spånformation

Spånformation is a geological term referring to the process by which sedimentary rocks are formed from the accumulation and lithification of fragments of pre-existing rocks. These fragments, known as clasts or detritus, can vary greatly in size, from microscopic clay particles to large boulders. The source of these clasts is typically the weathering and erosion of existing landforms, such as mountains or cliffs.

The eroded material is then transported by various agents, including rivers, glaciers, wind, and ocean currents. During transport, the clasts may be further broken down and rounded. Eventually, these transported sediments are deposited in depositional environments, such as ocean floors, lakebeds, or river deltas. Over time, layers of sediment accumulate, burying the older layers.

The process of lithification, or rock formation, occurs as the buried sediments are subjected to increased pressure from overlying material and are cemented together by minerals precipitating from groundwater. Common cementing agents include calcite, silica, and iron oxides. This lithification transforms the loose sediment into solid sedimentary rock. Rocks formed through spånformation are broadly classified as clastic sedimentary rocks, with their specific type determined by the size and composition of the clasts, such as sandstone (sand-sized grains), conglomerate (rounded pebbles and cobbles), or shale (clay-sized particles).