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The Earth's Crust- Plate Tectonics- and the Gulf of Mexico
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Some things I am just considering during this oil mess.
1. In the mid-ocean, the thickness of the crust can be as little as 5 km. The entire crust occupies just 1% of the Earth's volume.
The crust is composed of a variety of igneous, metamorphic and sedimentary rocks gathered together into tectonic plates. These plates float above the Earth's mantle, and it's believed that convection of rock in the mantle causes the plates to slide around.
[link to www.universetoday.com]
2. Oceanic crust:
As the name already suggests, this crust is below the oceans. There, the crust is 4-7 miles (6-11 km) thick. The rocks of the oceanic crust are very young compared with the rocks of the continental crust. The rocks of the oceanic crust are not older than 200 million years. The material of which the oceanic crust consists is for the greater part tholeiitic basalt (this is basalt without olivine). Basalt has a dark, fine and gritty volcanic structure. It is formed out of very liquid lava, which cools off quickly. The grains are so small that they are only visible under a microscope. The average density of the oceanic crust is 3g/cm³.
[link to mediatheek.thinkquest.nl]
3. In many respects the geology of the Gulf of Mexico is better understood than other comparable marginal seas due primarily to its long history of drilling and reflection seismic acquisition by the petroleum industry. However, the petroleum accumulations and thick Tertiary section that attract industry also restrict scientific ocean drilling. To date only the carbonate margin of the southern Gulf and Quaternary fans in the deep eastern basin have been targeted. Discovering new details of the nature and timing of the opening of the Gulf basin, therefore, presents a considerable challenge. The goal of this ongoing study is to determine whether the opening of the Gulf of Mexico is a predictable manifestation of the planetary-scale superswell-related mantle stresses that drive the movements of major plates and to evaluate implications for Gulf of Mexico petroleum systems.
Predicting microplate kinematics within the poorly defined boundary zone that separates North Atlantic and South Atlantic spreading is pivotal in this analysis. It is postulated that the movements of continental microplates in the Gulf of Mexico are driven by mantle stresses that moved first North America and then South America away from Africa.
Outcropping and drilled Mesozoic strata of the Gulf rim, the presence of buried plume-related alkalic basaltic volcanoes of middle and Late Cretaceous age, and the geometric requirement that the Yucatan Platform be rotated into a position along the Texas - Louisiana margin to allow the reassembly of Pangea are the principal constraints on the origin of the Gulf of Mexico. There is general agreement among researchers that the opening of the western basin of the Gulf of Mexico reflects the counterclockwise rotation of a Yucatan microplate. Following recently published paleomagnetic evidence the Chiapas portion of the Maya Block is treated as a separate microplate in this study. It is recognized that the rotation of a Yucatan microplate about the relatively well-known Euler rotation poles that opened the North Atlantic Ocean cannot account for the most probable trajectory of Yucatan. Published opening solutions designed to provide an ideal Yucatan trajectory are purely kinematic, not addressing the implications of a unique Gulf of Mexico stress field on planetary-scale mantle processes that drive plate motions.
[link to www.searchanddiscovery.net]
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I am no scientist, but I think there is a correlation here with the oil leak.
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