Место издания: Florence , Год издания: 2004

Microbenthos are extensively used for paleoenvironmental reconstructions. Although rather wide number of publications is devoted to the paleoecology of Jurassic foraminifers of different Arctic regions, microfauna data are rarely used for the paleofacies reconstructions of Jurassic Arctic paleobasins. Paleoecology of Jurassic microbenthos communities of Arctic have been profoundly investigated using morphofunctional analysis. The comparison of ancient and recent microbenthos communities as well as lithological and geochemical data allow to establish hydrodynamic groups. Ecological groups of microbenthos controlling by salinity (euryhaline and stenohaline preferring normal marine salinity groups) have been established on the base of geochemical materials. Monospecific communities with high population density have been considered as living at the abnormal salinity environments. Ecological groups of microbenthos controlling by bathymetry (stenobathyc, shallow water; stenobathyc preferring relatively deep water and eurybathic groups). Thermal ecological groups can not be reliably established and appreciated. Almostly all arctic taxa of microbenthos are cosmopolitan and hence eurythermal. Only ostracodes and foraminifers migrated from low-altitude paleoseas, which did not have any parents and offsprings, may be considered as thermophilic taxa. The succession of microbenthos communities reflects the peculiarities bottom relief. Recently special attention focuses to the catena analysis as the reliable tool for the reconstructions of bottom relief in paleobasins. Comprehensive analysis of biotic and abiotic factors allow to distinguish a number of bionomical area for Arctic Jurassic paleobasins, which reflect the paleoenvironments of lower (up to 200 m), middle (up to 100 m) and upper (up to 50 m) sublittoral. These zones may be subdivided into bionomical subzones (internal and external). During Jurassic period in Arctic paleobasins a number of drastic changes in microbenthos communities were cause by complex factor. Various ecological crisis's related with the regressions, global cooling, temperature rise following by circumboreal transgression and others resulted in reduction and configuration changes of bionomical zones as well as an essential taxonomical substitution of microbenthos associations. The periods of isolation of Arctic paleobasins especially in critical ecotone areas caused sharp diversity reduction of microbenthos communities all over the Arctic.