Interregional correlation of benthic foraminiferal faunas along the northeast pacific margin—climatic controls

Abstract

Similarity of benthic foraminiferal faunas from the Gulf of Alaska Tertiary Province and central California fluctuates during the middle Cenozoic, being highest (most similar) in the late Eocene and again in the early Miocene. A major lineage of benthic foraminifera, the uvigerinid—siphogenerinid, extends its range northward into the Gulf of Alaska at these times. These relationships can be correlated to climatic fluctuations as defined by oxygen isotopic analysis. Increased faunal cosmopolitanism during warm climatic periods increases the geographic extent to which benthic foraminiferal correlations can be made. During cold climatic periods faunal endemism increases and correlations become more difficult or impossible. Consideration of the effects of climate on faunal distributions, combined with detailed analysis of local paleoenvironmental influences, provides a basis for better evaluating both interbasinal and interregional foraminiferal correlations.