Marmarosh massif in Ukraine and holy cross mountains in Poland – the rootless allochthonous tectonic structures

Objective: The objective of this study is the investigation of the geological structure of the unique Holy Cross Mountains, located at the territory of Poland and also the unique area of the Marmarosh Massif in Ukraine, whose geodynamic conditions of forming have been studied by the authors earlier. Methods: Based on literature sources the geological structure of the Holy Cross Mountains and surrounding territories, stratigraphic occurrence of deposits, their lithological characteristics and tectonic setting have been considered. Results of investigations: Paleozoic deposits of the Holy Cross Mountains have more similarity with the Paleozoic rocks of Scandinavia and Great Britain, that is with the deposits of the margin of the East- European platform, than with the Paleozoic deposits of the closer located territories. Extension of Cambrian deposits to the territory of the Polish lowland is not confirmed. Ordovician deposits are correlated in detail with the classic British and Scandinavian sections. On the base of paleomagnetic and paleontological data Polish investigators highlight the close vicinity in Early Ordovician of the Holy Cross Mountains and the margin of Baltica. The special attention attracts the existence of crystalline rocks (ophiolites) in Cambrian, Silurian and Devonian. These are the diabase intrusions with width from 20 cm to 40 m in the middle of Cambrian, Silurian and Devonian rocks, formed during the Caledonian tectogenesis and formation of which in the present location of the mountains it is impossible to substantiate. Based on a comparison with the similar phenomenon of the ophiolites occurrence in the Marmarosh Massif as well as the revealing of the impossibility of forming of the Holy Cross Mountains in their present-day location, their rootless allochthonous development, resulting from shifting southwards during the huge phase of  the Alpine folding at the Paleogene-Neogene boundary, is stated. In Miocene in the region of the Holy Cross Mountains already in their present-day location the marine terrigenous molasse has deposited, forming the so called “bays”. Scientific novelty:  the Holy Cross Mountains are the rootless allochthonous tectonic structure, thrust southwards during the Alpine folding at the Paleogene-Neogene boundary. Practical value: In the underthrust of the Holy Cross Mountains the discovery of mineral resources, first of all oil and gas, is possible.