Lake Baikal, at more than 600 km long and 1632 m deep, covers the central third of the Baikal Rift (Figure 1). It is the world's most voluminous lake, containing 20% of the world's surficial freshwater, and it is probably also the oldest lake, at >15 Ma. The Lake Baikal Rift occupies the boundary between the Precambrian Siberian craton and several microplates of south-central Asia [Zonenshain and Savostin, 1981] (Figure 1). Topics of current geoscience research in Lake Baikal include the nature and history of extension and subsidence in the region, deep lithospheric structure, the paleoclimate record of central Asia, and the history of sedimentation and water level fluctuation in the lake. Another topic of recent debate is whether the rift formed actively via mantle doming [Logatchev and Florensov, 1978], or passively as a result of distant plate interactions [e.g., Tapponnier and Molnar, 1979].