Kirkwood Formation

Kirkwood Formation
Stratigraphic range: Berriasian-Hauterivian
~140–125 Ma
TypeGeological formation
Unit ofUitenhage Group
Sub-unitsSwartkops Member, Colchester Member, Bethelsdorp Member, Wood beds
UnderliesSundays River Formation, Buffelskloof Formation
OverliesEnon Formation
Thicknessup to 2,210 m (7,250 ft)
Lithology
PrimarySandstone, claystone
OtherMudstone, siltstone
Location
Coordinates33°24′S 25°30′E / 33.4°S 25.5°E / -33.4; 25.5
Approximate paleocoordinates45°00′S 11°30′W / 45.0°S 11.5°W / -45.0; -11.5
RegionWestern & Eastern Cape
Country South Africa
Type section
Named forKirkwood, Eastern Cape

Map showing extent of the Kirkwood Formation (green) in the Algoa and Gamtoos Basins

The Kirkwood Formation is a geological formation found in the Eastern and Western Cape provinces in South Africa. It is one of the four formations found within the Uitenhage Group of the Algoa Basin – its type locality – and in the neighbouring Gamtoos Basin. Outcrops of the Kirkwood are also found along the Worcester-Pletmos, Herbertsdale-Riversdale, Heidelberg-Mossel Bay, and Oudtshoorn-Gamtoos basin lines.[1][2] At these basins the Kirkwood Formation underlies the Buffelskloof Formation and not the Sundays River Formation.[3]

  1. ^ Shone, R.W. (2006-01-01). "Onshore post-Karoo Mesozoic deposits". The Geology of South Africa: 541–552.
  2. ^ Muir, R.A.; Bordy, E.M.; Reddering, J.S.V.; Viljoen, J.H.A. (2017-06-01). "Lithostratigraphy of the Kirkwood Formation (Uitenhage Group), including the Bethelsdorp, Colchester and Swartkops Members, South Africa". South African Journal of Geology. 120 (2): 281–293. Bibcode:2017SAJG..120..281M. doi:10.25131/gssajg.120.2.281. ISSN 1012-0750.
  3. ^ John Pether (April 2014) Extension of quarrying on Portion 12 of Farm Hartenbosch 217 (Maandagskop Crusher), Mossel Bay, Western Cape. Brief Palaeontological Assessment (Desktop Study). Link:http://www.phsconsulting.co.za/uploads/7593872PIA%20Brief%20Maandagskop.pdf