Morphotectonic Evolution of the Laterite Profiles over Sukinda Ultramafics, Jaipur District, Orissa

Sukinda ultramafic field of Jajpur district, Orissa is capped by thick lateritic duricrust. Two generations of laterite are inferred in the studied area. The older laterite (in situ) is capped by transported laterite (younger). The entire area is divided into two subareas (A₁ and A₂) Physiographically, three terraces are identified in A₁ area, of which, the oldest one (T₃) comprises of insitu lateritic hard crust. The other two terraces (T₂ and T₁) are made up of valley fill deposits, which are later lateritised. The area A₂ shows the lateral continuity of T₃ terrace of A₁ area along with valley fill deposit of T₁ terrace and the absence of T₂ terrace. Drainage analysis show the A₁ area is structurally more disturbed than A₂ area. Correlation of geomorphological evolution and lateritisation indicates three stages of development in the A₁ area. Lateritisation was initiated on a comparatively flat ground (T₃ terrace) and subsequent destabilisation of the area developed the younger terraces (T₂ and T₁) with the modification of older laterite profile.