page_title: Hesselberg
section_title: Late Jurassic (Malm) layers
hierarchical_section_title: Hesselberg / Origin and geological structure / Rock layers of the mountain / Late Jurassic (Malm) layers
caption_attribution_description: Informationstafel am Geologischen Lehr- und Wanderpfad auf dem Hesselberg Fotograf: Oswald Engelhardt
context_page_description: Hesselberg is the highest point in Middle Franconia and the Franconian Jura and is situated 60 km south west of Nuremberg, Germany. The mountain stands isolated and far from the center of the Franconian Jura, in its southwestern border region, 4 km to the north west of Wassertrüdingen. The mountain's first recorded name was Öselberg, which probably derived from öder Berg. This name later changed to Eselsberg and finally to the current name Hesselberg. As a butte the mountain provides an insight into Jurassic geology. It has also witnessed an eventful history, many incidents were handed down from generation to generation and these mixed with facts have become legends. Nowadays many people visit Hesselberg in order to enjoy nature and the wonderful vista. When the weather is clear the Alps 150 km away can be seen.
context_section_description: The topmost Jurassic layer is called the White Jurassic due to its light colour. These layers can be up to 400 m thick in the Franconian Jura, but at Hesselberg they are mostly ablated; only 85 m is left. The rocks of the Malm are partly sediments and partly formed from reefs of ancient sea sponges. This rock is widely distributed on the main peak. The light-coloured lime of the White Jurassic was a popular building material for houses (burnt lime) and for road construction (rubble). The depressions on the western plateau are caused by these excavations. The lowest layers form the Impressa-layers (low Malm alpha), which are approximately 25 m thick, and the Bimammatum-lime (high Malm alpha). The old name of the Planula-lime (Malm beta) is factory lime, which indicates the use as building material. This layer, which is 15 m thick and interspersed with sponge reefs, forms the plateau of the Osterwiese. The small quarry below the main peak consists of Planula-lime in its lower part, and the Ataxiocerate's layer (Malm gamma) in its upper, which builds up the main peak and is 20 m thick. The top layer of Malm gamma and the layers of Malm delta to Malm zeta have already been eroded away on Hesselberg.
caption: Information sign at the nature trail
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