Geologic Structure and History of Polar Urals, Pay-Khoy, Novaya Zemlya, and Northern Pechora Depression: ABSTRACT

Abstract

1. The late Paleozoic-early Mesozoic fold system of the Urals-Novaya Zemlya and the Paleozoic-Cenozoic strata of the Pechora depression formed on a folded basement. 2. Structures within the fold system may be divided into (a) the Polar Urals and Pay-Khoy anticlinoria and (b) the structures of Novaya Zemlya. In the mainland part of the Urals system, a set of foredeep basins is recognized at the junction of the fold system and the depression on the western sides. 3. The Urals-Novaya Zemlya fold system includes a complex of Precambrian, Paleozoic, and early Mesozoic (within a foredeep) sedimentary and volcanic rocks. The Precambrian thickness exceeds 3,000 m, and that of the Paleozoic, 10,000 m. The Paleozoic (Ordovician and younger strata) transgressively and unconformably overlies the older formations. Important hiatuses in the Paleozoic are established in pre-Late Devonian (Novaya Zemlya), and in the Late Carboniferous (Pay-Khoy, Novaya Zemlya). 4. Volcanic strata of predominantly basic composition occupy much of the Precambrian (Polar Urals, Novaya Zemlya, Pay-Khoy) and Late Devonian sections. Volcanic rocks of late Paleozoic and early Mesozoic ages are found in northeastern Pay-Khoy. An ancient pre-Ordovician and partly pre-Silurian ultrabasic to acid intrusive complex (Polar Urals, Pay-Khoy, Novaya Zemlya), a Caledonian (Silurian-Devonian) complex of ultrabasic, basic, and acid intrusions (Polar Urals and Novaya Zemlya), and Hercynian basic and acid intrusions (Novaya Zemlya, Polar Urals) are present in this area. 5. Within the fold system the following structural elements are clearly distinguished: (a) the Polar Urals with an adjacent foredeep of the Urals type; and the Pay-Khoy anticlinorium, an early Mesozoic structure, the strike of which is the same as that of the Baikalides and Novaya Zemlya. The Pay-Khoy and Novaya Zemlya areas thus have characteristics of both the Ural geosyncline proper and of the Scotland-Scandinavia Grampian geosyncline joining the Novaya Zemlya trough on the west. End_of_Article - Last_Page 2471------------