EVERYDAY SCIENCE

Detailed explanation-1: -A dike or dyke, in geological usage, is a sheet of rock that is formed in a fracture of a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin.

Detailed explanation-2: -Dikes are made of igneous rock or sedimentary rock. Igneous rock is formed after magma, the hot, semi-liquid substance that spews from volcanoes, cools and eventually becomes solid. Magmatic dikes are formed from igneous rock. Sedimentary rock is made of minerals and sediments that build up over time.

Detailed explanation-3: -Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma intrudes into a crack then crystallizes as a sheet intrusion, either cutting across layers of rock or through an unlayered mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.

Detailed explanation-4: -Compositions of dyke rocks vary from ultrabasic to acidic, and common types are dolerite, lamprophyre, microgabbro, microdiorite, granophyre, aplite, and felsite.

Detailed explanation-5: -A sill is a concordant intrusive sheet, meaning that a sill does not cut across preexisting rock beds. Stacking of sills builds a sill complex and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks.