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Volcanic rock. Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks.
20–25 mya (Late Oligocene to Early Miocene) Type of rock. Volcanic plugs. The Nine Sisters or the Morros are a chain of twenty-three, although typically only nine are included, volcanic mountains and hills in western San Luis Obispo County, Southern California. They run between Morro Bay and San Luis Obispo .
Kohala (mountain) / 20.08611°N 155.71722°W / 20.08611; -155.71722. Kohala is the oldest of five volcanoes that make up the island of Hawaii. Kohala is an estimated one million years old—so old that it experienced, and recorded, the reversal of Earth's magnetic field 780,000 years ago. It is believed to have breached sea level more ...
The volcanic rock pushing through the geologic layers on the way towards the surface would push the land around it up and volcanic intrusion into the local geology would likely devastate the ...
The Black Tusk, known as Q̓elqámtensa ti Skenknápa in the St'at'imcets (Lillooet) language and as T'ákt'akmúten tl'a Ín7inyáx̱a7en in the Sḵwx̱wú7mesh (Squamish) language, is a stratovolcano and a pinnacle of volcanic rock in Garibaldi Provincial Park of British Columbia, Canada.
Ocean island basalt (OIB) is a volcanic rock, usually basaltic in composition, erupted in oceans away from tectonic plate boundaries. Although ocean island basaltic magma is mainly erupted as basalt lava, the basaltic magma is sometimes modified by igneous differentiation to produce a range of other volcanic rock types, for example, rhyolite in ...
The bulk of geological research in the Northern Mariana Islands has focused on the large, populous island of Saipan. The U.S. Geological Survey first mapped the island in 1956 and it was remapped again in 2007. The oldest rocks exposed at the surface are Eocene volcanic rocks, belonging to the Izu-Bonin-Mariana (IBM) arc system.
Little is known about the history of the oldest exposed rocks in the area due to extensive metamorphism.This somber, gray, almost featureless crystalline complex is composed of originally sedimentary and igneous rocks with large quantities of quartz and feldspar mixed in. The original rocks were transformed to contorted schist and gneiss, making their original parentage almost unrecognizable.