The recent discovery of numerous large porphyry Cu deposits in the southern Qinghai-Tibet Plateau shows that porphyry Cu deposits can be hosted in magmatic suites in collisional settings. However, in contrast, only a few small porphyry Cu deposits have so far been discovered in association with collision-related granitoids in the northern Qinghai-Tibet Plateau. This raises questions about the origin of collision-related magmas and their mineralization potential. In this contribution, we comprehensively synthesize whole-rock geochemical and isotopic data on collision-related intrusions from the Qimantagh Metallogenic Belt in the northern Qinghai-Tibet Plateau, which hosts many skarn polymetallic deposits but only a few, small porphyry Cu-Mo deposits. This, combined with newly obtained zircon trace element data, provides a high-quality database that can yield insights on the nature and origin of the magmatic suites as well as their fertility in terms of Cu mineralization. Two volumetrically dominant intrusive suites are identified in the Qimantagh Metallogenic Belt: 435-370 Ma granitoids (Suite I) and 245-196 Ma granitoids (Suite II). They formed during syn- to post-collisional stages of the Caledonian and Hercynian-Indosinian Orogenies, respectively. In contrast, arc magmatic rocks are relatively scarce. Both Suites I and II are characterized by low zircon Ce/Ce* and Eu/Eu* values, low whole-rock Sr/Y and Eu/Eu* values with arc-like features (e.g., depletion of Nb and Ta). Furthermore, both suites display some evolved Sr-Nd-Hf isotopic values (e.g., εNdi = -8.1 to 0.1), with the majority of samples characterized by Paleo- to Meso-Proterozoic two-stage Nd and Hf model ages. These features suggest that the parental magmas of the two suites were probably derived from subduction fluid-modified mantle sources which underwent significant crustal AFC processes during magma ascent. The relative scarcity of arc magmatic rocks and the prevalence of collisional magmatism during the Caledonian and Hercynian-Indosinian Orogenies in the Qimantagh Metallogenic Belt can be explained by pre-collisional, flat-slab subduction and subsequent slab breakoff during collision, the later triggering asthenosphere upwelling and extensive magmatism in collisional settings. Compared to fertile plutons in some large porphyry Cu deposits worldwide, especially those in the Gangdese Metallogenic Belt, the two suites in the Qimantagh Metallogenic Belt have low magmatic oxidation states and low water content which inhibited the formation of large porphyry Cu deposits. Thus, skarn polymetallic deposits (probably as well as small porphyry Cu-Mo deposits) rather than large porphyry Cu deposits should be targeted during future mineral exploration in the northern Qinghai-Tibet Plateau, since such deposits do not necessarily need a parental magma with high oxidation state and water content.

最近在青藏高原南部发现了许多大型斑岩铜矿床，表明斑岩铜矿床可以在碰撞环境的岩浆组中存在。然而，相比之下，迄今为止，在青藏高原北部，仅发现了少量的斑岩铜矿床与碰撞相关的花岗岩类。这引起了与碰撞有关的岩浆的起源及其成矿潜力的疑问。在这项贡献中，我们综合了青藏高原北部奇曼塔格成矿带与碰撞有关的侵入体的全岩地球化学和同位素数据，该地带拥有许多矽卡岩多金属矿床，但只有少量小斑岩型铜钼矿床。结合新获得的锆石微量元素数据，提供了一个高质量的数据库，可以提供有关岩浆组的性质和起源以及其在铜矿化方面的肥力的见解。在奇曼塔格金属成矿带中发现了两个体积上占主导地位的侵入套件：435-370 Ma花岗岩（Suite I）和245-196 Ma花岗岩（Suite II）。它们分别形成于加里东期和海西－印度支那造山运动的碰撞到碰撞后阶段。相反，弧岩浆岩相对稀少。套房I和套房II的特征都是锆石Ce / Ce *和Eu / Eu *值低，全岩Sr / Y和Eu / Eu *值低，具有类似弧的特征（例如，Nb和Ta的消耗）。此外，这两个套件都显示一些演化的Sr-Nd-Hf同位素值（例如εNdi= -8.1至0.1），大多数样品的特征是古到中元古代两阶段Nd和Hf模型年龄。这些特征表明，这两个套件的父母岩浆可能来自俯冲流体修饰的地幔源，这些岩浆在岩浆上升过程中经历了重要的地壳AFC过程。奇曼塔格成矿带古苏格兰和海西-印支期造山运动期间弧岩岩浆的相对稀缺性和碰撞岩浆作用的普遍程度可以用碰撞前的平板俯冲作用和随后的板块破裂解释，随后触发软流圈上升和在碰撞环境中的大量岩浆作用。与世界范围内某些大型斑岩型铜矿床中的肥沃岩体相比，特别是在冈底斯成矿带中，奇曼塔格成矿带中的这两个套件具有较低的岩浆氧化态和较低的含水量，从而抑制了大型斑岩型铜矿床的形成。因此，在青藏高原北部的未来矿产勘探中，应将矽卡岩多金属矿床（可能还有小斑岩型铜钼矿床）而不是大型斑岩型铜矿床作为目标，因为此类矿床不一定需要具有高品位的母岩浆。氧化态和水含量。