Inferring a Neoproterozoic orogeny preceding the Rodinia break-up in the Sirohi Group, NW India

Abstract

Recent studies indicate the Delhi Orogeny to be a Grenvillian-age collision event in the NW Indian Shield. West of the southern part of the South Delhi Fold Belt, aeromagnetic anomalies show a high-angle relationship with the Delhi Fold Belt trend. We examined an argillaceous–calcareous metamorphosed sequence exposed within and adjacent to this aeromagnetic anomaly. This sequence, deposited over a granitic basement, is reported as the Sirohi Group. The basement granite is dated to be 892±10 Ma (Erinpura age) and this was partially reset at 815±43 Ma. The metapelites preserve a low- to medium-grade metamorphic assemblage (peak temperature of c. 460°C) and the metamorphism took place at 822±29 Ma, which was partially reset at 723±65 Ma. The partial resetting can be ascribed to the Malani eruption. Control of accessory minerals on the garnet trace element chemistry is evident in the Y distribution of the two analysed garnets.It is contended that the Rodinia break-up, marked by Malani Igneous Suite, was preceded by an orogenic event (the Sirohi Orogeny) which marked the culminating mountain-building event in the cratonization of the NW Indian Shield.

Differences in natural gamma radiation characteristics of Erinpura and Malani granites in NW India

“…The age range of the Erinpura granites is compiled in figure 4. The comparison with age data for the MIS (figure 4) (Deb et al 2001;Konopelko et al 2007;Gregory et al 2009;Dharma Rao et al 2012;Purohit et al 2012;Arora et al 2017) supports the model of separate magmatic events. Magmatic rocks of both these age groups have also been identified in Nagarparkar of SE Pakistan (Khan et al 2012;Jan et al 2014Jan et al , 2017, in Madagascar (Archibald et al 2016) and in South China (Wang et al 2010;Zhang and Zheng 2013) and have been related to the Neoproterozoic rifting of the continental crust along the periphery of the Rodinia supercontinent (Li et al 2010;de Wall et al 2018).…”

Aravalli Craton and its Mobile Belts: An Update

“…Orogeny: The supracrustals of Sirohi and Sindreth groups represents youngest sequences of Delhi Supergroup (Fig-1). Arora et al (2017) observed that the Sirohi metasediments were (i) deposited over a basement of 892 ±10 Ma old Erinpura granites (ii) metamorphosed under low to medium grade metamorphism at 822±29 Ma and (iii) the formational trends and the pervasive fabric in the metasediments are in NW-SE direction which corroborates well with the aeromagnetic signatures of this terrain (Fig. 1C: Gouda et al 2015).…”

“…The structural data, therefore, suggest an intense effect of the Aravalli and Delhi orogenies to generate the most prolific AF 1 folds in the Aravallis and AF 2 + (DF 1 +DF 2 ) fold phases in the Aravali-Delhi rocks. The musings over the effects of another younger orogeny such as Sirohi orogeny (Arora et al, 2017) or Champaner orogeny (Roy, 1988,p.22), however, requires more detailed studies for confirmation.…”

The use of heavy mineral chemistry in reconstructing provenance: A case study from Mesozoic sandstones of Kutch Basin, India

“…Transparency of symbols increased to avoid overlap of data points and to highlight compositional fields. Data sources: BGC—Sharma & MacRae, 1981, Dasgupta, Guha, Sengupta, Miura, & Ehl, 1997; ASG—Lal, Nagpaul, & Sharma, 1976, Roy, Kröner, Bhattachaya, & Rathore, 2005, Bhowmik, Bernhardt, & Dasgupta, 2010, Prakash et al, 2018; DSG—Bhowmik, Dasgupta, Baruah, & Kalita, 2018; SG—Arora, Pant, Sharma, & Sadiq, 2017 [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…The Mesozoic garnets, bearing amphibolite facies source signatures, are similar to those in rocks of the Aravalli Supergroup (Bhowmik et al, 2010; Lal et al, 1976; Prakash et al, 2018; Roy et al, 2005) (Figure 4c) and the Banded Gneissic Complex (Figure 5c). A few garnets, bearing amphibolite facies signatures in the Jhumara and Jhuran formations, resemble those of the Sirohi Granite (Arora, Pant, et al, 2017). Therefore, corroborating results from zircon and monazite geochronology (Chaudhuri, Das, et al, 2020), the mineral chemistry of garnets indicates the presence of sediment detritus from the Banded Gneissic Complex, Aravalli, and Delhi supergroups in the Mesozoic sedimentary succession of the Kutch Basin.…”