Forest Sandstone

The Forest Sandstone is a geological formation in southern Africa, dating to roughly between 200 and 190 million years ago and covering the Hettangian to Sinemurian stages of the Jurassic Period in the Mesozoic Era.^[1] As its name suggests, it consists mainly of sandstone.

Forest Sandstone
Stratigraphic range: Hettangian-Sinemurian ~200–190 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Dune beds in the Forest Sandstone, Chewore Safari Area, Hurungwe District, Zimbabwe
Type	Geological formation
Unit of	Karoo Supergroup  Upper Karoo Group
Underlies	Batoka Formation
Overlies	Pebbly Arkose Formation
Lithology
Primary	Sandstone
Location
Coordinates	20.0°S 28.4°E / -20.0; 28.4
Approximate paleocoordinates	35.0°S 5.1°E / -35.0; 5.1
Region	South-central Africa
Country	Botswana  Zambia  Zimbabwe
Type section
Named for	Forests of Nyamandlovu District, Zimbabwe
Named by	A.M. MacGregor, Zimbabwe Geological Survey
Forest Sandstone (Zimbabwe)

Fossils of the prosauropod dinosaur Massospondylus and the primitive sauropod Vulcanodon 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,^[2] laid down during a period of increasing aridity.^[3]

Extent

The Forest Sandstone is found in Botswana, Zambia and Zimbabwe, in the Mid-Zambezi, Mana Pools, Cabora Bassa and Limpopo Basins,^[4][5][6][7] with its greatest thickness in the Cabora Bassa Basin.^[8]

Deposition

Age

The formation is dated at 200 to 190 Ma.^[1]

Stratigraphy

The Forest Sandstone is the penultimate formation in the Upper Karoo Group of the Karoo Supergroup, lying above the Pebbly Arkose Formation and below the Batoka Formation.^[7] In the Thuli Basin it is sometimes referred to as the Samkoto Formation.^[9]

The Forest Sandstone has been correlated to the Clarens Formation of the Great Karoo Basin in South Africa.^[5][7][8]

Fossil content

Vertebrate fauna

Protosuchia
Genus	Species	Presence	Notes	Images
unknown protosuchid crocodile[10]	indeterminate	Geographically located in Matabeleland North, Zimbabwe.

Sphenodontia of the Forest Sandstone Formation
Genus	Species	Presence	Notes	Images
unknown, similar to Clevosaurus[10]	indeterminate	Unspecified, Zimbabwe

Sauropodomorphs of the Forest Sandstone Formation
Genus	Species	Presence	Notes	Images
Massospondylus[11]	M. carinatus[11]	Geographically located in Matabeleland North, Zimbabwe.[11]
Vulcanodon[12][13]	V. karibaensis	Geographically located in the Bumi Hills area and the Sibilobilo Islands, in Kariba (District), Mashonaland West, Zimbabwe	Partial skeleton and scapula
Prosauropoda[11]	Indeterminate remains[11]	Geographically located in Matabeleland North, Zimbabwe.[11]

Theropods of the Forest Sandstone Formation
Genus	Species	Presence	Notes	Images
Megapnosaurus[11]	M. rhodesiensis[11]	Geographically located in Nyamandhlovu area, Tsholotsho District, Matabeleland North, Zimbabwe.[11]	Note: Referred to as Syntarsus by Weishampel et al.[11]

Economic importance

Hydrogeology

The Forest Sandstone is the major groundwater-bearing unit of the Upper Karoo Group.^[14]