Absolute age dating definition
Local relationships on a single outcrop or archaeological site can often be interpreted to deduce the sequence in which the materials were assembled.This then can be used to deduce the sequence of events and processes that took place or the history of that brief period of time as recorded in the rocks or soil.To date past events, processes, formations, and fossil organisms, geologists employ a variety of techniques.These include some that establish a relative chronology in which occurrences can be placed in the correct sequence relative to one another or to some known succession of events.$(call my-dir) is calling macro function "my-dir", defined in /build/core/definitions.mk, you can check the definition of the macro, It finds the directory for ndk-build script to start working.
It may be used to date a wide range of natural and man-made materials.Radiometric dating and certain other approaches are used to provide absolute chronologies in terms of years before the present.The two approaches are often complementary, as when a sequence of occurrences in one context can be correlated with an absolute chronlogy elsewhere.It should be emphasized that linking sites together is essential if the nature of an ancient society is to be understood, as the information at a single location may be relatively insignificant by itself.
Similarly, in geologic studies, vast quantities of information from widely spaced outcrops have to be integrated.
Elements exist in different isotopes, with each isotope of an element differing in the number of neutrons in the nucleus.