Extra-tectonic
Relating to or resulting from forces or processes originating outside the immediate influence or direct action of tectonic activity. This term is frequently used in geology, geophysics, and related fields to describe phenomena that are either indirectly affected by tectonic processes, or entirely independent of them, arising from sources such as erosion, sedimentation, climate change, or extraterrestrial events. These forces shape landscapes and influence geological formations, but their primary drivers are outside the sphere of the Earth's internal plate motions. The effects of extra-tectonic forces can also be recorded in the rocks and sediments.
Extra-tectonic meaning with examples
- Coastal erosion, driven by wave action and sea level changes, is a classic example of an extra-tectonic process. This erosion carves away at land, shaping coastlines independently of tectonic forces, such as earthquakes and volcanic eruptions. It demonstrates how external forces influence the Earth's surface, showing a landscape changing over time as a result.
- The formation of vast sedimentary basins through the long-term accumulation of sediment from river systems is considered an extra-tectonic process. This is the accumulation of eroded particles, like sand, silt and clay, that are transported away from the tectonic influence to a low-lying region where they collect and form a sedimentary layer.
- Glacial cycles and their impact on sea levels and isostatic rebound are prime examples of extra-tectonic influences. Changes in climate that are not directly caused by tectonic activity, cause glaciers to expand or shrink. This subsequently influences the shape and the height of a landscape.
- The impact of meteorites, while relatively rare, represents a dramatic example of extra-tectonic forcing. The energy released from the impact creates huge craters and can cause widespread environmental changes, irrespective of whether or not the region is tectonically active.