Essay, Research Paper: The Pacific Ocean Basin
Geology
Free Geology essays posted on this site were donated by users and are provided for informational use only. The free essay on this page was not written by our writers and should not be viewed as a sample of our writing service. We are neither affiliated with the author of this essay nor responsible for its content. If you need high quality, fresh and competent research / writing done on the subject of Geology, use the professional writing service offered by our company.
Plate Tectonics is theory of global tectonics (geologic structural deformations) that has served as a master key in modern geology for understanding the structure, history, and dynamics of the earth's crust. The theory is based on the observation that the earth's solid crust is broken up into about a dozen semirigid plates. The boundaries of these plates are zones of tectonic activity, where earthquakes and volcanic eruptions tend to occur. Plate Tectonics also are the cause of major features that exist in the World ocean today such as ocean basins.
The Pacific is the oldest of the existing ocean basins, its oldest rocks having been dated at about 200 million years. The major features of the basin and rim have been shaped by the phenomena associated with plate tectonics. The coastal shelf, which extends to depths of about 180 m (about 600 ft), is narrow along North and South America but is relatively wide along Asia and Australia. The East Pacific Rise, a submarine ridge-and-trough system, extends some 9650 km (about 6000 mi) from Antarctica to the Gulf of California, and rises an average of about 2130 m (about 7000 ft) above the ocean floor. Along the East Pacific Rise molten rock upwells from the earth's mantle adding crust to the Pacific and Nazca plates on both sides of the rise. These plates, which are huge segments of the earth's surface, are thus forced apart, causing them to collide with the continental plates adjacent to their outer edges. Under this tremendous pressure, the continental plates fold into mountains, and the oceanic plates downbuckle, forming deep trenches (subduction zones) from which crust is carried back into the mantle.
Following the early rifting of a continent, narrow basins or primordial oceans such as the Red Sea are formed by incipient seafloor spreading. Having formed from a dome or arch, the lips of the basin may still be uplifted, thus preventing fluvial runoff and deposition of terrigenous clastic debris. Given the right climate, carbonate reefs and evaporites will form.
As the ocean widens, arkoses, sandstones, and shales may accumulate in clastic wedges along the continental margin, and marine limestones may be deposited. The successions on the coasts of Brazil and West Africa record symmetrically the change from nonmarine clastic sandstones and shales, via evaporites (about 120 million to 110 million years old), to marine sandstones and limestones. This sequence records the incoming of seawater into a continental rift valley, widened via a Red Sea-type narrow ocean into a mature ocean.
The mid-oceanic ridge, in the youngest part of a growing ocean basin, is usually free of sediment. Passing off the ridge, calcareous sedimentation, caused by microorganisms, is found. Clays and chert (silica rock) occur in deeper parts.
On the continental margins of mature oceans, the basal clastic wedge may be succeeded, if the climate is appropriate, by a carbonate platform, such as the Bahama Banks off the eastern United States and the Great Barrier Reef off northeastern Australia. Turbidity currents flow down the continental slope and deposit terrigenous sediments in the deeper water of the continental rise. River deltas locally add great thicknesses of clastic sediments to the trailing continental margin.
0
0
GOOD or BAD? How would you rate this essay?
Help other users to find the good and worthy free term papers and trash the bad ones.
Help other users to find the good and worthy free term papers and trash the bad ones.
Need a Custom Written Essay on Geology: The Pacific Ocean Basin
Free papers will not meet the guidelines of your specific project. If you need a custom essay on Geology: The Pacific Ocean Basin, we can write you a high quality authentic essay. While free essays can be traced by Turnitin (plagiarism detection program), our custom written papers will pass any plagiarism test, guaranteed. Our writing service will save you time and grade.
Related essays:
0
0
Geology / Geology Of New York
New York s Geology The bedrock of the earth is made up of rock bodies that va...
0
1
Geology / Mining
The EPA says environmental justice is the "fair treatment for people of all races, cultures, and incomes, regarding the development of environmental laws, regulations, and policies? (EPA: Sep...
0
0
Geology / Visit To Earth Observatory
Every year the Lamont – Doherty Earth Observatory holds an open house in which scientists share their studies and really let the public see what and how they do what they do. Scientists a...
0
0
Geology / Thomas Jefferson
Thomas Jefferson was born on April 13, 1743, at Shadwell inAlbemarle County, Virginia. His dad was a plantation owner that grewtobacco, and his mom belonged to the Randolph family they were ri...
0
0
Jules Verne: The Father of Science Fiction
The father of Science Fiction, a visionary French novelist, a short story writer, and a dramatist. This is the essence of the man we know today a...


1785 O'Brien Road, Columbus, Ohio, 43228, U.S.A.