2-D Crustal thermal structure along Thuadara-Sindad DSS profile across Narmada-Son lineament, central India

Abstract

Central India is traversed by a WSW-ENE trending Narmada-Son lineament (NSL) which is characterized by the presence of numerous hot springs, feeder dykes for Deccan Traps and seismicity all along its length. It is divided in two parts by the Barwani-Sukta Fault (BSF). To the west of this fault a graben exists, whereas to the east the basement is uplifted between Narmada North Fault (NNF) and Narmada South Fault (NSF). The present work deals with the 2-D thermal modeling to delineate the crustal thermal structure of the western part of NSL region along the Thuadara-Sindad Deep Seismic Sounding (DSS) profile which runs almost in the N-S direction across the NSL. Numerical results of the model reveal that the conductive surface heat flow value in the region under consideration varies between 45 and 47 mW/m 2 . Out of which 23 mW/m 2 is the contribution from the mantle heat flow and the remaining from within the crust. The Curie depth is found to vary between 46 and 47 km and is in close agreement with the earlier reported Curie depth estimated from the analysis of MAGSAT data. The Moho temperature varies between 470 and 500 • C. This study suggests that this western part of central Indian region is characterized by low mantle heat flow which in turn makes the lower crust brittle and amenable to the occurrence of deep focused earthquakes such as Satpura (1938) earthquake.

Tectonics and thermal structure of western Satpura, India

“…For an average P n value of 8.2 ± 0.05 km s À1 , the surface heat flow has been estimated as 48 ± 4 mW m À2 . These orders of values are reported in the adjacent region (Rai and Thiagarajan, 2004;Rai and Thiagarajan, 2006) and are typical value for Proterozoic mobile belts (Gupta, 1993b;Raval, 1995). Additional information on the thermal structure can be inferred from the Curie point isotherms analysis.…”

“…There is scanty information about the heat flow values in central part of NSL Gupta, 1993a;Roy and Rao, 2000;Rai and Thiagarajan, 2004;Rai and Thiagarajan, 2006). Shanker (1988) reported high surface heat flow (70-100 mW m À2 ) all along NSL based on silica contents in thermal waters.…”

The Magmatic Architecture of Continental Flood Basalts I: Observations From the Deccan Traps

“…Since the mean thickness of the majority of intra‐continental sedimentary basins globally is less than 4 km (Evenick, 2021, and references therein), these sediments will not contribute to the reservoir volatile content. This includes the Narmada‐Tapi rift valley in India (Figure 2) which has a typical sediment thickness less than 3 km (e.g., Evenick, 2021; M. R. Kumar et al., 2015; Rai & Thiagarajan, 2007; Talukdar & Behera, 2018). The presence of the Narmada‐Tapi rift may have other effects associated with the eruption likelihood because magma can ascend along pre‐existing fractures and zones of weakness (Section 6).…”