Fluorine absorption dating

16 Dec

But because decomposition happens at different speeds in different places, it's not possible to compare bones from different sites.

As not all objects absorb fluorine at the same rate, this also undermines the accuracy of such a dating technique.

However, relative methods are , which is that if there are layers of deposits, those laid down first will be on the bottom and those laid down last will be on the top. However, geological strata are not always found to be in a neat chronological order.

Wind and water erode strata and some areas are uplifted or even tilted.

Bones are primarily composed of the mineral calcium hydroxy apatite.

When exposed to water that contains fluoride, a fluoride ion (F-) can replace a hydroxyl ion (OH-) in the bone mineral.

Items such as bone that are in the soil will absorb fluoride from the groundwater over time.

Fluorine absorption dating can be carried out based on the fact that groundwater contains fluoride ions.Thus, basaltic magmas tend to be fairly fluid (low viscosity), but their viscosity is still 10,000 to 100,0000 times more viscous than water.Rhyolitic magmas tend to have even higher viscosity, ranging between 1 million and 100 million times more viscous than water.In the past, relative dating methods often were the only ones available to paleoanthropologists.As a result, it was difficult to chronologically compare fossils from different parts of the world.(Note that solids, even though they appear solid have a viscosity, but it very high, measured as trillions time the viscosity of water).Viscosity is an important property in determining the eruptive behavior of magmas.Although this can be compensated for by accommodating for the rate of absorption in calculations, such an accommodation tends to have a rather large margin of error.In 1953 this test was used to easily identify that the 'Piltdown Man' was forged, almost 50 years after it was originally 'unearthed'.Alternatively it blast out solid pieces of rock that once formed the volcanic edifice.All of these fragments are referred to as Pyroclasts = hot, broken fragments. Depending on size, tephra can be classified as bombs. Rock formed by accumulation and cementation of tephra called a pyroclastic rock or tuff.