shear zones. [Ref.: Bea et al., 1997].
Legend: Striped=Verkhisetsk batholith, Dots=continental-type batholiths, Black=subduction-related batholiths.
The batholith is composed of older, coarse grained, strongly deformed TTG suite outer envelope¾intruded by a core of younger, fine grained, undeformed granodiorites, adamellites, and granites with abundant dyke swarms of leucogranites, aplites, and pegamtites. Radiometric dating of samples from the older and younger rocks utilizing Rb-Sr isotopes has been conducted. The older rocks of the batholith show isochron ages of 316 +/- 6 Ma and 320 +/- 12 Ma. The older rocks also have a high-Al TTD (tonalite-trondhjemite-dacite)/adakite chemistry, eNd(320Ma/chur) = 2-5, and 87Sr/86Sr=0.7043 isotopic ratios. The magma source for the older rocks is believed to come from the melting of metabasalts in a subducted slab of oceanic lithosphere.
Two Rb-Sr isochrons for the younger rocks of
the batholith indicate an crystallization age of 276+/- 5
Ma and 284 +/- 16 Ma. The younger rocks were
generated by the remelting of older rocks during an melting event (275-290
Ma) that supposedly occurred throughout the Urals as a result of mafic
underplating of the crust. This same event is said to have produced
the huge continental-type batholiths observed in the eastern continental
sectors of the Uralian Domain.