Geodynamics of ophiolites of the Srednyaya Ters' Massif (Kuznetsk Alatau) inferred from paleomagnetic data

This paper reports new paleomagnetic data of dike series of the ophiolites from the Srednyaya Ters' Massif, Kuznetsk Alatau. Detailed paleomagnetic analysis supported by petrological and geochemical data permitted us not only to establish what position was occupied by this ophiolite association in the past but also to roughly estimate the age of separate parts of its section. Emphasis is placed on the discrepancy between paleomagnetic directions for dikes of different generations, which provided a possibility of their paleomagnetic dating. It has been established that the dike series is represented by subintrusive bodies of basic rocks (gabbros, gabbro-diabases, diabases, and diabase porphyries) of the first generation formed under the conditions of the island-arc system of the Paleoasian ocean, and by a set of dikes of second generation. The subintrusive bodies formed in the Vendian-Early Cambrian, whereas paleomagnetic data suggest that the dikes cutting hyperbasites and gabbros and, likely, the dike-sill complex are younger than of Early Cambrian age.