GENERAL GEOLOGY

Detailed explanation-1: -The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer of rock is older than the one above it and younger than the one below it (Figures 1 and 2). Accordingly, the oldest rocks in a sequence are at the bottom and the youngest rocks are at the top.

Detailed explanation-2: -Superposition: The most basic concept used in relative dating is the law of superposition. Simply stated, each bed in a sequence of sedimentary rocks (or layered volcanic rocks) is younger than the bed below it and older than the bed above it.

Detailed explanation-3: -Geologists use the law of superposition and law of original horizontality to determine the relative ages of sedimentary rock layers. According to the law of superposition, in horizontal sedimentary rock layers the oldest is at the bottom. Each higher layer is younger than the layer below it.

Detailed explanation-4: -The layers in order are Cambrian, Ordovician, Silurian, Devonian, Carboniferous, (Mississippian and Pennsylvanian), Permian, Triassic, Jurassic, Cretaceous, Tertiary, and Quaternary. Sedimentary rock is the type of rock in which fossils are most likely to form.

Detailed explanation-5: -The age of rocks is determined by radiometric dating, which looks at the proportion of two different isotopes in a sample. Radioactive isotopes break down in a predictable amount of time, enabling geologists to determine the age of a sample using equipment like this thermal ionization mass spectrometer.