A Mixed-Layer Clay Mineral Associated with an Evaporite

R. E. Grim, John B. Droste and W. F. Bradley
University of Illinois, Urbana, Illinois
Indiana University, Bloomington, Indiana
Illinois Geological Survey, Urbana, Illinois

Abstract: Clay partings in the ore beds in a New Mexico evaporite section include a range of mixed-layer clay mineral sequences of the corrensite type. Specimens range from nearly regular alternations to sequences which depart from regularity to moderate degrees. The ore bodies consist of halite, polyhalite, sylvite, magnesite, dolomite, carnallite, and iron oxides.

Observed x-ray diffraction effects from representative specimens are compared with synthesized effects for montmorillonite- or vermiculite-chlorite layer sequences.

It is concluded that the segregation of the abundant Mg interlayer content into specific, regularly spaced interlayers represents the equilibrium relationship between a montmorillonite—chlorite or vermiculite—chlorite mixed assemblage and a mildly acid, Mg2+-, Na+-, and K+-rich environment.

Clays and Clay Minerals; 1959 v. 8; no. 1; p. 228-236; DOI: 10.1346/CCMN.1959.0080121
© 1959, The Clay Minerals Society
Clay Minerals Society (www.clays.org)