stylistic:tone
Caldera Basin is a sedimentary basin located in the coast of northern Chile west of Copiapó. The basin has a fill of marine sediments of Late Cenozoic age. With a north–south extension of 43 kilometres (27 mi) and an east–west width of 20 kilometres (12 mi) the basin occupies an area between the coast and the Chilean Coast Range and between the port of Caldera and the mouth of Copiapó River. The sedimentary fill rests on metamorphic rocks of Paleozoic age and on plutonic rocks of Mesozoic age.