GEOLOGY

Detailed explanation-1: -We find molds where an animal or plant was buried in mud or soft soil and decayed away, leaving behind an impression of their bodies, leaves, or flowers. Casts are formed when these impressions are filled with other types of sediment that form rocks, which take the place of the animal or plant.

Detailed explanation-2: -Sometimes when an animal dies and its body decays, it can leave an imprint in the sediment. If this imprint fills in with minerals from sediment and groundwater, it can harden to form a fossil. This fossil is called a cast fossil. The fossilized imprint is called a mold fossil.

Detailed explanation-3: -Molds and casts are three-dimensional impressions in which the surface contours of an organism are preserved. Organisms buried in sediment slowly decompose, leaving a cavity that contains an exact imprint of the organisms’ shape and size.

Detailed explanation-4: -Preserved evidence of the body parts of ancient animals, plants and other life forms are called ‘body fossils’. ‘Trace fossils’ are the evidence left by organisms in sediment, such as footprints, burrows and plant roots.

Detailed explanation-5: -Impression fossils form when the organisms original bone or tissue is removed by processes that occur after burial, such as ground water flow. If the organisms remains are decomposed entirely, leaving an empty space in the shape of the organism, it is referred to as a cast.