Describe chemically formed sedimentary rocks under the following headings:
(a) mode of formation;
(b) three examples
(c) four importance
Explanation
a.Mode of formation of chemically formed sedimentary rocks
-materials for the formation may be obtained from streams, glacier, winds or organisms
-formed from the accumulation of materials derived from other rocks
-accumulation over a long period of time
-accumulation of these sediments usually under water
-formed through chemical precipitation from rock solutions
-cementation of precipitated rocks
-hardening of cemented rocks
-accumulation of sediments in layers/strata
-variation in thickness of strata
b.Examples of chemically formed sedimentary rocks
-rock salt
-Nitrates
-Gypsum/calcium sulphate
-dolorite
-dolomite(calcium carbonate)
-potash
-limorite(iron stone)
-limonite
-flint(silicate)
c.importance of chemically formed sedimentary rocks
-source of minerals
-construction purposes
-as ornaments
-tourist attraction
-soil formation
-raw materials for industries
-food