Geochemistry and geochronology of granitoid rocks of the Taatsiin Gol pluton of the Khangai Complex, Central Mongolia

Tsogoo Bayasgalan,Baatar Munkhtsengel,Battur Khurelbaatar,Sodnom Khishigsuren

doi:10.5564/mgs.v26i53.1788

Tsogoo Bayasgalan, Baatar Munkhtsengel + Show 2 more

Open Access

https://doi.org/10.5564/mgs.v26i53.1788

Copy DOI

Abstract

The Taatsiin Gol pluton is one of the major constitute the intrusive body of the Khangai Complex, and is composed the first phase of diorite, the second phase of porphyritic granite, biotite-hornblende granite, and granodiorite, and the third phase of biotite granite and alkali granite. This paper presents new geochemical and U-Pb zircon age data from intrusive rocks of the Taatsiin Gol pluton. Geochemical analyses show that the granitoid rocks of the pluton are high-K calc-alkaline, and metaluminous to weakly peraluminous I-type granites, depleted in HFSE such as Nb, Ta, Ti and Y and enriched in LILE such as Rb, Cs, Th, K and LREE, where some variations from early to later phases rock. Zircon U-Pb dating on the biotite granite of the third phase yielded weighted mean ages of 241.4±1.2 Ma and 236.7±1.4 Ma. Based on the new and previous researchers’ age results, the age of the Taatsiin Gol pluton of the Khangai Complex is 256-230 Ma consistent with the late Permian to mid-Triassic time. Although showing variated geochemical features, the rocks of the three phases are all suggested to form at an active continental margin setting, probably related to the southwestward subduction of the Mongol-Okhotsk Ocean plate during the late Permian to mid-Triassic period.

Highlights

Mongolian territory is situated in the central part of the Central Asian Orogenic Belt (CAOB), which is bounded by the Siberian and the East European cratons in the north and the North China and the Tarim cratons in the south (Xiao et al, 2015; Badarch et al, 2002; Windley et al, 2007)
Taking the Taatsiin Gol pluton, one major constitute the intrusive body of the Khangai Complex, as an example, it was mapped as the Tarvaragtai Complex and was designated a Carboniferous age in the 1:200,000 L-47-72 map Sheet (Tumurchudur et al, 1990), but was regarded as the Proterozoic in the L-48-61 Sheet (Togtokh et al, 1984), as the granitic rock of the Khangai Complex in the L-47-84 Sheet (Zabotkin et al, 1988), neighboring map sheets
Petrography The first phase of the Taatsiin Gol pluton (Fig. 3) is made up of medium-grained diorite, the second phase includes fine-to medium-grained granodiorite, and the third phase is dominated by fine-medium grained biotite granite

Summary

Introduction

Mongolian territory is situated in the central part of the Central Asian Orogenic Belt (CAOB), which is bounded by the Siberian and the East European cratons in the north and the North China and the Tarim cratons in the south (Xiao et al, 2015; Badarch et al, 2002; Windley et al, 2007). The formation time of the Khangai Complex has long been an issue of debate. The Khangai Complex was considered to be Paleozoic or older in age for a long time. The tectonic setting of the Khangai Complex is another major topic for discussion. In order to verify the formation age and determine the tectonic setting of the Khangai

Methods

Results

Discussion

Conclusion