Physical Oceanography, Primary Productivity, Sedimentology
This section consists of eight chapters covering the three broad topics of physical oceanography, primary productivity, and sedimentology. The physical processes of evaporation, precipitation, tidal movement, and wind forcing in the Gulf of California have been reviewed and updated (BRAY and ROBLES). The hydrographic features of the gulf control upwelling, and these, coupled with strong tidal mixing, result in high primary productivity. Seasonal primary productivity has been reviewed and reinterpreted within this updated framework (ALVAREZ-B. and LARA-L.).
Sedimentology is represented in terms of contemporary and Cenozoic time scales. The provenance of the modern fine-grained sediments in the central Gulf of California is discussed (BABA et al., a), and the effects of anthropogenic activity over the past century on supply and dispersal of terrigenous sediments also have been evaluated (BABA et al., b). The varve chronology of the central gulf has been established for most of the twentieth century (BAUMGARTNER et al., a). The anaerobic sediments of the slope off Guaymas are ideally suited for this study, and the formation of the individual dark and light varve couplets has been reinterpreted (BAUMGARTNER et al., b).
The existence of a marine environment in the Protogulf as early as the Oligocene is indicated by the study of marine mollusks from various locales throughout the region (SMITH). The Deep Sea Drilling Project devoted four legs in the province, mainly on the continental margins of California and Mexico. The sediments ranged in ages from Quaternary to Pliocene. Their organic matter was analyzed to evaluate sources