9417971 Axelrod Although numerous (50+) Middle Miocene (18-12 Ma) Floras have been collected and a good number described from the great Basin region, little is known of its vegetation and climatic history following 10 Ma. This proposal plans to collect and describe 16 new fosssil floras dataed 10-5 Ma from the region and integrate them with described pollen floras that contain "sage" taxa that make up the present lowland flora but are unrepresented by megafossils. Description and analysis of these floras will provide a resource for diverse fields of research. 1) Rates of climate change in the later Neogene and its role in modification of composition of floras and mammalian faunas. 2) Climatic conditions at these sites can provide a reliable basis for interpreting the developement of paleosoils. 3) Temperatures inferred for the fossil floras provide a basis for estimating elevation. 4) Rates of evoluation of woody plants and of mammals during the period 10-5 Ma. 5) Influence of taphonomy on floral composition at diverse sites (i.e., lake, floodplain, volcanic mudfow). 6) And as a resource, the species of each flora are entered into the data base in Mus. Paleo. UC Berkeley and are available via Internet.
