Geology ch 9

Geology ch 9 - Historical Geology Chapter 9 Review Triple...

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Historical Geology Chapter 9 Review Triple Junctions: continental rifts develop they often begin as three armed grabens at plate boundaries. These areas are often elevated into a dome giving signs of hotspots. Failed rifts: a plate tectonic dead end. Before it ceases to be active the third arm forms a graben or a system of grabens that projects inlan d from the new continental margin fromed by the other two arms. Many of the worlds largest rivers ( Mississippi) flow through valleys laceted in failed rifts. Block Faulting: normal faulting that produces blocks of crust. Expressed as a graben runnig along the ridge’s midline. Fault block basins: long narrow down faulted block of crust associated with mafic volcanoes that have welled up from the mantle along the faults; the rifting has also produced mafic dikes and sills and flood basalts. Creates rugged landscape that is subject to rapid erosion. Rifting continues the valleys become larger and extend to the sea. This causes an inflow of water creating areas such as the red sea. Active margins:
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This note was uploaded on 07/17/2011 for the course GEOL 4321 taught by Professor Staff during the Spring '11 term at Texas Tech.

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Geology ch 9 - Historical Geology Chapter 9 Review Triple...

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