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Cretaceous Sandbody Characters at Shallow‐Water Lake Delta Front and the Sedimentary Dynamic Process Analysis in Songliao Basin, China
Author(s) -
Xiyuan CAI,
Rong ZHU
Publication year - 2011
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2011.00600.x
Subject(s) - geology , delta , fluvial , sedimentary rock , front (military) , geomorphology , waves and shallow water , structural basin , river delta , sedimentary structures , sedimentary depositional environment , paleontology , hydrology (agriculture) , oceanography , geotechnical engineering , aerospace engineering , engineering
Based on the abundant information from drilling, cores, and logging, the influence of topography, size of rivers and lakes, climate changes and the lake level's fluctuation on the sandbodies at shallow‐water delta front are systematically summarized and the sedimentary dynamic processes are analyzed. The interwell communication among the sandbodies and their planar distribution revealed from the hydrodynamic features of the development wells are integrated during the analysis. The fundamental requirements for the development of the shallow‐water delta included flat topography and uniform subsiding rate. The delta plain was connected smoothly with the wide delta front and predelta, without the three‐fold structure of topset, foreset, and bottomset as defined in the Gilbert Delta Model. Because of the weak fluvial effect and the lake energy is strong, the small and scattered shallow‐water delta is destroyed by the scouring‐backwashing, coastal current, and lake wave, resulting in the coastal sheet deposition. As the fluvial effect became stronger and the lake energy became weaker, the shape of the shallow‐water deltas transferred from sheets to lumps and then branches.