Middleton was the first scientists in 1844 who recognized the older the fossils in age the bigger the content of their fluorine. Later this idea was applied by Oakley in 1951 for dating many prehistoric human and animal remains in order to place them in the correct time relations.
Bones are primarily composed of the mineral calcium hydroxy apatite. When bones were buried in the soil than fluoride ions (F-) that are present in trace amounts in most soils and also in groundwaters will replace a hydroxyl ion (OH-) in the bone mineral. The resulting fluor-apatite is more stable than the original form.
This concept is used for determination the relative age of archaeological specimens but cannot provide a calendrical date unless the fluoride chronology is calibrated with an absolute dating method. This method is called Fluoride (or fluorine) dating.
By this method Oakley et.al (1975) and Matsu’ura (1985) had carried out the determination of the relative age of some H.erectus speciemens from Sangiran.
As we have known that in Sangiran the stratigraphical provenance of the bone specimens ranging from the Upper Tuff (Kabuh) to T3 tuff (Pucangan). These layers, based on fission track date for tektites and primary zircon grains from several tuff layers found in the Kabuh and Pucangan formations, span the time from 0.7 to 1.6 million years ago.
Institut für Anthropologie, Universität Mainz