The Cretaceous Peninsular Ranges Forearc Basin extends along the western margin of the present day Baja California, and is one of the best exposed and most extensive convergent margin basin complexes; it is one of the few areas in the world where spatial and temporal evolution of a channel system can be studied in detail in outcrops.
The c. 1200 m thick Rosario Formation, in the central portion of the Peninsular Ranges Forearc Basin), represents a steep continental slope incised by several submarine canyons and entrenched slope channel systems. The channel systems have erosional bases and overall fining upwards patterns. In the Canyon San Fernando field area, the fill of a mid-slope submarine channel-levee system is exposed. The channel is oriented obliquely to the continental slope and is confined by levee deposits on one side and on laps the slope on the other.
Our team has been working in this area for 13 years, which has involved detailed mapping, sedimentary logging and sampling to constrain the biostratigraphic and radiometric age of the system, the petrography, provenance, and micropaleontolgical and ichnological fingerprints of various elements of the system, and facies distribution, for a better understanding of bypass dominated slope channel architectures and their identification using vertical sequences. We have also studied differentiation of different types of thin-bedded Turbidites, both within the channel belt and on the external levee, provenance studies of the sediments of the channels and of the relationships between the channels and the background sedimentation of the slope are nearing completion.