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.

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 composed of quartz, orthoclase feldspar and biotite some with minor pyroxene and amphibole.

2008年3月1日 · Flow-banded rhyolite artifacts, commonly with spheroidal textures which have originated in northern New Hampshire, have been recovered from various Paleoindian, Archaic and Woodland archaeological sites in New England and southeastern Quebec, Canada. To date there are two known sources for the artifacts.

Rhyolite is high silica lava, quite common in the conglomerates of the Keweenaw and also in some small bodies along and near the Keweenaw Fault, like Mount Houghton. Rhyolite is a hard rock and makes smooth beach stones, usually reddish in color.

2013年7月22日 · 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).

2017年10月1日 · archaeological sources of flow banded, and sometimes spherule bearing rhyolites in New Hampshire, located in the towns of Berlin and Jefferson. A location map showing where these rhyolite sources are within the state of New

Banded obsidian from BGM and MI can be found in close spatial proximity to brittle deformational textures. We therefore propose that a key element of banding formation in our samples may be magma brecciation or fragmentation.

1994年10月1日 · In this paper we present evidence of the role of gravity in forming folds in the near-vent part of a banded rhyolite lava flow and describe the way this process influences the development of more distal folds.

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.% SiO2, 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 ...

2009年6月10日 · This study focuses on the origin of flow-banded rhyolites that consist of compositionally similar darker and lighter flow bands of contrasting texture and color.