亲爱的研友该休息了!由于当前在线用户较少,发布求助请尽量完整地填写文献信息,科研通机器人24小时在线,伴您度过漫漫科研夜!身体可是革命的本钱,早点休息,好梦!

A Reevaluation of the Timing and Temperature of Copper and Molybdenum Precipitation in Porphyry Deposits

石英 地质学 斑岩铜矿 地球化学 流体包裹体 岩相学 围岩 辉钼矿 静脉 硅酸盐 矿物学 冶金 化学 材料科学 古生物学 有机化学 精神科 心理学
作者
F. Cernuschi,John H. Dilles,Jaime Osório,John M. Proffett,Kalin Kouzmanov
出处
期刊:Economic geology and the bulletin of the Society of Economic Geologists [Society of Economic Geologists]
卷期号:118 (5): 931-902 被引量:11
标识
DOI:10.5382/econgeo.5032
摘要

Abstract The timing and temperature at which copper-iron and molybdenum sulfide deposition occurs in porphyry deposits remain controversial. Petrologic estimates indicate that veins and wall-rock alteration zones containing copper-iron sulfides form in a wide temperature range from ~350° to 650°C. Most sulfides are hosted in potassium(K)-silicate–altered rock and quartz A veins or in early-halo alteration selvages formed above ~450°C. In contrast, cathodoluminescence (CL) imaging of A veins indicates that copper-iron sulfides are contained within a primary lucent (bright and gray)-CL quartz and are crosscut by microfractures filled with younger dull (dark and medium-gray)-CL quartz in direct contact with copper-iron sulfides. These observations have been interpreted as supporting late copper-iron sulfide introduction together with dull-CL quartz at moderate temperatures of ~300° to 450°C, based on fluid inclusion estimates. We provide new CL, QEMSCAN, and petrographic data and images of vein quartz as well as petrologic data of altered wall rock from Haquira East (Peru), Encuentro (Chile), and Batu Hijau (Indonesia) porphyry deposits, which were formed at conditions ranging from deep to shallow (~2–10 km). At all three deposits, dull-CL quartz in microfractures is ubiquitously observed crosscutting all generations of high-temperature lucent-CL quartz veins. Each lucent-CL vein type hosts distinct sulfide populations, crosscuts the others, and coexists in space within the copper and molybdenum ore zones. Within this ore zone, the dull-CL quartz only contains copper-iron sulfides where it transects old A veins and early halos, molybdenite where it transects young molybdenite-bearing quartz veins, and both copper-iron sulfides and molybdenite in younger B veins. Furthermore, where the dull-CL quartz crosscuts igneous or barren (deep) quartz veins, it typically lacks copper and molybdenum. Therefore, dull-CL quartz has no particular spatial or genetic affinity with copper-iron sulfides or molybdenite. We propose that copper was introduced and precipitated at high temperatures in stability with K-silicate alteration. In shallow porphyry deposits, most copper was introduced with lucent-CL quartz in A veins, likely formed via adiabatic decompression from magmatic lithostatic to hydrostatic conditions at ~450° to 600°C. In deep deposits, most copper is introduced with quartz-poor early halos, likely formed at a temperature range similar to that of A veins but during an early stage of retrograde silica solubility. The inferred timing and temperature of copper precipitation are consistent with available solubility experiments for copper-bearing solutions that suggest copper precipitation may start at a high temperature of ~600°C, and ~90% precipitates before it cools down to ~400°C. Much of the molybdenum is introduced and precipitated with discrete pulses of molybdenite-bearing quartz veins that crosscut and postdate copper-bearing A veins and early halos and, to a lesser degree, with B veins that may carry both copper and molybdenum. Whereas molybdenite-bearing and barren (deep) quartz veins form at relatively high temperatures of ~550° to 650°C, copper-molybdenum–bearing B veins likely form at lower temperatures near ~500°C. Copper precipitation and local copper remobilization from older veins and halos continued during the formation of copper-iron sulfide veinlets, named C veins, and during the precipitation of dull-CL quartz following K-silicate alteration. C veins and even younger pyrite-rich D veins may have chlorite or sericite selvages and are composed of dull-CL quartz that formed at ~450° and 300° to 450°C, respectively. Microfractures form through all lucent-CL quartz veins because of the thermal contraction of high-temperature quartz at the onset of sustained cooling after K-silicate alteration has ceased. The fluid that migrated through these microfractures was initially in retrograde silica solubility, which causes dissolution and corrosion of the older lucent-CL quartz. The formation of C veins may overlap in time with the initial stage. At a later stage and temperatures below <450°C, the fluid precipitates dull-CL quartz in microfractures and dissolution zones within older lucent-CL quartz. In copper-iron sulfide-bearing A and B veins and molybdenite-bearing quartz veins, corroded lucent-CL quartz and the younger dull-CL quartz infill can often be observed in contact with older sulfides because quartz sulfide grain boundaries are preexisting discontinuities, and they are preferentially opened during volume contraction. Collectively, these observations and estimates are consistent with silicate phase petrology and numerous observations that most copper-iron sulfides precipitate in K-silicate alteration zones or in early halos with K-feldspar-muscovite-biotite assemblages.

