Past exam of the year 2 of the earth sciences (geology) course of the University of Oxford / 2022 / Paper 1 / 3 / d / i / Solution

Use normalized image coordinates $(u,v)$ within the map rectangle, with $(0,0)$ at its upper left and $(1,1)$ at its lower right. A principal candidate thrust fault trace follows the sharp, approximately diagonal southwestern edge of the dissected high ground on the right: a practical tracing guide passes nearMark the upland, upper-right side as hanging wall and the smoother, lower-left basin side as footwall for a thrust dipping beneath the uplands. Use broken lines through the gaps, not one asserted continuous exposed rupture. A subsidiary candidate frontal segment follows the basin-facing edge of the isolated dissected ridge on the left, approximately $(0.04,0.32)$ through $(0.23,0.47)$ to $(0.34,0.61)$; place teeth toward its locally higher ridge side.

These are geomorphic interpretations of mountain fronts and scarps, not measured subsurface dip directions. On a conventional north-up reading the principal trend is broadly northwest–southeast, but the supplied map has no north arrow: the image-relative coordinates are the reproducible identification. Southwestern illumination means southwest-facing slopes are bright; brightness is a slope-orientation clue, not an elevation contour. Some aligned relief may be a fold scarp or an eroded lithological contact, so field confirmation and topographic profiles would test the candidate traces.