Khandizin Fm

Along the Handiza River, Southwest Gissar. V.A. Khokhlov, L.P. Ignatiev in 1967 (73, p.98). Upper formation in the Surkhantau Gr

Synonym: Khandizin Suite, Хандизинская св.

Formations of the suite constitute the upper part of the Surkhan-Tau Gr (Surkhantau Gr), and its characteristic feature is a high degree of diaphthoresis compared to other series.

Among the green-schist diaphthorites developed from biotite plagiogneisses, rare layers of amphibole-biotite gneisses with epidote are encountered, some of which, based on relict textural-structural features and geochemical characteristics, formed from effusive rocks of basic composition. Layers of amphibole-biotite slates, interbedded with gneisses and slates, are also present. Thickness 1300m. Extensive processes of silicification have occurred, resulting in a large part of the rocks acquiring a quartzitic appearance.

The age of the suite is conditionally determined as early Proterozoic. The undoubtedly Precambrian age of the formations is evidenced by the presence of gneiss, crystalline slate, migmatite, and granite pebbles in the Silurian-Devonian conglomerates of Koktepassay and the Lower Cambrian basin of the Obizarang River (75). However, in the early 1970s, a view emerged regarding the presence of two differently aged strata - Precambrian and Lower Paleozoic. In the Surkhan-Tau Range, E.D. Bezuglov et al. (92) discovered early to middle Cambrian microfossils in the graphitic slates of the Handizina suite, and in other localities, phytoliths and Precambrian microfossils (75). The presence of differently aged organic remains can be explained by the inclusion of both Precambrian and younger Paleozoic formations in the suite, as well as the difficulties in diagnosing the taxonomic affiliation of paleontological objects that have undergone metamorphism (16). Due to the findings of differently aged organic remains, the age of the suite is interpreted ambiguously. Considering the determinations of late Paleozoic microfossils, A.V. Pokrovsky (349) dates the suite to the late Cambrian to middle Ordovician; M.A. Akhmedjanov et al. (75) include the suite in the Lower Proterozoic; I.M. Mirkhodjaev, V.A. Khokhlov et al. (307), based on comparisons with Precambrian metamorphic formations of the Garm Massif, assign the suite to the Lower to Middle Proterozoic; in the Stratigraphic Lexicon (442), it is conditionally assigned to the Lower Proterozoic; on the State Geological Map-500 of Uzbekistan (460), it is conditionally dated to the late Proterozoic.