BIOTIC AND ABIOTIC EVENTS OF THE LATE CRETACEOUS ARCTIC BIOGEOGRAPHICAL REALM
V.A. Zakharov, N.K. Lebedeva*, and V.A. Marinov*
Geological Institute of the RAS, 7 Pyzhevskii per., Moscow, 119017, Russia
* Institute of Petroleum Geology, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibisrk, 630090, Russia
Keywords: Arctic biogeographical realm, marine biota, paleogeography, Late Cretaceous
Pages: 1053-1064
Abstract
The marine biota of the Arctic paleobiogeographical realm differed from the biota of the Boreal realm in being taxonomically depauperated rather than in having endemics of a high rank (superrealm). The biota of the West Siberian province is typical of the Arctic. The Upper Cretaceous composite section in northern West Siberia contains traces of biotic and abiotic events restricted to the boundaries of stages or substages: Cenomanian-Turonian, Middle-Upper Turonian, Turonian-Coniacian, Lower-Upper Coniacian, Coniacian-Santonian, Santonian-Campanian, and Maastrichtian-Danian. There are two levels at which the maximum diversity of bottom mollusks, foraminifers, and dinocysts coincides and the taxonomic composition of the same groups becomes most uniform: at the Cenomanian-Turonian boundary and in the Late Santonian. They coincide with the warmest episodes in the Late Cretaceous of northern Siberia. In time, the two bioevents correspond to the period of accumulation of
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