岩石学报  2022, Vol. 38 Issue (1): 109-123, doi: 10.18654/1000-0569/2022.01.08   PDF    
斑岩矿床成矿时间尺度的研究进展:以藏东玉龙斑岩铜(钼)矿床为例
陈奇1,2, 王长明1,2, 祝佳萱1,2, 杜斌3, 段泓羽1,2, 石康兴1,2, 钱金龙1,2, 刘俐君1,2     
1. 中国地质大学(北京)地球科学与资源学院,北京 100083;
2. 中国地质大学地质过程与矿产资源国家重点实验室,北京 100083;
3. 有色金属矿产地质调查中心,北京 100012
摘要: 精确限定多期次岩浆-热液活动的时间尺度一直是剖析斑岩矿床形成过程的热点和难点。借助矿物的高精度同位素定年、热力学数值模拟以及石英的钛扩散模型等方法,斑岩矿床中岩浆-热液活动的时间尺度已经被限定在几万年之内。本文以三江特提斯超大型玉龙斑岩铜(钼)矿床为例,重点识别含矿热液脉中普遍存在的石英,利用钛元素的扩散年代学方法,精确限定斑岩矿床中多期岩浆-热液流体活动的时间尺度。扩散模型表明玉龙斑岩矿床热液活动的时间尺度为32000~870000年,有力支持了超大型斑岩矿床可以在几万至几十万年甚至更短时间内形成的观点。此外,为避免钛扩散模型产生较大的误差,需要在精确测定石英中钛含量的基础上,结合矿床地质背景或其他实验方法合理地估测温度和压力条件。研究认为,将矿物的高精度同位素定年与元素的扩散年代学相结合,可以在更为精细的尺度上完善斑岩矿床岩浆-热液活动的时间框架。
关键词: 斑岩矿床    时间尺度    扩散模型    玉龙铜(钼)矿床    
Advances in research of the time scales of porphyry deposits: A case study of the Yulong porphyry Cu-Mo deposit in the eastern Tibet
CHEN Qi1,2, WANG ChangMing1,2, ZHU JiaXuan1,2, DU Bin3, DUAN HongYu1,2, SHI KangXing1,2, QIAN JinLong1,2, LIU LiJun1,2     
1. School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China;
2. State Key laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China;
3. China Non-ferrous Metals Resource Geological Survey, Beijing 100012, China
Abstract: Accurate determination of the time scales of multiple magmatic-hydrothermal pulses is a critical and difficult problem that could provide key information needed to better constrain the genesis of porphyry deposits. Recent high-resolution dating, diffusion chronometry in quartz, and numerical modeling of thermal processes have revealed that the time scales of individual ore deposition cycles may be constrained in tens of thousands of years. Taking the giant Yulong porphyry Cu-Mo deposit in Sanjiang Tethys metallogenic belt as an example, this study focuses on the ubiquitous quartz in hydrothermal veins through the titanium diffusion chronology to accurately determine time scales of multistage magma-related hydrothermal events in the porphyry deposit. Diffusion modeling for different quartz generations indicates that the time scale of hydrothermal pulses in the Yulong deposit can form in a short period of 70000 to 900000 years. These findings provide strong support that giant porphyry deposits can be formed in tens of thousands to hundreds of thousands of years or even less. Based on accurately determining titanium contents in quartz, in order to avoid tricky errors, the diffusion modeling needs to reasonably estimate the temperature and pressure combined with the geological background or other experimental methods to avoid errors. This study suggests that the combination of high precision dating and diffusion chronology models can further constrain the time frame of magmatic-hydrothermal events in porphyry deposits.
Key words: Porphyry deposits    Time scales    Diffusion model    Yulong Cu-Mo deposit    

斑岩矿床是世界上最重要的岩浆-热液矿床之一,常产出于与板片俯冲密切相关的岛弧和大陆边缘弧环境(Sillitoe, 1972, 2010; Richards, 2003; Cooke et al., 2005, 2014; Wilkinson, 2013; 陈华勇和吴超, 2020),以及与非俯冲有关的陆内环境和陆陆碰撞环境(侯增谦和杨志明, 2009; Hou and Cook, 2009; Hou et al., 2015; Yang et al., 2015, 2016; Wang et al., 2017, 2018c; Deng et al., 2018a; Zheng et al., 2019; 侯增谦等, 2020)。典型的斑岩矿床主要是由位于中-上地壳的岩浆房(通常≥100km3)释放大量热液(通常≥10km3Richards, 2003, 2011),岩浆热能驱动的岩浆-热液流体在上地壳发生超常元素富集,从而形成具有经济价值的斑岩矿床(Sillitoe, 2010)。成矿过程的持续时间是控制超大型斑岩矿床形成的重要因素(Chelle-Michou et al., 2017; Chiaradia and Caricchi, 2017; Richards, 2018; Korges et al., 2020)。然而,对于斑岩成矿系统的多期次岩浆-热液活动,仍缺少详细而精确的时间尺度来限定这些过程。

斑岩矿床的矿化事件最终会导致金属矿物和脉石矿物直接从热液中沉淀,或通过流体-岩石反应代替先前存在的矿物相(Chiaradia et al., 2014)。与成矿作用有关的矿石和脉石矿物在各个矿化阶段普遍存在,这就为确定斑岩系统中岩浆-热液活动的持续时间提供了最直接的测试对象。精细和准确地限定斑岩成矿系统中岩浆-热液活动的持续时间一直是矿床学研究的热点和难点(Chelle-Michou et al., 2015)。借助于传统的原位锆石U-Pb定年(LA-ICP-MS或SHRIMP)和辉钼矿Re-Os等时线定年(ICP-MS),一些斑岩矿床成矿的持续时间高达几个甚至十几个百万年(m.y.; Sillitoe and Mortensen, 2010)。这种“超长”的时间尺度,既可能是岩浆多期次侵入或矿化周期性叠加的结果(Chiaradia et al., 2013);也可能是由于定年方法有限的测试精度(~2%),导致无法获得精确限定成矿作用的时间尺度(von Quadt et al., 2011; Schaltegger et al., 2015; Li et al., 2017)。此外,对于某些短时间快速形成的斑岩矿床(例如在几十万年尺度内),传统的测试精度便无法限定其成矿过程的持续时间。越来越多的研究表明,许多超大型斑岩矿床的金属聚集和沉淀是多期次、周期性的岩浆-热液“脉冲”(pulses)的结果,且单次矿化事件很可能小于一个百万年(Chiaradia et al., 2014; Li et al., 2017)。因此,要解决成矿作用的时间尺度,就需要更为精确的年代学方法。

现今,借助高精度的同位素定年、热力学数值模拟以及石英的钛扩散模型等方法,斑岩矿床中岩浆-热液活动的时间尺度可以被限定在几千年到几十万年之间(Lawley and Selby, 2012; Weis et al., 2012; Mercer et al., 2015)。例如,将石英的钛扩散模型应用于斑岩矿床,岩浆和热液活动的持续时间被限定在几万年的尺度内(Mercer et al., 2015; Cernuschi et al., 2018; Wang et al., 2022; Zhang et al., 2021)。这一模型通常使用恒定的最高初始温度来模拟石英中钛扩散的时间,获得的时间尺度可以代表该温压条件下最短的扩散时间。这些最短的时间尺度为探索斑岩系统中岩浆停留、岩脉注入、热液活动冷却等过程的时间提供了一个起点。

精确限定成矿过程的时间尺度对于更好地理解斑岩矿床的形成和演化具有极其重要意义。本文在回顾斑岩矿床中各种定年方法限定成矿时间尺度的基础上,以三江特提斯成矿带超大型玉龙斑岩铜(钼)矿床为研究对象,构建石英的钛扩散模型以确定岩浆-热液活动的时间尺度,并与矿物的高精度同位素定年对比。本次研究将对限定玉龙矿床多期次岩浆-热液活动以及斑岩矿床成矿过程的时间尺度等内容提供重要的参考。

1 斑岩成矿系统时间尺度的研究进展

通过矿物系统定年建立的年代学框架,进而确定成矿的时代和持续时间,对理解和完善斑岩矿床的成矿模型具有重要意义(Chiaradia et al., 2013, 2014)。目前,斑岩系统中确定成矿过程时间尺度的方法主要包括:(1)通过放射性同位素定年直接测定矿物系统的时间尺度;(2)对与成矿相关的热扩散过程进行数值模拟(Cathles, 1997; Weis et al., 2012; Korges et al., 2020),并结合热年代学方法(Hickey et al., 2014);(3)通过在热液成矿系统中测量流体流速和金属浓度来推断所需的时间(Simmons and Brown, 2006)。

1.1 高精度同位素定年

随着矿物原位微区定年技术的广泛应用,直接测定矿床中代表岩浆-热液活动最早和最新的矿物,就可以从理论上确定斑岩系统的成矿时间(Chiaradia et al., 2014)。常见的矿物年代学应用包括锆石及热液矿物的U-Pb定年、辉钼矿的Re-Os定年以及部分脉石矿物(如黑云母、白云母或绢云母、明矾等)的40Ar/39Ar定年等(Chiaradia et al., 2009; Chelle-Michou et al., 2015; Hart-Madigan et al., 2020)。将不同的定年技术结合在一起,可以限定斑岩系统中从岩浆侵位到低温热液蚀变和剥露过程的时间框架(图 1)。矿物的同位素定年解决斑岩系统中时间尺度的能力,取决于所用方法相对于成矿过程持续时间的可实现精度。如果岩浆-热液活动的持续时间短于定年方法的不确定度,则无法限定成矿的时间尺度。

