Abstract:

Abstract: Troughlike and comblike folds make up the Juratype folds. From the traditional view, the Juratype folds are formed by decollement effect and the typical example is that when above rigid rocks (basal) there exists the soft bed, and the stratum above the soft bed performs “tablecloth” type sliding, and thus forms the troughlike or comblike fold. Base on the field survey of troughlike folds in eastern Guizhou, some characteristics of troughlike folds were figured out: （1）the stratum in the core of troughlike syncline is thicker than that in the limb of troughlike syncline and that in the core of anticline; （2）the multistage activated longitudinal faults whose strikes are consistent with those of the hinges of folds developed across the core of troughlike syncline; （3）the deformation of stratum in the core of syncline is more complex than that in the core of anticline, and the limbs of syncline are steep. Typical outcropscale troughlike folds developed in the Cambrian at the junction of Hunan and Guizhou provinces. Combining the outcrop and macroscopicscale structural interpretation we may come to the conclusion that the development of troughlike folds in southeast Guizhou is controlled by multistage activated faults; that the normal faults developed during the early deposition stage controlled the position of closed synclines of troughlike folds; that after structural inversion, the normal faults transferred into strikeslip or thrust ones, and complex deformation developed in the core of troughlike synclines. Furthermore, the control of normal faults over the development of troughlike folds is different from that of thrust faults over the development of fault bend folds; the former faults developed early and the latter ones developed late.

Key words: troughlike folds, comblike folds, faultrelated folding, genetic mechanism, southeast Guizhou