Search results
Results from the WOW.Com Content Network
Vesicular texture is a volcanic rock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside. [ 1 ] This texture is common in aphanitic , or glassy, igneous rocks that have come to the surface of the Earth, a process known as extrusion .
[11] [12] Variolitic basalts and variolitic komatiites occur commonly as Archean lava flows in the greenstone belts of South Africa and the Canadian Shield. [ 7 ] [ 8 ] Finally, there is a group of spotted volcanic rocks formerly known to French petrographers as the variolites du Drac from the locality in which they are found in Parc National ...
Basalt (UK: / ˈ b æ s ɒ l t,-ɔː l t,-əl t /; [1] [2] US: / b ə ˈ s ɔː l t, ˈ b eɪ s ɔː l t /) [3] is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon.
Scoria or cinder is a pyroclastic, highly vesicular, dark-colored volcanic rock formed by ejection from a volcano as a molten blob and cooled in the air to form discrete grains called clasts. [ 1 ] [ 2 ] It is typically dark in color (brown, black or purplish-red), and basaltic or andesitic in composition.
The vesicular basalt is sample 15016, and it is sometimes called the seatbelt basalt. Back at Falcon , Scott and Irwin set about deploying the Apollo Lunar Surface Experiments Package (ALSEP). Scott would drill the holes for the heat-flow experiment and put in the probes, while Irwin would set up the rest of the equipment.
Basalt is a very common volcanic rock with low silica content. Rhyolite is a volcanic rock with high silica content. Rhyolite has silica content similar to that of granite while basalt is compositionally equal to gabbro. Intermediate volcanic rocks include andesite, dacite, trachyte, and latite. [citation needed]
Shield volcanoes are large, slow forming volcanoes [6] that erupt fluid basaltic magma that cools to form the extrusive rock basalt. Basalt is composed of minerals readily available in the planet's crust, including feldspars and pyroxenes. [2] Fissure volcanoes pour out low viscosity basaltic magma from fissure vents to form the extrusive rock ...
The sample is a very vesicular basalt, rounded by surface erosion. Lithologically, it closely resembles samples 15535 and 15536, as well as a number of fragments in the rake samples from station 9A. [3] The seatbelt basalt is currently stored at the Lunar Sample Laboratory Facility at the Lyndon B. Johnson Space Center.