Name: The Hunsrück Slate Location: Western Germany Age: Devonian

The Hunsrück Slate is a term applied to the a sequence of lower Devonian age sediments. German stratigraphers have divided up the Lower Devonian into three units, the Gedinnian, the Siegenian and the Emsian. The Hunsrück was deposited between the end of the Siegenian and the middle of the lower Emsian (392-388 million years ago). This corresponds to three local subunits named after the type localities, the Herdorf, the Ulmen and the Singhofen.

The diagram shows the stratigraphy of the Lower Devonian, with the local subunits on the far right. The shaded band represents the Hunsrück slate. Used by kind permission of Bartels, Briggs and Brassel, taken from 'The fossils of the Hunsruck slate, Marine Life in the Devonian' figure 13, page 20, Cambridge University Press.

The sedimentary sequence is dominated by dark laminated mudstones with interbedded silt, clay and sandy layers. The muddy facies was first deposited in the NW (where maximum sedimentary thickness is 3700m) which then migrated over time to the South East, which has a minimum thickness of 2300m. After deposition, metamorphism in the early Carboniferous resulted in the formation of slates.

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