A.J. Bartel J.N. Rosholt 1969 <div id="abstracts" class="Abstracts u-font-serif"><div id="ab1" class="abstract author" lang="en"><div id="aep-abstract-sec-id4"><p>Uranium, thorium and lead concentrations and isotopic compositions were determined on total rocks and a feldspar sample from widely separated parts of the Granite Mountains in central Wyoming. Linear relations defined by²⁰⁶Pb/²⁰⁴Pb −²⁰⁷Pb/²⁰⁴Pb and²⁰⁸Pb/²⁰⁴Pb −²³²Th/²⁰⁴Pb for the total rock samples define 2.8 billion-year isochrons. In contrast,²³⁸U/²⁰⁶Pb ages are anomalously old by a factor of at least four. The low²³⁸U/²⁰⁴Pb values, coupled with the radiogenic²⁰⁶Pb/²⁰⁴Pb and radiogenic²⁰⁷Pb/²⁰⁴Pb ratios, indicate that contents of uranium in near-surface rocks would have had to have been considerably greater than those presently observed to have generated the radiogenic lead. It is possible that more than 10¹¹<span>&nbsp;</span>kg of uranium has been removed from the Granite Mountains, and the most feasible interpretation is that most of this uranium was leached from near-surface rocks at some time during the Cenozoic, thus providing a major source for the uranium deposits in the central Wyoming basins.</p></div></div></div> application/pdf 10.1016/0012-821X(69)90028-4 en Elsevier Uranium, thorium, and lead systematics in Granite Mountains, Wyoming article