Reply to Charrach (2019) comment on “Mount Sedom salt diapir - Source for sulfate replenishment and gypsum supersaturation in the last glacial Dead Sea (Lake Lisan)” by Levy et al. (2019)

Abstract

The main comment by Charrach (2019) on the Levy et al. (2019) paper is that the Sedom salt diapir could not have been a source for sulfate to Lake Lisan (last glacial Dead Sea), arguing that the dissolution of the salt diapir started following the onset of the Holocene Dead Sea. We refute the comment for the following reasons: (1) The nature of the unconformity between the salt diapir and the overlying sediments indicates that it emerged from the surface prior to the last glacial and was submerged in Lake Lisan; (2) The formation of a ∼40 m thick layer of dissolution residue (caprock) sitting on an almost flat dissolution unconformity surface (salt mirror) suggests that 600 m-to-800 m thick layer of Sedom Fm. was dissolved under phreatic settings. During most of the Holocene, the diapir has been subjected to vadose type dissolution which formed karst cutting through the caprock, salt mirror and rock-salt below; (3) Based on the Charrach (2019) hypothesis, estimated diapir uplift rates during the early Holocene would have required to be an order of magnitude higher than the measured and calculated rates for the present and Holocene, respectively, provided by other studies; (4) Na/Ca ratios from primary aragonite in the Lisan Fm. found at the vicinity of Mt. Sedom, as well as Na/Cl ratios, saturation state of halite and isotopic composition of chloride in the pore fluids from the deep Dead Sea Deep Drilling Project (DSDDP) core 5017-1-A, suggests significant dissolution of halite from Mt. Sedom into Lake Lisan. In addition to halite, dissolution of the next abundant evaporite mineral, anhydrite, resulted in mobilization of sulfate to the lake.