Reflective writing As a mountain climber, I find geography rather interesting. It is within this shallow life zone that geographers focus their interest and do their work. The word geography comes from the Greek words for "Earth Descriptions". Geography has always been and remains a generalized as opposed to a specialized discipline. It's viewpoint is one of broad understandings. With geography we can and will understand our planet better. Answering questions like how mountains where formed, or why we have deserts, forest, wetlands, or arctics ice-lands giving us Earths secrets. People live on the surface of Earth in a physical environment that is extraordinarily complex, extremely diverse, infinitely renewing, and yet ultimately fragile. This habitable environment exists over almost the entire land surface of Earth, which means that it's horizontal dimensions are vast. It is up to us to keep the Planet clean by not polluting or letting dangerous chemicals into to the waters or oceans and not taking what we have for granted for one day it may all be gone. I have really enjoyed taking this class our teacher gave us a good understanding and learning experience on how the system works, it is something all should know.
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Earth's Changing Landscape systemTheory of Plate tectonics By 1968, on the basis of these details and variety of other evidence, the theory of plate tectonics, as it had become known, was being accepted by the scientific community. Plate tectonics provides a framework with which we can understand and relate a wide range of internal processes and topographic patterns around the world. A pattern of magnetic reversals recorded in the ocean floor as it spreads away from mid-ocean ridges have helped establish the age of oceanic crust. The youngest ocean floor is found at mid-ocean ridges, while ocean floor farther from the ridges is the oldest. Most of the mid-ocean ridges of the world are either active or extinct spreading ridges. Such spreading centers are associated with shallow focus earthquakes. The earthquakes are within about 70 kilometers about 45 miles of the surface. Volcanic activity, and hydrothermal metamorphism. Divergent boundaries are said to be, "constructive" because material is being added to the crustal surface at such locations. With each passing year, we learn more about plate tectonics. Two examples of plate tectonic theory's are hot spots and accreted terranes. HOT SPOTS AND MANTLE PLUMES One augmentation to plate tectonic theory was introduced at the same time as the original model. The basic theory of plate tectonics can explain tectonic and volcanic activity along the margins of plates. However, there are many places on Earth where magma rising from the mantle comes either to or almost to the surface at locations that may not be anywhere near a plate boundary. These locations of volcanic activity in the interior of a plate are referred to as "HOT SPOTS'' . MANTLE PLUME The mantle plume model was proposed in the late 1960's. This explanation suggest that mid-plate volcanic activity develops over narrow plumes of heated material rising through the mantel. Perhaps originating as deep as the core-mantle boundary. Such mantle plumes are believed to be relatively stationary over long periods of time. As the magma rises through the plate above, it creates hot spots volcanoes and or hydrothermal features on the surface. As additional information is gathered, a more complete understanding of hot spots, mantle plumes, and mid-plate volcanic activity will likely emerge. Plate tectonic theory has advanced our understanding of the internal processes of Earth dramatically. However, a number of questions still remain unanswered for the time being. Like for example, several major mountain ranges in North America and Eurasia are in the middle of plates rather than in boundary zones. Although the genesis of some mid-plate ranges, such as the Appalachians in North America and the Ural mountains in Eurasia, can be traced to continental collisions in the geologic past. Other mid-plate mountains ranges or regions of seismic activity are not yet fully understood. Further, while convection of heated material within the mantle provides the general mechanism for plate movement. The details of heat flow within Earth and the possible relationship of mantle plumes to these overall patterns are still being worked out. |