GEOCHEMICAL CHARACTERISTICS OF MAFIC ROCKS IN THE STRUCTURE OF THE YENISEI-KHATANGA TROUGH AND THEIR BELONGING TO THE SIBERIAN TRAP PROVINCE

Abstract

Consideration is being given to the geochemical composition of the rocks, representing the hidden part of the volcanic and intrusive material in the structure of the Yenisei-Khatanga Trough (YKT), in relation to its belonging to a large igneous province (LIP) of Siberia. The geochemical characteristics of mafic rocks, presenting in the sedimentary complexes of the YKT, correspond to three types of mafic rocks allocated to the Siberian LIP: Nadezhdinsky (low Ti), Morongovsky (low Ti), and, in limited quantities, Ivakinsky (rift-related high Ti). Based on the seismic data, there was constructed a deep structural-tectonic cross-sectional model, and there was considered the position of mafic intrusions in the sedimentary section in the western junction zone of the Siberian Platform and the Kara (Taimyr-Severozemelsky) orogen. The seismic data show an anomalous area in the lower crust and at the crust–mantle boundary immediately below the YKT depocenter, whose seismic section is characterized by a chaotic scattered wave field with no reflective boundaries.