Ocean Gateways - opengeology.in

The oceans transport vast amounts of water, heat and salt across entire ocean basins and from low to high latitudes. As the ocean basins the gateways between them evolve over tectonic timescale, so does the circulation.

These tectonic induced changes in ocean circulation plays an important role in some of the major climatic events. These gateways time can be correlated to the paleoenvironmental change like the oceanic anoxic event of Cretaceous, onset of Antarctic glaciation in the earliest Oligocene, Onset of Northern Hemispheric glacial cycles in Pliocene etc.

Oceanic Gateways and associated effect on climate are as follows –

the opening of the Tasmanian Gateway and the glaciation of Antarctica during the Eocene–Oligocene
the water-mass exchange between the Atlantic and the Mediterranean via the Strait of Gibraltar that has occurred since the Miocene
the closure of the American Seaway and the constriction of the Indonesian Throughflow, both argued to have been instrumental in the intensification of Northern Hemisphere Glaciation during the late Pliocene and early Pleistocene.
the climatic impact of the flooding and submergence of the Bering Strait during the Plio-Pleistocene and its influence on the Atlantic Meridional Overturning Circulation.
The establishment of the Antarctic Circumpolar Current (ACC) is one of the most important events of the Cenozoic for both global oceanic circulation and climate. The onset of this major current hinges on the opening of two major oceanic passages, the Drake Passage and the Tasmanian gateways that connect Pacific, Atlantic and Indian oceans, allowing a modern-like thermohaline circulation.

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