The Neoproterozoic and Early Paleozoic geological history of the Ural-Kazakhstan margin of the Paleoasian Ocean using new isotopic and geochronological data obtained for the Polar Ural region

¹Geological Institute, Russian Academy of Sciences, Moscow, Russia
²Vernadski Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow, Russia
³Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, St. Petersburg, Russia
⁴Federal Department of Geoscience and Natural Resources, Hannover, Germany
⁵Institute of Geology, Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia

Abstract

[1]  The presence of pre-Paleozoic ophiolites in the Polar Ural region has been a matter of debate for a long time. In order to solve this problem rock samples were collected from the Enganepe Ridge and the Kharbei metamorphic rock complex to carry out their isotope and geochemical study. The U-Pb method was used to study the zircons from the plagiogranites of the ophiolite rocks from the Enganepe Ridge and from the granite and granite gneiss samples collected from the Kharbei complex. The Enganepe plagiogranite samples showed the concordant age values of 670 5 million years. The data obtained for the Kharbei metamorphosed volcanic and sedimentary rocks suggest that some of them had accumulated in pre-Vendian time (about 640 Ma) and were metamorphozed at 460 10 million years. These data suggest the same scenario for the evolution of the Paleoasian ocean, including its Ural margin, and the margins of the Paleoatlantic Ocean.

Received 15 September 2005; accepted 10 October 2005; published 24 December 2005.

Keywords: ophiolite, plagiogranite, isotopic geochronological studies, Polar Ural, granite gneiss.

Index Terms: 1040 Geochemistry: Radiogenic isotope geochemistry; 3040 Marine Geology and Geophysics: Plate tectonics; 3042 Marine Geology and Geophysics: Ophiolites.

Citation: Khain, E. V., A. A. Fedotova, E. V. Bibikova, E. B. Salnikova, A. B. Kotov, K.-P. Burgat, V. P. Kovach, and D. N. Remizov (2005), The Neoproterozoic and Early Paleozoic geological history of the Ural-Kazakhstan margin of the Paleoasian Ocean using new isotopic and geochronological data obtained for the Polar Ural region, Russ. J. Earth Sci., 7, ES5003, doi:10.2205/2005ES000188.