尖山混杂岩带由基性-超基性岩、基性火山岩、基性火山碎屑岩及硅质岩组成，各类岩石呈岩片(块)产出。带内硅质岩具富Al2O3、高Fe2O3和低TiO2特征，为含较高比例陆源泥质沉积物(SiO2含量74.71%~83.61%)。Al/(Fe+Mn+Al)=0.72~0.81、U/Th=0.14~0.34，显示生物沉积硅质岩特点。页岩标准化曲线主要为弱 Ce 正异常(Ce/Ce*=0.90~1.22)、无明显 Eu 异常(Eu/Eu*=0.78~1.01)、轻、重稀土分异不明显的平坦曲线，为典型大陆边缘硅质岩。硅质岩中Al2O3/(A12O3+Fe2O3)=0.62~0.75、Al2O3/TiO2=12.63~20.22(平均15.99)、MnO/TiO2=0.08~0.57、LaSN/CeSN=0.79~1.17、Ti/V=47.44~68.29、Th/U=2.94~7.39、δEuCN=0.53~0.69及Ceanom=-0.16~-0.03，均与大陆边缘硅质岩值相当，反映其形成明显受带内大面积出露的、以基性火成岩为主的陆源物质影响，但距大陆有一定距离的陆内裂谷环境之中。据放射虫时代，硅质岩形成于中三叠世，尖山混杂岩带还处于拉张发展阶段。其形成时代、构造背景可与区域上西金乌兰蛇绿混杂岩带进行对比。%Jianshan Mélange belt consists of basic-ultrabasic rock、basic volcanic rock、basic volcanic clastic rock and cherts,in schistose structure or massive structure.The chert from Jianshan Mélange belt were presented as Rich Al2O3, high Fe2O3 and low TiO2,and indicate that they contain high content of pelitic detritus(the SiO2 content is 74.71% ~83.61%).Al/(Fe+Mn+Al)=0.72~0.81、U/Th=0.14~0.34,showing the characteristic of biodeposition chert. The curve nor-malized by shales was the flat curve of the typical continental margin chert whose fractionation between LREE and HREE being not pronounced shows the weak positive anomaly of Ce (Ce/Ce*=0.90~1.22),none obvious anomaly of Eu (Eu/Eu* =0.78~1.01).Characteristic value of Al2O3/(A12O3 + Fe2O3) =0.62~0.75、Al2O3/TiO2=12.63~20.22(average value was 15.99)、MnO/TiO2=0.08~0.57、LaSN/CeSN=0.79~1.17、Ti/V=47.44~68.29、Th/U=2.94~7.39、δEuCN=0.53~0.69 and Ceanomwas -0.16~-0.03 from cherts equal to the continental margin siliceous,reflects the formafion of cherts affected by terrigenous matter which made up of mafic igneous rocks and outcropped widely in the jianshan Mélange belt,but there was a certain distance from the mainland to the inland rift environmen.According to radiolarian era,Siliceous Rocks formed during middle Triassic Period,and JianShan Mélange belt was still in the stage of development.Cherts of formation age and tectonic background were consistent with the ophiolite mélange belt from XiJin ulan.
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