Subtrappean Mesozoic sediments in the Narmada basin based on travel time and amplitude modelling - a revisit to old seismic data.

Abstract

Of late, the search for hydrocarbons amidst Mesozoic sediments hidden below high-velocity Deccan Traps has gained prominence in the quest for delineating new reserves of energy. The presence of Mesozoics is directly evident in the form of a low velocity layer (LVL) prominently indicated on the refraction records. To delineate such sediments, seismic refraction/wide angle reflection studies were carried out in different parts of India. Seismic data from the Deep Seismic Sound profile in the western part of the Narmada-Son lineament (NSL) that passes through the Narmada and Tapti rivers is used for this study. Since imaging of LVL is not possible from the refraction data alone, we have used travel time skips on the refraction records along with reflections from the top and bottom of the LVL. Data from reciprocal shot points are used for confirmation and precise delineation. The analysis of seismic refraction and wide angle reflection data shows a possible existence of low-velocity Mesozoic sediments of considerable thickness sandwiched between the high velocity thick Deccan Traps and the basement.