Ore precipitation in mineral deposits formed in the upper parts of a porphyry system, at shallow crustal level (< 1.5 km), such as epithermal Au-Ag-(Cu)-(As) and polymetallic deposits is often triggered by fluid cooling and/or mixing between fluids from different sources. Commonly, in such deposits, two main fluid sources are identified a deeply sourced magmatic fluid and a shallow meteoric water stored in a surficial aquifer. Oxygen and hydrogen isotope compositions of gangue and alteration minerals using conventional bulk isotopic methods support the existence of mixing between these two fluid types. However, bulk isotope analysis provides only limited information on the exact mixing mechanisms and on the changing proportions of the involved fluids. Due to their high spatial resolution, SIMS in-situ oxygen isotope and LA-ICP-MS trace element analyses, in transects across growth zones of single crystals are adequate tools to trace the dynamics of this fluid mixing. In this study, in-situ SIMS oxygen isotope and LA-ICP-MS trace element analyses were performed on 10 selected quartz crystals from the giant Cerro de Pasco porphyry-related epithermal polymetallic deposit in central Peru. The results, combined with previous microthermometric and LA-ICP-MS fluid inclusion studies on the same or equivalent crystals, allow quantifying and documenting the mixing between different types of fluids that formed the large Cerro de Pasco epithermal polymetallic deposit. The δ¹⁸O_quartz values range between 4‰ and 20‰ and display variations up to 11.5‰ inside single crystals that cannot be only, nor mainly ascribed to fluid temperature changes. Rather, these variations record variable mixing proportions of a rising moderate-salinity magmatic fluid with a δ¹⁸O_H2O around 10‰ and a low-salinity fluid with a δ¹⁸O_H2O between 0 and 4‰, the latter stored below the paleo-water table. Each analyzed quartz crystals also display important variation of their trace element content, with Al (43 to 2098 ppm), Li (0.7 to 18 ppm), Ge (1.1 to 24ppm) and Ti (0.8 to 10 ppm). These variations do not systematically correlate with oxygen isotope compositions. This suggests that quartz trace element content is controlled by a complex interplay of fluid composition, temperature, pressure, and growth rate. Application of published Ti-in-quartz geothermometers on quartz grains from which the precipitation temperature is well constrained by fluid inclusion microthermometry, shows that it can lead to overestimation or underestimation of precipitation temperatures by more than 50 °C.

The obtained δ¹⁸O_quartz patterns measured along profiles in the studied quartz crystals, and less clearly the in-situ trace element compositions, reveal abrupt changes and suggest that mixing between magmatic and surface-derived low-salinity fluids was not a continuous process. It rather took place through the influx of multiple short-lived pulses of magmatic fluid into the surface-derived low-salinity fluid surface aquifer.

斑岩系统上部浅地层（<1.5 km）上形成的矿床中的矿石沉淀，例如超热Au-Ag-（Cu）-（As）和多金属矿床，通常是由流体冷却和/或触发的或在不同来源的流体之间混合。通常，在这样的矿床中，可以识别出两种主要的流体源，即深层岩浆流体和浅层流水，它们存储在地表含水层中。煤bulk石和蚀变矿物的氧和氢同位素组成使用常规的大体积同位素方法支持了这两种流体类型之间的混合存在。但是，本体同位素分析仅提供了有关确切混合机理以及所涉及流体的变化比例的有限信息。由于其较高的空间分辨率，SIMS原位氧同位素和LA-ICP-MS痕量元素分析（横跨单晶生长区的样带）是追踪这种流体混合动力学的合适工具。在这项研究中，对秘鲁中部Cerro de Pasco斑岩相关超热多金属矿床中的10个选定石英晶体进行了原位SIMS氧同位素和LA-ICP-MS痕量元素分析。将结果与先前对相同或等效晶体的微量热法和LA-ICP-MS流体包裹体研究相结合，可以量化并记录形成大型Cerro de Pasco超热多金属沉积物的不同类型流体之间的混合。δ 在秘鲁中部Cerro de Pasco斑岩相关超热多金属矿床中，从10个选定的石英晶体上进行了原位SIMS氧同位素和LA-ICP-MS痕量元素分析。将结果与先前对相同或等效晶体的微量热法和LA-ICP-MS流体包裹体研究相结合，可以量化并记录形成大型Cerro de Pasco超热多金属沉积物的不同类型流体之间的混合。δ 在秘鲁中部Cerro de Pasco斑岩相关超热多金属矿床中，从10个选定的石英晶体上进行了原位SIMS氧同位素和LA-ICP-MS痕量元素分析。将结果与先前对相同或等效晶体的微量热法和LA-ICP-MS流体包裹体研究相结合，可以量化并记录形成大型Cerro de Pasco超热多金属沉积物的不同类型流体之间的混合。δ 可以量化和记录形成大型Cerro de Pasco超热多金属沉积物的不同类型流体之间的混合。δ 可以量化和记录形成大型Cerro de Pasco超热多金属沉积物的不同类型流体之间的混合。δ¹⁸ O_石英的值在4‰到20‰之间，并且在单晶内部显示的变化高达11.5‰，这不仅是，也不是主要归因于流体温度变化。相反，这些变型记录变量混合上升中等盐度岩浆流体的比例用δ ¹⁸ ö _H2O约10‰和低盐度流体具有δ ¹⁸ ö _H2O在0和4‰之间，后者存储在古地下水位以下。每个分析的石英晶体还显示出痕量元素含量的重要变化，其中Al（43至2098 ppm），Li（0.7至18 ppm），Ge（1.1至24ppm）和Ti（0.8至10 ppm）。这些变化与氧同位素组成没有系统地相关。这表明石英微量元素的含量受流体组成，温度，压力和生长速率之间复杂的相互作用所控制。将已发表的钛制石英地热仪应用于石英颗粒，通过流体夹杂微热法可以很好地控制其沉淀温度，这可能导致对沉淀温度的高估或低估超过50°C。

δ所得到的¹⁸ ö_石英沿着轮廓在所研究的石英晶体测定模式，以及较少清楚原位微量元素组合物中，揭示了突然的变化，并表明岩浆和表面衍生的低盐度流体之间的混合不是一个连续的过程。相反，它是通过将岩浆流体的多个短寿命脉冲涌入地表衍生的低盐度流体表面含水层中而发生的。