摘要
为了解江南造山带东北缘唐舍复式岩体成岩序列、岩石成因和找矿前景,采用区域地质填图、LA-ICP-MS锆石U-Pb定年和全岩地球化学特征分析等方法进行研究。野外地质接触关系厘定唐舍复式岩体的成岩序列为中粒二长花岗岩、中粗粒正长花岗岩、粗中粒斑状正长花岗岩和细粒正长花岗岩,锆石U-Pb年代学显示成岩时代分别为(140.4±3.3)、(131.7±3.2)、(132.2±1.6)和(125.0±2.0)Ma。各类岩石均具有高Si、富碱、低P、低Ti的特征,为准铝质—弱过铝质、高钾钙碱系列的I型花岗岩;岩石的轻、重稀土元素分异程度较强,球粒陨石标准化稀土元素配分模式右倾,富集Rb、Th、U、K等,亏损Ba、Nb、Ta、Sr、P、Ti等,呈中等—强负Eu异常。总体上,唐舍复式岩体从早到晚岩浆演化具有SiO_(2)含量、K_(2)O含量、K_(2)O/Na_(2)O值、A/CNK值逐渐增高,TiO_(2)、Al_(2)O_(3)、TFeO、MgO、CaO、P_(2)O_(5)含量逐渐降低,负Eu异常逐渐增强,分异程度逐渐增高的趋势,为古太平洋板块俯冲-碰撞造山后陆内拉张环境下的下地壳物质重融,经结晶分异作用沿唐舍背斜构造侵位的产物。唐舍复式岩体侵入接触带由内向外矿化类型及矿种具有钨→银铅锌→锑/萤石的分带性,形成了一个矽卡岩型-热液脉型矿化系统,具有较好的找矿前景。
In order to understand the diagenetic sequence,petrogenesis and prospecting prospect of Tangshe complex pluton in the northeastern margin of Jiangnan orogenic belt,the regional geological mapping,LA-ICP-MS zircon U-Pb age,and all-rock geochemical analysis were studied.According to the geological contact relationship,the diagenetic sequence of Tangshe complex pluton from early to late is determined as medium grained monzonitic granite,medium-coarse grained syenogranite,coarse-medium grained porphyritic syenogranite and fine grained syenogranite,respectively,and the diagenetic ages are(140.4±3.3),(131.7±3.2),(132.2±1.6),and(125.0±2.0)Ma.The rocks have the characteristics of high Si and alkali,low P and Ti,being metaluminum-weak peraluminous and high-K calc-alkaline series,which belong to I-type granites.In addition,the light and heavy rare earth elements are highly differentiated,and the chrondrite-normalized REE pattern leans to right with the enrichment of Rb,Th,U,and K,the depletion of Ba,Nb,Ta,Sr,P,and Ti,and the medium-strong negative Eu anomaly.Generally,the magmatic evolution from early to late shows that the contents of SiO_(2) and K_(2)O,the ratio of K_(2)O/Na_(2)O,and A/CNK gradually increase,the contents of TiO_(2),Al_(2)O_(3),TFeO,MgO,CaO,P_(2)O_(5) gradually decrease,negative Eu anomaly gradually increases,and the degree of differentiation gradually increases.Tangshe complex pluton is the product of anticline tectonic emplacement after crystal-separation of the remelting of lower crustal material in the inland tension environment after the subduction-collision orogenic of paleo-Pacific plate.Types of mineralization and minerals in the contact zone of Tangshe complex pluton are characterized by W→Ag-Pb-Zn→Sb/fluorite zoning from inside to outside,which form a skarn-hydrothermal vein-type mineralization system with a good prospecting prospect.
作者
张建芳
蔡晓亮
龚瑞君
刘远栋
王振
刘风龙
汪隆武
ZHANG Jian-fang;CAI Xiao-liang;GONG Rui-jun;LIU Yuan-dong;WANG Zhen;LIU Feng-long;WANG Long-wu(Zhejiang Institute of Geological Survey,Hangzhou 311203,Zhejiang,China)
出处
《地球科学与环境学报》
CAS
北大核心
2021年第4期643-660,共18页
Journal of Earth Sciences and Environment
基金
浙江省级地质专项资金项目([省资]2018006,[省资]2020005)
中国地质调查局地质调查项目(1212011220527,12120115030001)。
