Neogene radiolarian biostratigraphy and paleotemperatures: Southern California, the experimental mohole, antarctic core E 14-8

Abstract

Neogene radiolarians from southern California were compared to radiolarians from the Experimental Mohole and core E 14-8 from the Antarctic Ocean. An attempt to utilize the radiolarian zonation of Riedel was hampered by a sparsity of typical time-index forms in the southern California and Antarctic samples. These difficulties were partially overcome by using the Experimental Mohole to correlate Riedel's “warm” time-indices with selected “cold” time-indices from the Antarctic and southern California. Some “cold water” radiolarians useful in high-latitude correlations are Prunopyle titan, Lychnocanium grande and Theocyrtis redondoensis that drop out just below the Miocene-Pliocene boundary, and Lamprocyclas heteroporos (in the strict sense) that appears to evolve at or near the Miocene-Pliocene boundary. In high latitudes the Pliocene-pre-glacial Pleistocene boundary appears to be delineated by the extinction of L. heteroporos. Paleotemperatures, derived from radiolarian ratios, suggest large-scale synchronous warmings and coolings for the various areas studied.