Evaporite deposition and seafloor spreading are two salient geological processes in the geological history of the Red Sea. We piece together the available evidence about rift evolution and evaporite formation to constrain the deposition history, analyze creep, and advance a plausible explanation for the preservation of these soluble formations. At the end of evaporite deposition before the Indian Ocean flooded the Red Sea through the Bab al-Mandab's strait, the salt thickness must have exceeded ~1.5 times the current thickness. Reported plate rotation, rift rates and the presence of a salt suture zone in the central Red Sea allow us to estimate an effective large-scale viscosity of 10¹⁸ Pa·s. Thinned salt along the southern Red Sea flows up to 5 mm/yr, creep cannot keep up with seafloor spreading and oceanic crust remains exposed. Vast alluvial fans and carbonate platforms cause salt withdrawal; corresponding seafloor settlement rates can exceed ~10 mm/yr and overtake coral reef production. Salt dissolution leaves behind a residual sediment cap made of insoluble minerals that gradually retards further dissolution, i.e., self-armoring. New experimental evidence and the numerical solution of diffusion with a moving boundary show that self-armoring by selective dissolution controls early evaporite dissolution while background sedimentation dominates sediment accumulation over long time scales. Armoring-delayed evaporite dissolution prevents the formation of a vast regional brine pool.

蒸发岩沉积和海底扩张是红海地质史上两个突出的地质过程。我们将有关裂谷演化和蒸发岩形成的现有证据拼凑在一起，以限制沉积历史，分析蠕变，并为这些可溶性地层的保存提出合理的解释。在印度洋通过 Bab al-Mandab 海峡淹没红海之前的蒸发岩沉积结束时，盐的厚度必须超过当前厚度的约 1.5 倍。报告的板块旋转、裂谷速率和红海中部盐缝合带的存在使我们能够估计 10 ^{18的有效大尺度粘度} 帕·秒。沿红海南部稀薄的盐以每年 5 毫米的速度流动，蠕变跟不上海底扩张，洋壳仍然暴露在外。巨大的冲积扇和碳酸盐台地导致盐分撤退；相应的海底沉降率可能超过约 10 毫米/年，并超过珊瑚礁的产量。盐溶解留下由不溶性矿物构成的残余沉积物盖帽，逐渐延缓进一步溶解，即自我铠装。新的实验证据和具有移动边界的扩散数值解表明，通过选择性溶解的自装甲控制了早期的蒸发岩溶解，而背景沉积在长时间尺度上主导了沉积物的积累。装甲延迟蒸发岩溶解阻止了巨大的区域盐水池的形成。