Carbon dating of wood
Dates above and below a location provide minimum and maximum age determinations according to the law of superimposition.Thermoluminescence is a similar technique to optical dating, but uses heat instead of light to stimulate the minerals.Each helium nucleus has two protons and two neutrons.Under very hot temperatures — greater than 100,000,000 Kelvin (179,999,540.6 F) — the helium nuclei begin to fuse, first as pairs into unstable 4-proton beryllium nuclei, and eventually, as enough beryllium nuclei blink into existence, into a beryllium plus a helium.Working out how old archaeological remains are is a vital part of archaeology.Scientific dating has confirmed the long residence of Aboriginal people in Australia.Carbon is also the key ingredient for most life on Earth; the pigment that made the first tattoos; and the basis for technological marvels such as graphene, which is a material stronger than steel and more flexible than rubber.[See Periodic Table of the Elements] Carbon occurs naturally as carbon-12, which makes up almost 99 percent of the carbon in the universe; carbon-13, which makes up about 1 percent; and carbon-14, which makes up a minuscule amount of overall carbon but is very important in dating organic objects.
Complex dating problems often use a variety of techniques and information to arrive at the best answer.
The measurement is based on an isotope of potassium that radioactively decays at a known rate into argon.
K-Ar dating has been used to date lava flows above and below archaeological deposits that contain important hominid fossils in Africa's Olduvai Gorge.
Optical dating, also known as optically stimulated luminescence (OSL), dates the last time mineral sediments (usually quartz or feldspar grains ) were exposed to sunlight.
In the Willandra area it is typically used on quartz sand grains which have been buried and have not been exposed to sunlight since burial.