Sedimentary Basins

Sedimentary basins can be distinguished by their plate tectonic settings and characteristic rock types. At least six types can be recognised. These are summarised in the table below and related to our Tectonic models.

Within these global sedimentary basins, as deposition environments shift through time, patterns of sedimentary facies are produced, related to their depositional environment. As depositional environments change position, adjacent sedimentary facies will succeed each other in vertical deposition sequences, i.e. vertical changes of the lithology, due to transgression or regression, reflect similar lateral changes (e.g. sediments will coarsen laterally as well as upwards). Change may be caused by:

Tectonic downward or upward movement giving transgressive facies patterns with a reduction of the land area due to the encroachment of the sea, or a regressive facies pattern due to withdrawal of the sea.
Worldwide regressions and transgressions caused by the waxing and waning of continental glaciers, or by large-scale down or up warping of the earth's surface due to glacial loading or unloading.
Local transgression and regression by subsidence or uplift of the crust due to rapid coastal sedimentation or erosion (e.g. the loading on the crust by large deltas).

TYPES OF MAJOR SEDIMENTARY BASINS

Basin Type	Characteristic sediments	Depositional environments	Examples of Global Tectonic Models
Rift or aulacogen	Earliest rocks volcanic overlain by thick gravel and sand; younger rocks may include evaporites and limestones. Long lived sediment-filled grabens. Little deformation.	Rivers and lakes changing to shallow-marine	cratons, continental rifts
Intra cratonic	Homogeneous quartz-rich sands and limestones, but may include muds, evaporites, or coal at certain times. Little deformation.	Mostly shallow- marine with some deltaic	platform sediments and basins
Passive margin	Quartz-rich sands and limestones passing seaward to muds. Diapirism.	Shallow-marine shelf to deeper-marine	platform sediments and basins
Trench	Fine sediments overlying ocean-floor basalts. Extensive. Deformed accretionary wedge.	Deep marine	accretionary prisms
Forearc\Backarc	Varied thick sediments ranging from pelagic through turbidites to alluvial fans, much derived from adjacent orogenic belts. Volcanoclastics common. Deformed accretionary wedge.	Non-marine to deep marine	accretionary prisms, fold and thrust belts
Foreland	Heterogeneous gravels, sands and muds derived from the orogenic belt and shed on to the continental craton; may be coal-bearing. Relatively stable areas.	Mostly river and deltaic	foreland basins

(Partly after Dott and Batten, 1988)