocks. Webb25 okt. 2024 · Large-volume rhyolite lava flows were erupted in Yellowstone following the most recent caldera-forming super-eruption, mostly between 160,000 and 70,000 years ago. NPS—Yellowstone—Obsidian Cliff USGS—Lava Flows and Associated Hazards at Yellowstone National Parks Containing Lava Flows
Rhyolite - Wikipedia
WebbFlow banding. Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from the substance molten rock or magma.. … Webb3 jan. 2016 · 4. Flow banding can occur in all igneous rocks, regardless of their composition. Any kind of molten rock that flows may eventually cause some flow … jelawat
geology - Does flow banding only occur in silicic rocks? - Earth
WebbThe scales of the flowbands vary from millimeters to several centimeters, and this texture suggests that the Northbrae formed as a viscous volcanic flow. As the flow cooled, the viscous flow-bands broke into clasts (autobrecciation). In contrast, the Leona contains no flowbanding or brecciation. Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from magma (molten rock). Flow banding is caused by friction of the viscous magma that is in contact with a solid rock interface, usually the wall rock to an intrusive chamber or, if the magma is erupted, the surface of the earth across which the lava is flowing. WebbTexture ranges from chert-like to slightly grainy and it weathers to a light gray patina that lacks any indication of flow banding. 3) banded metarhyolite: a dark blue-gray to black … lahmacun serme