Geochronology of the Dovyren Intrusive Complex, Northwestern
Baikal Area, Russia, in the Neoproterozoic

A. A. Ariskin^a, Yu. A. Kostitsyn^a, E. G. Konnikov^b,†, L. V. Danyushevsky^c, S. Meffre^c,
G. S. Nikolaev^a, A. McNeill^c, E. V. Kislov^d, and D. A. Orsoev^d

^a Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences,
ul. Kosygina 19, Moscow, 119991 Russia

e-mail: ariskin@rambler.ru

^b Institute of Experimental Mineralogy, Russian Academy of Sciences,
ul. Institutskaya 4, Chernogolovka, Moscow oblast, 142432 Russia

^c Centre for Ore Deposit and Exploration Studies (CODES), University of Tasmania, Hobart, Australia

^d Geological Institute, Siberian Branch, Russian Academy of Sciences, ul. Sakh’yanovoi 6, Ulan-Ude, 670042, Russia

Received February 21, 2012; in final form, April 24, 2012

Abstract—The paper reports newly obtained data on the geochronology of the Dovyren intrusive complex and
associated metarhyolites of the Inyaptuk Formation in the Synnyr Range. The data were obtained by local LA-
ICPMS analysis of zircons in samples. The U–Pb age of olivine-free gabbronorite from near the roof of the
Yoko-Dovyren Massif is 7306 Ma (MSWD = 1.7, n = 33, three samples) is close to the estimated age of 731
4 Ma (MSWD = 1.3, n = 56, five samples) of a 200-m-thick sill beneath the pluton. These data overlap the
age of recrystallized hornfels found within the massif (“charnockitoid”, 7237 Ma, MSWD= 0.12, n = 10)
and a dike of sulfidated gabbronorite below the bottom of the massif (7258 Ma, MSWD = 2.0, n = 15). The
estimates are also consistent with the age of albite hornfels (7216 Ma, MSWD= 0.78, n= 12), which was
produced in a low-temperature contact metamorphic facies of the host rocks. The average age of the Dovyren
Complex is 728.43.4 Ma (MSWD = 1.8, n = 99) based on data on the sill, near-roof gabbronorite, and “char-
nockitoid”) and is roughly 55 Ma older than the estimate of 673 22Ma (Sm–Nd; [13]). The U–Pb system of
zircon in two quartz metaporphyre samples from the bottom portion of the Inyaptuk volcanic formation in the
northeastern part of the Yoko-Dovyren Massif turns out to be disturbed. The scatter of the data points can be
explained by the effect of two discrete events. The age of the first zircon population is then 729 14 Ma (MSWD
= 0.74, n = 8), and that of the second population is 667 14 Ma (MSWD= 1.9, n = 13). The older value pertains
to intrusive rocks of Dovyren, and the age of the “rejuvenated” zircon grains corresponds to the hydrothermal–
metasomatic processes, which affected the whole volcano-plutonic sequence and involved the serpentinization
of the hyperbasites. This is validated by the results of Rb–Sr isotopic studies with the partial acid leaching of
two serpentinized peridotite samples from the Verblyud Sill. These studies date the overprinted processes at 659
5 Ma (MSWD = 1.3, n = 3).

Keywords: layered massif, intrusive complex, geochronology, zircon, laser ablation, LA-ICPMS

DOI: 10.1134/S0016702913110025

Pleiades Publishing home page | journal home page | top

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