Paper No. 169-10
Presentation Time: 10:45 AM
CONTROL OF MULTIPLE DETACHMENTS ON THE STRUCTURAL EVOLUTION OF THIN-SKINNED FOLD-AND-THRUST BELTS, EASTERN SICHUAN BASIN, SW CHINA: INSIGHTS FROM ANALOGUE SANDBOX MODELING
Thin-skinned fold-and-thrust belts in the eastern Sichuan basin (southwest China, upper Yangtze plate) are characterized by fault-detachment folds. The geometry and kinematics have not been well documented as multiple detachments highly control the fold-and-thrust belts. The structural model of the study area was constructed by integrating geological maps, seismic interpretation, and balanced cross-sections in Midland Valley Move. Two NW-SE regional seismic sections (A-A' and B-B') crossing the fold-and-thrust belts were restored, suggesting a shortening rate of 26.13 km (**%) and 20.34 km (**%), respectively. Analogue sandbox modeling was employed to understand the control of multiple detachments on the deformation processes based on the structural model constructed upon seismic interpretation and balanced section restoration. Three detachment layers were set to represent the lower Cambrian salt layer, the Silurian shale layer, and the lower Triassic gypsum salt layer. Five sets of analogue sandbox modeling were carried out, with different parameters including layers’ thickness, shortening amounts, and contractional deformation rates. The results of analogue sandbox models were quantitatively evaluated by measuring and calculating a series of parameters. The control of detachment layers on structural deformation was also discussed. This research presented new insights into the structural controls of multiple detachments on the structural deformation that happened to the fold-and-thrust belts and provides potential hints for hydrocarbon exploration in the study area.