Quantifying Paleo-Water Depth Estimates from Lacustrine Sedimentary Features

Affiliation(s) PI Project period Funded by
DEES Adams, Kenneth D 01/01/2007 - 08/31/2010 The Petroleum Research Fund, American Chemical Society

Keywords: Sedimentology, stratigraphy, Lake Lahontan

Wave ripples in sectionProject Definition

The Lahontan basin in the western U.S. represents an ideal location to develop a lacustrine sedimentary model for large underfilled basins. This basin has been repeatedly filled by a succession of large lakes through the Quaternary and its sedimentary record is well exposed. The temporal framework and general sedimentary characteristics of this basin have long been known but the details of this record have not been sufficiently exploited.

This research seeks to utilize the sedimentary record of the Lahontan basin to develop a model relating sedimentary features to their formative water depths that can be applied to other underfilled lacustrine basins to document past lake-level fluctuations and elucidate their sedimentary architecture. The research will employ two different but complimentary approaches in developing this model. The first approach will take advantage of the distributions and elevations of three distinct tephra beds that were deposited when the lake surface was at different levels. The lake-surface elevation at the time of deposition for each of the tephras has been identified, so tephra outcrops at different elevations can be directly related to paleo-water depth and the sedimentary features characterized. The second, process-based approach will utilize the characteristics of wave-formed ripples to estimate paleo-water depth. Estimates from this approach can be directly compared to independent estimates of water depth by tracing subaerial features directly into the lacustrine environment where the ripples formed. The results of this work should be useful to others working in lacustrine basins on either outcrop or core.