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Storm-Dominated Diatomite: Transport And Deposition From Micro-Texture, Taylor Kelln

Loma Linda University Electronic Theses, Dissertations & Projects

Unusually thick accumulations of diatomite and diatomaceous mud- and siltstones occur throughout the Mio-Pliocene along the Pacific margin. These extensive micro-fossil assemblages represent an important biostratigraphic resource, record of environmental conditions, and are economically relevant as unconventional reservoirs, sources and seals. Most depositional models for diatomaceous sediments tend to emphasize diatom productivity sufficient to overcome siliciclastic dilution and reflect a low-energy depositional regime with passive settling of diatoms through the water column. However, the diatomaceous sediments of the Pisco Basin, Peru, have been observed in longitudinally bedded, wavy, non-parallel laminated deposits, interpreted as hummocky-swaley cross-stratification. Other outcrop observations include tempestite-like …