Multiple Deformation in the Precambrian Rocks to the Southeast of Ajmer, Rajasthan, India

The paper describes two phases of deformation, excluding thrusting, in the Precambrian metamorphites of the Delhi System and the underlying Banded Gneissic Complex. The first deformation, D_I, produced major folds, mainly overturned isoclinal and large antiforms and synforms, with NE trending northwesterly dipping axial surfaces and plunges at low angles. The second deformation, D_II, produced folds that were superimposed upon D_I major folds. These are commonly asymmetrical and are better developed in the Delhi rocks than in the underlying Banded Gneissic Complex. They have N to NNW trending, nearly vertical axial planes and plunges at high angles towards the north. These phases of deformation are also recorded on microscopic scale rocks from both the stratigraphic units.

The' basement' Complex was deformed more or less concordantly with the supracrustal rocks of the Delhi System during the Delhi Orogeny. The structural data also suggest that there was one more kinematic phase in the area. During this phase the overlying Delhi rocks slid over the Banded Gneissic Complex along a high-angle reverse fault that runs along the plane of unconformity between the two rock groups.