图 1 斑岩系统中各类同位素定年的封闭温度范围(据Chiaradia et al., 2014修改) Fig. 1 Range of closure temperatures for various geochronometers (modified after Chiaradia et al., 2014)

利用化学磨损-同位素稀释-热电离质谱法(CA-ID-TIMS: Isotope Dilution-Thermal Ionization Mass Spectrometry),锆石U-Pb定年的分析精度和准确度提高了一个数量级,从约±0.4%提高到约±0.1%(Schaltegger et al., 2015)。最新的高精度锆石U-Pb地质年代学研究表明,短时间的斑岩侵位和热液活动常发生在大型岩浆房驱动成矿演化的末期(von Quadt et al., 2011; Chelle-Michou et al., 2015; Buret et al., 2016; Tapster et al., 2016),并且已经能够在万年(~10k.y.)的时间尺度内解析母岩浆在几十万年里停留和结晶的历史(Buret et al., 2016; Tapster et al., 2016; Large et al., 2018; Rottier et al., 2020)。同位素稀释-负热电离质谱法(ID-NTIMS: Isotope Dilution-Negative Thermal Ionization Mass Spectrometric)辉钼矿Re-Os定年凭借其可以直接获得各阶段热液脉的高精度年龄(不确定度 < 0.2%)的特点,成为解析多期矿化事件时间尺度的有力工具(Selby et al., 2007; Lawley and Selby, 2012; Chiaradia et al., 2014; Chang et al., 2017; Li et al., 2017)。通过对智利El Salvador和El Teniente两个超大型斑岩矿床使用高精度辉钼矿Re-Os定年,获得其成矿持续时间分别为0.6m.y.和1.7m.y.,其单次热液矿化的时间尺度可以小于100k.y.(Zimmerman et al., 2014; Spencer et al., 2015)。国内学者也利用该方法成功确定了多个超大型斑岩铜(钼)矿床的时间尺度。例如,Li et al. (2017)通过对西藏超大型驱龙斑岩铜矿使用高精度辉钼矿Re-Os定年,发现矿床在266±13k.y.的成矿时间内,可能至少存在两个短期的A-B-D脉旋回(时间尺度分别为38±11k.y.和59±10k.y.)和一个不完整(B-D脉)旋回。由此表明,周期性的岩浆-热液活动既可以出现于持续时间较长的斑岩矿床(例如几个百万年; Chiaradia et al., 2014),也可以在短期形成的斑岩矿床中循环发生。与大多数斑岩型铜矿不同,Zhao et al. (2021)通过对我国东北超大型岔路口斑岩钼矿的年代学研究发现大部分钼金属发生沉淀的时间尺度小于650k.y.,即单次的、短暂的岩浆-热液活动同样具有形成超大型钼矿的潜力。

目前,已经有研究认为矿物的高精度同位素定年更适合于解决中新世和较年轻矿床中的几十万年尺度的热液事件;而对于较老的斑岩矿床,其定年不确定性增加会使年龄的分辨率变差(Li et al., 2017)。因此,斑岩系统中放射性同位素定年方法的选择需要结合实际情况,谨慎选择和考虑。

1.2 热力学模拟与钛扩散模型

通过对斑岩岩体的冷却速率研究发现,受热力学约束与成矿相关的热液系统的最大寿命仅仅为数万年(Cathles, 1997)。热力学数值模拟还表明,斑岩系统的形成可能发生在5~10万年的范围内(Weis et al., 2012)。从活跃地热系统获得的数据(Simmons and Brown, 2006)以及对年轻热液系统的U-Th不平衡定年也支持了这些模型约束(Grimes et al., 1998)。这些数据表明理论上仅需要几万年就能形成超大型斑岩矿床(Simmons and Brown, 2006)。此外,通过模拟斑岩系统中岩浆的幕式注入和多相流体活动,Korges et al. (2020)认为与斑岩成矿有关的岩浆房是通过岩浆快速、间歇性注入形成的。

基于脉石矿物中流体-岩石平衡的扩散模型可以为各种地质过程的时间尺度提供物理约束,并且已经成为一种可以量化几年至几万年时间尺度的方法(Matthews et al., 2012)。斑岩矿床中广泛分布不同阶段的热液脉体,石英凭借其物理化学性质的稳定性,成为记录岩浆-热液活动的重要载体。前人的研究表明,在高温条件下,斑岩矿床中石英生长结构的阴极发光(CL)亮度与钛元素的浓度密切相关(Rusk et al., 2008)。利用石英中钛的浓度、钛石英温度计(Huang and Audétat, 2012)和钛扩散速率(Cherniak et al., 2007; Jollands et al., 2020)相结合的方法,可以建立石英生长结构与钛浓度梯度的扩散模型。该扩散模型已经成功应用于确定火山系统喷发的时间尺度(Chamberlain et al., 2014; Seitz et al., 2016; Ackerson et al., 2018)和控制变质事件的时间尺度(Spear et al., 2012)。最新的研究显示,基于扩散年代学的钛扩散模型已经作为一种有效的工具应用于斑岩系统,约束成矿事件的持续时间以及不同阶段热液活动的时间尺度(Mercer et al., 2015; Cernuschi et al., 2018; Chen et al., 2021b; Zhang et al., 2021; Wang et al., 2022)。

2 藏东玉龙斑岩铜(钼)矿床应用实例 2.1 矿床地质背景

三江特提斯经历了增生造山到碰撞造山的复杂构造演化过程(邓军等, 2012, 2019; 杜斌等, 2016; 王长明等, 2017; 陈奇等, 2019; Deng et al., 2014, 2021; Wang et al., 2014b, 2018b, 2020; Chen et al., 2021a)。该研究区发育有一系列斑岩-矽卡岩型矿床,前人对其进行了综合分析和研究(邓军等, 2020; 毕献武等, 2019; Wang et al., 2014a, 2018a; Yang et al., 2019)。玉龙斑岩铜矿带位于三江特提斯构造带中部的东羌塘地块,与新生代碰撞造山作用相关(图 2a; Wang et al., 2016)。这条具有重要的研究价值和经济意义成矿带南北延长达300km,东西宽15~30km,分布有多个中型到大型的矿床(图 2b; 唐仁鲤和罗怀松, 1995; Hou et al., 2003)。

图 2 三江特提斯地质构造简图(a, 据Deng et al., 2017, 2018b; Wang et al., 2015a, b绘制)及始新世玉龙斑岩铜矿带地质简图(b, 据Hou et al., 2003绘制) 图b中年龄数据来源:Hou et al., 2003; Jiang et al., 2006; Chang et al., 2017; Huang et al., 2019b; 梁华英等, 2008 Fig. 2 Simplified tectonic framework of the Sanjiang Tethys metallogenic belt and its adjacent areas (a, modified after Deng et al., 2017, 2018b; Wang et al., 2015a, b) and simplified geological map of the Eocene Yulong porphyry Cu belt (b, modified after Hou et al., 2003.) Data sources in Fig. 2b: Hou et al., 2003; Jiang et al., 2006; Liang et al., 2008; Chang et al., 2017; Huang et al., 2019b

玉龙斑岩铜(钼)矿床位于该矿带的北端,蕴藏的Cu金属量超过6.24Mt(@0.62%;杨志明等, 2020; Yang and Cooke, 2019),同时伴生有大量的Mo、Au等金属,是该矿带储量最高、规模最大的矿床。研究区沉积地层以三叠纪碳酸盐岩和碎屑沉积岩为主,并被始新世多期斑岩体侵入(马鸿文, 1990; 唐仁鲤和罗怀松, 1995; Hou et al., 2003; 姜耀辉等, 2006a, b)。岩浆侵入体和矿体均受多条环形断裂和北西向恒星错背斜控制(图 3)。玉龙铜矿的矿化类型主要包括:斑岩侵入体内部的细脉浸染状的石英-黄铁矿-黄铜矿矿化,蚀变角岩带中的黄铁矿-黄铜矿-辉钼矿矿化,以及表生富集带内层状或透镜状的氧化矿化(唐仁鲤和罗怀松, 1995; Hou et al., 2003)。热液蚀变具有呈同心状叠加发育的特征,在斑岩侵入体的深部和中部发育钾硅酸盐蚀变,自内向外逐渐叠加了绢云母和泥化蚀变,外围发育广泛的青磐岩化蚀变(唐仁鲤和罗怀松, 1995; Hou et al., 2003)。

图 3 玉龙斑岩矿床地质图(据Chang et al., 2018绘制) Fig. 3 Geological map of the Yulong deposit (modified after Chang et al., 2018)

