The Kyrgyz-Ata Synform in the South Tien Shan:
Structural and Kinematic Aspects of Its Evolution

Yu. A. Morozov¹ and V. G. Talitskii²

¹Schmidt United Institute of Physics of the Earth, Russian Academy of Sciences,
Bol’shaya Gruzinskaya ul. 10, Moscow, 123995 Russia

²Faculty of Geology, Moscow State University, Vorob’evy gory, Moscow, 119992 Russia

Received November 23, 2004

Abstract—The complexes of metamorphic rocks that take part in the tectonic structure of the South Tien Shan
are mostly confined to the cores of large synforms and occupy high structural position therein. Problems of their
age, origin, metamorphic conditions, and relationships with the adjacent unmetamorphosed Paleozoic
sequences have remained debatable throughout the history of geological investigations. The results of detailed
studies of the Kyrgyz-Ata Synform, a typical structure of the Turkestan–Alay Zone in the South Tien Shan, are
reported in this paper. The metamorphic rocks of the Kan Group participate in the structure of this synform. On
the basis of the study of structural assemblages and the kinematic analysis, it is concluded that the multistage
evolution of this tectonic unit proceeded under transpressive conditions of volcanic trough “crushing.” The
detailed study of rock alteration in the contact zone between the Kan Group and the Middle Devonian basic
volcanic rocks allowed us to suggest that the metamorphic Kan Group is not a self-dependent stratigraphic unit
but represents an infrastructure (a metamorphosed analogue of the volcanic sequence and underlying rocks) dis-
placed tectonically over its own suprastructure.

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