The water couldn't have been stagnant, because we see the export of protactinium
," said the study's lead author, Sharon Hoffmann, a geochemist at Lamont-Doherty.
In addition to the uranium, the ore usually also contains traces of almost a dozen other elements, including lead, polonium, bismuth, thorium, radium, protactinium
, and radon gas (these are radioactive decay products from uranium) and nickel, cadmium, molybdenum, vanadium, arsenic, and mercury.
The word "radioactivity" was alternatively replaced by the names of the elements occurring in the decay chains of interest, namely uranium, thorium, protactinium
, actinium, polonium, bismuth, radon, thallium, and lead.
Under Marchal's direction, she is using mathematical models to understand how two heavy elements, protactinium
and thorium, can reveal how the Atlantic Ocean circulated in the past.
s 84 to 89) are radioactive and exist in Nature in insignificant quantities, and are followed by the significant radioactive elements thorium, protactinium
and uranium (Z = 90, 91, and 92 respectively).