玉龙斑岩铜(钼)矿床发育多种类型的含矿热液石英脉(Chang et al., 2017; Sun et al., 2021; 孙茂妤等, 2015)。根据脉体的横切关系、空间分布和矿物组合特征,将这些热液脉划分为三个阶段,即早阶段EB脉(黑云母+石英±钾长石±磁铁矿)和A脉(石英+钾长石±黑云母±辉钼矿±黄铜矿);主成矿阶段B脉(石英+黄铜矿+辉钼矿+黄铁矿±辉铜矿±黝铜矿);以及晚阶段D脉(黄铁矿+石英+黄铜矿±斑铜矿±铜蓝),并伴随有不同类型的热液蚀变(图 4)。根据矿物组合及相互关系,A脉和B脉均可以继续细分为三种不同类型(Chen et al., 2021b)。本文重点对早期成矿阶段(A3脉)和主成矿阶段(B3脉)的含矿热液石英脉进行研究。A3脉切穿早期的EB脉和A1脉(石英-钾长石-黑云母脉),主要由石英、黄铜矿和钾长石组成(图 5a, b);B3脉被晚期D脉(石英-黄铁矿脉)切穿,脉体主要由石英和黄铜矿组成,部分黄铜矿边缘可见辉铜矿(图 5d, e)。这些热液石英在阴极发光(CL)图中均可见亮暗交替的生长环带,且较亮的位置显示出较高的钛含量(图 5c, f),表明石英CL强度与钛含量具有一定的正相关关系。此外,热液金红石与硫化物伴生或单独出现(图 5f),表明热液脉中钛浓度可能处于饱和状态。

图 4 玉龙矿床矿化、脉体类型、斑岩侵入体及热液蚀变关系示意图 Fig. 4 Schematic space-time plot for mineralization, veins, and alteration relative to the intrusive history at Yulong deposit

图 5 玉龙矿床含矿热液石英脉的手标本、镜下以及石英的阴极发光图 (a、b)石英-黄铜矿-黄铁矿(A3)脉切穿早期黑云母(EB)脉和石英-钾长石-黑云母(A1)脉的手标本和透射光照片;(c)A3脉主要由半自形、具有弱振荡分带的石英构成;(d)石英-黄铜矿脉(B3)被晚期黄铁矿-石英脉(D脉)切穿的手标本照片;(e)石英黄铜矿脉(A3)的透射光照片;(f)B3脉石英显示出良好的生长环带且充填黄铜矿. 白色点位为使用EMPA测定的钛元素含量(×10-6).矿物代号:Bt-黑云母;Ccp-黄铜矿;Kfs-钾长石;Py-黄铁矿;Qz-石英;Rt-金红石 Fig. 5 Hand specimen photographs, photomicrographs and CL textures of the hydrothermal quartz veins at Yulong deposit (a, b) early biotite-quartz (EB) veins and quartz-K-feldspar-biotite (A1) veins cut by quartz-K-feldspar-pyrite-chalcopyrite (A3) veins; (c) A3 veins are dominated by subhedral quartz with oscillatory zoning; (d) quartz-chalcopyrite (B3) veins cut by late pyrite-quartz (D) veins; (e) B3 veins shown under plane polarised light; (f) bright-CL euhedral growth zones and filled with chalcopyrite in B3 veins. Representative EMPA analyses are shown with Ti concentrations given in ×10-6 (white font). Abbreviations: Bt-biotite; Ccp-chalcopyrite; Kfs-K-feldspar; Py-pyrite; Qz-quartz; Rt-rutile

前人已对玉龙矿床的岩浆活动和铜钼矿化开展了大量的年代学研究(Hou et al., 2003, 2006; Jiang et al., 2006; Liang et al., 2006; Li et al., 2012; 梁华英等, 2008; 王成辉等, 2009),成岩成矿时代得到很好限定(Chang et al., 2017; Huang et al., 2019b),这些工作为进一步解析斑岩矿床多阶段岩浆-热液过程的时间尺度奠定了坚实基础。

2.2 实验方法及数据处理

扫描电子显微镜-阴极发光技术(SEM-CL)揭示了石英中独特的生长环带结构,这些结构受控于矿物生长过程中压力、温度以及元素扩散速率的影响(Landtwing and Pettke, 2005; Rusk et al., 2006; Frelinger et al., 2015; Yuguchi et al., 2020)。已有研究表明,在高温条件下(>400℃),热液石英中具有亮暗交替特征的环带往往与钛元素的分布具有较强的相关关系(Rusk et al., 2008; Rusk, 2012)。扩散年代学的原理是通过一维空间的扩散模型模拟矿物内相邻环带间元素的剖面变化,以确定与元素成分变化相关的矿物生长所需的时间。石英中相邻的亮暗环带具有不同的钛含量,其交界位置的钛浓度梯度允许对不同石英世代之间的钛扩散进行建模。本次研究使用电子探针分析技术(EMPA)在更精细的尺度上(< 10μm)测定石英中不同阶段生长环带的钛含量。为构建石英生长结构和钛含量的联系,本文采用ImageJ V1.8获取CL图像中石英亮度的灰度值曲线,并以EMPA测定的元素含量来校正相同位置的灰度值,由此得到的灰度曲线量化了相对CL亮度和钛浓度的关系(Mercer et al., 2015)。

实验研究发现,石英中钛的浓度和扩散速率与压力和温度密切相关。随着校正方法的不断改进,地质学家们已经提出了多种适用于不同环境的石英钛温度计(TitaniQ: Thomas et al., 2010; Huang and Audétat, 2012)。在较低的压力条件下(1~10kbar),Huang and Audétat (2012)校准得到更适用于地壳浅部岩浆房或热液环境的石英钛温度计:

(1)

式中T的单位为开尔文(K),P的单位为千巴(kbar),该温度计已经在其他斑岩矿床中得到广泛应用(Mercer and Reed, 2013; Mao et al., 2017; Cernuschi et al., 2018)。斑岩系统的深度和压力估测一直是矿床学领域的研究难点。针对玉龙斑岩矿床的多期次岩浆-热液流体活动,本文采用了多种方法估测其各阶段的压力。根据斑岩体中角闪石的Al地质温度计(Huang et al., 2019a),估测石英斑晶的形成压力为1.5kbar。热液脉中石英的形成压力则参考最新的流体包裹体研究结果(Chang et al., 2018; Sun et al., 2021),早阶段脉体(A3脉)、主成矿脉体(B3脉)分别形成于1.1kbar和0.8kbar(Chen et al., 2021b)。

考虑到斑岩系统中石英生长的温度和压力条件,假设石英中平行于c轴(001)的扩散活化能为273±12kJ/mol,在700~1150℃的温度范围内,Cherniak et al. (2007)通过使用合成石英和天然石英以及TiO2粉末作为钛源的扩散实验,得到了平行于(001)扩散的阿伦尼乌斯关系式:

(2)

式中,R是通用气体常数,T是扩散的起始温度(K),DTi为钛的扩散速率。此外,Jollands et al. (2020)最新的研究使用TiO2和SiO2粉末混合作为钛源,提出了在900~1490℃范围内的钛扩散速率公式。在相同温度和压力条件下,本文发现两种方法计算的扩散速率相差可达二到三个数量级。当处于低压(< 3kbar)、中低温(< 700℃)等类似斑岩系统的条件时,通过Jollands et al. (2020)计算的扩散速率显得不合理的“漫长”(图 6)。相比之下,Cherniak et al. (2007)的钛扩散速率计算结果更适用于热液环境,并已广泛应用于斑岩矿床的研究(Mercer et al., 2015; Cernuschi et al., 2018)。假设石英中钛的扩散模型建立在一个一维的、与浓度无关的半无限介质中的扩散,本文使用Carslaw and Jaeger (1946)Crank (1975)计算扩散时间的方程:

(3)
图 6 不同钛扩散速率的对比及其在典型斑岩矿床的外推结果 Cherniak et al. (2007)Jollands et al. (2020)实验的扩散方向均平行于矿物结晶的c轴 Fig. 6 Comparison of different Ti-in-quartz diffusivities and their extrapolation results in typical porphyry deposits The Ti-in-quartz diffusion experiments of Cherniak et al. (2007) and Jollands et al. (2020) are parallel to the c-axis

式中C表示钛含量不同的两代石英中钛的浓度沿梯度分布;cmincmax是最小和最大钛含量(×10-6);x是扩散起始到扩散边缘的距离(μm);t是扩散时间(s);D是石英中钛的扩散速率(m2/s,公式2)。其中,钛扩散速率的选择是基于最高的温度估计(Mercer et al., 2015)。使用EXCEL的互补误差函数确定方程(3)的最佳拟合解,该函数使用最小二乘法解决非线性数据拟合问题,以确定大多数扩散边界的最佳拟合时间。最后,使用卡方检验(χ2)来确定扩散模型中最佳的拟合时间尺度,避免了由于主观的视觉判断造成的人为误差(Borradaile, 2003)。

2.3 数据结果及分析

利用钛扩散模型,本文选取了矿床早阶段(A2脉)和主成矿阶段(B3脉)中石英的典型结构,确定热液活动的时间尺度。对石英CL图中亮暗交替或变化明显的位置进行EMPA分析(图 7a图 8a表 1),并在同一位置使用ImageJ获取灰度值。对于每次线分析,细灰虚线表示原始的使用钛含量校正的灰度值,粗灰线表示使用ImageJ中“平滑”(smooth)处理后的灰度值(图 7b图 8b)。石英中钛的扩散模拟以校准后的粗灰线为拟合对象,忽略了原始灰度曲线的细微干扰。粗黑色曲线及其对应的时间尺度表示每个扩散曲线的最佳拟合结果,边界模拟以浅灰色细线表示,时间尺度以年为单位(图 7c图 8c)。

