Microhardness analysis of halite from different salt-bearing formations

Abstract

As so ci ate ed i tor: Wojciech Drzewicki Micro hard ness tests were car ried out on sin gle ha lite crys tals. They were con ducted on the (001) sur face, with the in denter set in two di rec tions: par al lel to the ha lite face (010); and par al lel to the (110) face. The ha lite crys tals rep re sent salt for mations of dif fer ent ages (De vo nian, Zechstein, Badenian), depths (from 1835.5 to 195 m) and in ten si ties of tec tonic dis turbance (hor i zon tally strat i fied, salt dome, strongly folded). The mea sure ment re sults re vealed spe cific fea tures of the ha lite crys tals ana lysed. Firstly, the data ob tained show micro hard ness ani so tropy in ha lite crys tals. More over, micro hard ness corre lates with the depth of the salt-bear ing for ma tions. Ha lite crys tals from deeper lev els showed higher micro hard ness, though there was no cor re la tion be tween the in ten sity of tec tonic de for ma tion and the av er age Vickers hard ness (HV). The sam ples ana lysed show a vari abil ity of HV val ues and and of the shapes of im prints. These in di cate zones where ha lite crystals are de formed at the atomic level and re flects the pres ence of de fects in the crys tal lat tice. Such de for ma tion is re flected in an ir reg u lar ity of the strike of cleav age planes. Con se quently, the anal y sis of im print shapes is a use ful method for the exam i na tion of duc tile min er als and ma te ri als. Key words: micro hard ness, ha lite, salt for ma tion, crys tal de fects, dis lo ca tions, shape of im print.

Archives of Mining Sciences

“…the post sedimentary processes like folding, stretching, shearing, and flowing result in recrystallisation, overprinting and the creation of new fabrics and structural features in rock salt [8,9], all can lead to the deformation of the crystal lattice. Polarised light microscopy observations revealed optical anisotropy (birefringence) of blue halite crystals from the Kłodawa salt dome (central Poland) and rock salt from the Pembina salt deposit (Alberta, Canada) resulting from the crystals' deformation at the atomic level [125][126][127]. In blue halite crystals, a deviation from cubic symmetry was indicated [128,129].…”

“…In blue halite crystals, a deviation from cubic symmetry was indicated [128,129]. Moreover, a variability of microhardness (Hv) value and the distortion of an imprint's shape were indicated in these crystals [125,126]. these microstructural features may have an impact on the macro-mechanical behaviour of rock salt but this issue requires further studies.…”