GENERAL GEOLOGY

Detailed explanation-1: -The sedimentary rock cover of the continents of the Earth’s crust is extensive (73% of the Earth’s current land surface), but sedimentary rock is estimated to be only 8% of the volume of the crust. Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks.

Detailed explanation-2: -In other words, 80–90 percent of the surface area of Earth is mantled with sediment or sedimentary rocks rather than with igneous or metamorphic varieties.

Detailed explanation-3: -Sediments are loose, unconsolidated rock particles and ions (i.e., charged atoms) dissolved in aqueous solutions. Sedimentary rocks, which constitute about 75% of all rocks exposed at the surface of the Earth, form when the particles are cemented together or when crystals precipitate from the solutions.

Detailed explanation-4: -Sedimentary rocks cover 75% of continents. Sedimentary rocks are sediments that have been compacted and cemented to form solid rock bodies (lithified). The original sediments can be composed of: 1) Fragments of other rocks and minerals, such as gravel from a river, sand from a beach (or desert), mud from a deep ocean.

Detailed explanation-5: -Igneous and metamorphic rocks represent 90-95 percent of the outer 10 miles of crust. But, at Earth’s surface, sediments and sedimentary rocks cover about 75 percent of land areas, and sediments cover the majority of the ocean floor.