Pict. 1.8. Radiolarite                                                                   Pict. 1.9. Diatomite

Evaporite sedimentary rocks are composed of minerals formed from the evaporation of water. Marine evaporites tend to have thicker deposits and are usually the focus of more extensive research. They also have a system of evaporation. The first phase of the experiment begins when about 50% of the original water depth remains. At this point, minor carbonates begin to form. The next phase in the sequence comes when the experiment is left with about 20% of its original level. At this point, the mineral gypsum begins to form, which is then followed by halite at 10%, excluding carbonate minerals that tend not to be evaporates. The most common minerals that are generally considered to be the most representative of marine evaporates are calcite, gypsum and anhydrite, halite, sylvite, carnallite, langbeinite, polyhalite, and kanite (Pict. 1.10.). Kieserite (MgSO₄) may also be included, which often will make up less than four percent of the overall content. However, there are approximately 80 different minerals that have been reported found in evaporite deposits, though only about a dozen are common enough to be considered important rock formers. Evaporite rocks commonly include abundant halite (rock salt), gypsum, and anhydrite.