In our 2019 paper on the Salt Range of Pakistan (Hughes et al., 2019, p. 1108), we wrote, “Recognizing significant geological differences between neighboring rocks separated by a major high-strain zone is, according to Martin (2017, p. 62), fundamental to terrane recognition.” Martin’s (2017) contention had been that the Salt Range thrust provides such a case, but his response to our paper reports no data suggesting significant geological differences across this structure. To do so would be challenging because, as we reported in our paper (Hughes et al., 2019), two boreholes drilled on either side of the thrust, located less than 25 km apart, reveal the same stratigraphy in terms of the rock succession, unit thickness, detrital zircon spectra, and depositional age of both hanging-wall and footwall rocks (Siddiqui, 2012, fig. 5; Hughes et al., 2019, figs. 3, 4, 11, and 12). The suite of rocks shared on both sides of the fault includes a distinctive 1000-m-thick evaporite succession, an overlying 200-m-thick sandstone, and then a transition to carbonate. Accordingly, by Martin’s own definition of a terrane boundary, the Salt Range thrust is excluded. In his response to our paper, and in order to preserve the terrane model, Martin relaxes the requirement for significant geological differences between adjacent terranes and instead claims that lateral displacement of several thousand kilometers along a transform fault resulted in two successions being juxtaposed—two successions that are so similar that they cannot be distinguished. A parsimonious alternative explanation, that there is no terrane boundary along the Salt Range thrust, is the explanation that we offered in our paper. We stand by that interpretation for the reasons presented in our paper and expanded upon below. We also correct a typographic error in the conclusion to our paper, noting that our Salt Range detrital zircon spectra contain abundant zircons with 1000−550 Ma ages, not 100−550 Ma ages, as printed (Hughes et al., 2019, p. 1110).
Cambrian geology of the Salt Range of Pakistan: Linking the Himalayan margin to the Indian craton: Reply
- PDF LinkPDF
- Share Icon Share
- Search Site
Nigel C. Hughes, Paul M. Myrow, Shahid Ghazi, N. Ryan McKenzie, Daniel F. Stockli, Joseph A. DiPietro; Cambrian geology of the Salt Range of Pakistan: Linking the Himalayan margin to the Indian craton: Reply. GSA Bulletin doi: https://doi.org/10.1130/B35365.1
Download citation file: