The Forest Sandstone is a

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

southern Africa Southern Africa is the southernmost region of Africa. No definition is agreed upon, but some groupings include the United Nations geoscheme for Africa, United Nations geoscheme, the intergovernmental Southern African Development Community, and ...

, dating to roughly between 200 and 190

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

and covering the

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triass ...

Sinemurian In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annu ...

stages Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

of the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

Period in the

Mesozoic Era The Mesozoic Era is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles such as the dinosaurs, and of gymnosperms s ...

. As its name suggests, it consists mainly of

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

. Fossils of the

prosauropod Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the Sauropoda, sauropods and their ancestral relatives. Sauropods generally grew to very large siz ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

Massospondylus ''Massospondylus'' ( ) is a genus of sauropodomorph dinosaur from the Early Jurassic of southern Africa. It was described by Sir Richard Owen in 1854 from remains discovered in South Africa, and is thus one of the first dinosaurs to have been ...

'' and the primitive sauropod ''

Vulcanodon ''Vulcanodon'' (meaning "volcano tooth") is an extinct genus of sauropod dinosaur from the Early Jurassic Uppermost Forest Sandstone of southern Africa. The only known species is ''V. karibaensis''. Discovered in 1969 in Zimbabwe, it was regard ...

'' have been recovered from the Forest Sandstone.

Geology

Description

The formation is a sedimentary unit, consisting mainly of aeolian sands and silts with interbedded fluvial sediments, laid down during a period of increasing aridity.

Extent

The Forest Sandstone is found in

Botswana Botswana, officially the Republic of Botswana, is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory part of the Kalahari Desert. It is bordered by South Africa to the sou ...

Zambia Zambia, officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa. It is typically referred to being in South-Central Africa or Southern Africa. It is bor ...

and

Zimbabwe file:Zimbabwe, relief map.jpg, upright=1.22, Zimbabwe, relief map Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Bots ...

, in the Mid-Zambezi, Mana Pools, Cabora Bassa and

Limpopo Basin Limpopo () is the northernmost province of South Africa. It is named after the Limpopo River, which forms the province's western and northern borders. The term Limpopo is derived from Rivombo (Livombo/Lebombo), a group of Tsonga settlers ...

s, with its greatest thickness in the Cabora Bassa Basin.

Deposition

Age

The formation is dated at 200 to 190 Ma.

Stratigraphy

The Forest Sandstone is the penultimate formation in the

Upper Karoo Group The Upper Karoo Group is a sequence of Triassic to Early Jurassic sedimentary and volcanic rocks found in Botswana, Zambia, and Zimbabwe. It comprises the Escarpment Grit (in the Mid-Zambezi and Limpopo basins) and the Angwa Sandstone (in the Ma ...

of the

Karoo Supergroup The Karoo Supergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Late Carboniferous and Early Jurassic, a per ...

, lying above the

Pebbly Arkose Formation The Pebbly Arkose Formation is a Late Triassic geologic Formation (geology), formation found in southern Africa. Geology Description The formation comprises mainly coarse, arkosic sandstones. Extent The Pebbly Arkose Formation is found in ...

and below the

Batoka Formation The Batoka Formation is a geological formation in the Zambezi valley in Botswana, Zambia and Zimbabwe. It is predominantly a volcanic unit comprising mainly basalts. It was formerly thought to contain sand stones containing the dinosaur ''Vulcanod ...

. In the Thuli Basin it is sometimes referred to as the Samkoto Formation. The Forest Sandstone has been correlated to the

Clarens Formation The Clarens Formation is a geological formation found in several localities in Lesotho and in the Free State, KwaZulu-Natal, and Eastern Cape provinces in South Africa. It is the uppermost of the three formations found in the Stormberg Group of ...

of the Great Karoo Basin in South Africa.

Fossil content

Vertebrate fauna

Economic importance

Hydrogeology

The Forest Sandstone is the major groundwater-bearing unit of the Upper Karoo Group.

References

{{Reflist Geologic formations of Botswana Geologic formations of Zambia Geologic formations of Zimbabwe Jurassic System of Africa Early Jurassic Africa Hettangian Stage Sinemurian Stage Geologic formations with imbedded sand dunes Sandstone formations Aeolian deposits Fluvial deposits Fossiliferous stratigraphic units of Africa Paleontology in Botswana Paleontology in Zambia Paleontology in Zimbabwe