HGH diagram for fold mechanism classification: the Zagros Simply Folded Belt case study

Spatial geometry of the folds serves as a valuable indicator of folding mechanisms, particularly in the frontal regions of young orogenic belts. This study provides a spatial analysis of fold types within the Fars Zone of the Zagros Simply Folded Belt, highlighting variations in folding geometry and kinematics. Surface geometrical parameters are employed to classify folds into symmetric and asymmetric detachment folds, fault-propagation folds, and symmetric and asymmetric fault-bend folds. The parameters used are hinge length, aspect ratio and an index known as fold symmetry index. Fault-bend folds, detachment folds and Fault-propagation fold represent three endmembers of these fold types, which can be represented on a ternary diagram named as HGH diagram. This diagram may be applied as a practical and efficient tool for identifying the folding mechanism based on geometrical parameters. We recommend using the coefficient Kc to assess the near-circular shape of folds. This coefficient enables a faster and more precise comparison of fold circularity.

کلیدواژه ها:

Fold geometry ، folding mechanism ، HGH diagram ، Zagros Simply folded Belt