0000000000820159
AUTHOR
Hao-yang Lee
Granulites and Palaeoproterozoic lower crust of the Baidarik Block, Central Asian Orogenic Belt of NW Mongolia
Abstract Mafic granulite xenoliths are hosted by garnetiferous charnockites in the Archaean to Palaeoproterozoic Bumbuger Complex of northwestern Mongolia, one of the exotic basement terranes in the Central Asian Orogenic Belt. These rocks crystallized at ca. 1850 Ma under granulite-facies conditions (800 ± 27 °C, 6.8 ± 0.6 kbar) in the lower crust and were partly retrogressed to amphibolite-facies during ascent to higher crustal levels as a result of strong deformation resulting in northwest-trending isoclinal folds. The mafic xenoliths are likely derived from gabbroic protoliths, and geochemical, Hf-in-zircon and Nd whole-rock isotopic data suggest these rocks to have originated from pare…
Early Neoproterozoic crustal growth and microcontinent formation of the north–central Central Asian Orogenic Belt: New geological, geochronological, and Nd–Hf isotopic data on the Mélange Zone within the Zavkhan terrane, western Mongolia
Abstract In this study, new geological, geochronological, geochemical, and Nd–Hf isotopic data are presented for the Melange Zone within the Zavkhan terrane, Mongolia, and the terrane structure, early Neoproterozoic continental crust growth, and microcontinent formation in the north–central part of the Central Asian Orogenic Belt (CAOB) are discussed. The Melange Zone separates high-grade complexes of the northwestern part of the Zavkhan terrane and unmetamorphosed Neoproterozoic Zavkhan Formation covered by Cryogenian–Cambrian shelf deposits of the southwestern part. Zone consist of a lower-grade association of basalts, basaltic andesites, rarely felsic volcanic rocks, trondhjemites of the…
EARLY NEOPROTEROZOIC CRUST FORMATON IN THE DZABKHAN MICROCONTINENT, CENTRAL ASIAN OROGENIC BELT
The Dzabkhan microcontinent was defined by [Mossakovsky et al., 1994] as a cratonic terrane with an early Precambrian basement that combines highgrade metamorphic complexes of the Songino, Dzabkhan, Otgon, Baidarik, Ider and Jargalant Blocks. However, early Precambrian ages have so far only been recognized in the Baidarik and Ider blocks [Kozakov et al., 2007, 2011; Kroner et al., 2015].