图 7 玉龙矿床热液脉(A3脉)中石英的钛扩散模拟图 Fig. 7 Examples of modeling Ti diffusion in quartz from A3 veins (0905B7) ar Yulong deposit

图 8 玉龙矿床热液脉(B3脉)中石英的钛扩散模拟图 Fig. 8 Examples of modeling Ti diffusion in quartz from B3 veins (17-08B10) at Yulong deposit

表 1 热液石英脉的EMPA元素含量(×10-6)及钛温度计的计算结果 Table 1 EMPA of trace elements (×10-6)in hydrothermal quartz veins and calculated Ti-in-Quartz temperatures

钛扩散模拟显示,早阶段(A3脉)热液脉中石英形成、充填和冷却过程所需的时间范围为32000~210000年(图 7);而主成矿阶段(B3脉)的扩散时间与早阶段石英类似,范围为110000~870000年(图 8)。这些时间尺度被解释为从石英边界形成到温度降到有效闭合温度以下(约400℃)发生钛扩散的总时间,也可以代表热液活动中离散的、短暂的加热事件所需时间的总和(Mercer et al., 2015)。通过模拟结果的对比可以发现(表 2),使用钛扩散模型估算的时间尺度常受到钛浓度梯度、扩散速率(或扩散初始温度)以及扩散距离的影响。例如,在相同的扩散速率,相近的钛浓度梯度条件下,扩散时间随扩散距离的增加而增加(A3脉:A和B);当扩散距离相同,钛浓度梯度相近时,扩散时间往往又与扩散速率或扩散起始温度呈正相关(B3脉:A和C;B和D)。在其他条件相似时,钛浓度梯度的增加往往会使扩散时间增长(A3脉:A和D)。

表 2 玉龙斑岩铜(钼)矿床不同类型热液石英脉(A3脉和B3脉)的时间尺度 Table 2 Time scales of hydrothermal quartz veins (A3 and B3 veins) in Yulong porphyry Cu (Mo) deposit

Chang et al. (2017)通过对不同阶段的脉体使用的高精度辉钼矿Re-Os定年(ID-NTIMS),发现玉龙斑岩铜(钼)矿床的成矿过程总体持续时间长达约5.1m.y.,但铜钼矿化集中发生在约1.3m.y.范围内,其中约80%的铜沉淀和富集在约820000年的时间尺度内。这一结果与使用扩散模型确定的最长时间尺度类似,即在几十万年的尺度范围内。此外,使用钛扩散模型可以将时间尺度最短限定在几万年内(如A3脉中D点:32000年)。由此表明,玉龙斑岩铜(钼)矿床热液活动的时间尺度可以被限定在几万年至几十万年内。

2.4 斑岩矿床时间尺度的约束

最新的研究显示,石英的钛扩散模型逐渐成为约束斑岩系统成矿持续时间以及不同阶段热液活动时间尺度有效方法。例如,Cernuschi et al. (2018)使用钛扩散模型成功估测了秘鲁Haquira East斑岩矿床最大岩浆-热液活动持续时间为170000年,并认为矿石可以在不到35000年的时期内发生快速地沉淀。Mercer et al. (2015)则使用该方法限定了美国Butte斑岩矿床的时间尺度,认为斑岩岩浆停留和石英晶体形成的时间尺度为50~6000年,而各期次热液石英脉形成和冷却的时间尺度为10~60000年。因此,利用石英中的钛扩散模型,斑岩矿床中岩浆和热液活动的时间尺度被精确限定在几万年之内。

值得注意的是,与国外具有较短时间尺度(最短可达几百年)的斑岩矿床相比(例如,Butte:Mercer et al., 2015; Haquira East: Cernuschi et al., 2018),玉龙斑岩铜矿则表现出较长的时间尺度。通过分析这些矿床的地质特征发现,Butte和Haquira East矿床往往形成于更大的深度(约8~10km;Mercer et al., 2015; Cernuschi et al., 2018),属于深成斑岩型矿床。这种深度所估测的压力条件会明显大于中浅成的玉龙矿床(深度约2~5km;Chang et al., 2018; Sun et al., 2021),因而会使用更高的起始扩散温度和扩散速率。此外,根据前人的钛扩散实验(Cherniak et al., 2007),Mercer et al. (2015)所外推的钛扩散速率值也发生明显“过高”的偏移。虽然尚不清楚其偏大的原因,但是更快钛扩散速率一定程度上会获得更小的时间尺度。因此,对于钛扩散模型的使用仍需小心谨慎,特别是在精确获得钛含量的基础上,需要结合矿床地质背景或其他实验方法合理估测温度和压力条件。

尽管钛扩散模型不能直接提供斑岩系统成矿过程的绝对时间,但是该模型仍然能够为某一阶段的岩浆-热液活动提供更精确的时间尺度。石英钛扩散模型的广泛使用,使我们能够从矿物的细微结构入手,基于不同阶段或期次的温压条件,来分析岩浆-热液流体活动的时间尺度。同时,精确限定斑岩矿床成矿过程的时间尺度离不开各种方法的协同合作。矿物高精度同位素定年所获得的绝对时间,与使用元素的扩散年代学获得的相对时间结合,可以在更为精细的尺度上完善斑岩矿床岩浆-热液活动的时间框架。

随着人们对斑岩成矿过程的研究程度不断提高,超大型斑岩矿床时间尺度的精度得到明显提升(Schaltegger et al., 2015; Spencer et al., 2015; Cernuschi et al., 2018; Zhao et al., 2021)。整体而言,传统定年方法确定了百万年尺度的成岩成矿持续时间;高精度同位素定年随测试精度的提升而获得几十万年尺度的持续时间;而石英的钛扩散模型从矿物结构的元素扩散年代学角度可以解析几万年甚至更小级别的时间尺度(图 9)。因此,斑岩系统的母岩浆房和成矿过程可能整体经历了百万年尺度的演化,但相对短暂的、几万到几十万年甚至更短时间尺度的岩浆-热液活动对金属超常富集过程具有重要影响(Chang et al., 2017; Li et al., 2017; Zhao et al., 2021)。通过对岩浆成因的矿物学研究也表明,下伏岩浆房的生长受原始岩浆多次幕式注入的影响,每次注入补充的关键成矿物质可以有效地释放到溶出流体中(Li et al., 2018; Zheng et al., 2020),这可能也决定了斑岩矿床的成矿体量。

图 9 超大型斑岩铜-钼矿床的储量与成矿持续时间和时间尺度的对比图 使用石英的钛扩散模型、高精度同位素定年(ID-TIMS辉钼矿Re-Os或锆石U-Pb)以及传统定年方法(LA-ICP-MS锆石U-Pb).数据来源:Sillitoe and Mortensen (2010), von Quadt et al. (2011), Mercer et al. (2015), Spencer et al. (2015), Buret et al. (2016), Chang et al. (2017), Li et al. (2017), Cernuschi et al. (2018), Large et al. (2018), Zhang et al. (2021), Zhao et al. (2021), Wang et al. (2022)以及本文 Fig. 9 The tonnage of selected giant porphyry Cu-Mo deposits versus the duration and time scales of main mineralization processes Age constrained by Ti diffusion model in quartz, high-precision dating (ID-TIMS molybdenite Re-Os or zircon U-Pb), and traditional dating (LA-ICP-MS zircon U-Pb). Data from Sillitoe and Mortensen (2010), von Quadt et al. (2011), Mercer et al. (2015), Spencer et al. (2015), Buret et al. (2016), Chang et al. (2017), Li et al. (2017), Cernuschi et al. (2018), Large et al. (2018), Zhang et al. (2021), Zhao et al. (2021), Wang et al. (2022), and this study
3 结论及展望

超大型斑岩矿床的形成往往与多期次的岩浆-热液成矿事件发生叠加有关。岩浆-热液活动的时间尺度对限定和量化斑岩矿床的形成过程具有重要意义。本文以玉龙超大型斑岩铜(钼)矿床为对象,重点识别和剖析热液脉中普遍存在的石英,利用钛元素的扩散年代学方法,来精确限定斑岩矿床中多期岩浆-热液活动的时间尺度。研究结果显示玉龙矿床中热液活动的时间尺度为32000~870000年,有力支持了超大型斑岩矿床可以在几万至几十万年甚至更短时间内形成的观点,同时也为斑岩矿床成矿时间尺度的研究提供了成功范例。这些短暂的成矿事件可能包括岩浆-热液活动的单次性或周期性补充,从而使金属在较长的成矿期内不断发生富集和沉淀,最终导致超大型斑岩矿床的形成。

目前,使用石英钛扩散模型的案例仍然较少且多集中于超大型斑岩矿床,尚无法确定中小型斑岩矿床的岩浆-热液活动是否也具有类似的矿物生长条件和时间尺度。随着人们对矿床学研究的不断深入,与矿物生长密切相关的元素扩散年代学不仅有助于限定斑岩成矿的时间尺度,而且可尝试和拓展到其他类型矿床的研究。

致谢      论文的完成得益于邓军教授等老师的指导。野外工作期间西藏玉龙铜业股份有限公司刘申态主任给予了大力支持;实验过程中得到了中国地质科学院矿产资源研究所陈振宇研究员和核工业北京地质研究院邓刘敏硕士的大力帮助。两位匿名审稿人提出了宝贵的意见和建议,使文章得以完善。在此一并致以诚挚的谢意。

