Crustal Mapping of Northern Extremity of Aravalli Delhi Fold Belt (ADFB) by High Resolution Gravity Survey in Haryana, India

Gravity data at a grid spacing of 2.5 sq. km., acquired by Geological Survey of India (GSI), have been analysed to discern the subsurface disposition of northern extremity of the Aravalli Delhi Fold Belt (ADFB). Geologically, the area has sparse exposure of the Aravalli Delhi Fold Belt and is predominantly covered by alluvium of Quaternary age. Apart from Bouguer gravity anomaly (BGA) map, residual gravity map, regional gravity map, radially averaged power spectrum (RAPS) and 3D Euler deconvolution maps have been prepared for better insights of the subsurface. Two 2D subsurface gravity models describe possible upwarpment of crustal and mantle materials for gravity high in southwest part of the study area. The significant change in trend of gravity contour pattern from NE-SW to NW-SE near Rohtak and further north is closely parallel to the trends of ADFB and Delhi Sargodha Subsurface ridge respectively. This deflection of the ADFB may probably be caused by rotation related to collision of plates. Earthquake data from International Seismological Centre (ISC), since the year 2000, has been used in the study. The earthquake data shows cluster of shallow focus earthquakes (from 2 to 39 km) with low magnitudes (from ML 1.8 to 5) in the study area near Rohtak. The presence of subsurface disturbance north of Rohtak is well supported by cluster of 3D Euler solutions and distribution of seismicity in that region. The multimodal distribution of the earthquake hypocentres is correlating well with the 2D gravity model along the Bhiwani to Panipat section.

Automated summary

This study analyzes the subsurface disposition of the northern extremity of the Aravalli Delhi Fold Belt (ADFB) using gravity data and earthquake data. The findings suggest that the deflection of the ADFB may be caused by rotation related to plate collision.