... all hinge points and the in ection linejoining all the in ection points (b) and (c). Cylindrical folds, as in (a) and (b), have a fold axis which is any line parallel to the hinge line ofconstant ... folds (the hinge line isalways horizontal) and finally, folds having inclined axialsurfaces are called steeply, moderately, or gently inclinedfolds depending on the inclination. Inclined folds ... plateboundary and a magmatic arc in both intra-oceanic and continental active margins. Thrust faulting results in crustal shortening and thickening (Fig. 4.100c, d). Thrust and fold belts are limited in...