Y.K. Kharaka J. R. O’Neil 1976 <div id="preview-section-abstract"><div id="abstracts" class="Abstracts u-font-serif text-s"><div id="aep-abstract-id5" class="abstract author"><div id="aep-abstract-sec-id6"><p>The extent of hydrogen and oxygen isotope exchange between clay minerals and water has been measured in the temperature range 100–350° for bomb runs of up to almost 2 years. Hydrogen isotope exchange between water and the clays was demonstrable at 100°. Exchange rates were 3–5 times greater for montmorillonite than for kaolinite or illite and this is attributed to the presence of interlayer water in the montmorillonite structure.</p><p>Negligible oxygen isotope exchange occurred at these low temperatures. The great disparity in D and O¹⁸<span>&nbsp;</span>exchange rates observed in every experiment demonstrates that hydrogen isotope exchange occurred by a mechanism of proton exchange independent of the slower process of O¹⁸<span>&nbsp;</span>exchange.</p><p>At 350° kaolinite reacted to form pyrophyllite and diaspore. This was accompanied by essentially complete D exchange but minor O¹⁸<span>&nbsp;</span>exchange and implies that intact structural units in the pyrophyllite were inherited from the kaolinite precursor.</p></div></div></div></div><div id="preview-section-introduction"><br></div><div id="preview-section-snippets"><br></div><div id="preview-section-references"><br></div> application/pdf 10.1016/0016-7037(76)90181-2 en Elsevier Hydrogen and oxygen isotope exchange reactions between clay minerals and water article