Status: this discussion paper is a preprint. It has been under review for the journal SOIL (SOIL). The manuscript was not accepted for further review after discussion.
Natural versus anthropogenic genesis of mardels (closed depressions) on the Gutland plateau (Luxembourg); archaeometrical and palynological evidence of Roman clay excavation from mardels
J. M. van Mourik,D. J. G. Braekmans,M. Doorenbosch,W. J. Kuijper,and J. van der Plicht
Abstract. Mardels, small closed depressions, are distinctive landforms on the Luxembourger Gutland plateau. In the present landscape most mardels are shallow fens, filled with colluvial sediments. The genesis of mardels has been studied intensively, inside and outside Luxembourg. Some researchers suggested a natural development and consider mardels as subsidence basins due to subsurface solution of gypsum veins, other researchers suggested cultural causes and consider mardels as prehistorical quarries.
In the Gutland, mardels occur on various substrates. Mardels on the Strassen marls (li3) are abandoned quarries, related to clay excavation in Roman Time. Mardels on the Luxembourger sandstone (li2) are sinkholes, related to joint patterns in the sandstone formation. Mardels on the Keuper marls (km1,3) are originally subsidence basins, related to subsurface dissolutions of gypsum lenses and veins, filled with colluvial clay. The results of pollen analysis and archaeometrical tests demonstrate Roman extraction of clay for the production of ancient ceramics. So, the natural depressions have been enlarged to the present mardels. After excavation, the sedimentation of colluvium restarted in the abandoned quarries.
Received: 14 Nov 2015 – Discussion started: 15 Jan 2016
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Paleoecological studies of mardels could not solve the problem concerning the geological versus anthropogenic genesis of mardels.
The results of archaeometrical tests show that colluvial clay, excavated from mardels has been used in Roman Time to produce ceramics.
Mardels are initially natural depressions, filled with pre Roman colluvial clay, excavated in the Roam Time and refilled with clay after the Roman Time.
Paleoecological studies of mardels could not solve the problem concerning the geological versus...
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