长江中下游晚古生代硅质岩构造背景及其对成矿作用的指示意义浅析
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摘要
安徽狸桥地区发现一套硅质建造,其赋存于黄龙组灰岩与五通组石英砂岩之间,呈层状产出,显微镜下主要由隐晶质石英组成,具角砾结构,未见硅质生物,局部有褐铁矿化、硅化重结晶现象。其地球化学特征显示,硅质岩SiO_2平均含量为97.22%,∑REE含量平均为11.288×10~(-6),δCe平均为0.58,呈负异常,δEu平均为1.49,呈明显的正异常。Al/(Al+Fe+Mn)值平均为0.45,Al_2O_3、TiO_2与SiO_2相关性较弱,而Fe_2O_3与SiO_2呈明显的正相关关系。结合双变量SiO_2-Al2O3,SiO_2-MgO,三变量Al-Fe-Mn,Fe-Mn-(Ni+Co+Cu)×10图解,指示其为热水沉积成因;其δEu、MnO/TiO_2、Fe2O3/TiO_2和Al_2O_3/(Al_2O_3+Fe_2O_3)值分析,反映其沉积于远离陆源的大陆边缘环境,受到强烈的热水活动影响。综上表明:晚石炭世时期,狸桥地区处于受基底深断裂及同沉积断裂控制的二级断陷盆地内,这一发现对于寻找宁芜地区深部喷流-沉积型块状硫化物矿床具有一定的指示意义。
the anhui raccoon dog found a set of siliceous built bridge region, its occurrence in the huanglong limestone and five group between quartz sandstone, brecciated structure, According to its geochemical characteristics, the average content of SiO_2 in siliceous rocks is 97.22%, the average content of sigma REE is 11.288 x 10~(-6), and the average distribution is 0.58, which is a negative anomaly. The average value of Al/(Al+Fe+Mn) is 0.45, Al_2 O_3, TiO_2 has a weak correlation with SiO_2, while Fe_2O_3 has a significant positive correlation with SiO_2. Combining SiO_2-Al_2O_3,SiO_2-MgO, Al-Fe-Mn, Fe-Mn-(Ni+Co+Cu) x 10 diagrams, it indicates that it is the genesis of hot water deposition. The results showed that it was deposited in continental margin environment far from land source and was influenced by strong hot water activity.a finding that for NingWu area deep jet-sedimentary type massive sulfide deposits has a certain instruction significance,
the anhui raccoon dog found a set of siliceous built bridge region, its occurrence in the huanglong limestone and five group between quartz sandstone, brecciated structure, According to its geochemical characteristics, the average content of SiO_2 in siliceous rocks is 97.22%, the average content of sigma REE is 11.288 x 10~(-6), and the average distribution is 0.58, which is a negative anomaly. The average value of Al/(Al+Fe+Mn) is 0.45, Al_2 O_3, TiO_2 has a weak correlation with SiO_2, while Fe_2O_3 has a significant positive correlation with SiO_2. Combining SiO_2-Al_2O_3,SiO_2-MgO, Al-Fe-Mn, Fe-Mn-(Ni+Co+Cu) x 10 diagrams, it indicates that it is the genesis of hot water deposition. The results showed that it was deposited in continental margin environment far from land source and was influenced by strong hot water activity.a finding that for NingWu area deep jet-sedimentary type massive sulfide deposits has a certain instruction significance,
引文
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[3]涂光炽.中国层控矿床地球化学,第三卷[M].科学出版社,1988.
[4]张莹,苏生瑞,于国新,苏忆,李景山.硅质岩单面山路堑边坡稳定性影响因素分析[J].长江科学院院报,2018,35(09):121-126.
[5]张金虎,金春爽,徐立明,王海荣,杨玉茹,邓克,高永进,吴兆剑.福建黄塘晚侏罗世长林组硅质岩地球化学特征及其沉积环境意义[J/OL].地学前缘:1-14
[6]谈昕.四川盆地重庆地区五峰组-龙马溪组硅质岩地球化学特征及地质意义[D].东华理工大学,2018.
[7]计波,王国强,唐卓,朱涛,罗根根.甘肃省肃南县西水地区奥陶纪硅质岩地球化学特征及其形成环境[J].地质科技情报,2018,37(05):21-29.
[8]张连发,廖云峰,徐旭明.新疆精河县中泥盆世汗吉尕组硅质岩成因及环境分析[J].西北地质,2018,51(02):9-17.
[9]游军,张锋军,曹宏远,等.陕西中村-湘河地区下寒武统水沟口组硅质岩地球化学特征及其意义[J].矿产勘查,2018,9(1):12-21.
[10]刘强隆,王迎春,洪托.云南省勐满金矿硅质岩地球化学特征及沉积环境分析[J].昆明理工大学学报(自然科学版),2018,43(02):32-38+50.
[11]徐学员,高超.云南勐满金矿硅质岩特征及其与金矿化关系[J].西部资源,2013(2):179-182.
[12]周贤荣,夏国平,黄世尧.湖北省咸宁地区震旦系老堡组硅质岩成因类型及找矿方向初探[J].西部资源,2011(5):57-58.