Common Reflection Surface Stack Imaging of the Proterozoic Chambal Valley Vindhyan Basin and Its Boundary Fault in the Northwest India: Constraints on Crustal Evolution and Basin Formation

Abstract

The Vindhyan basin of northwestern and central India is one of the largest undeformed Meso-Neoproterozoic basins in the world with likely potential of hydrocarbons. Crustal seismic reflection data along a 165-km long Chandli-Bundi-Kota-Kunjer profile of the Chambal Valley Vindhyan basin processed using common reflection surface stack method brought out new crustal features, which were missing in earlier images. A gently dipping structure of the basin is imaged with a maximum of 7.5-km thick Proterozoic sediments, 1.5-km thick volcanic sequence, and the granitic basement at 9.0-km depth. The Great Boundary Thrust, a NW dipping crustal-scale regional tectonic feature outcropping at Bundi, and a new NW dipping reflection band from 9-to 30-km depth, named here as the Chambal thrust, are imaged beneath Bundi-Kota segment. Subduction and collision are responsible for evolution of these thrusts implying horizontal crustal growth. Seismic images of compression on one side and extension on another side along with differences in the Moho characteristics and other constraints from geophysical data around Kota indicate the presence of a new tectonic boundary with a strong lateral discontinuity and strike-slip features. The Moho topography is delineated for the first time revealing a crustal thickness ranging from 40 to 44 km. A 9-to 12-km thick mafic underplating at the lower crust suggests an important postcollisional process indicating vertical crustal growth. Based on the images from the present reflection study, a geodynamic model of the region is suggested in a plate tectonic framework, which may apply to similar Paleoproterozoic collisional areas and associated basin formation.

Intraplate seismicity and earthquake hazard in the Aravalli–Delhi Fold Belt, India

“… 2000 ; Mandal et al . 2018 ). Deep seismic reflection images of the region along the Nagaur–Jhalawar profile that runs perpendicular to the strike of the ADFB clearly identify structural features such as the west-dipping Jahazpur Thrust and the Great Boundary fault that extend through the entire crust (Vijaya Rao et al .…”

“… 2000 ; Mandal et al . 2018 ). The converging reflections within the ADFB and the presence of the ramp-flat structure of the Jahazpur Thrust confirm compression across the region (Vijaya Rao et al .…”

Evolution of Bundelkhand Craton

“…Then, the report of basaltic pillow lava from Mauranipur area in a subductionrelated tectonic setting of Archean age (Malaviya et al, 2006) and very high pressure metamorphism (up to 20 kb; Saha et al, 2011) from Babina area revolutionized the understanding of the BuC. The field and petrographic evidences are now very well supported by geophysical data (Gokarn et al, 2013;Mandal et al, 2018;Nabakumar and Kumar, 2018) indicating the existence of the BTZ. The Bouguer gravity anomaly map of the Bundelkhand Craton clearly divides the craton into a gravity low (Southern BuC) and relatively gravity high (northern BuC) domains on either side of BTZ (Fig.…”

Shales of Palaeo-Mesoproterozoic Vindhyan Basin, central India: insight into sedimentation dynamics of Proterozoic shelf

“…The decades of study, although under debate and inconclusive, have projected widely varying tectonic models extending from an intracratonic setting (Chanda & Bhattacharyya, 1982;Soni et al 1987), to a foreland setting (Chakraborty & Bhattacharyya, 1996;Chakrabarti et al 2007;Shukla et al 2019) to a temporarily evolved rift-sag setting (Sarkar et al 1995;Bose et al 1997Bose et al , 2001Sarkar et al 2002b). In particular, trace-element data, Nd isotope-based studies and seismic reflection studies (Chakrabarti et al 2007;Mandal et al 2018;Shukla et al 2019) speculate on the initiation of the Vindhyan basin as a foreland basin with the existence of a subduction-related arc system. Interestingly, proponents of a foreland setting differ in their subduction model.…”

“…Interestingly, proponents of a foreland setting differ in their subduction model. Chakrabarti et al (2007) and Shukla et al (2019) conceived subduction of the Bundelkhand craton under the Bastar and Aravalli cratons; however, from consideration of seismic reflection stack imaging, Mandal et al (2018) suggested the opening of the Vindhyan Basin in an extensional strike-slip mode that followed subduction and collision between the Bundelkhand craton and the Mewar craton. However, none of these studies supported their claims with field-based documentation such as the basin-scale variation in stratigraphic thickness of different formations and the pervasive northwesterly palaeocurrent from different stratigraphic levels of the Vindhyan succession present in the Son valley.…”