Scharfenstein (Hesse)

Scharfenstein is a hill composed of basalt in the Schwalm-Eder-Kreis district of North Hesse, Germany. It is the remains of one of a number of extinct volcanoes in the West Hesse Depression.Geographical LocationScharfenstein lies ca. north-east of the town centre of Gudensberg, and ca. west-south-west of the village of Dissen. Directly next to it runs the Bundesautobahn 49, and the hill can be reached from a car park off the autobahn. Alternatively the outcrop can be reached on foot from Dissen by crossing a bridge over the autobahn.GeologyThe hill is the remains of an extinct volcano that belongs to the West Hesse Depression. The volcano was active in the Miocene, i.e. it began 20 million years ago and ended 7 million years ago. The only part of the volcano that is left is the neck or volcanic plug; the rest has been eroded. The alkali basalt has a silica (SiO2) volume percentage of 45-55%. The main minerals in the rock are plagioclase, augite and olivine.Peculiar to Scharfenstein, compared to other basalt outcrops in the area, are the very well-developed basalt columns, which are for the most part horizontal or slightly inclined. Basalt in columnar form is due to cooling, in which the long axis of the column is in the direction of the slowest cooling. It is likely that after eruption or intrusion, the basalt slumped back to produce the outcrop features at Scharfenstein.