Evaporites are sediments formed by the evaporation of seawater. Which statement best characterizes them?

• A. A sequence of minerals deposited in order
• B. A homogeneous rock type with a single mineral dominating
• C. A random mix of minerals with no defined order
• D. A quartz-rich metamorphic aggregate

Answer: (A)

Evaporites form as seawater or saline lake water evaporates, causing dissolved ions to precipitate as minerals in a predictable order as salinity increases. Because minerals have different solubilities, they precipitate step by step: less soluble minerals come in later, creating a sequence of deposits rather than a single mineral dominating. This results in layers that reflect the progressive evaporation, so the best description is a sequence of minerals deposited in order. The other statements don’t fit: evaporites are not a uniform rock with one mineral; they aren’t a random mix with no defined order; and they are not quartz-rich metamorphic rocks.