Kirkwood Formation

Kirkwood Formation
Stratigraphic range: Berriasian-Hauterivian
~
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
CountrySouth 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]

Geology

The Kirwood Formation was formed along the southern section of South Africa during the break up of Gondwana. Dating it has proven tricky, with some regarding it as a Late Jurassic (~145 Ma)[4][5] or Early Cretaceous deposit (~135 Ma).[6][7][8] However, dating the Kirkwood's abundant volcanic ash layers by U-Pb methods is currently underway.

The Kirkwood Formation is composed of sedimentary rocks deposited under fluvial conditions at or near sea level, such as variegated mudstone (an iconic feature), medium-grained lithic sandstone (often being charcoal-rich), and sporadic conglomerates. At its base, the Kirkwood Formation includes a significant deposit of fine-to-medium grained, poorly-sorted (often quartzitic) estuarine sandstone with subordinate dark grey to brow shale layers. This deposit was described as the Swartkops Member. The lower portion of the remainder of the Formation is composed predominantly of siltstones, but includes a smaller sandstone layer (described as part of the Bethelsdorp Member). The upper portion of the Formation is composed predominantly of fine, clay-rich mudstones, with multiple smaller layers of estuarine sandstone.[9]<[10]

The Kirkwood is the second formation of the Uitenhage Group, positioned between the overlying Sundays River Formation and the underlying Enon Formation. Only three geological members have been described within it: the Swartkops Member which contains estuarine sandstone deposits and lacks fossils. The Colchester Member is the most fossil-rich containing terrestrial and lacustrine fossils and is composed of dark grey shale, siltstones and sandstones. The third, the Bethelsdorp Member, resembles the Colchester in containing dark-grey shales and sandstone, and contains marine microfossils.[11] The upper section of the member is overlain by mudstone and siltstone.

Paleontology

Fragmentary remains of various reptile, frog, insect, and mammal fossils have also been found, including fish scales and freshwater bivalves.[12] In addition several plant species such as bryophytes, ferns, conifers, cycads, and bennettitaleans have been discovered, including silicified fossil tree trunks in the sandstone sections which show evidence of being burned.[13] Amber from possible Araucariaceae tree have been reported. [14]

Actinopterygii

Fishes of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Holostei indet.[10] indeterminate Site 6 Scale fragments Closely resembling Lepisosteus, but specific placement unknown
Teleostei indet.[10] indeterminate Site 6 Partial tooth Specific placement unknown

Lepidosaurs

Lepidosaurs of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Squamata indet.[15] indeterminate Kirkwood Cliffs ‘Lookout’ Braincase Specific placement unknown
Sphenodontia indet.[15] indeterminate Kirkwood Cliffs ‘Lookout’and Site 6 Palatine and dentary remains Different from aff. Opisthias sp. from the same formation
aff. Opisthias sp.[10] indeterminate Site 15 Jaw fragment

Testudines

Testudines of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Testudinata indet.[10] indeterminate Site 6 and Site 16 Shell fragments Specific placement unknown

Pseudosuchia

Pseudosuchians of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Mesosuchia indet.[10] indeterminate Site 6 and site 15 Dental remains, incomplete osteoderms and large (72 mm) centrum Specific placement unknown

Dinosaurs

Theropods

Theropods of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Theropoda indet. indeterminate Unknown Single tooth (MB R2352)[16] Specific placement unknown, estimated tooth size large as Tyrannosaurus
Theropoda indet. indeterminate Site 6 Dental remains[10] Much smaller than MB R2352, probably represents other group of small or juvenile theropod
Tetanurae indet.[17] indeterminate Kirkwood Cliffs ‘Lookout’ Proximal femur Probable basal tetanuran
Nqwebasaurus[18] N. thwazi Almost complete skeleton (AM 6040) Basalmost Ornithomimosaur[19]

