Olduvai Gorge is well known as a paleoanthropological site excavated by Louis and Mary Leakey in the 1950s and 60s. Several species of hominins found there: 1) Homo habilis, 2) Homo erectus, 3) and Paranthropous bosei, which make it an important location to understand climate and environment. I have worked on two projects at Olduvai Gorge: The Olduvai Paleonthropology and Paleoecology Project (TOPPP) and Ancient Climate and the Authigenic Clay Index of Aridity (ACACIA).
For TOPPP, I focused on the paleosols identified in uppermost Bed I. These deposits are ~1.8 Ma years old and are bracketed by tuffs that allow for reconstruction of slices of a landscape over a 20 kyr period. As paleo-Lake Olduvai expanded and contracted throughout the Pleistocene, lake clay was deposited followed by the formation of soils along a lake margin. Because there are a series of paleosols deposited throughout this 20 kyr time period, changes in climate can be tracked using changes in the bulk geochemistry. The paleosols have increased weathering of mobile elements like Na and Fe up section, likely due to changes in precession. You can read more about these paleosols in Quaternary International here and here.
The combination of paleosol features in outcrop, micromorphology (description of soil features and fabrics identified at the microscopic level), and bulk geochemistry allowed for a reconstruction of the landscape where slight changes in topography and proximity to a freshwater spring along a fault affected abundance of organic matter and degree of pedogenic development
The ACACIA Project is focused on the lacustrine authigenic clays deposited by paleo-Lake Olduvai. The lake was shallow, alkaline, and oxidizing and therefore does not preserve organic material like pollen, so a new method to understand changes in the lake was needed. Previous research in the Olduvai Basin has shown that the composition and abundance of authigenic clay mineral phases can record changes in the lake. Because paleo Lake Olduvai was a hydrologically restricted lake and saline-alkaline, Al-rich detrital clays washing into the lake interact with these brines and can be altered. When this occurs in the Olduvai Basin, more Mg is incorporated into the clay mineral. Therefore Al-rich clays are interpreted as freshwater and Mg-rich clays represent elevated salinity that is necessary to alter the clays. We only study very smallest clay-sized particles < 0.2 μm because the smallest sizes are more likely to be authigenic, but this clay mineral alteration in saline-alkaline waters also affects the overall bulk geochemistry, which is much easier to measure. This research was just published in Geology!