One of the isotope pairs widely used in geology is the decay of K is a radioactive isotope of potassium that is present in very small amounts in all minerals that have potassium in them.
It has a half-life of 1.3 billion years, meaning that over a period of 1.3 Ga one-half of the Figure 8.14 The decay of 40K over time.
The Accelerator Mass Spectrometry Group operates the AMS resources at ANSTO, including the measurement capabilities at the Australian National Tandem for Applied Research (ANTARES), the two million volt tandem accelerator STAR and sample processing and target preparation in the AMS chemistry laboratories.
Radiocarbon carbon-14 dating is a well-known method for determining the age of materials up to the age of 50,000 years.
The course will briefly outline the fundamental principles and applications of a range of non-radiometric dating techniques used in archaeology, including: amino acid racemization, archaeomagnetism, dendrochronology, electron spin resonance (ESR), and luminescence.
On completion of the course students should have acquired a knowledge and understanding of: - the fundamental principles of each technique and the instrumentation employed to make the measurements; - archaeological applicability and limitations of the various techniques; - the essential differences between non-radiometric and radiometric dating techniques.
To read in more depth print off our fact sheet (pdf).[SE] In order to use the K-Ar dating technique, we need to have an igneous or metamorphic rock that includes a potassium-bearing mineral.One good example is granite, which normally has some potassium feldspar (Figure 8.15).Radiocarbon dating is possible in diverse materials, such as charcoal, bones, textiles, foramifera, pollen grains and rock art, to name just a few.In some instances, ANSTO is capable of radiocarbon dating samples containing just five micrograms of carbon.Age and origin of ground water Radiocarbon and tritium analyses provide age-related information about the water from sandstone aquifers in the Sydney Basin assisted water authorities to identify groundwater sources that might be exploited sustainably.Regional and global climate variability Measurement of carbon-14 and stable isotopes in southern hemisphere tree rings, cave structures and corals provided researchers information on variations in atmospheric transport, ocean water circulation and rainfall over the last 15 000 years.ANSTO boasts world-class tandem accelerator facilities that can detect minute quantities of carbon-14 and a range of other long-lived naturally-occurring radioisotopes (e.g.beryllium-10 and aluminium-26) in a variety of materials, gaseous, liquid and solid.Ocean water circulation ANSTO researchers used radiocarbon dating of coral samples collected in 1836 from the Cocos (Keeling) Islands to gain valuable insights into the upward movement of deep ocean waters in the north-western Indian Ocean.Continental glacial cycles Researchers have tested for beryllium-10 and aluminium-26 in exposed rocks to date the ebb and flow of alpine glacier systems in the southern hemisphere over the past 100,000 years.