Red sea evaporites: Formation, creep and dissolution

Joshua E. Smith*, J. Carlos Santamarina

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

8 Scopus citations

Abstract

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.

Original languageEnglish (US)
Article number104115
JournalEarth-Science Reviews
Volume232
DOIs
StatePublished - Sep 2022

Bibliographical note

Funding Information:
Support for this research was provided by the KAUST Endowment at King Abdullah University of Science and Technology . Coastal & Marine Resources Core Lab assisted in field operations. We are grateful to A.M. Alafifi for insightful comments and to G.E. Abelskamp for editorial support.

Publisher Copyright:
© 2022 The Authors

Keywords

  • Evaporite dissolution
  • Marine evaporites
  • Red Sea rift
  • Salt tectonics
  • Self-armoring

ASJC Scopus subject areas

  • General Earth and Planetary Sciences

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