Sauropods

Sauropods of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Algoasaurus[20] A. bauri Port Elizabeth Brick and Tile Company Quarry A cervical vertebra, femur, an ungual phalanx and a scapula Neosauropod with uncertain placement
Brachiosauridae indet.[20] indeterminate Umlilo Game Farm Vertebrae remains
Dicraeosauridae indet.[20] indeterminate Outskirts of KwaNobuhle Township, 3.3 km south of Uitenhage. Vertebrate remains
Diplodocinae indet.[20] indeterminate Kirkwood Cliffs ‘Lookout’ Cadual vertebrae
Eusauropoda indet.[20] indeterminate Umlilo Game Farm Vertebrae remains Represents either a non-neosauropod eusauropod or a non-titanosauriform macronarian
Titanosauriformes indet. indeterminate[10] Site 15 Dental remains Initially reported as Camarasauridae, aff.Pleurocoelus sp., and aff. Astrodon sp., but subsequent research suggested taxonomic assignment anything lower than indeterminate titanosauriform not available.[20]

Ornithischians

Ornithischians of the Kirkwood Formation
Genus Species Region Member Material Notes Image
Paranthodon[21] P. africanus Bushmans River, Woodbury Farm Partial skull and incomplete vertebra A Stegosaurid Stegosaur.
Iyuku[22] I. raathi Kirkwood Cliffs ‘Lookout’ Uppermost member At least 27 individuals, from juveniles and hatchlings. A Dryosaurid ornithopod.

