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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
33.
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
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Geochemical analysis reveals that Middle Triassic radiolarian cherts from northern Thailand,including Chiang Dao,Lamphun and Den Chai,are of biogenic origin.These cherts present slightly high SiO2 content which was possibly modified by diagenetic alteration and migration processes as indicated by negative correlation between SiO2 and most of the other major elements.The relatively high content of Cr,Zr,Hf,Rb and Th and high positive correlation of these elements with Al and Ti from the majority of cherts su... 相似文献
37.
Shyam M. Gupta 《Marine Georesources & Geotechnology》2013,31(3):259-262
Abstract Radiolarian fossil study in the sediment cores collected during the pre- and postdisturbance cruises of the Environmental Impact Assessment (EIA) Indian Ocean Experiment (INDEX) program of deep sea mining in the Central Indian Ocean Basin suggests a pronounced directional deposition of fossil radiolarians exhumed during the deep sea benthic disturbance experiment. The relative occurrences of the Stylatractus universus species that became extinct ~0.425 million years before present were mostly confined to the older and deeper strata of the sediment of the disturbance tract in the southwestern direction. This pattern is remarkable and suggests that the disturbance plume has been preferentially redeposited in the southwestern direction. This observation is in concurrence with the prevailing southwestern abyssal current during the disturbance experiment in the Central Indian Basin. 相似文献
38.
西藏札达县夏浦沟的放射虫硅质岩和岛弧火山岩: 新特提斯洋内俯冲体系的记录? 总被引:1,自引:0,他引:1
在西藏阿里地区夏浦沟野外调查发现放射虫硅质岩、熔岩组合.放射虫硅质岩SiO2含量在89.47%~92.94%之间, Si/Al在43~67之间, Al/ (Al+Fe+Mn) 比值在0.68~0.74之间, MnO/TiO2平均比值为0.60, Ce/Ce*平均值为0.89, LaN/CeN平均值1.09, 指示它位于洋盆和大陆边缘过渡的环境, 总体更接近大陆边缘环境.伴生的火山熔岩以安山质为主, 具低TiO2 (0.75%~0.98%)、轻稀土弱富集和源自板片流体的易溶元素如Ba、U、Pb相对轻稀土富集, 亏损高场强元素(HFSE) Nb、Ta、Ti等, 指示形成于岛弧环境, 很可能是中生代新特提斯洋洋内俯冲系统的组分.放射虫动物群主要包括Alievium cf.regulare、Alievium cf.fatuum、Archaeospongoprunum cf.patricki、Archaeodictyimitra mitra Dumitrica等早白垩世分子, 其提供了岛弧活动时间上限的约束. 相似文献
39.
Igor V. KEMKIN 《地球学报》2009,30(Z1):21-24
The results of lithological-biostratigraphic study of volcanogenic–chert rocks developed on the left side of the Machtovaya River, a right tributary of the Amur River, are given. The composition, structure, and age of these strata and the rocks constituting the Kiselevka–Manoma accretionary complex are different, which indicates their different tectonic origins. 相似文献
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