The First Detrital Zircon Data on the Northwestern Precambrian Yenisei Ridge: Identification of the Continental–Arc Kiselikha Terrane

Abstract

Abstract—

Northwestern segment of the Precambrian Yenisei Ridge contains ophiolite and is known in literature as the Isakovka Terrane or Isakovka domain. We suggest to divide it into two belts: Kiselikha (western) and Torzhikha (eastern), which differed in geodynamic regime during the Late Neoproterozoic (750–600 Ma). It is believed that the Kiselikha belt is mostly composed of volcanic rocks erupted at island arc setting in the second half of the Neoproterozoic, and that collision of this arc with the Siberian Continent formed the Yenisei Ridge orogen. This idea has not been sufficiently supported by geological and geochronological data. Dating of four detrital zircons samples extracted from sedimentary and volcanic-sedimentary rocks in the southern part of the belt revealed that the sampled strata belong to three different Precambrian levels: the Mesoproterozoic, the mid-Neoproterozoic (800–750 Ma), and the end of the Neoproterozoic (620–600 Ma). Thus the authorized stratigraphic layout of the belt, as well as its proposed island-arc origin requires revision. By this paper we announce the identification of the Kiselikha Terrane , which was a part of active margin of the Siberian Paleocontinent at the beginning of the Neoproterozoic. Approximately in the middle of the Neoproterozoic, this block was rifted off Siberia and further evolved as a microcontinent bounded by an active margin from the outer side.