Search results
Results From The WOW.Com Content Network
An example of a minor avulsion is known as a meander cutoff, when a pronounced meander (hook) in a river is breached by a flow that connects the two closest parts of the hook to form a new channel. This occurs when the ratio between the channel slope and the potential slope after an avulsion is less than about 1/5. [1]
During the Permian-Triassic extinction, the largest extinction event in the Earth's history, the global sea level fell 250 m (820 ft). [ 3 ] A major regression could cause marine organisms in shallow seas to go extinct, but mass extinctions tend to involve both terrestrial and aquatic species, and it is harder to see how a marine regression ...
The opposite of transgression is regression where the sea level falls relative to the land and exposes the former sea bottom. During the Pleistocene Ice Age, so much water was removed from the oceans and stored on land as year-round glaciers that the ocean regressed 120 m, exposing the Bering land bridge between Alaska and Asia.
The oceanic zone is typically defined as the area of the ocean lying beyond the continental shelf (e.g. the neritic zone), but operationally is often referred to as beginning where the water depths drop to below 200 metres (660 ft), seaward from the coast into the open ocean with its pelagic zone.
The Atlantic Ocean is teeming with life, but for the first time researchers have discovered dead zones in these waters - areas low in both oxygen and salinity - off the coast of Africa. Fish can't ...
Fracture zones represent the previously active transform-fault lines, which have since passed the active transform zone and are being pushed toward the continents. These elevated ridges on the ocean floor can be traced for hundreds of miles and in some cases even from one continent across an ocean to the other continent.
Earlier theories by Alfred Wegener and Alexander du Toit of continental drift postulated that continents in motion "plowed" through the fixed and immovable seafloor. The idea that the seafloor itself moves and also carries the continents with it as it spreads from a central rift axis was proposed by Harold Hammond Hess from Princeton University and Robert Dietz of the U.S. Naval Electronics ...
Oceanic crust age differences and ridge-ridge transform faulting associated with offset mid-ocean ridge segments lead to the formation of fracture zones. A fracture zone is a linear feature on the ocean floor—often hundreds, even thousands of kilometers long—resulting from the action of offset mid-ocean ridge axis segments.