参考文献
Ackerson MR, Mysen BO, Tailby ND and Watson EB. 2018. Low-temperature crystallization of granites and the implications for crustal magmatism. Nature, 559(7712): 94-97 DOI:10.1038/s41586-018-0264-2
Bi XW, Tang YY, Tao Y, Wang CM, Xu LL, Qi HW, Lan Q and Mu L. 2019. Composite metallogenesis of sediment-hosted Pb-Zn-Ag-Cu base metal deposits in the Sanjiang Collisional Orogen, SW China, and its deep driving mechanisms. Acta Petrologica Sinica, 35(5): 1341-1371 (in Chinese with English abstract) DOI:10.18654/1000-0569/2019.05.03
Borradaile G. 2003. Statistics of Earth Science Data: Their Distribution in Time, Space, and Orientation. Berlin, Heidelberg: Springer
Buret Y, von Quadt A, Heinrich C, Selby D, Wälle M and Peytcheva I. 2016. From a long-lived upper-crustal magma chamber to rapid porphyry copper emplacement: Reading the geochemistry of zircon crystals at Bajo de la Alumbrera (NW Argentina). Earth and Planetary Science Letters, 450: 120-131 DOI:10.1016/j.epsl.2016.06.017
Carslaw HS and Jaeger JC. 1946. Linear Flow of Heat: The Infinite and Semi-Infinite Solid, Conduction of Heat in Solids. London: Oxford University Press
Cathles LM. 1997. Thermal aspects of ore formation. In: Barnes HL (ed. ). Geochemistry of Hydrothermal Ore Deposits. New York: John Wiley and Sons, 191-227
Cernuschi F, Dilles JH, Grocke SB, Valley JW, Kitajima K and Tepley Ⅲ FJ. 2018. Rapid formation of porphyry copper deposits evidenced by diffusion of oxygen and titanium in quartz. Geology, 46(7): 611-614 DOI:10.1130/G40262.1
Chamberlain KJ, Morgan DJ and Wilson CJN. 2014. Timescales of mixing and mobilisation in the Bishop Tuff magma body: Perspectives from diffusion chronometry. Contributions to Mineralogy and Petrology, 168(1): 1034 DOI:10.1007/s00410-014-1034-2
Chang J, Li JW, Selby D, Liu JC and Deng XD. 2017. Geological and chronological constraints on the long-lived Eocene Yulong porphyry Cu-Mo deposit, eastern Tibet: Implications for the lifespan of giant porphyry Cu deposits. Economic Geology, 112(7): 1719-1746 DOI:10.5382/econgeo.2017.4527
Chang J, Li JW and Audétat A. 2018. Formation and evolution of multistage magmatic-hydrothermal fluids at the Yulong porphyry Cu-Mo deposit, eastern Tibet: Insights from LA-ICP-MS analysis of fluid inclusions. Geochimica et Cosmochimica Acta, 232: 181-205 DOI:10.1016/j.gca.2018.04.009
Chelle-Michou C, Chiaradia M, Selby D, Ovtcharova M and Spikings RA. 2015. High-resolution geochronology of the Coroccohuayco porphyry-skarn deposit, Peru: A rapid product of the Incaic Orogeny. Economic Geology, 110(2): 423-443 DOI:10.2113/econgeo.110.2.423
Chelle-Michou C, Rottier B, Caricchi L and Simpson G. 2017. Tempo of magma degassing and the genesis of porphyry copper deposits. Scientific Reports, 7: 40566 DOI:10.1038/srep40566
Chen HY and Wu C. 2020. Metallogenesis and major challenges of porphyry copper systems above subduction zones. Science China (Earth Sciences), 63(7): 899-918 DOI:10.1007/s11430-019-9595-8
Chen Q, Wang CM, Du B, He ZC, Zhu JX, Yang LF and Shi KX. 2019. Zircon LA-ICP-MS U-Pb dating and geochemistry of the Jitang metamorphic complex in eastern Tibet and their geological implications. Acta Petrologica Sinica, 35(5): 1423-1446 (in Chinese with English abstract) DOI:10.18654/1000-0569/2019.05.07
Chen Q, Wang CM, Bagas L, Du B, Shi KX, Yang LF, Zhu JX and Duan HY. 2021a. Petrogenesis of the Late Triassic Biluoxueshan granitic pluton, SW China: Implications for the tectonic evolution of the Paleo-Tethys Sanjiang Orogen. Journal of Asian Earth Sciences, 211: 104700 DOI:10.1016/j.jseaes.2021.104700
Chen Q, Wang CM, Bagas L, Zhang ZC and Du B. 2021b. Time scales of multistage magma-related hydrothermal fluids at the giant Yulong porphyry Cu-Mo deposit in eastern Tibet: Insights from titanium diffusion in quartz. Ore Geology Reviews, 139: 104459 DOI:10.1016/j.oregeorev.2021.104459
Cherniak DJ, Watson EB and Wark DA. 2007. Ti diffusion in quartz. Chemical Geology, 236(1-2): 65-74 DOI:10.1016/j.chemgeo.2006.09.001
Chiaradia M, Vallance J, Fontboté L, Stein H, Schaltegger U, Coder J, Richards J, Villeneuve M and Gendall I. 2009. U-Pb, Re-Os, and 40Ar/39Ar geochronology of the Nambija Au-skarn and Pangui porphyry Cu deposits, Ecuador: Implications for the Jurassic metallogenic belt of the northern Andes. Mineralium Deposita, 44(4): 371-387 DOI:10.1007/s00126-008-0210-6
Chiaradia M, Schaltegger U, Spikings R, Wotzlaw JF and Ovtcharova M. 2013. How accurately can we date the duration of magmatic-hydrothermal events in porphyry systems? An invited paper. Economic Geology, 108(4): 565-584 DOI:10.2113/econgeo.108.4.565
Chiaradia M, Schaltegger U and Spikings R. 2014. Time scales of mineral systems: Advances in understanding over the past decade. In: Kelley KD and Golden HC (eds. ). Building Exploration Capability for the 21st Century. Littleton: Society of Economic Geologists, 37-58
Chiaradia M and Caricchi L. 2017. Stochastic modelling of deep magmatic controls on porphyry copper deposit endowment. Scientific Reports, 7: 44523 DOI:10.1038/srep44523
Cooke DR, Hollings P and Walshe JL. 2005. Giant porphyry deposits: Characteristics, distribution, and tectonic controls. Economic Geology, 100(5): 801-818 DOI:10.2113/gsecongeo.100.5.801
Cooke DR, Hollings P, Wilkinson JJ and Tosdal RM. 2014. Geochemistry of porphyry deposits. Treatise on Geochemistry (Second Edition), 13: 357-381
Crank J. 1975. The Mathematics of Diffusion. 2nd Edition. London: Oxford University Press
Deng J, Wang CM and Li GJ. 2012. Style and process of the superimposed mineralization in the Sanjiang Tethys. Acta Petrologica Sinica, 28(5): 1349-1361 (in Chinese with English abstract)
Deng J, Wang QF, Li GJ, Li CS and Wang CM. 2014. Tethys tectonic evolution and its bearing on the distribution of important mineral deposits in the Sanjiang region, SW China. Gondwana Research, 26(2): 419-437 DOI:10.1016/j.gr.2013.08.002
Deng J, Wang CM, Bagas L, Selvaraja V, Jeon H, Wu B and Yang LF. 2017. Insights into ore genesis of the Jinding Zn-Pb deposit, Yunnan Province, China: Evidence from Zn and in-situ S isotopes. Ore Geology Reviews, 90: 943-957 DOI:10.1016/j.oregeorev.2016.10.036
Deng J, Wang CM, Bagas L, Santosh M and Yao EY. 2018a. Crustal architecture and metallogenesis in the south-eastern North China Craton. Earth-Science Reviews, 182: 251-272 DOI:10.1016/j.earscirev.2018.05.001
Deng J, Wang CM, Zi JW, Xia R and Li Q. 2018b. Constraining subduction-collision processes of the Paleo-Tethys along the Changning-Menglian Suture: New zircon U-Pb ages and Sr-Nd-Pb-Hf-O isotopes of the Lincang Batholith. Gondwana Research, 62: 75-92 DOI:10.1016/j.gr.2017.10.008
Deng J, Wang CM, Li GJ and Zhou DQ. 2019. The theory of composite metallogenic system: Key of recovering metallogenic mystery in the SW Tethys. Acta Petrologica Sinica, 35(5): 1303-1323 (in Chinese with English abstract) DOI:10.18654/1000-0569/2019.05.01
