Trace element geochemistry and tectonic characterization of the granulite facies rocks from Southwes

来源 :Chinese Journal of Geochemistry | 被引量 : 0次 | 上传用户:xuejun2004
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The trace elements characteristics of the migmatitic gneisses (biotite-garnetand hornblende-biotite), granulite facies rocks (charnockitic gneisses) and meta-peridotite in the area of Southwest Obudu Plateau indicate that the area exhibits a high degree of geochemical variability. Compatible trace elements (Ni and Cr) are comparatively high in the granulite facies rocks and meta-peridotite. Ni ranges from 28×10-6 to 266×10-6 whilst Cr ranges from 62×10-6 to 481×10-6 for the granulite facies rocks (charnockitic gneisses), and for the meta-peridotite Ni varies between 2045×10-6 and 2060×10-6. Incompatible trace elements show a higher variability in these rocks. The rocks in the area of Southwest Obudu Plateau generally are characterized by the high concentrations of Ba, Ce, Sr, Rb, Ga, Ni, Cr, Co, Zr, Pr and moderate concentrations of Cu, Sm and Th. The available data show that the charnockitic gneisses are of lower crustal origin. The enrichment of the meta-peridotite in compatible trace elements suggests the primitive mantle would be the source region, with slight contamination during ascent. These diverse origins collaborate the tectonic setting of the area as shown by discrimination diagrams. The diverse tectonic settings range from arc to collisional. Alkaline to sub-alkaline magmatism in the area was probably contemporaneous with the tectonic events that occurred in the area during the Proterozoic. The trace elements characteristics of the migmatitic gneisses (biotite-garnetand hornblende-biotite), granulite facies rocks (charnockitic gneisses) and meta-peridotite in the area of ​​Southwest Obudu Plateau indicate that the area exhibits a high degree of geochemical variability. Compatible trace elements (Ni and Cr) are comparatively high in the granite facies rocks and meta-peridotite. Ni ranges from 28 × 10-6 to 266 × 10-6 carrying Cr ranges from 62 × 10-6 to 481 × 10-6 for the granulite facies rocks (charnockitic gneisses), and for the meta-peridotite Ni varies between 2045 × 10-6 and 2060 × 10-6. Incompatible trace elements show a higher variability in these rocks. The rocks in the area of ​​Southwest Obudu Plateau generally are characterized by the high concentrations of Ba, Ce, Sr, Rb, Ga, Ni, Cr, Co, Zr, Pr and moderate concentrations of Cu, Sm and Th. Available data show that the charniticitic gneisses are of lower crustal origin. enrichment of the meta-peridotite in compatibl e diverse trace elements suggests the primitive mantle would be the source region, with slight contamination during ascent. These diverse teesonic settings of the area as shown by discrimination diagrams. The diverse tectonic settings range from arc to collisional. Alkaline to sub-alkaline magmatism in the area was probably contemporaneous with the tectonic events that occurred in the area during the Proterozoic.
其他文献
许多人都会说“评价”两个字,但在具体的实践过程中过去许多老师却把评价简化成“考试”,重甄别与选拔,轻诊断与激励;重书本知识,轻能力展示;重结果,轻过程,评价主体和方法单
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
在大学英语教学改革的新形势下大学英语课堂尤其是英语听说课常是否需要语法教学,笔者在这里做出了探讨,给出了肯定的答案,并针对听说课堂的语法教学提出了相应的教学策略及
随着新一轮课程改革的不断深入,“一切为了学生,为了学生的一切”,合作学习、自主学习等诸如此类的现代教学方式已广泛运用于小学课堂教学,课堂教学逐渐活了起来.
暮色暗淡,残阳如血。北方的风凛冽地刮着,刮得人生疼。一个十八岁的少女坐在河边,手里拿着最后一次的模考卷,上面的分数令她心寒。她考差了,离自己梦想的学校还差了好多,然而更令她伤心的是,她的父母非但没有安慰她,反而将她痛骂了一顿。  女孩于残阳中站了起来,撕碎了手里的试卷,回到了家。没有人知道那个夜晚女孩想了什么、想了多久。只是从那以后,女孩仿佛在书桌旁生了根。  几个月后,女孩坐在高考考场上,答完了
期刊
通过对90名学生进行教学实验研究发现,网球正手击球的教学宜直接从挥拍方向入手、宜先进行挥拍方向的教学,判断与移动是击好球基础,是和击球技术融为一体的技能,不宜以独立的
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
科学课要培养学生的探究能力,而实验是一个主要的载体.实验教学是学生学习科学知识和技能的主要途径之一,小学科学课程改革使实验教学以崭新的姿态出现在世人面前,传统的实验
一、目前多媒体教学中存在的问题rn尽管多媒体教学在有限的时间内提供更多的信息、有利于激发学生的学习兴趣和能加强与学生的互动等优势,但是我们在机房教试验课的时候常常
课堂教学是使学生获得知识、形成技能技巧、发展智力和能力、培养良好的思想品德的最基本的途径.因此,要提高教育教学质量,首先就要提高课堂教学质量,而要提高课堂教学质量,