Tectonic evolution of the Madawara greenstone belt, southern Bundelkhand craton, central India: a window to see the Meso- to Neoarchaean geodynamics

ABSTRACT

The Palaeo- to Neoarchaean Bundelkhand Craton (BkC) in central India has received attention due to its felsic crust evolution. There are two linear patches of relict greenstone belts in the BkC, and the central greenstone belt has been the focus of extensive research for the past two decades. In contrast, the southern greenstone belt has received inadequate attention. At the southern BkC, the E-W Madawara Greenstone Belt is represented by patches of remnant mantle serpentinites and metasedimentary rocks that are tectonically juxtaposed with Archaean basement TTG gneisses and Proterozoic Bijawar Group of rocks. This study highlights key findings from fields, geological maps, petrography, and a large number of whole rock chemical analyses of serpentinites and spinel chemistry to unravel the tectonic evolution story. We identified two serpentinites with contrasting petrological and geochemical properties: spinel peridotite (SP) and talc-tremolite schist (TTS). SP is primarily dunite to harzburgite with relatively high MgO (33 wt%), enriched Yb, and shows strong re-fertilization. TTS, on the other hand, is lherzolitic and less refractory (MgO = 25 wt%). Chemically, these two serpentinites were mantle wedge and subducted peridotites, respectively. The unaltered cores of the chromium spinels represent a fore-arc setting. These findings, in conjunction with prior research, paint a compelling picture of a Neoarchaean (~2.5 Ga) subduction system once present in the southern Bundelkhand Craton. The serpentinites represent relict ophiolites – from a northerly dipping trench. It also explains a Mesoarchaean rift basin system between the two cratonic nuclei of southern Bundelkhand, which amalgamated during the Kenorland Supercontinent formation.

KEYWORDS:

• Serpentinite
• Bundelkhand Craton
• spinel chemistry
• subduction
• Madawara

Acknowledgments

This study benefited from geological mapping and a subset of the chemical data obtained through the Geological Survey of India’s (GSI) annual programme in the Bundelkhand Craton. We sincerely thank the EPMA Laboratory at NCEGR, GSI, Kolkata, for analysing the spinel chemistry data. We are grateful to Dr Robert Stern for his efficient manuscript handling and initial suggestions. We would also like to thank the two anonymous reviewers for their insightful comments, which have greatly improved the work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00206814.2024.2370506

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.