Kinematic models of fluvial terraces over active detachment folds : Constraints on the growth mechanism of the Kashi-Atushi fold system, Chinese Tian Shan

摘要: During detachment folding, the relationship between differential uplift and shortening depends on mechanism of fold growth, such as limb rotation or hinge migration, may vary over lifetime a fold. Thus, neither long-term rates nor present geometry unambiguously constrain kinematics growth. Where rivers cut through growing anticlines, flights abandoned fluvial terraces act passive kinematic markers. As progresses, become deformed thereby preserve critical information about evolution active To recent growth across three folds in Kashi-Atushi system SW Tian Shan, China, we surveyed compared them with geometric models successively emplaced horizontal unconformities (terraces) pregrowth strata by rotation, combination two. Migration angular hinges curved zones were also compared. Each model predicts both distinct for contrasting relationships strata. Notably, migration result progressively rotated that strata, whereas all limb-lengthening parallelism terrace straths much The show clear evidence axial surfaces, concentrated deformation near core folds, progressive tilting age. When to predictions, are likely tight cores hinge-zone flanks folds.