Aachen chalk

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As Aachen Formation is historically and colloquially the deposits of the southern Aachen - Limburger chalkboard . The sediments on the chalk board were deposited in the Upper Cretaceous during a Europe-wide sea ​​advance from the north . The flints stored in some horizons were already the subject of mining activity in the Neolithic , 5500 to 5000 years ago in the area of ​​Aachen and western South Limburg, near Sint Pietersberg .

Definition

The Aachen Chalk is colloquially and in older geological and paleontological literature the sediments in the Aachen area that were deposited in the Upper Cretaceous . This term is no longer in use today because the term “ chalk ” is widely used as a synonym for certain calcareous, soft sediments. Since the Upper Cretaceous layer profile of Aachen contains not only chalk stones but also sands and clays, the more generally applicable term deposits from the Aachen-Limburg chalk board is used today for the sequence of layers .

Geological and stratigraphic development

Stratigraphic table of chalk deposits in the southern Limburg and Aachen area

After the elevation of the Variscan Mountains in the Upper Carboniferous , the area of ​​the northern Eifel and Ardennes was covered by deep weathering and largely leveled. It was not until the Upper Cretaceous, about 85 million years ago, that the sea penetrated from the north into the Aachen area. The southernmost chalk deposits are found today as erosion relics in the High Fens at an altitude of 600 to 700  m above sea level. NHN . The formerly extensive chalk deposits have largely been eroded again in the course of the elevation of the Eifel from the Upper Cretaceous .

North of Aachen, in South Limburg and in the neighboring Belgian Herver Land, the deposits from the Upper Cretaceous period are largely present as a closed chalk cover up to a total thickness of 160 m. The chalk board was slightly displaced by the elevation of the Eifel, so that today the layers fall at 1–3 ° to the north or north-northwest .

The sequence of layers of the Aachen chalk deposits covers a period of around 18 million years from the Santonian to the Upper Maastrichtian . After the deposit, the chalk board was broken up into mostly NNW-SSE clods by tectonic movements associated with the sinking of the Lower Rhine Bay . The tectonic movements continue to the present day and are expressed through numerous earthquakes .

Aachen formation

Transition from the Hergenrath clays to the Aachener sands in a construction pit in Aachen

Hergenrath member

In the area around Aachen, the Upper Cretaceous sedimentation begins with the deposition of dark gray clays, light gray silts and sands. The Hergenrath strata, up to 25 m thick, were deposited in a flat, limnic - terrestrial environment. They are characterized by the accumulation of silicified woods , lignite pieces and marcasite lumps. For centuries, the Hergenrath clay was the basis for the pottery industry of major national importance in the Aachen and Raeren area . The Hergenrath layers in the area around Aachen also represent one of the most important water-retaining horizons , so that its upper limit forms one of the most important source horizons in the Aachen forest and surroundings.

According to the latest stratigraphic structure of the chalk, the Hergenrath layers deposited in the Santonium are now called Hergenrath members of the Aachen formation .

In a south-easterly direction, on the edge of the High Fens and in the vicinity of Eupen , the clayey-sandy sediments of the Hergenrath strata change into fluviatil- deposited coarse sands and gravels of the so-called Mospert strata.

Aachen member

Over the predominantly clayey Hergenrath strata, 20–50 m thick fine sands were sedimented in a shallow marine deposit environment. The sandy sequence can be divided into two sections - the sand of Aachen (also: Aachener sand) and the sand of Hauset (also: Hauseter sand). The sands are characterized by a pronounced parallel and oblique stratification. They are interpreted as formations near the beach in a shallow sea with a strong current.

Individual parts of the sequence of layers show intensive silicification and, due to their resistance to weathering, form large blocks that are known as Cyclops stones in the Aachen forest . The sands are characterized by the appearance of numerous marine fossils , such as snails, mussels and foraminifera, as well as leaf prints and silicified woods.

