In this study, new geological, geochronological, geochemical, and Nd–Hf isotopic data are presented for the Mélange 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 Mélange 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 Kharuul Massif and variably metamorphosed from greenschist- to upper amphibolite-facies, and high-grade metamorphic rocks including quartzite–gneisses, hornblende schists, and amphibolites with relics of eclogite and blueschist-facies metamorphism assemblages. Emplacement of trondhjemites and gabbro dykes of the Kharuul Massif occurred at about 960–930 Ma. Geochemical, Nd whole-rock, and Hf-in-zircon isotopic data indicate an oceanic island arc setting for the lower-grade association. LA-ICP-MS dating and Hf-in-zircon data for detrital zircons from the quartzite–gneisses of the Mélange Zone indicate that the sources comprise Palaeoproterozoic (ca. 2.02 and 2.48 Ga), Neoarchean (ca. 2.59 and 2.67 Ga), and Mesoarchean (ca. 2.8 and 3.0 Ga) magmatic and metamorphic crustal rocks as well as 2.6–2.5 Ga juvenile complexes. High-grade amphibolites show geochemical similarity to continental arc and within-plate basalts, and were formed from enriched mantle sources. Obtained combined with published data demonstrate that the Zavkhan terrane represents composite terrane composed of ca. 960–930 Ma island arc complex, and ca. 860–800 Ma active continental margin complexes in the north and reworked at ca. 800–720 Ma early Precambrian continental crust in the south, which are separated by a Mélange Zone. We speculate that formation of the latest Mesoproterozoic–early Neoproterozoic island arc and active continental margin complexes in the north–central CAOB could be related to the assembly of the Rodinia supercontinent at ca. 1.1–1.0 Ga, which initiated subduction in Mirovian Ocean and led to the development of accretionary orogens around supercontinent margins.

在这项研究中，新的地质，地球年代，地球化学和Nd-Hf同位素数据被提供给蒙古Zavkhan地形内的Mélange地带，以及北部中部的地形结构，新元古代早期地壳生长和微大陆形成。讨论了中亚造山带（CAOB）。梅朗日地区将Zavkhan地层西北部的高品位复合体和西南部的低温-寒武纪陆架沉积物覆盖的未变质的新元古代Zavkhan组分隔开来。地带由玄武岩，玄武质安山岩，稀有的长石质火山岩，卡鲁尔断层的长生硬质变质岩（从绿片岩－上闪石岩相变质变质）和包括石英岩－片麻岩的高级变质岩组成，角闪片岩和闪长岩与榴辉岩遗迹和蓝片岩相变质组合。Kharuul地块的特隆赫密特人和辉长岩堤防发生在大约960-930 Ma。地球化学，Nd全岩和锆石中的Hf同位素数据表明，低级联合的海洋岛弧环境。来自梅朗日地区石英岩-片麻岩的碎屑锆石的LA-ICP-MS年代测定和锆石中Hf数据表明，这些来源包括古元古代（约2.02和2.48 Ga），新古宙（约2.59和2.67 Ga），和Mesoarchean（约2.8和3.0 Ga）岩浆和变质的地壳岩石以及2.6–2.5 Ga的幼岩。高品位角闪石显示出与大陆弧和板内玄武岩的地球化学相似性，并由丰富的地幔源形成。结合公开数据获得的数据表明Zavkhan地层代表由ca组成的复合地层。960–930 Ma岛弧复合体，约。北部有860–800 Ma活跃的大陆边缘复合体，并于大约190年进行了重新加工。南部800-720 Ma的前寒武纪早期大陆壳，被Mélange地带隔开。我们推测，最新的中元古代—新元古代早期岛弧的形成和中北部CAOB的活跃大陆边缘复合体可能与罗丹尼亚超大陆在加利福尼亚州的组装有关。1.1–1.0 Ga，在米罗维亚洋引起俯冲，并导致超大陆边缘增生造山带的发展。北部有860–800 Ma活跃的大陆边缘复合体，并于大约190年进行了重新加工。南部800-720 Ma的前寒武纪早期大陆壳，被Mélange地带隔开。我们推测，最新的中元古代—新元古代早期岛弧的形成和中北部CAOB的活跃大陆边缘复合体可能与罗丹尼亚超大陆在加利福尼亚州的组装有关。1.1–1.0 Ga，在米罗维亚洋引起俯冲，并导致超大陆边缘增生造山带的发展。北部有860–800 Ma活跃的大陆边缘复合体，并于大约190年进行了重新加工。南部800-720 Ma的前寒武纪早期大陆壳，被Mélange地带隔开。我们推测，最新的中元古代—新元古代早期岛弧的形成和中北部CAOB的活跃大陆边缘复合体可能与罗丹尼亚超大陆在加利福尼亚州的组装有关。1.1–1.0 Ga，在米罗维亚洋引起俯冲，并导致超大陆边缘增生造山带的发展。我们推测，最新的中元古代—新元古代早期岛弧的形成和中北部CAOB的活跃大陆边缘复合体可能与罗丹尼亚超大陆在加利福尼亚州的组装有关。1.1–1.0 Ga，在米罗维亚洋引起俯冲，并导致超大陆边缘增生造山带的发展。我们推测，最新的中元古代—新元古代早期岛弧的形成和中北部CAOB的活跃大陆边缘复合体可能与罗丹尼亚超大陆在加利福尼亚州的组装有关。1.1–1.0 Ga，在米罗维亚洋引起俯冲，并导致超大陆边缘增生造山带的发展。