Cenozoic Nonmarine Diatoms from the Great Basin

Citation

Lohman, Kenneth Elmo (1957) Cenozoic Nonmarine Diatoms from the Great Basin. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/X235-B763. https://resolver.caltech.edu/CaltechETD:etd-08192004-140258

Abstract

The wide distribution in the Great Basin area of the Western United States, both geographically and geologically, of the Cenozoic nonmarine diatoms would make them particularly useful for stratigraphic correlation and age determination if their geologic ranges were better known. For this reason, diatoms were collected from some well known vertebrate collecting localities in Nevada, Idaho, and Utah, and the geologic ranges of the individual species established. Of the 353 different species and varieties of nonmarine diatoms identified from the six stratigraphic units chosen, ranging from late middle Miocene to late Pleistocene in age, 85 have been described and illustrated as new, 40 have been known previously only as fossils, and 228 have been recorded previously from living assemblages elsewhere. Paleoecological interpretations of the environmental conditions which obtained during the deposition of the sediments studied were made on the basis of the 228 species and varieties of diatoms in the last category. The investigation has shown that many of the fossil nonmarine diatoms have satisfactorily short ranges in geologic time, and therefore are valuable guides for stratigraphic correlation and age determination of the sediments in which they occur. Furthermore, the Recent species in each assemblage have been shown to supply much useful data on which to base paleoecological interpretations, limited principally to published ecologic data on the living organisms.

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