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卡拉麦里断裂带西段南侧下石炭统山梁砾石组中基性火山岩分布广泛,呈夹层整合产出。岩石具有变化的Si O2(49.43%~59.08%)、Mg O(3.81%~6.28%)、K2O(0.16%~1.55%)含量,高Ti O2(1.18%~2.49%)、Na2O(2.89%~5.44%)、P2O5(0.21%~0.92%)含量,为玄武岩、玄武安山岩及安山岩,属钙碱性系列。样品具相对高的HFSE含量(Ti,Zr,Y)和高的La/Nb(1.96~2.98)、Zr/Y(3.65~9.36)比值,微量元素原始地幔标准化蛛网图显示岩石富集大离子亲石元素Rb,Ba,K和U,Pb,相对亏损高场强元素Nb,Ta和Ti,在球粒陨石稀土元素配分图上,LREE轻微富集,(La/Yb)N=2.04~10.11,弱的负Eu异常(δEu=0.87~0.95),显示出该火山岩兼有板内玄武岩和火山弧玄武岩的地球化学特征。结合区域地质背景研究认为,山梁砾石组中火山岩形成于后造山伸展的构造背景,是由先前被俯冲流体交代过的富集地幔发生部分熔融,并有俯冲沉积物参与,经历一定的结晶分异作用和地壳混染后喷出地表而形成,且该区在晚石炭世早期伸展运动最为强烈,火山活动达到顶峰。
Basaltic volcanic rocks in the Lower Carboniferous Beam Gravel Group on the south side of the western section of the Kalamaili fault zone are widely distributed and are characterized by intercalation and consolidation. The rocks are characterized by varying contents of Si O2 (49.43% -59.08%), MgO (3.81% ~ 6.28%), K2O (0.16% -1.55%), high Ti O2 (1.18% -2.49% 5.44%) and P2O5 (0.21% -0.92%), which are basalt, basaltic andesite and andesite. The sample has a relatively high HFSE content (Ti, Zr, Y) and a high La / Nb ratio (1.96-2.98) and a Zr / Y ratio (3.65-9.36). Trace element mantle normalized cobweb maps show that the rock- The LREEs of Rb, Ba, K and U, Pb are relative depleted in high field strength elements Nb, Ta and Ti. The LREE is slightly enriched in the REE map of chondrule meteorites with (La / Yb) N = 2.04-10.11, The weak negative Eu anomaly (δEu = 0.87 ~ 0.95) shows that the volcanic rocks have both the geochemical features of intraplate basalts and volcanic arc basalts. BACKGROUND that regional geological studies, the ridge structure is formed volcanic gravel group built in the mountain background extending, partial melting is previously explained to the subduction by the fluid enriched mantle occurs, and there dive deposits involved experience some fractional crystallization The surface is formed after the surface is mixed with the earth’s crust, and the area has the strongest stretching activity in the early Late Carboniferous and the peak of volcanic activity.