DEVELOPMENT OF MICROPALEONTOLOGICAL TECHNIQUES FOR COASTAL SETTINGS: NEW AND OLD

Finding former sea-level positions is fundamental in coastal studies because many coastal problems result from changes in sea level, either very rapid (e.g. earthquakes, hurricanes) or long-term phenomena such as glacial/deglacial transitions. Marsh foraminifera are accepted as the most accurate paleo-sea level indicator known at this point and they can be used for an almost unlimited array of problems that occur on coastlines. For example the technique was first developed as a tool to relocate the shoreline of California in 1859 to aid in the enforcement of the 1973 California Coastal Zone Act. We will also present brief case studies on various estuarine/lagoonal areas where catastrophic events have been detected; primarily periodicities of hurricanes and precursors of giant mega-thrust earthquakes have been detected using marginal marine foraminifera as the indicators. A new study in northern California showed that the mega-thrust zone that extends from Alaska to northern California has precursor markers along its length including N. California-precursors that may provide 5-10 years of warning before a major earthquake. These techniques also provide histories of hurricanes on the east coast of the US.