PALEOMAGNETISM OF PHANEROZOIC GEOLOGICAL COMPLEXES IN TUVA
The authors have investigated palaeomagnetically the Ordovician, Upper Devonian and Lower Carboniferous strata in Tuva. In the rocks, postfolding secondary and prefolding magnetization components were isolated. Paleomagnetic poles were calculated from primary magnetization components: for the Ordovician - Φ = 4° N, Λ = 307°E, A95 = 5.4°, if the Ordovician strata were formed in the Northern hemisphere and Φ = -41° N, Λ = 127°E, A95 = 5.4°, if the strata accumulated in the southern hemisphere; for the lower part of the Upper Devonian - Φ = 3.7° N, Λ = 139.8° E, A95 = 9.3°, for the upper part of the Upper Devonian - Φ = 51.7° N, Λ = 148.8° E, A95 = 16°; for the lower carbon - Φ = 53.8° N, Λ = 141.7° E, A95 = 9.6°. Probably, at least since the Ordovician, Tuva was part of the Siberian structure and was moving latitudinally with it. The Devonian and Lower Carboniferous strata are rotated in different degrees in the horizontal plane in relation to Siberia. The rotations could be associated with local deformations of rocks, but it is also possible that the rotation of a large geological block was caused by large-amplitude shifts after the Early Carboniferous.