广西佛子冲矿田二长花岗斑岩的年代学、地球化学特征及其意义

发布时间：2018-05-07 03:29

本文选题：佛子冲矿田 + 二长花岗斑岩　；参考：《吉林大学学报(地球科学版)》2017年03期

【摘要】：佛子冲铅锌矿田位于广西岑溪市诚谏镇境内,从北向南主要由古益、河三、龙湾3个铅锌矿床组成。矿田内发育有三期花岗质侵入岩及两期火山岩,其中二长花岗斑岩与成矿关系密切,是本文研究的重点。通过对二长花岗斑岩的野外地质、岩相学、地球化学特征的研究,结合矿田内控岩控矿构造的研究,探讨二长花岗斑岩的成因,确定佛子冲铅锌矿的成矿地质体及成矿构造。利用LA-ICP-MS对采自古益、河三、龙湾的二长花岗斑岩进行锆石U-Pb定年,获得加权平均年龄分别为(105.1±1.7)、(105.2±0.5)、(104.2±1.5)Ma。主量元素成分显示,二长花岗斑岩为准铝—弱过铝高钾钙碱性I型花岗岩。球粒陨石稀土元素模式图特征显示,轻稀土强烈富集,具有显著的Eu负异常。在微量元素原始地幔标准化蛛网图中,显示强烈的Ti、P负异常和Pb的正异常。主微量元素特征显示二长花岗斑岩起源于地壳,并经历了同化混染和分离结晶作用(ACF)过程。二长花岗斑岩的εSr(t)为78.98~162.66、εNd(t)为-10.4~-8.3,亏损地幔模式年龄为1.424~1.672Ga,进一步表明二长花岗斑岩来自中—古元古代基底的部分熔融,进而可能暗示佛子冲矿田与云开古陆具有相同的前寒武纪基底,是云开古陆的组成部分。二长花岗斑岩的空间展布、断裂构造的控岩控矿特征显示,二长花岗斑岩侵位中心位于矿田南部的新塘,向北进行岩墙扩展式侵位,是太平洋板块向欧亚板块俯冲的产物。二长花岗斑岩是龙湾、河三矽卡岩型矿床相关的花岗岩体,也是古益岩浆热液型矿床的成矿地质体,从河三、龙湾的矽卡岩型矿床,到古益岩浆热液充填型矿床,构成了同时同成因的热液矿床系列。
[Abstract]:Fuzichong lead-zinc ore field is located in Chengjian Town, Cengxi City, Guangxi. From north to south, it is mainly composed of three lead-zinc deposits: Guyi, Hesan and Longwan. There are three stages of granitic intrusive rocks and two periods of volcanic rocks in the ore field, among which the second long granitic porphyry is closely related to mineralization, which is the focus of this paper. Based on the study of the field geology, petrography and geochemistry of Erchang granitic porphyry, combined with the study of the ore-controlling structure of the inner control rock in the ore field, the genesis of the Erchang granitic porphyry is discussed, and the ore-forming geological body and ore-forming structure of the Fuzichong lead-zinc deposit are determined. The zircon U-Pb dating of the Erchang granitic porphyry collected from Guyi, Huesan and Longwan has been carried out by using LA-ICP-MS, and the weighted mean ages are 105.1 卤1.7, 105.2 卤0.5, 104.2 卤1.5MaA, respectively. The main element composition shows that the Erchang granitic porphyry is quasi-aluminum-weak peraluminum-high potassium calc-alkaline I-type granite. The REE patterns of chondrites show that LREE are strongly enriched and have significant EU negative anomalies. The trace element primitive mantle-normalized spider webs show strong negative anomalies of tippon P and positive anomalies of Pb. The characteristics of main trace elements show that the Erchang granitic porphyry originated from the crust and experienced assimilation and crystallization (ACFs) process. The 蔚 Sr ~ (t) of Erchang granitic porphyry is 78.98 ~ (162.66), 蔚 Ndnt) is -10.4 ~ (-8.3) and the age of depleted mantle model is 1.424 ~ 1.672Ga, which further indicates that the Erchang granitic porphyry originated from the partial melting of the Meso-Paleoproterozoic basement, which may suggest that the Fozichong ore field has the same Precambrian basement as the Yunkai Paleo-continent, and that the ore-field has the same Precambrian basement as the Yunkai Paleozoic. Is a part of the Yunkai ancient land. The spatial distribution of Erchang granitic porphyry and the ore-controlling characteristics of fault structure show that the emplacement center of Erchang granitic porphyry is located in Xintang in the south of the ore field, and the extended emplacement of rock wall is carried out northward, which is the product of Pacific plate subducting to Eurasian plate. Erchang granitic porphyry is a granite body related to Longwan and he San skarn type deposits, and is also the ore-forming geological body of Guyi magmatic hydrothermal deposits, from skarn type deposits in Hesan and Longwan, to magmatic hydrothermal filling type deposits in Guyi. A series of hydrothermal deposits of the same origin have been formed at the same time.
【作者单位】：桂林理工大学广西矿冶与环境科学实验中心;桂林理工大学广西隐伏金属矿产勘查重点实验室;青海省地质调查院;
【基金】：广西壮族自治区国土资源厅找矿突破战略行动地质矿产勘查项目(桂国土资函[2016]429) 广西自然科学基金项目(2014GXNSFBA118230)~~
【分类号】：P588.13;P618.4

【相似文献】