ABSTRACT
Geomorphology is the science of how the surface topography of the earth is a result primarily from the interactions of the environment upon the underlying geology (Hunt 1988). The resulting landscapes reflect not only the chemical and physical composition of the underlying rocks, but also the effect of water and weathering of those rocks, atmosphere and hydrosphere; the soils created from the rocks by the presence and flow of water; the microbes in the soils; the botanical diversities that are successful in the environment; and the combined influence of herbivores and predators within the ecological community, namely the biosphere. Finally, the effect of humans also may contribute significantly to the landscape and thereby may undermine some of the balancing forces that had been in effect for millennia.
This chapter describes a few examples of the geomorphology of regions within the San Francisco Bay Area that represent the results of different interactions between the environment, humans, and the earth’s surface and which have created the landscapes we see today. We summarize the eight processes that affect geomorphology as they relate to the San Francisco Bay Area: aeolian, biological, fluvial, glacial, hillslope, igneous, tectonic, and marine. We will describe a number of localities in the Bay Area that demonstrate either a particular process or a combination of processes. These localities are of interest when viewed in the context of the Bay Area, including how the underlying rock influences the overlying vegetation and how past volcanism and plate tectonics result in the structures of the East Bay hills. We also summarize how precipitation and water flow, estimated over the past 2000 years, has affected the geomorphology of the Bay Area.
