Question

The mineral gypsum formed in lagoons that are fed by ocean waters that are high in calcium and sulfate. Slow evaporation and replenishment of the ocean water leads to the formation of thick sedimentary deposits of gypsum. Gypsum (calcium sulfate) is commonly found with rock salt (sodium chloride) and sulfate deposits. Limestone and shale may be found in between layers of gypsum. What can you conclude about rock salt and sulfate based on that evidence?

a) Rock salt and sulfate are not related.
b) Rock salt and sulfate often coexist.
c) Rock salt and sulfate are only found together in certain regions.
d) Rock salt and sulfate cause the formation of gypsum.

Answer 1

The evidence suggests that rock salt and sulfate often coexist, as both are commonly found in evaporite deposits resulting from the evaporation of mineral-rich water in lagoons.

Step-by-step explanation:

Based on the evidence provided, it can be concluded that rock salt and sulfate often coexist. This is evidenced by the fact that gypsum, a mineral composed of calcium sulfate, is commonly found alongside rock salt (sodium chloride) in evaporite deposits formed in lagoons. These lagoons are areas where water has evaporated, leaving behind salts and other minerals. Sedimentary deposits like gypsum and limestone form when dissolved minerals like calcium and sulfate are left behind after water evaporates.

Evaporite deposits, including rock salt (sodium chloride), gypsum (calcium sulfate), and anhydrite (anhydrous calcium sulfate), are formed in marine environments where evaporation exceeds the rate of replenishment of water. Furthermore, the chemical dissolution and precipitation process, during which calcium carbonate from sources like the remains of clams and corals transform into limestone deposits or cave formations, operate under similar principles of chemical sedimentation.

The continuous creation and deposition of these minerals suggest a close relationship, given the specific environmental conditions needed for their formation. Therefore, the correct conclusion to draw from the evidence is choice b) Rock salt and sulfate often coexist.