西秦岭上三叠统浊积岩系中波痕的主要特征及其成因探讨
- 中国科学院兰州地质研究所
作者简介:
张晓宝 男 36岁 助理研究员 沉积学
- 收稿日期:
1994-02-16
- 刊出日期:
1994-12-10
摘要: 西秦岭上三叠统为一套半深海环境中形成的陆源碎屑浊积岩系，于该该积岩系中发现了大量的波痕。本文详细研究了这些波痕的形态特征及其与鲍马尾序和浊积岩相组合的关系。研究结果表明这些波痕是浊流演化过程中转化而来的牵引流作用于底部床沙形成的。
A Discussion on Main Characteristics and Origin of the Ripple Marks of Upper Triassic Turbidites in west Qinling Mts.
- lanzhou Institute of Geololgy, Chinese Academy of Sciences, 730000
- Received Date:
1994-02-16
- Publish Date:
1994-12-10
Abstract: For a long time, ripple marks were often regarded as one of sedimentary indicators of shallow water, but large quantities of them were also found in bathyal terrigenous elastic turbidites of Upper Triassic of west Qinling Mts. The ripple marks characterize that(1)they occour on the surface of Tc of Bouma sequence, which means that they were formed by tractive currents derived from turbidity flows, ( 2 ) they exist in the lobe facies associations of seafloor fan sequences, which indicates that the most favourable hydrodynamic }rtditions to form them appeared in outer fans,(3)they are all symmetrical，which shows that tractfve currents to form them were unidirectional, ( 4 ) They are smal l-scale，which proves that the veIocIty of tractive currents and the grain size of bottom bed sands varied in a certain extend,(5)their wavelengths and heights are directly proportional to the thickness of turbidites, which means that the strength of tractive currents was controlled by the scale and strength of turbidity flows, (6)the shapes of wave crests and troughs are smooth and the shapes of ripple ridges are regularly changeable , ( 7 ) their shapes and scales are closely related with those of ripple laminations in Tc intervals of Bouma sequences, which reflects that they were two forms of expression produced by the same tractive currents,(8 ) The flow directions determined by ripple marks are consistent with those determined by bottom marks,which reflects that the flow directions of tractive currents were controlled by those of turbidity flows. The characteristics above reflect that ripple marks occoured not only in shallow-water enviroments but also in deep water enviroments.
张晓宝, 方国庆, 何海清. 西秦岭上三叠统浊积岩系中波痕的主要特征及其成因探讨[J]. 沉积学报, 1994, 12(4): 124-131.
| 引用本文: |
张晓宝, 方国庆, 何海清. 西秦岭上三叠统浊积岩系中波痕的主要特征及其成因探讨[J]. 沉积学报, 1994, 12(4): 124-131.
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Zhang Xiaobao, Fang Guoqing, He Haiqing. A Discussion on Main Characteristics and Origin of the Ripple Marks of Upper Triassic Turbidites in west Qinling Mts.[J]. Acta Sedimentologica Sinica, 1994, 12(4): 124-131.
| Citation: |
Zhang Xiaobao, Fang Guoqing, He Haiqing. A Discussion on Main Characteristics and Origin of the Ripple Marks of Upper Triassic Turbidites in west Qinling Mts.[J]. Acta Sedimentologica Sinica, 1994, 12(4): 124-131.
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