The mid-Carboniferous Minkinfjellet Formation accumulated in the Billefjorden Trough, central Spitsbergen. It consists of a carbonate-dominated succession interbedded with evaporites, sandstones and shales. The lower unit, the Carronelva Member, has a heterolithic composition with mixed carbonates, clastics and minor evaporites. These sediments were deposited in a narrow, shallow, tidally influenced basin. Clastics were shed into the basin from structural highs to the east and west and distributed by tidal currents. Clastic input was not sufficient to prohibit a dominance of carbonate deposits. The transition to the upper unit, the Terrierfjellet Member, is marked by an angular unconformity in the north and thick evaporites in the south, representing a major sea-level fall with ensuing erosion and evaporation in the basin. The subsequent transgressive deposits consist of carbonates and subordinate evaporites. By this time, the adjacent structural highs were no longer active provenance areas for clastics, despite the Nordfjorden Block to the west still being subaerially exposed.