Oblique convergent margins host slip-partitioned faults with simultaneously active strike-slip and reverse faults. Such systems defy energetic considerations that a single oblique-slip fault accommodates deformation more efficiently than multiple faults. To investigate the development of slip partitioning, we record deformation throughout scaled experiments of wet kaolin over a low-convergence (<30°), obliquely slipping basal dislocation. The presence of a precut vertical weakness in the wet kaolin impacts the morphology of faults but is not required for slip partitioning. The experiments reveal three styles of slip partitioning development delineated by the order of faulting and the extent of slip partitioning. Low-convergence angle experiments (5°) produce strike-slip faults prior to reverse faults. In moderate-convergence experiments (10°–25°), the reverse fault forms prior to the strike-slip fault. Strike-slip faults develop either along existing weaknesses (precut or previous reverse-slip faults) or through the coalescence of new echelon cracks. The third style of local slip partitioning along two simultaneously active dipping faults is transient while global slip partitioning persists. The development of two active fault surfaces arises from changes in off-fault strain pattern after development of the first fault. With early strike-slip faults, off-fault contraction accumulates to produce a new reverse fault. Systems with early lobate reverse faults accommodate limited strike-slip and produce extension in the hanging wall, thereby promoting strike-slip faulting. The observation of persistent slip partitioning under a wide range of experimental conditions demonstrates why such systems are frequently observed in oblique convergence crustal margins around the world.
Topography along strike‐slip fault restraining bends is theoretically self‐limited by erosion, block translation and the expected abandonment of fault bends. However, Denali (6,194 m) and Foraker (5,304 m) are located within a restraining bend of the dextral Denali Fault system. We reveal the role of bend evolution in mountain building with physical experiments scaled to simulate the Alaska Mount McKinley restraining bend (MMRB). Despite the natural complexity of the MMRB, first‐order patterns (of strike‐slip separation rates, uplift and lateral bend migration) from the geologic data align with patterns from scaled experiments. Thermochronology, seismicity, and slip rate data show that the persistence of a single Denali Fault strand through the ~6 Ma MMRB is facilitated by simultaneous advection of crust through the bend and migration of the eastern vertex of the bend.
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