Deng J, Wang QF, Chen FC, Li GJ, Yang LQ, Wang CM, Zhang J, Sun X, Shu QH, He WY, Gao X, Gao L, Liu XF, Zheng YC, Qiu KF, Xue SC and Xu JH. 2020. Further discussion on the Sanjiang Tethyan composite metallogenic system. Earth Science Frontiers, 27(2): 106-136 (in Chinese with English abstract)
Deng J, Wang QF, Gao L, He WY, Yang ZY, Zhang SH, Chang LJ, Li GJ, Sun X and Zhou DQ. 2021. Differential crustal rotation and its control on giant ore clusters along the eastern margin of Tibet. Geology, 49(4): 428-432 DOI:10.1130/G47855.1
Du B, Wang CM, He XY, Yang LF, Chen JY, Shi KX, Luo Z and Xia JS. 2016. Advances in research of bulk-rock Nd and zircon Hf isotopic mappings: Case study of the Sanjiang Tethyan Orogen. Acta Petrologica Sinica, 32(8): 2555-2570 (in Chinese with English abstract)
Frelinger SN, Ledvina MD, Kyle JR and Zhao DG. 2015. Scanning electron microscopy cathodoluminescence of quartz: Principles, techniques and applications in ore geology. Ore Geology Reviews, 65(4): 840-852
Grimes S, Rickard D, Hawkesworth C, van Calsteren P and Browne P. 1998. A U-Th calcite isochron age from an active geothermal field in New Zealand. Journal of Volcanology and Geothermal Research, 81(3-4): 327-333 DOI:10.1016/S0377-0273(98)00005-5
Hart-Madigan L, Wilkinson JJ, Lasalle S and Armstrong RN. 2020. U-Pb dating of hydrothermal titanite resolves multiple phases of propylitic alteration in the Oyu Tolgoi porphyry district, Mongolia. Economic Geology, 115(8): 1605-1618 DOI:10.5382/econgeo.4780
Hickey KA, Barker SLL, Dipple GM, Arehart GB and Donelick RA. 2014. The brevity of hydrothermal fluid flow revealed by thermal halos around giant gold deposits: Implications for Carlin-type gold systems. Economic Geology, 109(5): 1461-1487 DOI:10.2113/econgeo.109.5.1461
Hou ZQ, Ma HW, Zaw K, Zhang YQ, Wang MJ, Wang Z, Pan GT and Tang RL. 2003. The Himalayan Yulong porphyry copper belt: Product of large-scale strike-slip faulting in eastern Tibet. Economic Geology, 98(1): 125-145
Hou ZQ, Zeng PS, Gao YF, Du AD and Fu DM. 2006. Himalayan Cu-Mo-Au mineralization in the eastern Indo-Asian collision zone: Constraints from Re-Os dating of molybdenite. Mineralium Deposita, 41(1): 33-45 DOI:10.1007/s00126-005-0038-2
Hou ZQ and Cook NJ. 2009. Metallogenesis of the Tibetan collisional orogen: A review and introduction to the special issue. Ore Geology Reviews, 36(1-3): 2-24 DOI:10.1016/j.oregeorev.2009.05.001
Hou ZQ and Yang ZM. 2009. Porphyry deposits in continental settings of China: Geological characteristics, magmatic-hydrothermal system, and metallogenic model. Acta Geologica Sinica, 83(12): 1779-1817 (in Chinese with English abstract)
Hou ZQ, Yang ZM, Lu YJ, Kemp A, Zheng YC, Li QY, Tang JX, Yang ZS and Duan LF. 2015. A genetic linkage between subduction- and collision-related porphyry Cu deposits in continental collision zones. Geology, 43(3): 247-250 DOI:10.1130/G36362.1
Hou ZQ, Yang ZM, Wang R and Zheng YC. 2020. Further discussion on porphyry Cu-Mo-Au deposit formation in Chinese mainland. Earth Science Frontiers, 27(2): 20-44 (in Chinese with English abstract)
Huang ML, Bi XW, Hu RZ, Gao JF, Xu LL, Zhu JJ and Shang LB. 2019a. Geochemistry, in-situ Sr-Nd-Hf-O isotopes, and mineralogical constraints on origin and magmatic-hydrothermal evolution of the Yulong porphyry Cu-Mo deposit, Eastern Tibet. Gondwana Research, 76: 98-114 DOI:10.1016/j.gr.2019.05.012
Huang ML, Bi XW, Richards JP, Hu RZ, Xu LL, Gao JF, Zhu JJ and Zhang XC. 2019b. High water contents of magmas and extensive fluid exsolution during the formation of the Yulong porphyry Cu-Mo deposit, eastern Tibet. Journal of Asian Earth Sciences, 176: 168-183 DOI:10.1016/j.jseaes.2019.02.008
Huang RF and Audétat A. 2012. The titanium-in-quartz (TitaniQ) thermobarometer: A critical examination and re-calibration. Geochimica et Cosmochimica Acta, 84: 75-89 DOI:10.1016/j.gca.2012.01.009
Jiang YH, Jiang SY, Ling HF and Dai BZ. 2006. Low-degree melting of a metasomatized lithospheric mantle for the origin of Cenozoic Yulong monzogranite-porphyry, East Tibet: Geochemical and Sr-Nd-Pb-Hf isotopic constraints. Earth and Planetary Science Letters, 241(3-4): 617-633 DOI:10.1016/j.epsl.2005.11.023
Jiang YH, Jiang SY, Ling HF and Dai BZ. 2006a. Petrogenesis of Cu-bearing porphyry associated with continent-continent collisional setting: Evidence from the Yulong porphyry Cu ore-belt, East Tibet. Acta Petrologica Sinica, 22(3): 697-706 (in Chinese with English abstract)
Jiang YH, Jiang SY, Dai BZ and Ling HF. 2006b. Comparison on elemental and isotopic geochemistry of ore-bearing and barren porphyries from the Yulong porphyry Cu deposit, East Tibet. Acta Petrologica Sinica, 22(10): 2561-2566 (in Chinese with English abstract)
Jollands MC, Bloch E and Müntener O. 2020. New Ti-in-quartz diffusivities reconcile natural Ti zoning with time scales and temperatures of upper crustal magma reservoirs. Geology, 48(7): 654-657 DOI:10.1130/G47238.1
Korges M, Weis P and Andersen C. 2020. The role of incremental magma chamber growth on ore formation in porphyry copper systems. Earth and Planetary Science Letters, 552: 116584 DOI:10.1016/j.epsl.2020.116584
Landtwing MR and Pettke T. 2005. Relationships between SEM-cathodoluminescence response and trace-element composition of hydrothermal vein quartz. American Mineralogist, 90(1): 122-131 DOI:10.2138/am.2005.1548
Large SJE, von Quadt A, Wotzlaw JF, Guillong M and Heinrich CA. 2018. Magma evolution leading to porphyry Au-Cu mineralization at the Ok Tedi deposit, Papua New Guinea: Trace element geochemistry and high-precision geochronology of igneous zircon. Economic Geology, 113(1): 39-61 DOI:10.5382/econgeo.2018.4543
Lawley CJM and Selby D. 2012. Re-Os geochronology of quartz-enclosed ultrafine molybdenite: Implications for ore geochronology. Economic Geology, 107(7): 1499-1505 DOI:10.2113/econgeo.107.7.1499
Li JX, Qin KZ, Li GM, Cao MJ, Xiao B, Chen L, Zhao JX, Evans NJ and McInnes BIA. 2012. Petrogenesis and thermal history of the Yulong porphyry copper deposit, eastern Tibet: Insights from U-Pb and U-Th/He dating, and zircon Hf isotope and trace element analysis. Mineralogy and Petrology, 105(3-4): 201-221 DOI:10.1007/s00710-012-0211-0
Li Y, Selby D, Condon D and Tapster S. 2017. Cyclic magmatic-hydrothermal evolution in porphyry systems: High-precision U-Pb and Re-Os geochronology constraints on the Tibetan Qulong porphyry Cu-Mo deposit. Economic Geology, 112(6): 1419-1440 DOI:10.5382/econgeo.2017.4515
Li Y, Li XH, Selby D and Li JW. 2018. Pulsed magmatic fluid release for the formation of porphyry deposits: Tracing fluid evolution in absolute time from the Tibetan Qulong Cu-Mo deposit. Geology, 46(1): 7-10 DOI:10.1130/G39504.1
Liang HY, Campbell IH, Allen C, Sun WD, Liu CQ, Yu HX, Xie YW and Zhang YQ. 2006. Zircon Ce4+/Ce3+ ratios and ages for Yulong ore-bearing porphyries in eastern Tibet. Mineralium Deposita, 41(2): 152-159 DOI:10.1007/s00126-005-0047-1
Liang HY, Mo JH, Sun WD, Yu HX, Zhang YQ and Allen CM. 2008. Study on the duration of the ore-forming system of the Yulong giant porphyry copper deposit in eastern Tibet, China. Acta Petrologica Sinica, 24(10): 2352-2358 (in Chinese with English abstract)
