In recent years, a newly rare metal metallogenic belt has been discovered in the North Qaidam Terrane (NQT), NW China, of which the Chakabeishan (CKBS) Li-Be pegmatitic deposit is an important part. In this study, CMS (chemical composition-mineral assemblage-structural geology) classification is applied on CKBS pegmatitic rocks, based on their CMS features, the rocks are identified as pegmatite type. The CKBS pegmatites exhibit unique internal vertical zonation characteristics, and six zones are identified: biotite-muscovite-albite zone, graphic zone, layered tourmaline-albite zone, beryl-albite zone, spodumene-beryl-albite zone, and spodumene-albite zone. In this article, we present U-Pb zircon ages, Hf isotope dating, whole-rock geochemistry, and mineral geochemistry to elucidate pegmatite evolution. The zircon U-Pb ages of the spodumene-bearing pegmatite are 258.1 ± 1.4 Ma and 219.6 ± 6.3 Ma, indicate that the magma experienced two stage crystallization. The negative εHf(t) values range from −14.55 to −9.4 with T_2DM model ages of 1845–2173 Ma, indicate that the magma originated from ancient rocks anatexis. The first anatectic event occurred during the Paleo-Tethys Ocean subduction process, as the magma originated from the anatexis of ancient metasedimentary rocks, provided enough rare elements (Li, Be, Nb, Ta). However, the second anatectic event occurred during post-orogenic stage and intruded in the host rocks forming pegmatite veins in the Late Triassic. Subsequently, intruded magma experienced mild fractionated crystallization, melt-fluid immiscibility and subsequent metasomatism, forming the vertical zonings.

近年来，柴北地区（NQT）新发现稀有金属成矿带，其中茶卡北山（CKBS）锂铍伟晶岩矿床是重要组成部分。本研究对CKBS伟晶岩应用CMS（化学成分-矿物组合-构造地质）分类，根据其CMS特征，将岩石确定为伟晶岩类型。CKBS伟晶岩具有独特的内部垂直分带特征，确定了6个带：黑云母-白云母-钠长石带、图形带、层状电气石-钠长石带、绿柱石-钠长石带、锂辉石-绿柱石-钠长石带和锂辉石-钠长石带。在本文中，我们介绍了 U-Pb 锆石年龄、Hf 同位素测年、全岩地球化学和矿物地球化学，以阐明伟晶岩的演化。含锂辉石伟晶岩的锆石U-Pb年龄分别为258.1±1.4 Ma和219.6±6.3 Ma，表明岩浆经历了两期结晶。负 εHf(t) 值范围为 -14.55 至 -9.4，T_2DM模型年龄为 1845-2173 Ma，表明岩浆起源于古岩石深熔。第一次深熔事件发生在古特提斯洋俯冲过程中，岩浆来源于古变沉积岩的深熔，提供了足够的稀有元素（Li、Be、Nb、Ta）。然而，第二次深熔事件发生在造山后阶段，并在晚三叠世侵入主岩形成伟晶岩脉。随后，侵入岩浆经历温和的分异结晶、熔液不混溶和随后的交代作用，形成垂直分带。