Sequence Stratigraphy in Active Tectonic Settings: Transverse Ranges, Southern California

Kirt M. Campion and Morgan D. Sullivan

Active basin subsidence, uplift, and faulting along with sparse biostratigraphic control has conspired to make development of a high-resolution stratigraphic framework a challenge in the Transverse Ranges. In the past, correlation and mapping of Paleogene strata between fault blocks has relied on recognition of gross Iithofacies patterns, macrofossil assemblages, and local biostratigraphic control. Although Paleogene rocks in the Transverse Ranges exhibit elements of sequences that are typical of stable tectonic settings, utilization of sequence stratigraphic concepts has not been widely used. Surfaces, such as unconformities and parasequence boundaries, can be mapped and provide a stratigraphic framework to assess paleogeographic reconstructions, fault timing and basin subsidence patterns. For example, facies distribution within the Matilija Sandstone include slope, distal delta front, stream mouth bar, fluvial, shoreface, subtidal, and offshore marine. These facies are not coeval but existed at different times and in three different sequences. Recognition and correlation of these sequences enhances the paleogeographic reconstruction for the Matilija and provides insight regarding the effects of faulting on facies distribution and sediment dispersal patterns. Similarly, the Coldwater Formation fits into parts of three sequences, which include subtidal, coastal plain, flood plain and fluvial facies. The age model for the Coldwater and overlying Sespe is problematic because of sparse biostratigraphic control, but linkage of paleomagnetic and biostratigraphic data to the sequence stratigraphic framework provides a working age model.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California