fig02.htm

Figure 2. Vendian remnant basin in the Sayan belt of accreted terranes and basins (Mana zone). (A) Vendian fold-and-thrust pile (near the mouth of the Angaloi Creek). Thrust sheets are made up of oceanic crustal fragments (Kuvai volcanic suite), shelf carbonate deposits of the cratonic margin (Angaloi Formation), and a deformed remnant flysch basin. Thrust sheets are separated by zones of volcanomictic carbonate melange. (B) Same, at the Bespalsky Utes (Bespalsky Cliff)-Stolbik locality. Right, transverse section across a recumbent fold composed of the upper thrust sheet of Angaloi dolomites. Composition and shape of carbonate clasts are the same in tectonic melange and in gravitational flow deposits in the remnant flysch basin, deformed during accretion of island arc onto the craton in the Vendian. (C) A model for remnant flysch basin during the Early Vendian accretion of the Siberian craton. Zone of olistostrome and coarse debrite ("wild flysch") was related to syndepositional overthrusts. Slope deposits give way to medial flysch with submarine streams and the fan of graywacke turbidites (distal thin-bedded flysch) fringing it.
Symbols: 1 - basic effusives, Kuvai Group, 2 - dolomites, Angaloi Formation, 3 - same, preserving microphytolith and stromatolite structures, 4 - coarse-grained debrites with blocks and boulders of Kuvai and Angaloi rocks, 5 - thick-bedded sand debrites and turbidites lacking large fragments, 6 - tectonic melange of volcanomictic-carbonate composition, 7 - same, of carbonate composition, 8 - submarine streams and turbidites of fans and levees, 9 - thin-bedded turbidites: siliciclastic, carbonate, and hybrid, 10 - sense of overthrusting.


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