Pacific Rim Marsh Foraminiferal Distributions: Implications for Sea-Level Studies

Abstract

New data on marsh foraminiferal distributions are presented for Hokkaido (Japan), Washington State and northern central California (USA). These data, when compared to recently published information from British Columbia, Oregon, Chile and New Zealand, and older data from southern California, allow a comprehensive comparison of biogeographic zonations around the Pacific Rim. Most significant is that high marsh faunas change from brackish to more saline at the California border but all high marsh faunas have the same 2--4 species present. In the southern hemisphere, the species Trochamminita salsa becomes an important high marsh indicator. Their narrow range makes high marsh faunas excellent markers for relocating former sea levels. These data can be used to detect rapid, high amplitude sea-level events associated with earthquakes on the Pacific Rim.