Penetrative strain data

The file contains the penetrative strain data from ~3.4 km of the leading-edge exposure of the Ramgarh thrust (RT) sheet in Darjeeling-Himalaya. To estimate finite penetrative strain, we analyzed 15 oriented quartzite samples from ~3.4 km of the Ramgarh thrust (RT) sheet. We made three oriented thin sections per sample: a-parallel to the transport direction, b-perpendicular, and c-oblique (Figure 3b). All 45 thin sections were cut perpendicular to the foliation. We measured the axial ratio (Rs) and long axis orientation (X) with respect to the horizontal (ϕ) of ~80-100 deformed quartz grains, approximating an elliptical shape, from each thin section using NIS-Elements D and EllipseFit software (Vollmer, 2010, 2011a, 2011b, 2017, 2019). Following Parui et al. (2022) and Parui and Bhattacharyya (2024), we calculated the best-fit strain ellipse (Rs and ϕ) for each thin section using the Eigen vector method (Shimamoto & Ikeda, 1976) and performed a bootstrap error analysis of 5000 resamples. We used Rs and ϕ values from three thin sections to construct the 3D best-fit strain ellipsoid for each sample (Figure 3d) using the best-fit Ellipsoid program in Mathematica (Mookerjee & Nickleach, 2011). The orientations of principal strain axes have been structurally restored by unfolding the structure.