Abstract
Of 12 salt-efflorescences collected in the winter of 1989-90, from the Rechna doab, all qualified as "saline" with pH ranging from 8.1 to 10.5, EC 34.4 to 89.7 dS m-1.Solution (l:iO) chemistry was dominated by soi->Cr>HCOJ- + COJ2- and Na+ >Ca2+ >Mg2+ >K+. X-ray diffraction analysis (XRDA) showed that the mineralogy of the 8 selected efflorescences was dominated by thenardite (Na2S04)' accompanying this mineral in varying amounts weretr~na-NaJH(COJ)2.2H20 (major); ealcite-Caf.O, (minot) together with traces of natron (Na2COJ.lOH20), burkeite (NCi(,COJ(S04hland halite (NaCI).The most common mineral assemblage detected is thenardite-trona-calcite,
