부산대학교 도서관

A part of the Grand Saline, Texas, salt dome is exposed in the Morton Salt Company's Kleer Mine. The megascopic structural features of the salt were mapped on all available surfaces, and oriented specimens were examined microscopically. Layers of salt are visible in all tunnels. Near the southeastern border of the dome, they dip steeply southeast and south, assumably parallel with the dome border. Elsewhere, the layers form intricate systems of folds. The axes of all folds plunge nearly vertically, and the limbs are also in steep planes. The microscopic features of the salt resemble closely those described by Taylor in other salt domes. Anhydrite and halite display a linear alignment. Single crystals of anhydrite, elongate parallel with the crystallographic axis b, tend to orient this direction parallel with the nearest axes of folds, that is, nearly perpendicularly. Aggregates of anhydrite, also, are slender lenses and streaks in nearly vertical attitudes. Halite grains show elongation in the same direction, though less noticeably. The absence of any fractures, faults, cross-cutting salt layers, foreign inclusions, and brine indicate an undisturbed evolution of the deformation structure in a nearly homogeneous, layered salt mass, which resembles closely that produced experimentally by Escher and Kuenen. The movements are analyzed that can give rise to folds with vertical axes and lineation, and the critical physical properties of halite are reviewed.