Abstract
In this study, we present zircon U/Pb, plagioclase and K-feldspar 40Ar/39Ar and apatite fission track (AFT) data along the South Tannuol Fault Zone (STFZ). Integrating geochronology and multi-method thermochronology places constraints on the formation and subsequent reactivation of the STFZ. Cambrian (~510 Ma) zircon U/Pb ages obtained for felsic volcanic rocks date the final stage of STFZ basement formation. Ordovician (~460–450 Ma) zircon U/Pb ages were obtained for felsic rocks along the structure, dating their emplacement and marking post-formational local magmatic activity along the STFZ. 40Ar/39Ar stepwise heating plateau-ages (~410–400 Ma, ~365 and ~340 Ma) reveal Early Devonian and Late Devonian–Mississippian intrusion and/or post-magmatic cooling episodes of mafic rocks in the basement. Permian (~290 Ma) zircon U/Pb age of mafic rocks documents for the first time Permian magmatism in the study area creating prerequisites for revising the spread of Permian large igneous provinces of Central Asia. The AFT dating and Thermal history modeling based on the AFT data reveals two intracontinental tectonic reactivation episodes of the STFZ: (1) a period of Cretaceous–Eocene (~100–40 Ma) reactivation and (2) the late Neogene (from ~10 Ma onwards) impulse after a period of tectonic stability during the Eocene–Miocene (~40–10 Ma).
Highlights
The South Tannuol Fault Zone (STFZ) is situated in the Tuva Region (Russian Federation) of theAltay–Sayan Fold Belt (ASFB) in the northwestern (Siberian) part of the Central Asia Orogenic Belt (CAOB) (Figure 1)
The results of the zircon U/Pb dating are shown alongside previously published results [5,6,7] in
Five zircon U/Pb ages were obtained for samples 2218-3, 2251-1, 17002-4, 2223-1 and 2189-1
Summary
The South Tannuol Fault Zone (STFZ) is situated in the Tuva Region (Russian Federation) of theAltay–Sayan Fold Belt (ASFB) in the northwestern (Siberian) part of the Central Asia Orogenic Belt (CAOB) (Figure 1). The South Tannuol Fault Zone (STFZ) is situated in the Tuva Region (Russian Federation) of the. The STFZ is characterized by steep fall of the fault blocks and the vertical displacement amplitude along the largest fault segments from 300 to 3000 m. It controls the tectonic evolution of the Tannuol Mountain Range, the most prominent topographic feature with an altitude of up to 2400 m in the Tuva–Mongolia border zone (800–1000 m). The Tannuol Range is composed mainly of Paleozoic volcanic rocks of island arc affinity, intruded by various plutons of different ages and compositions (Figure 2). The volcanic rocks are deformed into intricate linear folds
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