Dacite (/ˈdeɪsaɪt/) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained...

although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day) The characteristic dome shape is attributed to high...

called the Pagosa Peak Dacite, made of dacite that is very similar to that of the Fish Canyon Tuff. The Pagosa Peak Dacite, which has characteristics...

working in the area were not there. By the time of the climactic eruption, dacite magma intruding into the volcano had forced the north flank outward nearly...

characteristic mixture of dacite and andesite, while modern lava is very diverse (ranging from olivine basalt to andesite and dacite).: 214  St. Helens started...

ranges from 63 to 69 percent. The dacite volcanic plugs, lava domes, intrusive sheets, and felsitic rhyolite-dacite between Morro Rock and Islay Hill...

(611 m), about 1,400 feet (430 m) above the flat prairie. This Pleistocene dacite lava dome is part of the Cascade Volcanic Arc, and with an age of only about...

erupt from the vent were hornblende-pyroxene andesites with a hornblende dacite dome at its summit. Glacial erosion has since modified its shape.[citation...

The Tooth of Time is an igneous intrusion of dacite porphyry formed in the tertiary period some 22 to 40 million years ago. It is a geological feature...

is dacite. The columns, or pipes, were formed in the later stages of Mount Boucherie's volcanic period, as evidenced by the fact that the dacite columns...

percentage (>63%) of silica, the lava is described as felsic. Felsic lavas (dacites or rhyolites) are highly viscous and are erupted as domes or short, stubby...

often felsic, having high to intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less viscous mafic magma. Extensive...

containing orthopyroxene Enderbite – Igneous rock of the charnockite series Dacite – Volcanic rock intermediate in composition between andesite and rhyolite...

basalt, ferro-basalt, tholeiitic basaltic andesite, tholeiitic andesite, dacite and rhyolite. The variety of basalt in the series was originally called...

rich in silica extrusive rock obsidian and sometimes dacite domes form the extrusive rock dacite, like in the case of Mount St. Helens. Calderas are volcanic...

'slate' or 'bluestone', a metamorphic phyllite rock, with both andesite and dacite mineral composition. Dacitic phyllite is a predominant type of rock found...

smaller dacite domes formed around Lassen. The largest of these, Chaos Crags, is just north of Lassen Peak. Phreatic (steam explosion) eruptions, dacite and...

volcanic activity over the last 260,000 years. This activity produced mostly dacite, the main type of volcanic rock forming Mount Garibaldi. Volcanism between...

Paleozoic and Mesozoic rocks. The city's Mount Elden is a lava dome made of dacite, Sunset Crater is the youngest feature of the San Francisco volcanic field...

corner of the Long Valley Caldera and consists of about 12 rhyodacite and dacite overlapping domes. These domes formed in a long series of eruptions from...

the calc-alkaline series include volcanic types such as basalt, andesite, dacite, rhyolite, and also their coarser-grained intrusive equivalents (gabbro...

dormant. The recent vents active in the last million years include some dacite in composition. Composition details are freely available for most of the...

Monte Amiata, Tuscany Glynn Hill, County Antrim, Northern Ireland Scafell Dacite (including Great Gable), Cumbria, England Skerry Fell Fad, Argyll and Bute...

8.3, 7.2, 4.8 and 3.4 million years ago. The volcano is constructed by dacite and pyroxene or hornblende andesite. These form lava flows or pyroclastic...

then, smaller dacite domes such as the 1,100-year-old Chaos Crags have formed around Lassen. Phreatic (steam explosion) eruptions, dacite and andesite...

: 81  Many of the eruptions commence with thicker more explosive rhyolite, dacite or andesite eruptives which create tephra and have the potential for pyroclastic...

been predominantly andesitic, but it has also erupted large volumes of dacite. Magma produced in the current cycle of activity tends to be a mixture of...

Esprit, and Mt. Grand Magazin, all greater than 1 Ma in age. Andesitic and dacite pyroclastic flows from these volcanoes are found at Morne Tabac dome (532...

burnt) have formed over the past two millennia through repeated eruptions of dacite lava and ash. The Roman historian Cassius Dio records in the year 47 CE...

the upper crust averaging a more felsic composition similar to that of dacite, while the lower crust averages a more mafic composition resembling basalt...