Useries isotopic composition of kasolite associat

Authors: Yehia H Dawood Hamdy H Abd ElNaby Bassam Ghaleb

Publish Date: 2013/05/16

Volume: 7, Issue: 7, Pages: 2881-2892

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Abstract

Uranium and thorium isotopic composition of kasolite PbUO2SiO4H2O from Jabal Sayid area was determined by thermal ionization mass spectrometry Secondary electron imaging backscattered electron imaging and energy dispersive spectral scans were used to investigate the mineralogical characteristics of this uranyl mineral phase Distinct crystal faces and crystal growth of kasolite from the study area confirm mineral precipitation near the surface from the circulating groundwater The obtained data were used to interpret the mechanism of uranium mobility in Jabal Sayid weathering profile and to construct a tentative model to explain the isotopic evolution of uranium and thorium This model indicates that 1 uranium was leached at depth 2 uranyl mineralization was precipitated along fractures and cavities in the host rocks during humid conditions and pluvial periods 3 preferential leaching of 234U from uranyl mineralization by recoil processes was continuous indicative of a weakly circulating groundwater and 4 234Udeficiency resulted in isotopic signatures characterized by low 234U/238U and high 230Th/234U ratios The modification pattern of these activity ratios suggests that uranyl mineralization of Jabal Sayid most probably has been precipitated during the same Late Quaternary pluvial periods responsible for the formation of the corresponding mineralizations in the Eastern Desert of EgyptThis paper was funded by the Deanship of Scientific Research DSR King Abdulaziz University Jeddah under grant no 3145D1432 The authors therefore acknowledge with thanks DSR technical and financial support GEOTOP Research center in Montreal Canada is acknowledged for carrying out U and Th isotope analyses

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