© 2015, Geological Society of India. Existence of an Archaean protolith is suggested in present study from an ensemble of rocks named as Sandmata Complex from northwestern India which have a debatable stratigraphic status of Archaean vs. Proterozoic. Rocks of the Sandmata Complex are represented by a highly metamorphosed volcano-sedimentary complex with multiple cycles of deformation. The manifold tectono-thermal events have obscured the pristine character of the protoliths. In this work we present geochemical features of calc-silicate protolith that show consistent Archaean affinity in the Hammer-Head Syncline (HHS) from southern part of the Sandmata Complex. Notable geochemical characteristics of calc-silicate metasediments in the HHS include high Th/U, high Cr concentrations, high La/Th, moderate La/Yb, and weak positive Eu anomaly. Carbon and oxygen stable isotope compositions of these carbonate metasediments vary between -3.0 and -0.3‰ (δ¹³Ccarb),- 11.6 and -35.0 (δ¹³Corg) and -19.1 and -13.4‰, (δ¹⁸O) respectively. These geochemical observations are in conjunction with the recently published Neoarchaean ages from the HHS and the proximal Hooke syncline.