sedimentary rock
n. C / U B2 Upper Intermediate
n. a type of rock that forms when layers of sand, mud, and small stones are pressed together over a very long time.
n. a rock type formed by the accumulation and lithification of mineral or organic particles at the Earth's surface.
Sandstone is a common type of sedimentary rock.
Scientists study layers of sedimentary rock to see how the local climate has changed over millions of years.
The preservation of delicate fossils is most common within sedimentary rock formations, where fine silt can quickly cover and entomb organic remains before decay occurs.
Usage
Uncountable when referring to the material in general; countable when referring to specific geological classifications or types.