Hyaloclastite between pillows of lava in MontanaPahoehoe lava enters the Pacific at Hawaii Volcanoes National Park, the Big Island of Hawaii
Hyaloclastite is a volcanoclastic accumulation or breccia consisting of glass (from the Greek hyalus) fragments (clasts) formed by quench fragmentation of lava flow surfaces during submarine or subglacial extrusion. It occurs as thin margins on the lava flow surfaces and between pillow lavas as well as in thicker deposits, more commonly associated with explosive, volatile-rich eruptions as well as steeper topography. Hyaloclastites form during volcanic eruptions under water, under ice or where subaerial flows reach the sea or other bodies of water. It commonly has the appearance of angular flat fragments sized between a millimeter to few centimeters. The fragmentation occurs by the force of the volcanic explosion, or by thermal shock and spallation during rapid cooling.
Several mineraloids are found in hyaloclastite masses. Sideromelane is a basalt glass rapidly quenched in water. It is transparent and pure, lacking the iron oxide crystals dispersed in the more commonly occurring tachylite. Fragments of these glasses are usually surrounded by a yellow waxy layer of palagonite, formed by reaction of sideromelane with water.
Hyaloclastite ridges, formed by subglacial eruptions during the last glacial period, are a prominent landscape feature of Iceland and the Canadian province of British Columbia. Hyaloclastite is usually found at subglacial volcanoes, such as tuyas, which is a type of distinctive, flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet.
In lava deltas, hyaloclastites form the main constituent of foresets formed ahead of the expanding delta. The foresets fill in the seabed topography, eventually building up to sea level, allowing the subaerial flow to move forwards until it reaches the sea again.[1]
^Naylor, P.H., Bell, B.R., Jolley, D.W., Purnall, P. & Fredsted, R. 1999. Palaeogene magmatism in the Faeroe-Shetland Basin: influences on uplift history and sedimentation. In: Fleet, A.J. & Boldy, S.A.R. (eds) Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference, 545-558. Geological Society, London.
Hyaloclastite is a volcanoclastic accumulation or breccia consisting of glass (from the Greek hyalus) fragments (clasts) formed by quench fragmentation...
Hyaloclastite Dam was a 1,201 ft (366 m) high lava dam that occupied the Grand Canyon of the U.S. state of Arizona. It formed during the Pleistocene epoch...
(5 mi) wide. Most of the volcano is formed by trachytic lava flows, but hyaloclastite is also found. Snow, ice, and glaciers cover most of Mount Takahe. With...
result of the much higher fragmentation of phreatomagmatic eruptions. Hyaloclastite is glass found with pillow basalts that were produced by non-explosive...
Hornblendite – Plutonic rock consisting mainly of the amphibole hornblende Hyaloclastite – Volcaniclastic accumulation or breccia Icelandite – Igneous rock type...
curvilinear shards that represent the spalled rims of pillow basalt (see: Hyaloclastite). This material is commonly partly altered to chlorite, epidote, quartz...
pebbles of obsidian Helenite – Artificial glass made from volcanic ash Hyaloclastite – Volcaniclastic accumulation or breccia and tachylite – volcanic glasses...
or fully coalesce to form a clastogenic lava flow. Silicon dioxide Hyaloclastite – Volcaniclastic accumulation or breccia Peperite – Sedimentary rock...
geological data. The cave itself is around 7m deep and made of soft hyaloclastite, which is why the figures could be carved by abrasion and then polished...
of tachylyte. Palagonite, an alteration product of basaltic glass. Hyaloclastite, a hydrated tuff-like breccia of sideromelane and palagonite. Pele's...
the eastern slopes of the rhyolitic Laugarfjall lava dome, but the hyaloclastite nature of the rock that the water erupts through, may be important in...
comes in contact with the cold ice, forming a glassy breccia called hyaloclastite. After a while the ice finally melts into a lake, and the more explosive...
tuffs with sandstones, mudstones and siltstones and important basalt, hyaloclastites and breccias erupted or sedimented during the Caradocian Epoch of the...
mounds (very rare). There are many hyaloclastite ridges, with most consisting of mixtures of pillow lavas, hyaloclastite and lapilli tuff. There are also...
the breakup of Rodinia, linking the eruption and rapid alteration of hyaloclastites along shallow ridges to massive increases in alkalinity in an ocean...
composite of sideromelane aggregate in palagonite matrix is called hyaloclastite. Based on infrared spectroscopy, the fine-grained component of Mauna-Kea...
failure, and hyaloclastite delta; and into five structural units. The volcano gets its name from its steep slopes and brown-to-black hyaloclastite. It was...
06667°N 157.08333°W / 22.06667; -157.08333 Geography Location Pacific Region US-HI (Hawaii) Geology Age of rock 1.5 to 2 ma Mountain type hyaloclastite...
formed under the influence of ice and are constructed by lava flows and hyaloclastite, these are so-called tuyas which form by eruptions of volcanoes into...
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