Physical Geology

Physical Geology: Term Paper The break that now separates the Ouachita Mountains from the Appalachians, a feature known as the Mississippi Embayment, constitutes one of the largest and least understood landforms of the central U.S. In the article, “The Mississippi’s Curious Origins” the authors, Roy B. Van Arsdale and Randel T. Cox shed light on the mysterious Mississippi Embayment. They begin by explaining the origins of the horseshoe-shaped lowland that is underlain by massive quantities of sand, silt and mud deposits. They begin at what geologist call Pangea, which is when North America, South America, Africa and Eurasia came together to form one supercontinent. This collision raised several mountain ranges, including the Ouachita-Appalachian. Pangea is said to be ripped apart where it had previously been sutured together: just outside the arc of the Ouachita-Appalachian Mountains. This opening formed both the Atlantic Ocean and the Gulf of Mexico. This article then states that for a long period of time the Gulf Coast remained geologically stable, with no continents plowing into it or rifting away. The northern coast of the Gulf Coast began to warp upward over a large area; this is the footprint of what is now the Mississippi Embayment. As the very large arch that formed up to three kilometers high and then subsided just as much below sea level, what had been the crest of a high, arched mountain range became inundated with seawater and was eventually buried by as much as 2.6 kilometers of marine sediment. The article states that the passage of a tectonic plate over a hot spot can reactivate ancient faults, causing slippage to occur on them 2 from time to time, even many millions of years later. The might Mississippi is said to be fundamentally controlled by goings-on a full 2,900 kilometers away and straight downward, at the boundary between the earth’s core and mantle. The