Relative and 'absolute' dating of land surfaces

摘要: Abstract The dating of land surfaces has long posed problems for geomorphologists. Relative methods (stratigraphic, geomorphic, topographic) are sound and convincing. Exhumed forms may complicate identification relationships, both epigene etch have been buried, exhumed, but in tectonically undisturbed areas, the higher older than those preserved at lower levels. Also, an age range. relationship with volcanic deposits, old shorelines, genetically related sedimentary sequences provides ages, correlation dated duricrusts faults is also useful. There no temporal limits to relative dating, equally applicable say, Proterozoic as Pleistocene age. disadvantage such that necessary evidence frequently either not or exposed. so-called ‘absolute’ (physical, numerical) methods, especially based on exposure situ cosmogenic radionuclides, appealing because they produce direct numerical appear be widely applicable, there severe limitations, sampling complicate, invalidate, interpretation. Absolute determinations must consistent stratigraphic geomorphologic settings. best results obtained when physicists earth scientists pool their knowledge experience. A background local regional geology important.