The surface traces and trajectories of "joints" and "fractures" located over simple subsurface structures, with configurations optimized to a horizontal cyl¬inder and vertical hemisphere and combinations thereof, are examined for two hypothetical methods of fracture development. The models are generated for a "rubber sheet" deformation and assume (a) that a fracture system may be in¬herited from the basement rocks through any overlying consolidated sediment, (to) that these fractures would be deformed by any subsequent movements in the basement rocks, (c) that in any kinematic folding, these fractures would be ro¬tated and displaced by a flexural slip mechanism, and (d) that for supratenuous folds, any fractures developed during compaction would be focused through the center of curvature. It is asserted that (a) the inherited fractures, while being rotated and displaced by the bedding plana slip, would project vertically to the surface, i. e., orthographically, and (b) that fractures induced during compaction would converge upward in a down-warp or diverge in an upwarp from a focal point in the case of a dome or basin (periclinal structure) and a focal line for a supra-tenuous fold, and that these would project gnomonically to the surface. While the former mechanism is considered to be "active" and may be generated by local basement uplifts, the latter is "passive" and is typified by differential compaction of sediments over a reef core.
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