| Kapthurin Formation | |
|---|---|
| Stratigraphic range: Middle Pleistocene, | |
| Type | Geological formation |
| Unit of | Tugen Hills Sequence |
| Sub-units | See stratigraphy |
| Underlies | Kokwob (Loboi) Formation |
| Overlies | Chemeron Formation |
| Thickness | ~125 m |
| Lithology | |
| Primary | Silt, gravel |
| Other | Basalt, tuff, trachyte, conglomerate, tufa |
| Location | |
| Location | Great Rift Valley, Kenya |
| Coordinates | 0°19′N 35°35′E / 0.31°N 35.58°E |
| Extent | ~150 km2 |
  Kapthurin Formation outcrop W of Lake Baringo | |
The Kapthurin Formation is a series of Middle Pleistocene sediments associated with the East African Rift Valley. Part of the East African Rift System, it is also an important archaeological site in the study of early humans who occupied the area and left stone tools and animal bones behind. It outcrops in Kenya west of Lake Bogoria and northwest of Lake Baringo in the Kenya Rift Valley, exposed on the surface in a 150 km2 (58 sq mi) area.[1] It also outcrops in portions of the Tugen Hills farther east.[2] The ~125 metres (410 ft) of sediment that comprises the Kapthurin formation represents more than 600,000 years of depositional history.[1][3] Clastic sediments, tuffs, and carbonate beds, in the Kapthurin give information on past river and lake environments. Additionally, intercalated tuffs and extrusive igneous rocks associated with Rift Valley volcanic activity have allowed for multiple argon–argon dating studies. The high resolution dating enables archaeological studies regarding changing hominin behavior. The Kapthurin Formation has been used to study the Acheulian-Middle Stone Age transition.[4]
- ^ a b Tryon, Christian A.; McBrearty, Sally (10 March 2006). "Tephrostratigraphy of the Bedded Tuff Member (Kapthurin Formation, Kenya) and the nature of archaeological change in the later middle Pleistocene". Quaternary Research. 65 (3): 492–507. Bibcode:2006QuRes..65..492T. doi:10.1016/j.yqres.2006.01.008. ISSN 0033-5894.
- ^ Hill, A.; Curtis, G.; Drake, R. (1986). "Sedimentary stratigraphy of the Tugen Hills, Baringo, Kenya". Geological Society, London, Special Publications. 25 (1): 285–295. Bibcode:1986GSLSP..25..285H. doi:10.1144/GSL.SP.1986.025.01.23. ISSN 0305-8719.
- ^ Cornelissen, E.; Boven, A.; Dabi, A.; Hus, J.; Yong, K. Ju; Keppens, E.; Langohr, R.; Moeyersons, J.; Pasteels, P.; Pieters, M.; Uytterschaut, H.; Van Noten, F.; Workineh, H. (1990). "The Kapthurin Formation revisited". African Archaeological Review. 8 (1): 23–75. doi:10.1007/bf01116871. ISSN 0263-0338.
- ^ Tryon, Christian A. (April 2006). ""Early" Middle Stone Age Lithic Technology of the Kapthurin Formation (Kenya)". Current Anthropology. 47 (2): 367–375. doi:10.1086/503066. ISSN 0011-3204.