Geologic materials composed of broken fragments of volcanic rock
The Espinaso Formation includes a wide variety of volcaniclastic materials.
Volcaniclastics are geologic materials composed of broken fragments (clasts) of volcanic rock.[1] These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it was deposited in, or whether nonvolcanic material is mingled with the volcanic clasts.[2] The United States Geological Survey defines volcaniclastics somewhat more narrowly, to include only rock composed of volcanic rock fragments that have been transported some distance from their place of origin.[3]
In the broad sense[2][4] of the term, volcaniclastics includes pyroclastic rocks such as the Bandelier Tuff;[5] cinder cones and other tephra deposits; the basal and capping breccia that characterize ʻaʻā lava flows; and lahars and debris flows of volcanic origin.[6]
Volcaniclastics make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed as much as a third of all sedimentation in the geologic record.[2]
^Fisher, Richard V. (1961). "Proposed classification of volcaniclastic sediments and rocks". Geological Society of America Bulletin. 72 (9): 1409. Bibcode:1961GSAB...72.1409F. doi:10.1130/0016-7606(1961)72[1409:PCOVSA]2.0.CO;2.
^ abcFisher, Richard V.; Schminke, H.-U. (1984). Pyroclastic rocks. Berlin: Springer-Verlag. ISBN 3540127569.
^"Volcaniclastic". Volcanic Hazards Program. United States Geological Survey. 2012. Retrieved 28 September 2020.
^Vincent, Pierre (2000). Volcaniclastic rocks, from magmas to sediments(PDF). Amsterdam, the Netherlands: Gordon and Breach Science Publishers. p. 1. ISBN 9056992783. Retrieved 28 September 2020.
^Ross, Clarence S.; Smith, Robert L. (1961). "Ash-flow tuffs: Their origin, geologic relations, and identification". USGS Profession Paper Series. Professional Paper (366). doi:10.3133/pp366.
flows of volcanic origin. Volcaniclastics make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed as much...
Artesian Basin (GAB) was flooded by the Eromanga Sea and filled with volcaniclastic sediments eroded from the Cordillera's volcanic arc. A theory was proposed...
origin, lying on the Lesser Antilles volcanic island arc, and tuffs and volcaniclastic breccias of Eocene age are exposed locally on the island. The island...
rock consisting mainly of the amphibole hornblende Hyaloclastite – Volcaniclastic accumulation or breccia Icelandite – Igneous rock type Ignimbrite –...
Tephra and other volcaniclastics (shattered volcanic material) make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed...
are glassy, marginal sheet flows, indicative of larger-scale flows. Volcaniclastic sedimentary rocks are common in shallow-water environments. As plate...
uncertain. Special classifications exist for metamorphic rocks with a volcaniclastic protolith or formed along a fault or through hydrothermal circulation...
fragments are known as pyroclasts. Pyroclastic rocks are a type of volcaniclastic deposit, which are deposits made predominantly of volcanic particles...
Luzon arc. The age is Neogene and the rock consist of melange and volcaniclastics. The rock units are firstly Chimei Volcanics Miocene andesite. Next...
straddles the border near McDermitt, Nevada–Oregon, although there are volcaniclastic piles and arcuate faults that define caldera complexes more than 60 km...
and white bedded chert; pillow basalt; carbonate rocks; minor felsic volcaniclastic sandstone and conglomerate; hydrothermal barite; evaporites; and stromatolites...
Helenite – Artificial glass made from volcanic ash Hyaloclastite – Volcaniclastic accumulation or breccia and tachylite – volcanic glasses with basaltic...
Volcanics on the north side of the island consist of andesitic flows and volcaniclastics, overlying the San Onofre Breccia, and dated at about 16 Ma. The eruptive...
which are glassy and marginal, and indicative of larger-scale flows. Volcaniclastic sedimentary rocks dominate shallow-water seamounts. They are the products...
treated by Hadley and Schmidt (1980) as being part of a silicic and volcaniclastic sequence referred to as the "Shammar group", in a broader, regional...
and the mudstones of the Hope Shale Formation with their interbedded volcaniclastics form much of the afforested ground to the west. The outcrop of the...
volcaniclastics; the Bullseye Rhyolite of dacite flows and volcaniclastics; and the Grapevine Gulch Formation mostly of fine-grained volcaniclastics interpreted...
usually millimetres to centimetres in size, seen on surfaces of some volcaniclastic rocks. They can occur in welded pyroclastic fall deposits and in ignimbrites...
record, volcanic arcs can be recognized from their thick sequences of volcaniclastic rock (formed by explosive volcanism) interbedded with greywackes and...
Retrieved 22 May 2011. Fisher, R. V. (1961). "Proposed classification of volcaniclastic sediments and rocks". Geological Society of America Bulletin. 72 (9):...
Inactive arcs are a chain of islands which contains older volcanic and volcaniclastic rocks. The curved shape of many volcanic chains and the angle of the...
[specify] particularly in Scotland, referred to any coarse-grained volcaniclastic rock as 'agglomerate', which led to debris flow deposits, talus deposits...
Classification of Volcaniclastic rocks and sediments Pyroclastic deposit Clast size in mm Pyroclast Primarily unconsolidated: tephra Primarily consolidated:...
produced 52 tonnes of gold by 1982. Gold deposits are found within volcaniclastics, associated with pyrite. Schools in Shamva include Chindunduma, madziva...
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