A Morphometric Investigation of Large?Scale Crustal Shortening on Mars

Mars' surface exhibits abundant topographic expressions of large thrust fault-related folds that have been attributed to global planetary contraction. Morphometric analyses such structures provide insight into their growth history. With THEMIS imagery and HRSC–MOLA data, 49 thrusts with lengths between 35 544 km were mapped across surface. Assuming planar fault geometries dips 30°, the average maximum displacement-length ratio (Dmax/L) these is 6.1 × 10?3 ± 1.4 10?3, smaller ratios observed for faults within northern lowlands (2.9 0.9 10?3) compared southern highlands (9.2 1.9 10?3). However, differences may be accounted if mechanical layering in lowland crust promotes either a shallowing dip angle relative or development ramp-flat scarp height under-estimate total displacement combination two scenarios together. Alternatively, Dmax/L patterns reflect hemispheric brittle-ductile transition (BDT) depth; however, pattern stratigraphically inconsistent Martian crustal dichotomy, whereby thinner (or denser) therefore presumably deeper BDT than highlands. Fault profiles are commonly asymmetric, multiple local minima along lengths. Spectral analysis profiles, using Fourier- S-Transforms, indicates power at range spatial frequencies, reflecting complex linkage histories, peak spectral frequency, number segments, being negatively correlated ratios.