A conceptual tectonostratigraphic model for seismic facies migrations in a fluvio-lacustrine extensional basin

摘要

One of the most fundamental differences between lacustrine basins and many marine basins is the stratigraphic response to differential tectonic subsidence. Because the water volume of a lake is finite, tilting of the valley floor redistributes the lake water. If the lake water level is below a hinge point (fulcrum) that experiences no net subsidence, the lake shoreline is translated toward the site of subsidence, and a deeper lake forms. This tectonostratigraphic model for rift-lake sedimentation is tested in a seismic and sequence stratigraphic study of deltaic and lacustrine deposits that accumulated in a Cenozoic extensional basin beneath Goshute Valley, Nevada. Seismic sequences exhibit an internal, cyclic stacking hierarchy of seismic reflections interpreted as the stratigraphic response of a lowstand paleolake to tectonism (forced regression) and subsequent lake level restoration (transgressive and highstand systems tracts). [References: 63]