Erosion-related: •
Blowout: a depression created by
wind erosion typically in either a partially vegetated
sand dune ecosystem or dry soils (such as a post-glacial
loess environment). Collapse-related: •
Sinkhole: a depression formed as a result of the collapse of rocks lying above a hollow. This is common in karst regions. •
Kettle: a shallow, sediment-filled body of water formed by melting glacial remnants in
terminal moraines. •
Thermokarst hollow: caused by volume loss of the ground as the result of
permafrost thawing. Impact-related: •
Impact crater: a depression created by an impact, such as a
meteorite crater. Sedimentary-related: •
Sedimentary basin: in
sedimentology, an area thickly filled with
sediment in which the weight of the sediment further depresses the floor of the basin. Structural or tectonic-related: •
Structural basin: a
syncline-like depression; a region of tectonic downwarping as a result of
isostasy (the
Hawaiian Trough is an example) or subduction (such as the
Chilean Central Valley). •
Graben or
rift valley: fallen and typically linear depressions or basins created by
rifting in a region under tensional
tectonic forces. •
Pull-apart basin caused by offset in a
strike-slip or
transform fault (example: the
Dead Sea area). •
Oceanic trench: a deep linear depression on the ocean floor. Oceanic trenches are caused by
subduction (when one tectonic plate is pushed underneath another) of
oceanic crust beneath either the oceanic crust or
continental crust. • A basin formed by an
ice sheet: an area depressed by the weight of the ice sheet resulting in
post-glacial rebound after the ice melts (the area adjacent to the ice sheet may be pulled down to create a peripheral depression.) Volcanism-related: •
Caldera: a
volcanic depression resulting from collapse following a
volcanic eruption. •
Pit crater: a volcanic depression smaller than a caldera formed by a sinking, or caving in, of the ground surface lying over a void. •
Maar: a depression resulting from
phreatomagmatic eruption or
diatreme explosion. == List of depressions ==