MID- TO LATE-HOLOCENE PALEOCLIMATE CHANGE IN BALLONA LAGOON, SOUTHERN CALIFORNIA AND ITS EFFECTS ON HUMAN ADAPTATION

Quaternary coastal environments, including estuaries, are significant to archaeologists, geologists, and palaeoecologists because dramatic changes in geographic settings have strongly affected human land use and adaptation. Estuaries are characterized by a rich biota that includes ostracodes, molluscs, foraminifers, siliceous organisms (diatoms and silicoflagellates), and traces of vegetation represented by palynomorphs. Estuaries are mainly affected by climate and geologic agents like tectonism, subsidence, and isostatic and eustatic sea level change. This study of the Ballona Lagoon, located in the Los Angeles metropolitan area, presents the paleoenvironmental reconstruction of an estuary using ostracodes and palynomorphs in combination with stratigraphic and chronometric analyses. A central goal of this study was to delineate the lagoon edge and to document how it migrated through time in response to climate change and sea level rise. The location of the lagoon edge was important in determining how and why prehistoric land-use patterns shifted through time.