Forest Sandstone Formation

Forest Sandstone Formation
Stratigraphic range: Hettangian
↓

Dune beds in Forest Sandstone Formation, Chewore Safari Area, Hurungwe District, Zimbabwe
Type Geological formation
Unit of Upper Karoo Group, Karoo Supergroup
Underlies Batoka Formation
Overlies Pebbly Arkose Formation
Location
Country Botswana, Zambia, Zimbabwe
Type section
Named for Forests of Nyamandlovu District, Zimbabwe
Named by A.M. MacGregor, Zimbabwe Geological Survey

The Forest Sandstone Formation is a geological formation in southern Africa, dating to roughly between 200 to 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.

Fossils of the prosauropod dinosaur Massospondylus 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 Formation is found in Botswana, Zambia, Zimbabwe, in the Mid-Zambezi, Mana Pools, Cabora Bassa and Limpopo basins[4][5][6][7] with its greatest thickeness 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 Karroo Basin, South Africa.[5][7][8]

Fossils

Vertebrate fauna

Protosuchia of the Forest Sandstone Formation
Taxa Presence Notes Images

Genus:

  • unknown protosuchid crocodile[10]
  1. Geographically located in Matabeleland North, Zimbabwe.
Sphenodontia of the Forest Sandstone Formation
Taxa Presence Notes Images

Genus:
  1. Unspecified, Zimbabwe.
Sauropodomorphs of the Forest Sandstone Formation
Taxa Presence Notes Images

Genus:

  1. M. carinatus[11]
  1. Geographically located in Matabeleland North, Zimbabwe.[11]
Massospondylus

Infraorder:

  1. Indeterminate remains.[11]
  1. Geographically located in Matabeleland North, Zimbabwe.[11]
Theropods of the Forest Sandstone Formation
Taxa Presence Notes Images

Genus:

  1. M. rhodesiensis[11]
  1. Geographically located in Nyamandhlovu area, Tsholotsho District, Matabeleland North, Zimbabwe.[11]
  1. Note: Referred to as Syntarsus by Weishampel et al.[11]
Megapnosaurus

Economic importance

Hydrogeology

The Forest Sandstone is the major groundwater-bearing unit of the Upper Karoo Group.[12]

References

  1. 1 2 "Forest Sandstone Formation". Paleobiology Database. Retrieved 2010-01-03.
  2. ↑ Danielsen, Jens E.; Dahlin, Torleif; Owen, Richard; Mangeya, Pride; Auken, Esben (2007). "Geophysical and hydrogeologic investigation of groundwater in the Karoo stratigraphic sequence at Sawmills in northern Matabeleland, Zimbabwe: a case history". Hydrogeology Journal 15 (5): 945. Bibcode:2007HydJ...15..945D. doi:10.1007/s10040-007-0191-z.
  3. ↑ Maurice E. Tucker; Michael J. Benton (1982). "Triassic environments, climate and reptile evolution" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology 40 (4): 361–379. doi:10.1016/0031-0182(82)90034-7.
  4. ↑ Bordy, Emese M.; Catuneanu, Octavian (2001). "Sedimentology of the upper Karoo fluvial strata in the Tuli Basin, South Africa". Journal of African Earth Sciences 33 (3–4): 605. Bibcode:2001JAfES..33..605B. doi:10.1016/S0899-5362(01)00090-2.
  5. 1 2 d'Engelbronner, E.R. (1996). "New palynological data from Karoo sediments, Mana Pools basin, northern Zimbabwe". Journal of African Earth Sciences 23: 17. Bibcode:1996JAfES..23...17D. doi:10.1016/S0899-5362(96)00049-8.
  6. ↑ Jones, D. L.; Duncan, R. A.; Briden, J. C.; Randall, D. E.; MacNiocaill, C. (2001). "Age of the Batoka basalts, northern Zimbabwe, and the duration of Karoo Large Igneous Province magmatism". Geochemistry Geophysics Geosystems 2 (2). Bibcode:2001GGG.....2.1022J. doi:10.1029/2000GC000110.
  7. 1 2 3 Nyambe, Imasiku A.; Utting, John (1997). "Stratigraphy and palynostratigraphy, Karoo Supergroup (Permian and Triassic), mid-Zambezi Valley, southern Zambia". Journal of African Earth Sciences 24 (4): 563. Bibcode:1997JAfES..24..563N. doi:10.1016/S0899-5362(97)00081-X.
  8. 1 2 Catuneanu, O.; Wopfner, H.; Eriksson, P.G.; Cairncross, B.; Rubidge, B.S.; Smith, R.M.H.; Hancox, P.J. (2005). "The Karoo basins of south-central Africa". Journal of African Earth Sciences 43: 211. Bibcode:2005JAfES..43..211C. doi:10.1016/j.jafrearsci.2005.07.007.
  9. ↑ Rogers, Raymond R.; Rogers, Kristina Curry; Munyikwa, Darlington; Terry, Rebecca C.; Bradley s.Singer (2004). "Sedimentology and taphonomy of the upper Karoo-equivalent Mpandi Formation in the Tuli Basin of Zimbabwe, with a new 40Ar/39Ar age for the Tuli basalts". Journal of African Earth Sciences 40 (3–4): 147. Bibcode:2004JAfES..40..147R. doi:10.1016/j.jafrearsci.2004.11.004.
  10. 1 2 Paul E. Olsen; Peter M. Galton (1984). "A review of the reptile and amphibian assemblages from the Stromberg of southern Africa, with special emphasis on the footprints and age of the Stromberg" (PDF). Palaeont. Afr. 25: 87–110.
  11. 1 2 3 4 5 6 7 8 9 10 Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Jurassic, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 535–536. ISBN 0-520-24209-2.
  12. ↑ Larsen, Flemming; R. Owen; T. Dahlin; P. Mangeya; G. Barmen. "A preliminary analysis of the groundwater recharge to the Karoo formations, mid-Zambezi basin, Zimbabwe" (pdf). Physics and Chemistry of the Earth 27: 765–772. Bibcode:2002PCE....27..765L. doi:10.1016/s1474-7065(02)00064-5.


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