Source of brines feeding sabkha anhydrite growth

 At the broadest scale, modern deserts result from large-scale atmospheric circulation cells. Local variation  is influenced by factors such as the presence of rain shadows (adiabatic deserts), mild desert climates located near zones of cool upwelling ocean currents, and deserts formed due to continentality.

Subaqueous halite in the deeper Dead Sea Basin, Middle East

The current seasonal thermal layering in the Northern Basin makes it a magnificent analog basin for deepwater halite and textural variations outside the chevron-rafte dominated systems we know in halite saturated brine bottoms that are less than a few metres deep.

World-scale controls of the distribution of modern deserts and their salts

 At the broadest scale, modern deserts result from large-scale atmospheric circulation cells. Local variation  is influenced by factors such as the presence of rain shadows (adiabatic deserts), mild desert climates located near zones of cool upwelling ocean currents, and deserts formed due to continentality.

Clays in saline sumps

Fine-grained clays can be found in both modern and ancient evaporite deposits. They appear in layers and as dispersed particles within and between various salt crystals. Historically, studies of many continental salt lakes have shown that much of the clay in a play or saline pan originates from suspended load, brought in by occasional fluvial or storm-derived sheet floods. However, in the vast extent of ancient evaporite seaways, most of the fine materials were transported as wind-suspended (eolian) dust.

Hydrothermal carbonate - a nonevaporite

In this video we delve into the fascinating world of hydrothermal carbonate precipitates. Precipitation of non-solar mineral salts (aragonite-calcite-brucite) is chemosynthetically facilitated by methanogenesis and the escape of associated hydrogen and abiogenic short-chain hydrocarbons. Over 30,00 years, the vents have created huge seafloor vent chimneys, all hosted atop faulted and fractured regions of mantle exposure and serpentinisation in water depths ranging from the abyssal to the photic zone.

Hydrothermal anhydrite - a nonevaporite

The video  explores retrograde solubility in and near active mid-oceanic ridges, where black and white smokers occur, with significant volumes of anhydrite. In the a later video, we'll look at zones of deeply circulating marine brine atop zones of serpentinite formation. This is a chapter video from Module 6 - Salts that are not “true" evaporites. 

Sedimentary Copper: An introduction

Historically, most models of ore genesis in stratiform sedimentary copper (SSC) deposits mention the presence of evaporites but lack detail on why particular evaporite styles, textures, and structures are so important. At best, there are statements like, “There are sabkha associations with some sedimentary copper deposits.”
But such proposed ties to syndepositional brines and saline mudflats are simply wrong. What is correct is that all giant and supergiant sedimentary copper deposits are associated with evaporites. However, the evaporite association is epigenetic and begins in the subsurface with mega-evaporites at the plate tectonic scale. The association is dynamic and evolves across the burial realm as salt flows and alters. These subsurface processes set up the appropriate brine chemistries and salt edge positions for copper accumulations across settings ranging from the diagenetic into the greenschist and amphibolite realms.

Copper, zinc and salt in the Red Sea rift - Atlantis II Deep

In this video, I focus on the cupriferous hydrothermal laminites of the Atlantis II Deep in the Red Sea and discuss the role of evaporites interacting with rift brines in the enrichment of metals in this deposit. In the Atlantis II Deep in the axial-rift deepwater sediments of the Red Sea, significant volumes of base metals are accumulating in a halokinetic rift province.
It is a modern, world-class Zn-Cu deposit, hosted in deepwater siliceous ferruginous laminites. Some have called it a SedEx deposit; others consider it a sedimentary copper deposit because of the elevated levels of copper. It has aspects of both. I prefer to call it an example of a halokinetically-focused, brine-focused, metal accumulation. Dissolution of adjacent halokinetic salt sets up bottom brine pools where anoxic metal-rich hydrothermal brines are seeping and ponding into sumps on the deep seafloor. Cooling and mixing between the stratified bottom-brine layers and volcanics-derived copper in the pools sets up redox precipitates that accumulate as laminates containing very fine-grained zinc and copper sulphide minerals.

Salt Tectonics

Salt Tectonics: Overview

Across the world's salt basins, oil and gas fields form under the influence of flowing salt, as do many base and precious metal ores. Understanding how and why flowing salt creates structure is critical to practical exploration and development.

Dolomite

Dolomite problem: Phanerozoic 

Large-scale models of carbonate dolomitisation, including reflux dolomitisation by mesohaline to hypersaline brines, mixing of seawater and groundwater, and hydrothermal circulation of seawater.