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In geology, a fault or fault line is a planar fracture in rock in which the rock on one side of the fracture has moved with respect to the rock on the other side. Large faults within the Earth's crust are the result of differential or shear motion and active fault zones are the causal locations of most earthquakes. Earthquakes are caused by energy release during rapid slippage along a fault. A fault that runs along the boundary between two tectonic plates is called a transform fault. Since faults do not usually consist of a single, clean fracture, the term fault zone is used when referring to the zone of complex deformation that is associated with the fault plane. The two sides of a non-vertical fault are called the hanging wall and footwall. By definition, the hanging wall occurs above the fault and the footwall occurs below the fault. This terminology comes from mining. When working a tabular ore body the miner stood with the footwall under his feet and with the hanging wall hanging above him. ... Read more

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Chapters: Plate tectonics, Age of the Earth, History of the Earth, Toba catastrophe theory, Sirente crater, Scriptural geologists, Slab pull, Morley-Vine-Matthews hypothesis,. Source: Wikipedia. Pages: 101. Not illustrated. Free updates online. Purchase includes a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: The history of the Earth describes the most important events and fundamental stages in the development of the planet Earth from its formation 4.6 billion years ago to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of the Earth's past. The age of Earth is approximately one-third of the age of the universe. Immense geological and biological changes have occurred during that time span. Starting with the Earth's formation by accretion from the solar nebula 4.54 billion years ago (4.54 Ga), the first eon in the Earth's history is called the Hadean. It lasted until the Archaean eon, which began 3.8 Ga. The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in some rocks have been dated to about 4.4 Ga, close to the formation of the Earth's crust and the Earth itself. Because not much material from this time is preserved, little is known about Hadean times, but scientists hypothesize at an estimated 4.53 Ga, shortly after formation of an initial crust, the proto-Earth was impacted by a smaller protoplanet, which ejected part of the mantle and crust into space and created the Moon. During the Hadean, the Earth's surface was under a continuous bombardment by meteorites, and volcanism must have been severe due to the large heat flow and geothermal gradient. The detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, considered as proof that the planet already had oceans or seas at that time. From crater co...http://booksllc.net/?id=2068726 ... Read more

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Geology of Venus - Venus, Impact crater, Observations andexplorations of Venus, Volcanism on Venus, Platetectonics,Fault (geology), Fold (geology), Perovskite, Pyrochlore,Arachnoid (astrogeology), Greenhouse effect ... Read more

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A mantle plume is an upwelling of abnormally hot rock within the Earth's mantle. As the heads of mantle plumes can partly melt when they reach shallow depths, they are thought to be the cause of volcanic centers known as hotspots and probably also to have caused flood basalts. It is a secondary way that Earth loses heat, much less important in this regard than is heat loss at plate margins (see Plate tectonics). Some scientists think that plate tectonics cools the mantle, and mantle plumes cool the core. The geometry of the Hawaiian-Emperor seamount chain and the regular progression of ages of volcanism along it were taken as important evidence in support of the mantle plume theory. ... Read more