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
欢喜的毛豆完成签到 ,获得积分10
刚刚
白雅颂完成签到 ,获得积分10
6秒前
17秒前
29秒前
29秒前
朝闻道完成签到 ,获得积分10
30秒前
35秒前
CRUSADER发布了新的文献求助10
36秒前
40秒前
平淡如天完成签到,获得积分10
44秒前
Paris发布了新的文献求助10
44秒前
CRUSADER完成签到,获得积分10
48秒前
陶醉的钢笔完成签到 ,获得积分0
50秒前
科研通AI6应助刘显贵采纳,获得10
50秒前
FashionBoy应助赵悦采纳,获得10
1分钟前
坚定的一德完成签到,获得积分20
1分钟前
老实的南风完成签到 ,获得积分10
1分钟前
1分钟前
HaoZhang发布了新的文献求助10
1分钟前
sweetbear发布了新的文献求助10
1分钟前
陈竺完成签到 ,获得积分10
1分钟前
沉默寻凝完成签到,获得积分10
1分钟前
123完成签到,获得积分10
1分钟前
NexusExplorer应助yzkyg采纳,获得10
1分钟前
可爱的函函应助感谢采纳,获得10
1分钟前
慕青应助科研通管家采纳,获得10
1分钟前
科研通AI2S应助科研通管家采纳,获得10
1分钟前
Jasper应助科研通管家采纳,获得50
1分钟前
Wuyt应助科研通管家采纳,获得10
1分钟前
BowieHuang应助科研通管家采纳,获得10
1分钟前
感谢完成签到,获得积分20
1分钟前
1分钟前
1分钟前
感谢发布了新的文献求助10
1分钟前
Biwanbo完成签到 ,获得积分10
1分钟前
我是老大应助个性的电源采纳,获得20
1分钟前
1分钟前
1分钟前
sszxlijin发布了新的文献求助10
1分钟前
2分钟前
高分求助中
(应助此贴封号)【重要!!请各用户(尤其是新用户)详细阅读】【科研通的精品贴汇总】 10000
Theoretical modelling of unbonded flexible pipe cross-sections 3000
List of 1,091 Public Pension Profiles by Region 1581
Encyclopedia of Agriculture and Food Systems Third Edition 1500
Minimizing the Effects of Phase Quantization Errors in an Electronically Scanned Array 1000
Specialist Periodical Reports - Organometallic Chemistry Organometallic Chemistry: Volume 46 1000
Current Trends in Drug Discovery, Development and Delivery (CTD4-2022) 800
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 纳米技术 计算机科学 内科学 化学工程 复合材料 物理化学 基因 遗传学 催化作用 冶金 量子力学 光电子学
热门帖子
关注 科研通微信公众号,转发送积分 5534135
求助须知:如何正确求助?哪些是违规求助? 4622256
关于积分的说明 14582179
捐赠科研通 4562367
什么是DOI,文献DOI怎么找? 2500155
邀请新用户注册赠送积分活动 1479721
关于科研通互助平台的介绍 1450795