CRUSTAL ARCHITECTURE OF THE DONETS BASIN - TECTONIC IMPLICATIONS FOR DIAMOND AND MERCURY-ANTIMONY MINERALIZATION

Kimberlite-like rocks and minor diamond finds are reported in the Prec ambrian Ukrainian Shield south of the Donets Basin. Prolific mercury-a ntimony mineralization occurs in Carboniferous quartz arenites within the Basin. The tectonic setting is examined on the basis of recent dat a compilations and ongoing research in the Ukraine and Voronezh shield areas and the Pripyat-Dnieper-Donets palaeorift. In the Donets region , a straightforward analogy of any diamond district with the Archangel sk province is not likely in the absence of a Proterozoic shear compar able with the White Sea-Belomorian Mobile Belt. A deep-reaching, NNW-s triking lithosphere lineament is identified here as the Kharkov-Donets k lineament. It transects the rift between the Donets and Dnieper basi ns. The structures involved in this lineament have controlled Palaeozo ic sedimentation and the extent of Late Permian inversion of the Donet s basin. During the inversion, the lineament and associated deep-reach ing longitudinal structures provided pathways for the migration of min eralizing fluids from deep levels in the lower crust and upper mantle. The intersection, in the Kharkov area, of this lineament with a north easterly striking lithosphere root should focus diamond exploration to wards the northern shoulders of the rift. The extreme attenuation of t he crust beneath the Donets Basin, relative to the western basins of t he rift, is associated with crustal detachment and subsidence during a nd possibly after inversion, concomitant with emplacement of asthenosp heric materials at higher levels. Together with the continued subsiden ce in the western Donets Basin, during the Late Permian inversion, thi s invokes a tectonic setting for the Hg-Sb mineralization not unlike t he orogenic-collapse-associated settings of Hg-Sb deposits in western Europe. Further investigation of the geodynamics of the Donets Basin w ould benefit from deep reflection seismics, petrogenetic studies of ma gmatic products and their xenoliths, and satellite remote sensing anal ysis.