Ma HW. 1990. Granitoid and Mineralization of the Yulong Porphyry Copper Belt in Eastern Tibet. Wuhan: China University of Geosciences Press, 1-158 (in Chinese)
Mao W, Rusk B, Yang FC and Zhang MJ. 2017. Physical and chemical evolution of the Dabaoshan porphyry Mo deposit, South China: Insights from fluid inclusions, cathodoluminescence, and trace elements in quartz. Economic Geology, 112(4): 889-918 DOI:10.2113/econgeo.112.4.889
Matthews NE, Huber C, Pyle DM and Smith VC. 2012. Timescales of magma recharge and reactivation of large silicic systems from Ti diffusion in quartz. Journal of Petrology, 53(7): 1385-1416 DOI:10.1093/petrology/egs020
Mercer CN and Reed MH. 2013. Porphyry Cu-Mo stockwork formation by dynamic, transient hydrothermal pulses: Mineralogic insights from the deposit at Butte, Montana. Economic Geology, 108(6): 1347-1377 DOI:10.2113/econgeo.108.6.1347
Mercer CN, Reed MH and Mercer CM. 2015. Time scales of porphyry Cu deposit formation: Insights from titanium diffusion in quartz. Economic Geology, 110(3): 587-602 DOI:10.2113/econgeo.110.3.587
Richards JP. 2003. Tectono-magmatic precursors for porphyry Cu-(Mo-Au) deposit formation. Economic Geology, 98(8): 1515-1533 DOI:10.2113/gsecongeo.98.8.1515
Richards JP. 2011. Magmatic to hydrothermal metal fluxes in convergent and collided margins. Ore Geology Reviews, 40(1): 1-26 DOI:10.1016/j.oregeorev.2011.05.006
Richards JP. 2018. A shake-up in the porphyry world?. Economic Geology, 113(6): 1225-1233 DOI:10.5382/econgeo.2018.4589
Rottier B, Kouzmanov K, Ovtcharova M, Ulianov A, Wälle M, Selby D and Fontboté L. 2020. Multiple rejuvenation episodes of a silicic magma reservoir at the origin of the large diatreme-dome complex and porphyry-type mineralization events at Cerro de Pasco (Peru). Lithos, 376-377: 105766 DOI:10.1016/j.lithos.2020.105766
Rusk B. 2012. Cathodoluminescent textures and trace elements in hydrothermal quartz. In: Götze J and Möckel R (eds. ). Quartz: Deposits, Mineralogy and Analytics. Berlin, Heidelberg: Springer, 307-329
Rusk BG, Reed MH, Dilles JH and Kent AJR. 2006. Intensity of quartz cathodoluminescence and trace-element content in quartz from the porphyry copper deposit at Butte, Montana. American Mineralogist, 91(8-9): 1300-1312 DOI:10.2138/am.2006.1984
Rusk BG, Lowers HA and Reed MH. 2008. Trace elements in hydrothermal quartz: Relationships to cathodoluminescent textures and insights into vein formation. Geology, 36(7): 547-550 DOI:10.1130/G24580A.1
Schaltegger U, Schmitt AK and Horstwood MSA. 2015. U-Th-Pb zircon geochronology by ID-TIMS, SIMS, and laser ablation ICP-MS: Recipes, interpretations, and opportunities. Chemical Geology, 402: 89-110 DOI:10.1016/j.chemgeo.2015.02.028
Seitz S, Putlitz B, Baumgartner LP, Escrig S, Meibom A and Bouvier AS. 2016. Short magmatic residence times of quartz phenocrysts in Patagonian rhyolites associated with Gondwana breakup. Geology, 44(1): 67-70 DOI:10.1130/G37232.1
Selby D, Creaser RA, Stein HJ, Markey RJ and Hannah JL. 2007. Assessment of the 187Re decay constant by cross calibration of Re-Os molybdenite and U-Pb zircon chronometers in magmatic ore systems. Geochimica et Cosmochimica Acta, 71(8): 1999-2013 DOI:10.1016/j.gca.2007.01.008
Sillitoe RH. 1972. A plate tectonic model for the origin of porphyry copper deposits. Economic Geology, 67(2): 184-197 DOI:10.2113/gsecongeo.67.2.184
Sillitoe RH. 2010. Porphyry copper systems. Economic Geology, 105(1): 3-41 DOI:10.2113/gsecongeo.105.1.3
Sillitoe RH and Mortensen JK. 2010. Longevity of porphyry copper formation at Quellaveco, Peru. Economic Geology, 105(6): 1157-1162 DOI:10.2113/econgeo.105.6.1157
Simmons SF and Brown KL. 2006. Gold in magmatic hydrothermal solutions and the rapid formation of a giant ore deposit. Science, 314(5797): 288-291 DOI:10.1126/science.1132866
Spear FS, Ashley KT, Webb LE and Thomas JB. 2012. Ti diffusion in quartz inclusions: Implications for metamorphic time scales. Contributions to Mineralogy and Petrology, 164(6): 977-986
Spencer ET, Wilkinson JJ, Creaser RA and Seguel J. 2015. The distribution and timing of molybdenite mineralization at the El Teniente Cu-Mo porphyry deposit, Chile. Economic Geology, 110(2): 387-421 DOI:10.2113/econgeo.110.2.387
Sun MY, Qu HC, Li QY, Zhou LM, Yang ZM, Liu ST and Liu YG. 2015. Recognition of the ore-forming porphyry in the Yulong Cu deposit and its geological significance. Acta Petrologica et Mineralogica, 34(4): 493-504 (in Chinese with English abstract)
Sun MY, Monecke T, Reynolds TJ and Yang ZM. 2021. Understanding the evolution of magmatic-hydrothermal systems based on microtextural relationships, fluid inclusion petrography, and quartz solubility constraints: Insights into the formation of the Yulong Cu-Mo porphyry deposit, eastern Tibetan Plateau, China. Mineralium Deposita, 56(5): 823-842 DOI:10.1007/s00126-020-01003-6
Tang RL and Luo HS. 1995. The Geology of Yulong Porphyry Copper (Molybdenum) Ore Belt, Xizang (Tibet). Beijing: Geological Publishing House, 1-320 (in Chinese)
Tapster S, Condon DJ, Naden J, Noble SR, Petterson MG, Roberts NMW, Saunders AD and Smith DJ. 2016. Rapid thermal rejuvenation of high-crystallinity magma linked to porphyry copper deposit formation: Evidence from the Koloula porphyry prospect, Solomon Islands. Earth and Planetary Science Letters, 442: 206-217 DOI:10.1016/j.epsl.2016.02.046
Thomas JB, Bruce Watson E, Spear FS, Shemella PT, Nayak SK and Lanzirotti A. 2010. TitaniQ under pressure: The effect of pressure and temperature on the solubility of Ti in quartz. Contributions to Mineralogy and Petrology, 160(5): 743-759 DOI:10.1007/s00410-010-0505-3
von Quadt A, Erni M, Martinek K, Moll M, Peytcheva I and Heinrich CA. 2011. Zircon crystallization and the lifetimes of ore-forming magmatic-hydrothermal systems. Geology, 39(8): 731-734 DOI:10.1130/G31966.1
Wang CH, Tang JX, Chen JP, Hao JH, Gao YM, Liu YW, Fan T, Zhang QZ, Ying LJ and Chen ZJ. 2009. Chronological research of Yulong copper-molybdenum porphyry deposit. Acta Geologica Sinica, 83(10): 1445-1455 (in Chinese with English abstract)
Wang CM, Zhang D, Wu GG, Santosh M, Zhang J, Xu YG and Zhang YY. 2014a. Geological and isotopic evidence for magmatic-hydrothermal origin of the Ag-Pb-Zn deposits in the Lengshuikeng district, east-central China. Mineralium Deposita, 49(6): 733-749 DOI:10.1007/s00126-014-0521-8
Wang CM, Deng J, Santosh M, Lu YJ, McCuaig TC, Carranza EJM and Wang QF. 2015a. Age and origin of the Bulangshan and Mengsong granitoids and their significance for post-collisional tectonics in the Changning-Menglian Paleo-Tethys Orogen. Journal of Asian Earth Sciences, 113: 656-676 DOI:10.1016/j.jseaes.2015.05.001
Wang CM, Deng J, Lu YJ, Bagas L, Kemp AIS and McCuaig TC. 2015b. Age, nature, and origin of Ordovician Zhibenshan granite from the Baoshan Terrane in the Sanjiang region and its significance for understanding Proto-Tethys evolution. International Geology Review, 57(15): 1922-1939 DOI:10.1080/00206814.2015.1043358
