The Age of the Last Episode of the Precambrian
Regional Metamorphic Event in South Ulutau (Central
Kazakhstan): Results of UPb Geochronological Studies
of Granites from the Aktas Complex

A. A. Tretyakov^a, Corresponding Member of the RAS K. E. Degtyarev^a, A. B. Kotov^b, E. B. Sal’nikova^b,
K. N. Shatagin^c, E. F. Letnikova^d, S. Z. Yakovleva^b, and I. V. Anisimova^b

Received February 22, 2012

Abstract—The basement of the south Ulutau sialitic massif, which is located in the western part of Central
Kazakhstan, comprises metamorphized volcanogenic–sedimentary and plutonic complexes of Proterozoic age.
The upper boundary of the metamorphism age corresponds to the age of nonmetamorphized syenites from the
Karsakpai massif (673 ± 2 Ma, Late Riphean). U–Pb geochronological studies of accessory zircon were made,
and a Late Riphean age of biotite alkali granite from the Aktas massif (the youngst metamorphic Precambrian
igneous units in South Ulutau) was found. The obtained age estimate of 791 ± 7 Ma can be considered as the
lower age limit of metamorphism. Thus, the last stage of regional metamorphism in South Ulutau took place in
the second half of the Late Riphean, in the time interval of 790–670 Ma.

DOI: 10.1134/S1028334X12090085

Pleiades Publishing home page | journal home page | top

If you have any problems with this server, contact webmaster.