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.

2005年7月2日 · Today, rhyolite is used rather widely as the first term of binomial rock names -- e.g., rhyolite porphyry, rhyolite breccia and rhyolite tuff -- as well as a freestanding noun for rocks of this composition be they banded or not.

Flow banded rhyolite with secondary iron often showing a boundary of possible arrested alteration. Rhyolite is generally a light coloured, finely crystalline extrusive acid igneous rock …

2014年4月30日 · Rhyolite is an igneous, extrusive volcanic rock high in silica forming typically in continental arc settings. The flow-banding in this sample is caused by the friction of the viscous magma in contact with a solid rock surface or by compaction, causing flattening and welding of shards and pummice.

Flow-banded rhyolite forms when the molten rock flows as it cools, causing the minerals to align in thin, parallel bands. This flow-banding gives the rock a distinctive appearance, often with wavy or swirled patterns of different colors.

Rhyolite is possible, but so are several clastic sedimentary rocks (e.g. sandstone, siltstone). The red bands appear to be liesegang bands, which are a weathering feature caused by dissolution and redeposition of iron minerals (they sometimes form around siderite nodules or where the host rock contained pyrite).

2014年12月12日 · At Graveyard Butte, the White River has cut a winding canyon 150 m deep, exposing at its base, a 40-meter-thick outcrop of flow-banded rhyolite (73 wt.% SiO 2, 3.67±0.01 Ma) that laterally extends along the canyon wall for about 1 km. Stratigraphically above the flow-banded rhyolite is locally-erupted iron-rich andesites (lava flows ...

2019年1月3日 · One promising avenue is quantitative 3-D petrographic study of the size, shape and orientation distributions of vesicles and microlites in flow-banded obsidian (i.e., rhyolitic volcanic glass with distinct bands typically defined by differences in abundance of microlites and/or bubbles).

Hickoryite is banded rhyolite with swirls of light and dark bands. It is found in south-western Utah in the mineral mountains, where volcanic activity was very common about 50 million years ago.

2017年10月1日 · There are two known archaeological sources of flow banded, and sometimes spherule bearing rhyolites in New Hampshire, located in the towns of Berlin and Jefferson.