The Kapthurin Formation is a

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

outcrop in

Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

near

Lake Bogoria Lake Bogoria (formerly Lake Hannington) is a saline, alkaline lake that lies in a volcanic region in a half-graben basin south of Lake Baringo, Kenya, a little north of the equator. Lake Bogoria, like Lake Nakuru, Lake Elementeita, and Lake Ma ...

and

Lake Baringo Lake Baringo is, after Lake Turkana, the most northern of the Kenyan Rift Valley lakes, with a surface area of and an elevation of . The lake is fed by several rivers: the Molo, Perkerra and Ol Arabel. It has no obvious outlet; the waters ar ...

. Part of the

East African Rift System East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the fa ...

, it is also an important

archaeological site An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or historic or contemporary), and which has been, or may be, investigated using the discipline of archaeology an ...

in the study of early humans who occupied the area and left

Acheulean Acheulean (; also Acheulian and Mode II), from the French ''acheuléen'' after the type site of Saint-Acheul, is an archaeological industry of stone tool manufacture characterized by the distinctive oval and pear-shaped "hand axes" associated ...

stone tools and animal bones behind.

Argon–argon dating Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer ...

of volcanic ash overlying

ochre Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced ...

fragments found there has dated what may represent some of the earliest human aesthetic sensibility to 285,000 years ago. The ochre fragments must have been brought to the site by human agency and may have been used as body adornment.

Sources

Tryon, CA and McBrearty, S, 2002, "Tephrostatigraphy and the Acheulean to Middle Stone Age transition in the Kapthurin Formation, Kenya", ''Journal of Human Evolution'' 42, 211–35, qtd in Scarre, C (ed.) (2005). The Human Past, London: Thames and Hudson. . {{Archaeological sites in Kenya Archaeological sites in Kenya Pleistocene Archaeological sites of Eastern Africa