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Transgression - Definition and Overview |
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Transgression refers to an action that breaks some code or set of rules, that is, goes across or against basic assumptions or norms. See for example transgressive art.
In geology, a transgression is an event during which sea level rises relative to the land and the shoreline moves toward higher ground, resulting in coastal flooding.
Transgressions can be caused either by the land sinking or the ocean basins filling with water (or decreasing in capacity).
During the Cretaceous, seafloor spreading created a relatively shallow Atlantic basin at the expense of deeper Pacific basin. This reduced the world's ocean basin capacity and caused a rise in sea level worldwide. As a result of this sea level rise, the oceans transgressed completely across the central portion of North America and created the Western Interior Seaway from the Gulf of Mexico to the Arctic Ocean.
The opposite of transgression is regression, in which sea level falls relative to the land and exposes former sea bottom. During the Pleistocene Ice Ages, so much water was removed from the oceans and stored on land as year-round glaciers that the ocean regressed 120 meters, exposing the Bering land bridge between Alaska and Asia.
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