A model of the magnetically active layer of Western Mezen syneclise
Category: 16-1
UDC 550.838.3
Yu.V. Brusilovsky (1), V.A. Bush (2)
(1) Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia
(2) GNPP Aerogeophysica, Moscow, Russia
Abstract. Basing on the results of analyzing and interpreting an airborne magnetic survey (scale 1:50000)
a model of the magnetically active layer of the western Mezen syneclise consisting of three structural levels (horizons) of different genesis was created. The lowest level of the structural floor is represented by linear extended bodies with northwestern extension; it coincides with tectonic disorders in the crystalline basement and reflects the rift stage of the Mezen syneclise evolution. The presence of the middle and upper levels can be explained by the existence of dikes and sills of basal composition within the sedimentary cover. The middle structural level is generated by two large systems of dikes, Snopinskaya and Ust-Vyiskaya, included in the Mezen trap province. The age of those dike systems is determined as the interval from the top of Upper Carbon till the lower parts of the Kazan stage of the Upper Permian, for Snopinskaya system, and from the Riphean till Late Carbone for Ust-Vyiskaya. The upper structural level is represented by local bodies of various shapes and reflects the high frequency part of the field, connected with strong magnetic sources of anomalies, located in the upper part of the sedimentary cover. This enables us to assume that the upper level was formed during the latest phase of magmatism that established the upper level of Mezen trap field, which dates back to the Late Permian or possibly Early Triassic.
Keywords: Mezen syneclise, magnetic field, model of a magnetically active layer, inverse problem, effective magnetism.
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