TRIASSIC TRANSGRESSIONS, REGRESSIONS, AND MARINE BIOTA OF NORTHERN SIBERIA

Abstract

The analysis of transgression and regression curves for 13 facies zones of the Triassic successions in Siberia was carried out for the first time. The established ten transgressive-regressive cycles of the 1st and 2nd orders developed in the early Induan, early Olenekian, terminal late Olenekian, early and late Anisian, early Ladinian, early and late Carnian, early-middle Norian, and also in the Rhaetian. The early Induan, early Olenekian, early Anisian, early Ladinian, early Carnian and early-middle Norian transgressions in the Central Siberian and Verkhoyansk basins were likely controlled by eustatic movements, whereas all other events were probably triggered by tectonic movements. Connections between these movements and changes in basic groups of marine Triassic invertebrates of Siberia are considered. The development of Triassic biota is shown to have been directly dependent on global eustatic movements.