GEOLOGY FREE NOTES

  Thrust surfaces usually have stair-case geometry. FLAT Sub-horizontal or gently-dipping (at the time of initiation) part of a thrust. Fault segments running parallel to each other RAMP The moderately-dipping part (at the time of initiation) of a thrust. Ramps usually climb up-section across stiffer layers. Fault segments cutting across the beddings Hanging wall flat (HWF) : The portion of the thrust where the fault is parallel to the bedding surfaces on the hanging wall side. Hanging wall ramp (HWR) : The portion of the thrust where the f ault is oblique to the bedding surfaces on the hanging wall side. Footwall flat (FWF): The portion of the thrust where the f ault is parallel to the bedding surfaces on the footwall side. Footwall ramp (FWR): The portion of the thrust where the fault is oblique to the bedding surfaces on the footwall side. Frontal ramp : Strike of the ramp is perpendicular to the regional tectonic transport direction. Lateral ramp : Strike of the ramp is p...

  If bed dip upstream: V point upstream Dip of the bed is gentler than contours For Horizontal beds : V point upstream Dip of the bed is same as contours Bed dip gently downstream: V point upstream Dip of the bed is sharper or little steeper than contours Bed dip with stream gradient: No v shape Bed dip steeply downstream: V point downstream (only case) Bed is vertical No v shape QUESTIONS 1) A plunging fold will NOT show a V-shaped outcrop pattern on a planar ground surface if the plunge of the fold axis is (JAM-2024) (A) equal to the dip of the ground surface in the same direction  (B) steeper than the dip of the ground surface in the same direction  (C) equal to the dip of the ground surface in the opposite direction  (D) steeper than the dip of the ground surface in the opposite direction Solution:         There are two conditions when we can't get any V-shape If the beds are vertical If the beds dip with stream gradient i.e dip of t...