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The Architecture of Braided Deltas in Modern Daihai Lake, Northern China: Implications for 3-D Sedimentation Models of Rift Lakes

Shunli, Li *1; Yu, Xinghe 1; Li, Shengli 1
(1) China University of Geosciences, Beijing, Beijing, China.

Daihai Lake, a modern lacustrine rift basin, located in the Inner Mongolia, Northern China, serves as an important modern analog for understanding processes and architecture of deltaic sedimentation in an active rift setting. Two of the largest deltas (Muhuahe delta and Tianchenghe delta) on the margins of Daihai Lake were surveyed to compare and contrast stacking patterns using aerial photographs, field trenching and sediment sampling. The Tianchenghe delta on border fault has much steeper offshore gradients than the Muhuahe delta on the axial shoaling margin where the trend of faults is orthogonal to the shoreline, resulting in relative narrow sandy dominated shelf and typical sigmoid progradational configuration. In contrast, the Muhuahe delta on shoaling margin has broad, sandy shelf and shingled progradational configuration which are strongly influenced by coastal currents.

This research presents preliminary results of integrated study using sedimentary logs and cores data collected from 49 trenches in the two deltas. Grid spacing of trenches is approximately 200 m over most of the study area, allowing for reasonably detailed mapping of spatial sedimentary facies. Two 3-D sedimentation models which employ chronostratigraphic correlation technique were generated utilizing the Schlumberger proprietary simulation software Petrel. The chronostratigraphic sedimentation models predict and represent the architectures and sand-body continuity of sediments, which can be applied in reservoir characterization of braided deltas in rift lakes.


AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California