Opaline Sediments of the Southeastern Coastal Plain and Horizon A: Biogenic Origin

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Science  24 May 1974:
Vol. 184, Issue 4139, pp. 899-901
DOI: 10.1126/science.184.4139.899


Scanning electron microscope techniques show that Eocene opaline claystones (fuller's earth and buhrstone) of the Atlantic and Gulf Coastal Plain, deposits long considered volcanic in origin, are actually highly altered diatomites formed as transgressive facies in normal marine continental shelf environmnents. These findings are in agreement with a biogenic origin for time-equivalent horizon A and A deep-sea cherts of the North Atlantic and Caribbean.