AGE CONSTRAINTS AND SOURCE AREAS FOR THE PRECAMBRIAN TO CAMBRIAN STRATA OF THE SOUTHERN YENISEI RIDGE (REDKOLESNAYA AND OSTROVNOY FORMATIONS)

The Precambrian to Cambrian strata at the southwestern margin of Siberian Platform are ubiquitously characterized by a gradual transition from red-colored alluvial and deltaic deposits shallow-marine carbonates, reflecting transgressive infill accommodation space foreland basin. However, supposed synchronicity Early marine events calls for verification geochronological bio- chemostratigraphic dating. herein-presented data on small skeletal fossils, trace fossils variations in carbon isotope composition carbonates mixed carbonate-terrigenous succession (Redkolesnaya Ostrovnoy formations) southern Yenisei ridge show that base Fortunian stage is placed within Redkolesnaya formation. Age distribution detrital zircons studied suggests craton be major source clastic material basin during development An increase amount derived "non-Siberian" sources, located periphery paleocontinent time, coeval northern part ridge, indicates complex morphology paleobasin considerable differentiation among sources therein.