Great Rift Valley support its current biological variety. The southern section of the Rift Valley includes Lake Malawi, the third-deepest freshwater body in the world, reaching in depth and separating the Nyassa plateau of Northern Mozambique from Malawi; it ends in the Zambezi valley. Great Rift Valley The Great Rift Valley is a continuous geographic trench, approximately in length, that runs from Lebanon's Beqaa Valley in Asia to Mozambique in Southeastern Africa. The name continues in some usages, although it is today considered geologically imprecise as it combines features that are today regarded as separate, although related, rift and fault systems. Today, the
Geology of the Death Valley area covered what would later become the Grapevine Mountains in of ash. This ash filled in valleys and depressions; by 20 million years ago, the region from the Death Valley area across Nevada was a volcanic plain. Starting around 16 Ma in Miocene time and continuing into the present, a large part of the North American Plate in the region has been under extension by literally being pulled apart. Debate still surrounds the cause of this crustal stretching, but an increasingly popular idea among geologists called the slab gap hypothesis states that the spreading zone of the subducted Farallon Plate is