Modern and Ancient Coastal Sedimentary Facies, Monterey Bay, California: ABSTRACT

Abstract

Depositional processes and sedimentary structures in both barred and non-barred nearshore environments of the Pacific Coast vary systematically with water depth. These variations allow the construction of idealized progradational sequences of sediments deposited along a wave-dominated coastline. The idealized sequences are very similar to the vertical sequences of sedimentary structures preserved in Pleistocene marine terrace deposits exposed along the margin of Monterey Bay. The central Monterey Bay coastal region has been a subsiding depocenter for marine, fluvial, and eolian sedimentation throughout the Quaternary. It provides an opportunity to study the role of climatic change (including fluctuating sea level) in controlling patterns of Quaternary sedimentation and terrace formation along the non-uplifted portions of the California coastline. Most of the fluvial sediment in these regions was deposited during intervals of rising sea level, hence is out of phase with marine and eolian sediments deposited mainly during intervals of lowering sea level. In combination, however, these deposits form suites of sediments by which glacio-eustatic cycles can be recognized. Evidence of at least 11 such cycles is present within the Quaternary deposits in the north- entral Monterey Bay region. End_of_Article - Last_Page 440------------