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Fold mountains are formed from sedimentary rocks that accumulate along the margins of continents, when two tectonic plates move together. When the plates and the continents riding on them collide, the accumulation layers of rock may crumple and fold, particularly if there is a mechanically weak layer such as salt. These accumulated layer or sediments are then pushed together by volcanic islands to form folds, which eventually form fold mountains.  Mostly, in the interaction between oceanic plate and continental plate, oceanic plate gets subducted beneath the margins of continental plates, giving rise to mighty mountains. This activity can occur only on the margins of continents, as a result of which fold mountains are observed along the margins of continents.  Fold mountains are distributed throughout the world in the eastern margins of Mediterranean to Western Pacific, West Coast of South America and Appalachians Mountains of North America. The earth quakes in these regions o...

Mantle plume is an up-welling of abnormally hot rock within the earth’s mantle which carries heat upward in narrow, rising columns, driven by heat exchange across the core-mantle boundary. Eventually, the rising column of hot rock reaches the base of the lithosphere, where it spreads out, forming a mushroom-shaped cap to the plume.  Geophysicist, W. Jason Morgan, developed the hypothesis of mantle plumes in 1971. The largest (and most persistent) mantle plumes are presumed to form where a large volume of mantle rock is heated at the core-mantle boundary, about 1800 miles below the surface, although smaller plumes may originate elsewhere within the mantle. Heat transferred from the plume raises the temperature in the lower lithosphere to above melting point, and forms magma chambers that feed volcanoes at the surface.  Role of Mantle Plume in Plate Tectonics :  •Mantle plumes transport primordial mantle material from below the zone of active convection; produce time-p...

Dead zones are low-oxygen, or hypoxic, areas in the world’s oceans and lakes. Because most organisms need oxygen to live, few organisms can survive in hypoxic conditions. That is way these areas are called dead zones. Dead zones in the coastal oceans have spread exponentially since the 1960s and have serious consequences for ecosystem functioning. One of the largest dead zones forms in the Gulf of Mexico every spring. Hypoxic zones can occur naturally but climate change, nutrients run-off from the land, and eutrophication are leading to algal bloom and causing further depletion of oxygen level in water. As a result dead zones are spreading at much faster pace.  Consequences of spreading of Dead Zones on Marine Ecosystem  •The reduced dissolved oxygen in ocean water results in loss of marine life thus the habitats which were once teeming with life are transformed into biological deserts.  •Elevated nutrient levels and algal blooms can also cause problems in drinking water ...