Index fossil relative dating
Radiometric Dating and the Geologic Time Scale, The Talk Origins Archive. Provides brief overview of (1) relative dating and stratigraphic methods, (2) absolute dating and radiometric dating, including a table with parent to daughter isotopes and half lives of those isotopes commonly used in radiometric dating, (3) paleomagnetics and (4) geologic time. Includes tables of common radioactive parent isotopes and their stable daughter products, and half lives of common radioactive isotopes.
The Grand Canyon’s rock layers can be directly correlated with those of nearby Bryce Canyon and Zion Canyon, for example. Let’s say at site 1 you have a set of fossils that are only found together in one particular layer. Fossils called are particularly useful for correlating layers.
Right: A crushed ammonite from the Shales-with-Beef Member, found on the foreshore beneath Black Ven.
Left: A large nautilus in cross-section on the surface of a foreshore boulder at Monmouth Beach, beneath Ware Cliffs. Norman Mac Leod and Dr Paul Davis at the Natural History Museum of London for their continued support and guidance identifying the stratigraphy of Black Ven and Church Cliffs.
Right: A second nautilus shell partly exposed on a foreshore boulder, also on the foreshore at Monmouth Beach. Edmonds, Discover Dorset - Fossils; The Geology of Britain, P. Picture credits: Crinoid by 'imran kmm' at ichthyosaur reconstruction, uk; plesiosaur by Doug Henderson.
References: British Lower Jurassic Stratigraphy, M. Toghill; A Dynamic Stratigraphy of the British Isles, A. Safety notice: Fossil hunting can at times pose a risk to personal safety, in particular within environments close to the coast, cliffs or in quarries and when using the tools and equipment illustrated.
They get uplifted, tilted, faulted, squashed and squeezed, and magma gets injected into them.