| Autor: |
LÜ JunLing, ZHU YiJie, XIA Rui, ZHENG YunKe, LIU ChenHu, FENG WenJie, LI GuoYan, DU XiaoFeng |
| Zdroj: |
Acta Sedimentologica Sinica; 2020, Vol. 38 Issue 5, p994-1005, 12p |
| Abstrakt: |
Distributive fluvial systems (DFS) are large sedimentary accretions that develop at the margin of basins and extend to the shoreline of the lake. The main part of a DFS is generally known as an alluvial fan. In arid climatic conditions, large-scale DFS usually form at the margin of basins. The deposition process is complex, and may form large-scale oil, gas and water reservoirs. To gain an insight into the evolution of arid DFS and the variations in their sedimentary characteristics, the sedimentation process was modeled in a flume-tank experiment-and precisely recorded by 3D laser scanning and a time-lapse camera. The experiment revealed that: (1) During the simulation process, the mean radius and edge roughness was correlated to the logarithm of the run time under constant boundary conditions. DFS growth-occurred in three obvious stages: an early stage, middle stage and late stage, each with large differences in sedimentation characteristics. (2) In the early stage, plate-like sheet-flood units-formed in multi-periodic movements superposed on the surface of the experimental DFS. The middle stage was dominated by the lateral migration of unconfined channels and the formation of confined channels originating at the ends of the unconfined channels. In the late stage, the development of unconfined channels decreased, while the number of confined channels increased and drove the sedimentation process. (3) The three-stages resulted in three layers of sediment, each having different sedimentary characteristics and spatial structure. The lowest layer was characterized by sheet-flooding lobe complexes; the middle layer consisted of filled unconfined channels and axial confined channels; the top layer was characterized by intersecting confined channels. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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