Some Notes on the Lugiin Gol, Mushgai Khudag and Bayan Khoshuu Alkaline Complexes, Southern Mongolia

Abstract

Volcanic-plutonic alkaline complexes from Lugiin Gol, Mushgai Khudag and Bayan Khoshuu, southern Mongolia (244, 139 and 131 Ma, respectively) occur within grabens in E-W lineaments. They are represented by syenitic rock-types (silica undersaturated to slightly silica oversaturated) potassic rocks and are associated to stockworks of carbonatitic veins, dykes and so on. Geochemical characteristics and isotope systematics point to a veined mantle source particularly enriched in LILE and LREE. The carbonatitic veins show high contents of Ba, Sr, Th and REE and are suitable as potential ore deposits.

The Overmaraat-Gol Alkaline Pluton in Northern Mongolia: U–Pb Age and Preliminary Implications for Magma Sources and Tectonic Setting

“…Similar signatures of interaction were reported for many alkaline and carbonatite plutonic complexes of different ages in the western CAOB ( Figure 3). Simultaneous involvement of EM-type and mature continental crust material was inferred for Mesozoic intrusions in areas of thick lithosphere, such as Western Transbaikalia, Southern Mongolia, and Russian Altai [4,40,41], but not in the southwestern Hovsgol area and the Sangilen Plateau in southeastern Tuva (Korgeredaba pluton). Therefore, magma sources may differ even in adjacent areas.…”

“…εNd(t) vs. εSr(t) plot for the Overmaraat-Gol pluton and some other alkaline complexes from the western Central Asian Orogenic Belt: Paleozoic intrusions of the Sangilen Plateau, Vitim Plateau, Russian Altai (complex Edelveis), Kuznetsk Alatau, and basalts of the Minusa Basin (MBB), after[5][6][7][8][9]11,33,34]. Korgeredaba nepheline syenites (~295 Ma, SE Tuva), after[35,36] and Beltesin-Gol carbonatites (~480 Ma, Northern Mongolia), after[37,38]; Mesozoic intrusions of Southern Mongolia (Mushgai Khudag, Bayan Khoshuu), Western Transbaikalia (Oshurkovo, Arshan, Khaluta) and lamproites of the Russian Altai, after[37,[39][40][41]. White stars are average compositions of the North Asian (NA), Devonian (D), and Siberian (S, AB = alkali basalts) mantle plumes, after[18,34,42].…”

Mineral Chemistry of REE-Rich Apatite and Sulfur-Rich Monazite from the Mushgai Khudag, Alkaline Volcanic-Plutonic Complex, South Mongolia

“…Late Jurassic alkaline complex consists of trachytic volcanics and alkaline syenites, melanephelinite, and melaleucitite. K-Ar ages of alkaline rocks vary from 161 to 121 Ma [5] and Rb-Sr isochron ages is 139 Ma, respectively [2].…”

Carbonatites and Alkaline Igneous Rocks in Post-Collisional Settings: Storehouses of Rare Earth Elements

“…This event was associated with a transition from subductionrelated, through post-collisional to extensional magmatism (Wang et al, 2015). Numerous alkaline-carbonatite complexes were formed at this time (Nikiforov and Yarmolyuk, 2019), of which the most important are those in southern Mongolia, including the Mushghai Khudag, Bayan Khoshuu and Ulgii Khiid complexes, all of which are REE-enriched (Nikolenko et al, 2020(Nikolenko et al, , 2018Baatar et al, 2013). These complexes have commonly been described as rift-related, but several features, including enrichment in Ba, Sr, F, K and the LREE, are consistent with derivation from a mantle source that has been affected by subduction (Feng et al, 2020;Nikolenko et al, 2020).…”