Krossbergskvalitet och petrografi i den kambriska Hardebergasandstenen i Skåne

Sammanfattning: The Lower Cambrian Hardeberga Sandstone Formation of Scania, southern Sweden, consists of a basal arkosic sandstone unit, overlain by three vertically stacked, shallowing-upward sequences. These three sequences consist predominantly of light grey or whitish, quartz-arenitic sandstones deposited in shallow marine environments. The formation reaches a total thickness of about 120 m and is extensively quarried. At Hardeberga, east of Lund, the Hardeberga Sandstone is quarried and crushed, principally for roadbeds and for concrete aggregate. The quarry is operated by AB Sydsten. The succession in and outside the quarry is penetrated by Permo-Carboniferous dolerite dikes. The technical properties of the sandstones vary within the quarry, both laterally and vertically. Factors that determine the quality and the strength are mineralogical composition, grain size, type of intergranular contacts, and degree of silica cementation. Various analyses are carried out at the laboratory used by AB Sydsten, but their results are not unequivocal. For this study, 32 samples were taken in the Hardeberga quarry. Thin sections were prepared and the composition, grain size, cementation, and matrix were analysed under a microscope. The samples were then divided into three quality groups: group A with the best quality for production of macadam, an intermediate group B, and group C, which is not suitable for production of macadam with high strength. These groups are relatively easy to use for classifying various sandstones in the Hardeberga quarry, but require geological expertise by the operating company.