The lithosphere of Mars accommodates shortening through folding and faulting, producing landforms qualitatively categorized as wrinkle ridges or lobate scarps. However, we lack a deep understanding of the morphological differences between these landforms. This study aimed to develop a quantitative model for shortening landform classification based on surface morphology and subsurface architecture. We developed this model by mapping 100 landforms in a GIS, recording parameters for each landform. We conducted a Discriminant Function Analysis (DFA) using these morphometrics. This DFA produced a predictive linear function for categorizing wrinkle ridges and lobate scarps. We then modeled the subsurface structural geology of 50 landforms using MOVE Structural Geology Modeling Software and conducted a second DFA on subsurface metrics. These analyses revealed the three most important variables when classifying shortening structures. Our results show that by using the surface morphology and subsurface geometry together, they can be distinguished quantitatively 96% of the time.

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<p>This thesis addresses the spatial distribution of structures and deformation geometry in the southern Sudbury Basin, Ontario, a synclinal fold basin. Major components are low-temperature fabric development in the Sudbury Igneous Complex (SIC), the relation between fabrics and fold structures in Huronian rocks, and kinematic modeling of deformation of the southern Sudbury Basin. These topics lead to a synthetic model of the structural history of the SIC and its host rocks. Analysis of structures in the Norite layer of the SIC shows that this unit deformed under a single deformation regime and variable rheological conditions. This is evident by foliation planes, folded granitoid dikes, brittle shear faults and ductile high-strain zones. Brittle deformation preceded the formation of foliation planes and caused hydrolytic weakening of the Norite. Bulk thinning led to steepening of lithological contacts and igneous layering in the SIC. Structures in Huronian rocks and Sudbury Breccia display components of post-impact deformation that cannot be accounted for by thrusting along a high-strain zone, the so-called South Range Shear Zone, and by large-scale folding of the SIC. Shape change of the SIC from a convex outward to concave inward geometry led to basin-concentric shortening, the formation of a buckle fold of the SIC and axial-planar fabrics in Huronian rocks. Mutually perpendicular fabric orientations compatible with overall NW-SE shortening indicate that discordant foliations can form as a consequence of local strain perturbations near lithological contacts. Kinematic modelling of deformation based on field-based structural data tests the validity of trishear fault propagation folding as a possible deformation mechanism for the southern Sudbury Basin. Trishear deformation of the central South Range accounts for angular discordances between the upper and basal contacts of the SIC, local overturning of southern SIC, steepening of foliation planes, strain gradients in the Sudbury Basin, and thickness variations of SIC layers. Implications are shallowly dipping SIC layers both at greater depths and above the current erosion level, translation of Huronian rocks, and thinning in a section of the trishear zone manifested at surface by the South Range Shear Zone.</p> / Doctor of Philosophy (PhD)

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Science. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 345-370. / Ph.D.

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Bibliography : leaves 34-39. / by Norman C. Burr. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982. / Microfiche copy available in Archives and Science. / Two maps and one illustration on 3 folded leaves in pocket. / Includes bibliographies. / by Brian Philip Wernicke. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1979. / Microfiche copy available in Archives and Science. / Bibliography: leaves 73-75. / by Steven J. Hellinger. / Ph.D.

Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Bibliography : leaves 202-217. / Ph.D.