Gravity Study using Multi-2.5D Modeling and 3D Presentation for Al Ma'aniyah Depression, Southwest of Iraq

Tectonic depression area within and/or beside widespread basin is regarded as an important location for sub-basin sedimentary sequence of Iraq which may represent an excellent accumulation of bounded sediments. Al-Ma'aniyah depression, southwest Iraq is one of such type of sub-basin. Free-air gravity data show a NS extend of this depression inside Saudi Arabia. This work focuses on studying and multi-2.5D model creation for the depression in the Iraqi territory part using Bouguer gravity data and mapping its basement relief. Firstly, the exact boundary of the depression was outlined utilizing the Free-Air gravity data. Then, a precise selection of regional field for the study area was determined by using the power spectrum method, which accordingly defines the residual anomalies that could represent structural enclosures. Many positive anomalies were assigned and enhanced using vertical and total horizontal derivatives, where they were interpreted as basement-related features. Subsequently, a 2.5D multi modeling and depth inversion for the Bouguer gravity data were accomplished by converting the gravity map to a stacked profiles depth map. A nineteen gravity profiles, which cover the study area, were modeled by assuming 2D intra-sedimentary bodies. These bodies were best presented by a 3D view that clarifies the nature of the subsurface modeled structures. The modeling shows an extra density at the northern part of the depression, in contrast, it suggests low density bodies at its southern part, the case that appears inconsistent with a previously performed magnetic interpretation. The inversion of gravity data shows that the basement depth at Al-Ma'aniyah depression ranges from 7.5 to10 km.

Delineation of subsurface features by gravity technique in parts of Shivpuri District, M.P.

This research paper represents the search of faults/ fractures/ shear zones/ altered zones, to find out mineral target zones in part of Shivpuri district, M.P. Geologically, the study area is represented by Vindhyan Supergroup of Meso to Neoproterozoic age. The area is mainly covered by alluvium which is characterized river gravels, sand and residual soil. The gravity survey was carried out with a station density of 1 gravity station per 2.5 sq km along with elevations of each gravity stations covered 2800 sq km. The rock samples have been collected from different litho-units of the study area for measurement of physical property (Density) which are useful for understanding & evaluating of geological response. The general trend of contour pattern of Bouguer gravity is NW-SE directions. Bouguer gravity anomaly contour map is characterized by broad gravity ‘high’ in southern part whereas ‘low’ in northern part which inferred depression of basement toward the north. The nosing in aligned approximately NW-SE direction is recorded in central part which may be interpreted as inferred lineament and it is clearly reflected on residual gravity map. The regional gravity anomaly aligned in NW-SE is characterized by broad gravity ‘high’ in southern part whereas ‘low’ in northern part which reflects basement deepening towards north. The majority of Euler 3D solutions are falling on linear bodies (inferred lineament) with varying depths from 0.5 to 2.5 km.