SPECIAL ISSUE ARTICLE Geochemistry, petrogenesis, and geodynamic implications of NE–SW to ENE–WSW trending Palaeoproterozoic mafic dyke swarms from southern region of the western Dharwar Craton Apratim K. Rai 1,2 | Rajesh K. Srivastava 1 | Amiya K. Samal 1 | Valiveti Venkata Sesha Sai 3 1 Centre of Advanced Study in Geology, Institute of Science, Banaras Hindu University, Varanasi, India 2 Geological Survey of India, Northern Region, Lucknow, India 3 Geological Survey of India, Central Region, Nagpur, India Correspondence Rajesh K. Srivastava, Centre of Advanced Study in Geology, Institute of Science, Banaras Hindu University, Varanasi 221005, India. Email: rajeshgeolbhu@gmail.com Funding information Council of Scientific and Industrial Research, India, Grant/Award Number: 24 (0348)/17/ EMR‐II); UGC‐CAS‐II, Grant/Award Number: 5055; DST‐PURSE, Grant/Award Number: 5050 Handling Editor: K.R. Hari A number of NE–SW to ENE–WSW trending Palaeoproterozoic mafic dykes, intruded within the Archean basement rocks and more conspicuous in the southern parts of the western Dharwar Craton (WDC), was studied for their whole‐rock geochemistry to understand their petrogenetic and geodynamic aspects. Observed mineralogical and tex- tural characteristics classify them either as meta‐dolerites or dolerites/olivine‐dolerites. They show basaltic to basaltic–andesitic compositions and bear sub‐alkaline tholeiitic nature. Three geochemically distinct groups of mafic dykes have been identified. Group 1 samples show flat REE patterns (La N /Lu N = ~1), whereas the other two groups have La N /Lu N = ~2–3 (Group 2; enriched LREE and flat HREE patterns) and La N /Lu N = ~4 (Group 3; inclined REE patterns). Chemistry is not straightforward to support any signif- icant role of crustal contamination and probably reflect their source characteristics. How- ever, their derivation from melts originated from a previously modified metasomatized lithospheric mantle due to some ancient subduction event cannot be ignored. Most likely different mantle melts were responsible for derivation of these distinct sets of mafic dykes. The Group 2 dykes are derived from a melt generated within spinel stability field by ~10% batch melting of a lithospheric mantle source, whereas the Group 3 dykes have their derivation from a melt originated within the spinel–garnet transition zone and were fed from slightly higher (~12–15%) batch melting of a similar source. The Group 1 sam- ples were also crystallized from a melt generated at the transition zone of spinel– garnet stability field by higher degrees (~20%) of melting of a primitive mantle source. Geochemistry of the studied samples is typical of Palaeoproterozoic mafic dykes emplaced within the intracratonic setting, reported elsewhere globally as well as neighbouring cratons. Geochemistry of the studied mafic dyke samples is also compared with the mafic dykes of the eastern Dharwar Craton (EDC). Except the Group 3 samples, which have good correlation with the 1.88–1.89 Ga Hampi swarm, no other group shows similarity with the EDC mafic dykes. There is an ample possibility to have some different mafic magmatic events in the WDC, which could be different from the EDC. However, it can only be confirmed after precise age determinations. KEYWORDS geochemistry, geodynamic implications, mafic dyke swarms, Palaeoproterozoic, petrogenesis, southern India, western Dharwar Craton Received: 21 November 2018 Revised: 4 February 2019 Accepted: 5 February 2019 DOI: 10.1002/gj.3493 Geological Journal. 2019;1–23. © 2019 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/gj 1