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The mafic rocks also typically have a higher density than felsic rocks. The term roughly corresponds to the older basic rock class. [9] Mafic lava, before cooling, has a low viscosity, in comparison with felsic lava, due to the lower silica content in mafic magma. Water and other volatiles can more easily and gradually escape from mafic lava.
Level Mountain is a large volcanic complex in the Northern Interior of British Columbia, Canada. It is located 50 kilometres (31 miles) north-northwest of Telegraph Creek and 60 kilometres (37 miles) west of Dease Lake on the Nahlin Plateau. With a maximum elevation of 2,164 metres (7,100 feet), it is the second-highest of four large complexes ...
While the temperature of common silicate lava ranges from about 800 °C (1,470 °F) for felsic lavas to 1,200 °C (2,190 °F) for mafic lavas, [16] its viscosity ranges over seven orders of magnitude, from 10 11 cP (10 8 Pa⋅s) for felsic lavas to 10 4 cP (10 Pa⋅s) for mafic lavas. [16] Lava viscosity is mostly determined by composition but ...
Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Felsic magma or lava is higher in viscosity than mafic magma/lava, and have low temperatures to keep the felsic minerals molten. Felsic rocks are usually light in color and have specific ...
Diorite. Diorite (/ ˈdaɪ.əraɪt / DY-ə-ryte) [1][2] is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silica (mafic) gabbro and high-silica (felsic) granite.
Pyroclastic plateaus are produced by massive pyroclastic flows. They are underlain by pyroclastic rocks: agglomerates, tephra, volcanic ashes cemented into tuffs, mafic or felsic. Pyroclastic plateaus are also called ignimbrite plateaus. Examples include the Shirasu-Daichi, which makes up almost all of southern Kyūshū, Japan, [3] and the ...
Obsidian (/ ə b ˈ s ɪ d i. ən, ɒ b-/ əb-SID-ee-ən ob-) [5] is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. [6] Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. [1] Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit ...