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 (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.

Oct 24, 2023 · The dacite domes erupted along the northern flank of Brokeoff Volcano and are divided on the basis of age into the Bumpass (~300–190 ka) and Eagle Peak (~70–0 ka) sequences.

The world's largest known dacite flow is the Chao dacite dome complex, a huge coulée flow-dome between two volcanoes in northern Chile. This flow is over 14 kilometres (8.7 mi) long, has obvious flow features like pressure ridges, and a flow front 400 metres (1,300 ft) tall (the dark scalloped line at lower left). [ 15 ]

Jun 25, 2024 · We present diffusion and thermal modeling on 20 sanidine megacrysts from a single dacite dome eruption of Taápaca volcanic complex (TVC; 5824 m above sea level, 18°S, 69°W) in the Central Andes.

Oct 26, 2023 · Basalt lava typically forms thin flows that may reach distances of more than 50 km (30 mi) from their vent. Dacite and rhyolite lavas typically produce short, thick flows that seldom move as far as 5 km (3 mi) from the vent. These short flows often build mound-shaped features called lava domes.

The Santiaguito dome is a compound dome comprising four major vents. Dome growth has consisted of alternating exogenous (effusive outpouring of dacite lava flows), and endogenous (dome inflation) periods (Rose 1972).

Nov 21, 2013 · Lava domes tend to have steep, cliff-like fronts at their leading edge and wrinkle-like pressure ridges on their surfaces. The Chao dacite is a type of lava dome known as a coulée. These elongated flow structures form when highly-viscous lavas flow onto steep surfaces.

Nov 1, 2023 · Black Butte is a group of overlapping dacite domes about 13 km (8 mi) west of Mount Shasta. It erupted during the Holocene.

At ~9 km3, the six dacite domes of Burney Mountain (db1–db6) constitute the most voluminous Quaternary dome complex in the Cascades volcanic arc. Whole-rock geochemistry, electron microprobe, and petrographic data indicate that the domes are magmatically related, which, when integrated with geomorphology and stratigraphy, indicate early (db1 ...

Oct 30, 2019 · At ∼9 km 3, the six dacite domes (db1 – db6) of Burney Mountain, northern California, USA, constitute the most voluminous Quaternary dome complex in the Cascades volcanic arc.