Search results
Results from the WOW.Com Content Network
The following is a list of rock types recognized by geologists. There is no agreed number of specific types of rock. There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
A bornhardt (/ ˈ b ɔːr n ˈ h ɑːr t /) is a dome-shaped, steep-sided, bald rock outcropping at least 30 metres (100 ft) in height and several hundred metres in width. [1] They are named after Wilhelm Bornhardt (1864–1946), a German geologist and explorer of German East Africa , who first described the feature.
Gabbroids (also known as gabbroic-rocks [8]) are a family of coarse-grained igneous rocks similar to gabbro: [10] Quartz gabbro contains 5% to 20% quartz in its QAPF fraction. One example is the cizlakite at Pohorje in northeastern Slovenia, [16] Monzogabbro contains 65% to 90% plagioclase out of its total feldspar content.
Rocks formations and the Dedo de Deus (God's Finger) peak in the background, Serra dos Órgãos National Park, Rio de Janeiro state, Brazil Raouché or Pigeons' Rock in Beirut, Lebanon Druid Arch, Canyonlands National Park, Utah, US View of Meteora, Greece Rock formations in Ongamira Valley, Sierras de Córdoba, Argentina Belogradchik Rocks, Balkan Mountains, Bulgaria "Jaws", an erosional fin ...
Crude oil, a transformed biogenic substance Natural gum, a secretion from Hevea brasiliensis. A biogenic substance is a product made by or of life forms. While the term originally was specific to metabolite compounds that had toxic effects on other organisms, [1] it has developed to encompass any constituents, secretions, and metabolites of plants or animals. [2]
The origin of life is related to organic chemistry, some of which is preserved in these rocks from 4.5 billion years ago," said astrobiologist and study co-author Jason Dworkin, the OSIRIS-REx ...
Rock considered lamprophyres to be part of a "clan" of rocks, with similar mineralogy, textures and genesis. Lamprophyres are similar to lamproites and kimberlites . While modern concepts see orangeites, lamproites and kimberlites as separate, a vast majority of lamprophyres have similar origins to these other rock types (Tappe et al., 2005).
Foid, a contraction of the term feldspathoid, is applied to any igneous rock containing up to 60% modal feldspathoid minerals. For example, a syenite with significant nepheline present can be termed a nepheline-bearing syenite or nepheline syenite , with the term nepheline replaceable by any foid mineral.