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排序方式: 共有94条查询结果,搜索用时 46 毫秒
21.
ZHANG Kexin HUANG Jichun YIN Hongfu WANG Guocan WANG Yongbiao FENG Qinglai TIAN Jun 《中国科学D辑(英文版)》2000,43(4)
The main character of melange strata in an orogenic belt is the integration of mixed materials due to the superposition, displacement or loss of various tectonic slices (blocks) of different origins and environments, different scales, different grades of deformation and metamorphism, and different stages of tectonic evolution. The approach to non-Smith strata in an orogenic belt is to focus on the understanding of the age, facies, tectonic setting of the original formation and the process of deformation-metamorphism of each tectonic slice, reconstruct the history of dispersal and integration of these tectonic slices in time and space, i.e. 4-dimensional. This paper studies the age and facies of the original formation of tectonic slices in the A'nyêmaqên melange belt based on new data of radiolarians, sporo-pollen and trace fossils, and cast new lights on the research of the evolution process of that belt. 相似文献
22.
南天山区域大地构造与演化 总被引:27,自引:0,他引:27
塔里木和中天山之间的南天山造山带,经历了复杂的构造演化与地壳增生过程。综合分析南天山造山带的构造、地层、古生物、岩石、地球化学和同位素年代学等方面的资料,特别是放射虫、蛇绿岩、蓝片岩等方面的最新研究成果,讨论了南天山的区域构造格局和演化过程。南天山主体为一上百公里宽的增生-碰撞混杂带-南天山(蛇绿)混杂带;其北侧为中天山岛弧,是仰冲壳楔;南侧为塔里木陆块,是俯冲壳楔。古南天山洋为一广阔的大洋,南天山碰撞造山作用起始于二叠纪末-三叠纪初,新近纪-第四纪进入陆内造山作用阶段。 相似文献
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25.
目前关于思茅地块西缘大凹子组的形成时代仍有分歧.在思茅地块西缘大中河剖面采集了硅质岩、砂岩、凝灰岩和玄武岩,通过放射虫组合和锆石U-Pb年龄方法,厘定其地质时代,并结合区域资料恢复地层序列.通过详细剖面实测,发现该剖面由6个地层断片组成:第一、四断片以含放射虫硅质岩为特征,放射虫组合指示其时代为晚泥盆世至早石炭世早期;第二、五断片以火山碎屑岩、具有鲍玛序列沉积特征的火山碎屑沉积岩为主,锆石U-Pb同位素年龄指示其时代为志留纪中期至早泥盆世;第三、六断片以火山岩沉积为特征,锆石U-Pb同位素年龄指示其时代为志留纪早期.结合前人资料认为思茅地块西缘分布的海相火山岩、碎屑岩和含放射虫硅质岩地层层序代表了志留纪到早石炭世早期的岛弧火山-沉积地层序列. 相似文献
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27.
The Origin of Bedded Cherts of the Early Permian Gufeng Formation in the Lower Yangtze Area, Eastern China 总被引:3,自引:0,他引:3
Xia Bangdong Zhong Lirong Fang Zhong Lu HongboDepartment of Earth Sciences Nanjing University Nanjing Jiangsu Fei Zhenbi 《《地质学报》英文版》1995,69(4):372-386
Bedded cherts occurring in the Early Permian Gufeng Formation in the Lower Yangtze region, eastern China, are nearly 20-80 m in thickness and contain varying amounts of radiolarians and sponge spicules. There are three types of section for the Gufeng Formation: chert, carbonate and chert-carbonate mixing types. Bedded cherts mainly occur in the first and third types of section. The depocentres of silica are marked by some small (not larger than a few thousand square kilometres in area) rhombic or elliptic hollows and their formation was controlled by faults. Argillaceous volcanic rocks in cherts occur as numerous thin layers. Bedded cherts are characterized by higher Fe and lower Al contents, enrichment in such trace elements as As, Sb, Bi, Ga, Au, Ag and Cr, lower total REE abundance, negative Ce anomaly and varying degrees of HREE enrichment. These characteristics are important evidence for hydrothermal cherts. Minor amounts of substances of non-hydrothermal origin are mixed in the cherts. The tempera 相似文献
28.
Kexin Zhang Jichun Huang Hongfu Yin Guocan Wang Yongbiao Wang Qinglai Feng jun Tian 《中国科学D辑(英文版)》2000,43(4):364-374
The main character of melange strata in an orogenic belt is the integration of mixed materials due to the superposition, displacement
or loss of various tectonic slices (blocks) of different origins and environments, different scales, different grades of deformation
and metamorphism, and different stages of tectonic evolution. The approach to non-Smith strata in an orogenic belt is to focus
on the understanding of the age, facies, tectonic setting of the original formation and the process of deformation-metamorphism
of each tectonic slice, reconstruct the history of dispersal and integration of these tectonic slices in time and space, i.e.
4-dimensional. This paper studies the age and facies of the original formation of tectonic slices in the A’nyêmaqên melange
belt based on new data of radiolarians, sporo-pollen and trace fossils, and cast new lights on the research of the evolution
process of that belt. 相似文献
29.
试图通过南海更新世以来3个柱状样中Botryocyrtis scutum (放射虫) 的研究, 探讨其地层和古海洋学意义. 根据南海更新世以来3个柱状样中Botryocyrtis scutum的丰度变化与氧同位素记录的对比研究发现, 氧同位素18期以来Botryocyrtis scutum丰度变化与氧同位素记录有较好的对应关系, 其丰度变化随冰期与间冰期旋回而波动.冰期丰度降低, 间冰期丰度增加.其丰度变化基本上与氧同位素记录一样, 反映了冰期与间冰期旋回, 并且可以作为地层划分和对比的工具. 相似文献