9 10 11. In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent deformation.Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. Metamorphic core complexes and associated detachment faults of the North American Cordillera represent gently dipping, normal-displacement shear zones (detachment zones) along which hot, deeper levels of the crust were transported upward and outward from underneath a ⦠The dominant structure of the range is the Plomosa detachment fault, a low-angle normal fault that separates a single tilted footwall block from a highly extended hanging wall with diverse stratigraphy and complex structure. The Detachment itself is a gouge zone, approximately 5 mm wide, at the contact. Needham, 2004; Fagereng, New Rb-Srmineral ages from the shear zone and its footwall show that ductile deformation was ongoing at 26 Ma, and continued to ⦠In zone A (NW sector of the study area), the stratigraphically shallowest Dahomey detachment is dominant and is associated with thrust truncated folds. Folding in shear zones They occur as single isolated folds or in periodic sets (known as fold trains).Synsedimentary folds are those formed during sedimentary deposition. Detachment Zone (NSDZ), a major normal-sense detach-ment zone thought to be the primary structure responsible for the exhumation of Norwegian (U)HP rocks, and to evaluate the different models for the exhumation of UHP rocks. When a thrust fault continues to displace above a planar detachment without further fault propagation, detachment folds may form, typically of box-fold style. detachment and the regional isograds north of the anticline (i.e., Frank et al., 1973) is consis-tent with overturned folding of the South Tibet detachment at this location. The pluton lies in the fo⦠The fault is remarkably thin given that it has accommodated about 10 kilometers of displacement at this location. A survey of detachment systems in the North American Cordillera indicates that the footwall of detachment faults consists of a detachment shear zone that ranges in thickness from 100 m to 1 km. The data support a three-stage exhumation model for western Norway: rapid exhumation of a (U)HP body ... and Pennsylvanian detachment zones. Much of the geology and structure along the eastern Cumberland Plateau escarpment in Tennessee was resolved in the 1960s and 1970s. Figure 4. Clastic dike crosscutting andesitic volcanic breccia, about 5 meters above the Heart Mountain Detachment Fault at Jim Smith Creek. Tibetan detachment system, a north-dipping normal fault and shearzone that unroofed high-grade metamorphic rocks during contraction of the Himalayan orogen. nated detachment zone that bounds the Raft River core complex in northwest Utah (United States). detachment zone in the Khao Khwang Fold and Thrust Belt and demonstrate the heterogeneity of deformation at a scale rarely documented in shale detachments (e.g. Detachment folding. Hydrogen isotope values of musco-vite (δD Ms ~ â100â°) and ï¬ uid inclusions in quartz (δD Fluid ~ â85â°) indicate the presence of meteoric ï¬ uids during detachment dynamics. The northern Plomosa Mountains are a small metamorphic core complex in La Paz County, western Arizona. Fluid inclusions were trapped in sealed microfractures in quartz in quartz-muscovite veins in and near the Red Butte pluton. 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