Improvement Of The U-Th Method For Dating Of Impure Calcite Having A Large Amount Of Clay And Very Low Uranium Content

Abstract The U-Th method also called series method of uranium is improved by a new experimental protocol and successfully applied to the impure calcite with uranium concentration 005 dpmg which was previously difficult to be dated accurately. Our experiments performed on 15 calcite samples taken from France and Morocco have highlighted the importance of this methodological improvement by enabling i the elimination of 100 of clay residues ii the reduction of calcite quantity necessary to the chemical manipulation from 20g to 5g iii the analysis of calcite samples poor in uranium and on the other hand rich with clay and iiii the reduction of the lower limit of the U-Th method from 10 Kyrs to 6 Kyrs. The optimization of U-Th method in this work provided a better dating of the accurate age of calcite. Thus this technique is important for the chemical analysis of stalagmite floors of different caves in the region of the Near East.