Turkana Basin

[4] The oldest sedimentary records go back to the Cretaceous, including units previously informally referred to as the Turkana grits like the Lapurr Sandstone and are dominated by eastward flowing fluvial sequences draining into the Indian Ocean;[3] later formations from the Oligocene and Miocene are characterised by similar fluvial regimes that are not however unified under a single geological group or system.

[9] As in other regions, the end-Miocene Messinian aridification crisis and global cooling trend seem to have influenced fossil assemblages in the Turkana Basin, either through migrations or de novo evolutionary events.

[10] Fossilized leaves characteristic of more mesic landscapes, faunal community compositions, and increase "C4" or arid-adapted plant contribution to herbivore carbon intake, all suggest that the Miocene world was more lush than the Pliocene.

[15] One cause of focus on the late Pliocene and early Pleistocene is the large literature on hominin fossil remains showing an apparent "adaptive radiation" across this boundary.

While previous hominin species are considered to be part of a single, continuously evolving "anagenetic" lineage,[16] hominin fossil remains become extraordinarily diverse in East Africa 2.5 million years ago, with numerous species of robust australopithecine and early human ancestors found first in the Turkana Basin, and ultimately in South Africa as well.