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Primary rocks (geol.) a term early used for rocks supposed to have been first formed, being crystalline and containing no organic remains, as granite, gneiss, etc.; – called also primitive rocks. The terms Secondary, Tertiary, and Quaternary rocks have also been used in like manner, but of these the last two only are now in use.
Igneous rock (igneous from Latin igneus 'fiery'), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust.
Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was formed. This process is called metamorphism, meaning to "change in form". The result is a profound change in physical properties ...
The Midas Monument, a Phrygian rock-cut tomb dedicated to Midas (700 BCE).. Ancient monuments of rock-cut architecture are widespread in several regions of world. A small number of Neolithic tombs in Europe, such as the c. 3,000 B.C. Dwarfie Stane on the Orkney island of Hoy, were cut directly from the rock, rather than constructed from stone blocks.
The Giant's Causeway (Irish: Clochán an Aifir) [1] is an area of approximately 40,000 interlocking basalt columns, the result of an ancient volcanic fissure eruption. [3] [4] It is located in County Antrim on the north coast of Northern Ireland, about three miles (4.8 km) northeast of the town of Bushmills.
Angadippuram Laterite is a notified National Geo-heritage Monument [1] [2] [3] in Angadippuram town in Malappuram district in the southern Indian state of Kerala, India.The special significance of Angadippuram to laterites is that it was here that Dr. Francis Buchanan-Hamilton, a professional surgeon, gave the first account of this rock type, in his report of 1807, as "indurated clay", ideally ...
How we traced the origin of the sarsen stones. For premium support please call: 800-290-4726 more ways to reach us
Trachyte – Extrusive igneous rock – A silica-undersaturated volcanic rock; essentially a feldspathoid-bearing rhyolite; Troctolite – Igneous rock – A plutonic ultramafic rock containing olivine, pyroxene and plagioclase; Trondhjemite – Light-colored intrusive igneous rock – A form of tonalite where plagioclase-group feldspar is ...