Wang CM, Bagas L, Lu YJ, Santosh M, Du B and McCuaig TC. 2016. Terrane boundary and spatio-temporal distribution of ore deposits in the Sanjiang Tethyan Orogen: Insights from zircon Hf-isotopic mapping. Earth-Science Reviews, 156: 39-65 DOI:10.1016/j.earscirev.2016.02.008
Wang CM, Deng J, Bagas L and Wang Q. 2017. Zircon Hf-isotopic mapping for understanding crustal architecture and metallogenesis in the Eastern Qinling Orogen. Gondwana Research, 50: 293-310 DOI:10.1016/j.gr.2017.04.008
Wang CM, Chen JY, Yang LF, Zhang D, Du B and Shi KX. 2017. Tectonic-fluid-mineral system in the Lanping basin, Sanjiang Tethys. Acta Petrologica Sinica, 33(7): 1957-1977 (in Chinese with English abstract)
Wang CM, Bagas L, Chen JY, Yang LF, Zhang D, Du B and Shi KX. 2018a. The genesis of the Liancheng Cu-Mo deposit in the Lanping Basin of SW China: Constraints from geology, fluid inclusions, and Cu-S-H-O isotopes. Ore Geology Reviews, 92: 113-128 DOI:10.1016/j.oregeorev.2017.11.012
Wang CM, Zhu JX, Bagas L, Chen Q, Zhang ZC, Duan HY and Liu LJ. 2022. Whether short-lived or prolonged duration of multistage combined magmatic and hydrothermal events in the giant Chalukou porphyry Mo deposit, China. Ore Geology Reviews, 140: 104576 DOI:10.1016/j.oregeorev.2021.104576
Wang QF, Deng J, Li CS, Li GJ, Yu L and Qiao L. 2014b. The boundary between the Simao and Yangtze blocks and their locations in Gondwana and Rodinia: Constraints from detrital and inherited zircons. Gondwana Research, 26(2): 438-448 DOI:10.1016/j.gr.2013.10.002
Wang QF, Deng J, Li GJ, Liu JY, Li CS and Ripley EM. 2018b. Geochronological, petrological, and geochemical studies of the Daxueshan magmatic Ni-Cu sulfide deposit in the Tethyan Orogenic Belt, southwest China. Economic Geology, 113(6): 1307-1332 DOI:10.5382/econgeo.2018.4593
Wang QF, Yang L, Xu XJ, Santosh M, Wang YN, Chen FG, Wang RX, Gao L, Liu XF, Yang SJ, Zeng YS, Chen JH, Zhang QZ and Deng J. 2020. Multi-stage tectonics and metallogeny associated with Phanerozoic evolution of the South China Block: A holistic perspective from the Youjiang Basin. Earth-Science Reviews, 211: 103405 DOI:10.1016/j.earscirev.2020.103405
Wang R, Weinberg RF, Collins WJ, Richards JP and Zhu DC. 2018c. Origin of postcollisional magmas and formation of porphyry Cu deposits in southern Tibet. Earth-Science Reviews, 181: 122-143 DOI:10.1016/j.earscirev.2018.02.019
Weis P, Driesner T and Heinrich C. 2012. Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes. Science, 338(6114): 1613-1616 DOI:10.1126/science.1225009
Wilkinson JJ. 2013. Triggers for the formation of porphyry ore deposits in magmatic arcs. Nature Geoscience, 6(11): 917-925 DOI:10.1038/ngeo1940
Yang LF, Wang CM, Bagas L, Du B and Zhang D. 2019. Mesozoic-Cenozoic sedimentary rock records and applications for provenance of sediments and affiliation of the Simao Terrane, SW China. International Geology Review, 61(18): 2291-2312 DOI:10.1080/00206814.2019.1587671
Yang ZM, Lu YJ, Hou ZQ and Chang ZS. 2015. High-Mg diorite from Qulong in southern Tibet: Implications for the genesis of adakite-like intrusions and associated porphyry Cu deposits in collisional orogens. Journal of Petrology, 56(2): 227-254 DOI:10.1093/petrology/egu076
Yang ZM, Goldfarb R and Chang ZS. 2016. Generation of postcollisional porphyry copper deposits in southern Tibet triggered by subduction of the Indian continental plate. In: Richards JP (ed. ). Tectonics and Metallogeny of the Tethyan Orogenic Belt. Littleton: Society of Economic Geologists Special Publication, 279-300
Yang ZM and Cooke DR. 2019. Porphyry copper deposits in China. In: Chang ZS and Goldfarb RJ (eds. ). Mineral Deposits of China. Littleton: Society of Economic Geologists Special Publication, 133-187
Yang ZM, Hou ZQ, Zhou LM and Zhou YW. 2020. Critical elements in porphyry copper deposits of China. Chinese Science Bulletin, 65(33): 3653-3664 (in Chinese) DOI:10.1360/TB-2020-0246
Yuguchi T, Ogita Y, Kato T, Yokota R, Sasao E and Nishiyama T. 2020. Crystallization processes of quartz in a granitic magma: Cathodoluminescence zonation pattern controlled by temperature and titanium diffusivity. Journal of Asian Earth Sciences, 192: 104289 DOI:10.1016/j.jseaes.2020.104289
Zhang Q, Zhang ZC, Cheng ZG, Santosh M, Wang ZC and Jin SK. 2021. Magma volume and timescales in the formation of porphyry molybdenum deposits: A case study from the Central Asian Orogenic Belt. Lithos, 382-383: 105951 DOI:10.1016/j.lithos.2020.105951
Zhao QQ, Zhai DG, Mathur R, Liu JJ, Selby D and Williams-Jones AE. 2021. The giant chalukou porphyry Mo deposit, Northeast China: The product of a short-lived, high flux mineralizing event. Economic Geology, 116(5): 1209-1225 DOI:10.5382/econgeo.4818
Zheng YC, Liu SA, Wu CD, Griffin WL, Li ZQ, Xu B, Yang ZM, Hou ZQ and O'Reilly SY. 2019. Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting. Geology, 47(2): 135-138 DOI:10.1130/G45362.1
Zheng YC, Wang L, Xue CD, Xu B, Ghaffar A, Yang ZS, Lu YJ, Zhou LM, Griffin WL and Hou ZQ. 2020. Porphyry Cu deposits linked to episodic growth of an underlying parental magma chamber. Science China (Earth Sciences), 63(11): 1807-1816 DOI:10.1007/s11430-020-9634-2
Zimmerman A, Stein HJ, Morgan JW, Markey RJ and Watanabe Y. 2014. Re-Os geochronology of the El Salvador porphyry Cu-Mo deposit, Chile: Tracking analytical improvements in accuracy and precision over the past decade. Geochimica et Cosmochimica Acta, 131: 13-32 DOI:10.1016/j.gca.2014.01.016
毕献武, 唐永永, 陶琰, 王长明, 胥磊落, 戚华文, 兰青, 木兰. 2019. 西南三江碰撞造山带沉积岩容矿Pb-Zn-Ag-Cu贱金属复合成矿与深部过程. 岩石学报, 35(5): 1341-1371.
陈华勇, 吴超. 2020. 俯冲带斑岩铜矿系统成矿机理与主要挑战. 中国科学(地球科学), 50(7): 865-886.
陈奇, 王长明, 杜斌, 贺知成, 祝佳萱, 杨立飞, 石康兴. 2019. 藏东吉塘变质杂岩体锆石U-Pb年龄、地球化学特征及其地质意义. 岩石学报, 35(5): 1423-1446.
邓军, 王长明, 李龚健. 2012. 三江特提斯叠加成矿作用样式及过程. 岩石学报, 28(5): 1349-1361.
邓军, 王长明, 李龚健, 周道卿. 2019. 复合成矿系统理论: 揭开西南特提斯成矿之谜的关键. 岩石学报, 35(5): 1303-1323.
邓军, 王庆飞, 陈福川, 李龚健, 杨立强, 王长明, 张静, 孙祥, 舒启海, 和文言, 高雪, 高亮, 刘学飞, 郑远川, 邱昆峰, 薛胜超, 徐佳豪. 2020. 再论三江特提斯复合成矿系统. 地学前缘, 27(2): 106-136.
杜斌, 王长明, 贺昕宇, 杨立飞, 陈晶源, 石康兴, 罗政, 夏锦胜. 2016. 锆石Hf和全岩Nd同位素填图研究进展: 以三江特提斯造山带为例. 岩石学报, 32(8): 2555-2570.
侯增谦, 杨志明. 2009. 中国大陆环境斑岩型矿床: 基本地质特征、岩浆热液系统和成矿概念模型. 地质学报, 83(12): 1779-1817. DOI:10.3321/j.issn:0001-5717.2009.12.002
侯增谦, 杨志明, 王瑞, 郑远川. 2020. 再论中国大陆斑岩Cu-Mo-Au矿床成矿作用. 地学前缘, 27(2): 20-44.
姜耀辉, 蒋少涌, 凌洪飞, 戴宝章. 2006a. 陆-陆碰撞造山环境下含铜斑岩岩石成因——以藏东玉龙斑岩铜矿带为例. 岩石学报, 22(3): 697-706.
姜耀辉, 蒋少涌, 戴宝章, 凌洪飞. 2006b. 玉龙斑岩铜矿含矿与非含矿斑岩元素和同位素地球化学对比研究. 岩石学报, 22(10): 2561-2566.
梁华英, 莫济海, 孙卫东, 喻亨祥, 张玉泉, Allen CM. 2008. 藏东玉龙超大型斑岩铜矿床成岩成矿系统时间跨度分析. 岩石学报, 24(10): 2352-2358.
马鸿文. 1990. 西藏玉龙斑岩铜矿带花岗岩类与成矿. 武汉: 中国地质大学出版社, 1-158.
孙茂妤, 曲焕春, 李秋耘, 周利敏, 杨志明, 刘申态, 刘永刚. 2015. 西藏玉龙铜矿床成矿斑岩的厘定及地质意义. 岩石矿物学杂志, 34(4): 493-504. DOI:10.3969/j.issn.1000-6524.2015.04.004
唐仁鲤, 罗怀松. 1995. 西藏玉龙斑岩铜(钼)矿带地质. 北京: 地质出版社, 1-320.
王成辉, 唐菊兴, 陈建平, 郝金华, 高一鸣, 刘耀文, 凡韬, 章奇志, 应立娟, 陈志皎. 2009. 西藏玉龙铜钼矿同位素年代学研究. 地质学报, 83(10): 1445-1455. DOI:10.3321/j.issn:0001-5717.2009.10.009
王长明, 陈晶源, 杨立飞, 张端, 杜斌, 石康兴. 2017. 三江特提斯兰坪盆地构造-流体-成矿系统. 岩石学报, 33(7): 1957-1977.
杨志明, 侯增谦, 周利敏, 周怿惟. 2020. 中国斑岩铜矿床中的主要关键矿产. 科学通报, 65(33): 3653-3664.