References

  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 Archived 2018-08-15 at the Wayback Machine
  4. ↑ McLachlan, I.R.; McMillan, I.K. (1979-01-01). "Microfaunal biostratigraphy, chronostratigraphy and history of Mesozoic and Cenozoic deposits on the coastal margin of South Africa". Geological Society of South Africa, Special Publication. 6: 161–181.
  5. ↑ Brenner, P.W. McLachlan, I.R., McMillan, I.K. & (1976-09-01). "Micropalaeontological study of the Cretaceous beds at Mbotyi and Mngazana, Transkei, South Africa". South African Journal of Geology. 79 (3). ISSN 1012-0750.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ↑ McMillan, I.K.; Brink, G.I.; Broad, D.S.; Maier, J.J. (1997-01-01). "Chapter 13 Late Mesozoic Sedimentary Basins Off the South Coast of South Africa". Sedimentary Basins of the World. 3: 319–376. Bibcode:1997SedBW...3..319M. doi:10.1016/S1874-5997(97)80016-0. ISBN 978-0-444-82571-1. ISSN 1874-5997.{{cite journal}}: CS1 maint: periodical has ISBN (link)
  7. ↑ Gomez, Bernard; Bamford, Marion; Delclòs, Xavier (2002-03-01). "Lower Cretaceous plant cuticles and amber (Kirkwood Formation, South Africa)". Comptes Rendus Palevol. 1 (2): 83–87. Bibcode:2002CRPal...1...83G. doi:10.1016/S1631-0683(02)00014-3.
  8. ↑ W. McPhee, Blair; Mannion, Philip; De Klerk, William; Choiniere, Jonah (2016-04-01). "High diversity in the sauropod dinosaur fauna of the Lower Cretaceous Kirkwood Formation of South Africa: Implications for the Jurassic–Cretaceous transition". Cretaceous Research. 59: 228–248. Bibcode:2016CrRes..59..228M. doi:10.1016/j.cretres.2015.11.006. hdl:10044/1/27470.
  9. ↑ 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.
  10. 1 2 3 4 5 6 7 8 Rich, Tom H. V; Molnar, Ralph E.; Rich, Patricia V. (1983). "Fossil vertebrates from the Late Jurassic or Early Cretaceous Kirkwood Formation, Algoa Basin, southern Africa". Transactions of the Geological Society of South Africa. 86: 281–291.
  11. ↑ 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.
  12. ↑ 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.
  13. ↑ Muir, Robert A.; Bordy, Emese M.; Prevec, Rose (2015-09-01). "Lower Cretaceous deposit reveals first evidence of a post-wildfire debris flow in the Kirkwood Formation, Algoa Basin, Eastern Cape, South Africa". Cretaceous Research. 56: 161–179. Bibcode:2015CrRes..56..161M. doi:10.1016/j.cretres.2015.04.005. ISSN 0195-6671.
  14. ↑ Gomez, Bernard; Bamford, Marion; Martı́nez-Delclòs, Xavier (January 2002). "Lower Cretaceous plant cuticles and amber (Kirkwood Formation, South Africa)". Comptes Rendus Palevol. 1 (2): 83–87. Bibcode:2002CRPal...1...83G. doi:10.1016/S1631-0683(02)00014-3.
  15. 1 2 Ross, Callum F.; Sues, Hans-Dieter; de Klerk, William J. (15 March 1999). "Lepidosaurian remains from the Lower Cretaceous Kirkwood Formation of South Africa". Journal of Vertebrate Paleontology. 19 (1): 21–27. Bibcode:1999JVPal..19...21R. doi:10.1080/02724634.1999.10011119.
  16. ↑ Galton, Peter M.; Molnar, Ralph E. (1 January 2012). "An unusually large theropod dinosaur tooth from the Kirkwood Formation (Lower Cretaceous) of South Africa". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 263 (1): 17–23. Bibcode:2012NJGPA.263...17G. doi:10.1127/0077-7749/2011/0204.
  17. ↑ Forster, Catherine A.; Farke, Andrew A.; Mccartney, Jacob A.; de Klerk, William J.; Ross, Callum F. (12 March 2009). "A "basal" tetanuran from the Lower Cretaceous Kirkwood Formation of South Africa". Journal of Vertebrate Paleontology. 29 (1): 283–285. Bibcode:2009JVPal..29..283F. doi:10.1671/039.029.0101.
  18. ↑ De Klerk, William; Forster, Catherine; Sampson, Scott; Chinsamy-Turan, Anusuya; Ross, Callum (2000-06-27). "A new coelurosaurian dinosaur from the Early Cretaceous of South Africa". Journal of Vertebrate Paleontology. 20 (2): 324–332. doi:10.1671/0272-4634(2000)020[0324:ANCDFT]2.0.CO;2. S2CID 128622530.
  19. ↑ Choiniere, Jonah N.; Forster, Catherine A.; de Klerk, William J. (August 2012). "New information on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous Kirkwood Formation in South Africa". Journal of African Earth Sciences. 71–72: 1–17. Bibcode:2012JAfES..71....1C. doi:10.1016/j.jafrearsci.2012.05.005.
  20. 1 2 3 4 5 6 McPhee, Blair W.; Mannion, Philip D.; de Klerk, William J.; Choiniere, Jonah N. (1 April 2016). "High diversity in the sauropod dinosaur fauna of the Lower Cretaceous Kirkwood Formation of South Africa: Implications for the Jurassic–Cretaceous transition". Cretaceous Research. 59: 228–248. Bibcode:2016CrRes..59..228M. doi:10.1016/j.cretres.2015.11.006. hdl:10044/1/27470.
  21. ↑ Raven, Thomas J.; Maidment, Susannah C.R. (20 March 2018). "The systematic position of the enigmatic thyreophoran dinosaur Paranthodon africanus , and the use of basal exemplifiers in phylogenetic analysis". PeerJ. 6 e4529. Bibcode:2018PeerJ...6e4529R. doi:10.7717/peerj.4529. PMC 5865477. PMID 29576986.
  22. ↑ Forster, Catherine A.; de Klerk, William J.; Poole, Karen E.; Chinsamy-Turan, Anusuya; Roberts, Eric M.; Ross, Callum F. (July 2023). "Iyuku raathi , a new iguanodontian dinosaur from the Early Cretaceous Kirkwood Formation, South Africa". The Anatomical Record. 306 (7): 1762–1803. doi:10.1002/ar.25038. PMID 35860957.
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