Metallogeny of the Altaids – Identifying new terranes BASED ON

INTERDISCIPLINARY GEOTRAVERSE STUDY

Seltmann R. & CERCAMS team*, Borisenko A.S. & SB RAS team**,

Petrov O., Shatov V., Shevchenko S., Sergeev S.***

*Centre for Russian and Central EurAsian Mineral Studies, NHM, London, UK, rs@nhm.ac.uk

**Institute for Geology and Mineralogy SB RAS, Novosibirsk, Russia, borisenko@uiggm.nsc.ru

*** VSEGEI, St Petersburg, Russia, vsgdir@vsegei.ru

The Altaid orogenic collage extends from the Urals over Central Asia (Kazakhstan, Tien Shan) to the Mongol-Okhotsk belt. It comprises assembled fragments of sedimentary basins, island arcs, accretionary wedges and microcontinents of Neoproterozoic to Cenozoic age now joined to surrounding continental regions (e.g. East European craton). The clockwise rotation of Siberia relative to Eastern Europe during middle and late Paleozoic resulted in multiple episodes of arc collisions, both between themselves and with the cratons, as well as the progressive oroclinal bending. This complex cycle of rifting, subduction, accretion and collision has culminated in the current complex assembly.

Despite the wealth of documented deposit types of undoubted high economic value and the wealth of empirical information and genetic interpretations concerning the individual deposits, inter-terrane correlation in the region is sketchy at best. This is a legacy of the past political and physical barriers against compilation work in a huge area of enormous geological complexity.

Based on utilization of existing data a working model of paleogeographic reconstruction and tectonic modelling has been assembled. Selective mapping in specific terranes has been used by to improve the existing database coupled with targeted wholerock geochemistry and precise geochronology. Proterozoic crustal slivers and Paleozoic oceanic-subduction-accretion complexes with former magmatic arcs in the regions formed the first priorities for established correlation. These could be better defined in time and space using new data, reconstructing their current and past distribution patterns, defining regionally controlling major fault structures and post-depositional processes. From this, known terranes hosting key deposit types were extrapolated into geographical gaps in exploration activity and new prospective regions could be outlined.

Based on the precursor study of the CERCAMS team and associated partners in the Eastern and Western Altaids situated to the south of Russian state border, and based on the vast experience and data sets existing in the research institutions of Russia, the three research teams have agreed to combine their efforts in a follow-up approach extending the study into Russian territory to the south of the Siberian craton from the Altai Republic in the west to Chita and Amur regions in the east.