Preliminary Magnetic Investigation of Samples from Reference Permian-Triassic Sequence, Kemerovo Region, Russia

We performed magnetic investigations of samples from the Babyi Kamen' section in the left bank of the Tom' River, Kemerovo region, Russia (54 degrees 23.079'N, 087 degrees 32.105'E). This section is proposed as a reference for the Kuznetsk Basin. It has been studied since the 1930s and is widely described in the literature. The succession is formed by sandstone, siltstone, and claystone which contain a vast amount of tuffaceous material. Age of the samples is PermianTriassic. The principal aim of our study is to find the stratigraphic position of the boundary between the two eras. Measurements of magnetic susceptibility (MS), natural remanent magnetization (NRM), hysteresis parameters, and induced magnetization versus temperature were carried out to determine samples magnetic mineralogy. According to the obtained data, the sequence is divided into two parts. In the lower one low values of the magnetic susceptibility, NRM are observed, remanence is carried by magnetite, and pyrite or siderite are also present. In the upper part higher values of magnetic parameters are observed, and magnetization carriers are magnetite and minor hematite.