碧口地块北缘花岗岩脉地球化学特征、成因机制及与金成矿关系探讨

来源 :矿物岩石 | 被引量 : 0次 | 上传用户:dashler
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
碧口地块夹持于秦岭造山带、松潘-甘孜造山带与扬子板块之间,伴随中国大陆印支期造山事件,在其内部及北缘产出有大量花岗岩类侵入体,其中北缘主要为花岗岩脉,由东向西可分为康县月照—琵琶寺、文县联合村—阳山等多个产出密集区,在密集区内先后发现了塘坝、水洞沟、阳山、联合村、甲勿池等多个金矿床,针对琵琶寺、阳山及甲勿池等地的花岗岩脉的地球化学研究表明,它们具有高的w(SiO2)67.65%~74.86%、w(Al2O3)13.68%~19.61%,A/CNK=1.11~5.46,稀土元素总量较低(24.22×10-6~97.26×10-6),LREE富集,HREE亏损,轻重稀土分馏明显(LaN/YbN=3.29~22.40),具有弱负铕异常(δEu=0.70~0.79),微量元素特征表现为大离子亲石元素(LILE)强富集和高场强元素(HFSE)相对亏损。对岩浆源区及成分进行判别发现岩浆源区为下覆的陆壳基底,成分以杂砂岩为主。综合分析认为碧口地块北缘花岗岩脉活动高峰为晚三叠世,属后碰撞构造环境,成因机制与碰撞造山过程中加厚地壳拆沉作用和幔源物质底侵作用密切相关,地壳增厚导致的减压增温和幔源热流的注入诱使中上地壳杂砂岩部分熔融形成花岗质岩浆上侵而形成;同时,碧口地块北缘在早侏罗世(190Ma~195Ma)发生大规模金成矿作用,晚于岩浆活动高峰期近20Ma,成矿流体与岩浆岩极可能共用一个通道,花岗岩脉密集发育区易于成矿流体的聚集从而形成诸如阳山世界级超大型金矿床。 The Bikou massif is sandwiched between the Qinling orogenic belt and the Songpan-Garze orogenic belt and the Yangtze Plate. With the Indosinian orogeny in mainland China, a large number of granite intrusions are produced in the interior and the northern margin. For the granite veins, from east to west can be divided into Kangxian moonlight - Pipa Temple, Wenxian United Village - Yangshan multiple output-intensive areas, in the dense area have been found in Tangba, water ditch, Yangshan, Geochemistry of the granite veins of Pipa Temple, Yangshan and Jiapechi shows that they have high contents of 67.65% -74.86% w (SiO2), w (Al2O3 ) Ranged from 13.68% to 19.61%, with A / CNK ranging from 1.11 to 5.46. The total REE content was relatively low (24.22 × 10-6 ~ 97.26 × 10-6). LREE enrichment, HREE depletion and REE fractionation were obvious (LaN / YbN = 3.29 ~ 22.40) with weak negative europium anomaly (δEu = 0.70 ~ 0.79). The trace elements are characterized by strong enrichment of LILE and relative loss of high field strength element (HFSE). Discrimination of the magma source area and its composition reveals that the magma source area is the underlying continental crust basement, and the composition is mainly composed of miscellaneous sandstone. The comprehensive analysis shows that the granite vein in the northern margin of the Bikou block has a late peak in the Late Triassic and belongs to the post-collision structural environment. The genetic mechanism is closely related to thickened crustal delamination during collision orogeny and to the underplating of mantle-derived materials. The pressure-induced increase of temperature and the influx of mantle source heat induce the formation of granitic magma by partial melting of the middle-upper crustal sandstone. At the same time, the northern margin of the Bikou block formed during the Early Jurassic (190Ma-195Ma) Large-scale gold mineralization occurred later than the peak of magmatic activity in the past 20Ma. It is probable that ore-forming fluids and magmatic rocks share a common channel. Granite vein-dense development zones tend to accumulate ore-forming fluids to form the Yangshan world-class superlarge gold deposit .
其他文献
在市郊农村,由于在原有城乡二元结构基础上嵌入了新的一元——外来移民,产生了原住民(主要是当地农民)与外来移民(主要是流动民工)之间的新二元差别,从而形成了当代中国城乡
本文首次报导江西南昌梅岭地区的鸟类调查及鸟类食性分析材料。介绍了该地区的鸟类种类、分布及食虫鸟的比重和危害鸟类的主要因素,并对鸟类保护提出了意见。 This paper re
在语文课堂教学中恰当地使用信息技术,能为教学增添亮点。信息技术的使用,能优化教学情境,激发学生学习的兴趣,使其迅速进入课文的情境和氛围当中,使语文课堂生动起来。信息
小组合作学习作为课程改革积极倡导的有效学习方式之一,因为它具有使学生优势互补、形成良好人际关系和促进学生个性健全发展的优点。合作学习小组一般以4~6人为宜,强调的是学
“微时政”即短小精悍的时事播报,它既是适应当今“互联网+”背景下快节奏生活的需要,又是新课改理念下提升学生学科核心素养的需要。在长期相关教学实践的基础上,探讨了“微
因数字而战——冲印和打印数字冲印和打印之间的战争已经开始,不过或许它们都不会成为失败者,一个新兴而且潜力巨大的市场会让所有顺应市场变化的人受益。过去的一年里,数字相机
目的探讨基质金属蛋白酶1(matrixmetalloproteinase1,MMP1)及其抑制剂金属蛋白酶组织抑制因子1(tissueinhibitorofmetalloproteinase1,TIMP1)和影响两者作用的转化生长因子β
以CuCl2.2H2O为铜源,InCl3为铟源,硫脲(Tu)为硫源,分别以N,N二甲基甲酰胺(N,N-dimethylformamide,DMF)、乙二醇、乙醇、聚乙二醇-300为溶剂在200℃下反应12h合成花状CuInS2微
自从1999年话题作文诞生以来,这种题材已成为近年来作文的一种重要写作形式。言为心声、率性而为、展现自我、体现个性的写作形式,深受广大学生的喜爱。但如何指导学生在有限
今天,天气晴朗,野兔明明起了个大早,准备去地里收自己种的大西瓜.rn“哇!好大的西瓜啊!”它不敢相信这个大西瓜是自己地里长的,心想,不是做梦吧.接着它拧了一下自己的胳膊,疼