Jos Map of Nigeria showing the major sites of the Nok culture clickable map Preliminary excavations at the beginning of January began near a remote valley named Taruga near the village of Takushara. The trial excavations took place during a period of eight days. The finds included objects of wrought iron , a quantity of iron slag, fragments of tuyere , pottery, figurine fragments, red ocher , quartz hammer-stones, and small concentrations of charcoal. The most famous finds at the site were the pottery graters which were shallow, flat-bottomed dishes which were deeply scored inside with diced patterns to produce a sharp abrasive surface.

These pottery graters were probably used for food preparation.

Implications of burial alterations on luminescence dating of archaeological ceramics. tions on luminescence dating of ancient pottery, in- In luminescence dating, the potassium.

Functionality Natural crystalline materials contain imperfections: These imperfections lead to local humps and dips in the crystalline material’s electric potential. Where there is a dip a so-called ” electron trap” , a free electron may be attracted and trapped. The flux of ionizing radiation—both from cosmic radiation and from natural radioactivity —excites electrons from atoms in the crystal lattice into the conduction band where they can move freely. Most excited electrons will soon recombine with lattice ions, but some will be trapped, storing part of the energy of the radiation in the form of trapped electric charge Figure 1.

Depending on the depth of the traps the energy required to free an electron from them the storage time of trapped electrons will vary as some traps are sufficiently deep to store charge for hundreds of thousands of years. In practical use In thermoluminescence dating, these long-term traps are used to determine the age of materials: