Which is the inverse order of evaporite deposition?

• A. Sylvite, halite, anhydrite, calcite
• B. Calcite, anhydrite, halite, sylvite
• C. Halite, sylvite, calcite, anhydrite
• D. Gypsum, halite, sylvite, calcite

Answer: (A)

As evaporite deposition proceeds, minerals precipitate in order of the brine’s saturation as it becomes more concentrated. Minerals with lower solubility come out first, while those with higher solubility require more evaporation to crystallize. In a typical evaporative sequence, calcite (a carbonate) forms early, followed by sulfate minerals like gypsum or anhydrite, then halite (table salt), and finally the highly soluble potassium salts such as sylvite as salinity reaches its peak. Therefore, the reverse of that sequence—starting with the mineral that forms last and ending with the first to crystallize—would be sylvite, halite, anhydrite, calcite. This matches the correct choice.