THE EBBADALEN FORMATION (CARBONIFEROUS), SPITSBERGEN

Abstract
Summary: The Ebbadalen Formation (Carboniferous) of Spitsbergen lies in an elongated basin on the downthrown side of the Billefjorden Fault Zone. Apart from the lower part of the formation, where all the beds are clastic, evaporites dominate in the basin and separate red beds, adjacent to the fault-belt, from marine carbonates. Several unconformities are recorded within the formation towards the margins of the basin. Four members and three sets of beds are proposed as well as a number of informal facies units. A limestone breccia (Ragnarbreen Breccia) which occurs locally at the top of the formation is interpreted as a solution breccia. Fusulinacea from the top of the formation indicate a Bashkirian age, but the lowest part may belong to the Namurian rather than to the Bashkirian as previously supposed. The early clastic strata are thought to be largely fluviatile in origin, while the later red beds, evaporites and carbonates are similar to modern arid-area sediments, notably those of the Persian Gulf. Laterally continuous cyclothems occur throughout the sequence and are thought to be the result of regional or even world-wide agencies rather than of local causes.