According to the current stratigraphic classification of the Federal Institute for Geosciences and Natural Resources , the sands are defined as Aachen members within the Aachen formation. Due to the lack of key fossils , only an indirect age classification of the deposits in the upper santonium is possible.

Vaals formation

After a sedimentation interruption, which is shown by an erosion discordance , the sedimentation of the Vaals layers begins with a base conglomerate , which is composed of quartz and Paleozoic rocks of the area, such as sandstone , limestone , quartzite and mudstone .

Fine-grained sands and silts were deposited over the scree horizon 45–70 m, in the Netherlands up to 150 m . The characteristic green color, which justified the earlier name Vaalser Grünsand , is due to the appearance of finely divided glauconite , an iron-containing mineral that is formed from other minerals such as mica and clay minerals under reducing conditions in shallow seawater . Green sands are widespread in the Upper Cretaceous on the northern edge of the Rhenish Slate Mountains and are an indicator of a supra-regional transgression of the Chalk Sea from the area of ​​today's North Sea . In the eastern distribution area, the Vaals formation on the Aachen-Limburger chalk board can be divided into seven different sand horizons, which are separated from each other by silty deposits. In general, it can be stated that the glaucoma content in the younger deposits gradually decreases.

The stratigraphic classification of the sequence of layers is carried out with the help of belemnites in the lower campanium .

Gulpen formation

After another sedimentation interruption, a clear change in the petrographic formation of the rocks can be observed. Sandy deposits recede completely and white to light gray, fine-grain limestones dominate. While the younger Upper Cretaceous rocks are only sparsely distributed in the Aachen area, the Gulpen Formation in the Dutch part of the Aachen-Limburg chalk board is up to 175 m thick and can be divided petrographically into seven different limestone horizons.

The limestones are the result of a lime sludge that has formed in a warm shallow sea from dead remnants of microfossils , especially so-called coccoliths . Often fossil-rich layers are stored in the limestones, mainly consisting of the broken shells of snails, brachiopods , mussels and sea ​​urchins . The age classification of the calcareous deposits of the gulp formation is carried out with the help of belemnites, ammonites and foraminifera. The Zevenwegen lime was deposited in the Upper Campanium, the Vylen lime in the Lower Maastrichtian and the Orsbach flint chalk in the lower Upper Maastrichtian.

Zevenwegen member

In the Aachen area, the Zevenwegen lime was called Gulpen marl together with the Vylen lime in earlier literature . The Zevenwegen limestone, which can be up to 30 m thick in the Aachen area, usually begins at the base with a 0.5 to 1.5 m thick, sandy, glauconite-bearing conglomerate, which is mainly composed of relocated rubble from the Vaals formation . A soft, only slightly solidified limestone and marlstone follows the scree horizon. The term writing chalk is often used in the literature for these soft, white limestones . The Zevenwegen limestone is locally rich in fossils, in particular numerous remains of sea urchins can be observed.

Vylen member

Over a new layer gap , the sedimentation of the Vylen limestone is often initiated by a conglomerate, which mainly consists of rusts from belemnites. Colloquially, this horizon is therefore called the Belemnite Cemetery by Bovenste Bos . The rocks of the Vylen member are mainly formed from yellowish-gray marl stones and limestone marl stones, which are now deeply decalcified on the surface. The insoluble residues of the weathered marl stones form a layer of clay that covers large parts of the distribution area of ​​the Vylen limestone. On average, the Vylen limestone reaches a thickness of 15–20 m, locally up to 100 m. The limestone has been used as a building material since Roman times . Vylen limestone can be found, among other things, as stone in the Barbarossa Wall and in the Aachen Cathedral .

Orsbach member

Flint deposits in chalk-limestone

The Orsbach limestones are characterized by the mostly layered appearance of blue-gray to black flint stones, which are embedded as cm to dm-large, irregular concretions in the chalky chalk sediments. This characteristic feature gave the sequence of layers in the past the name Orsbach flint chalk. While the up to 70 m thick Orsbach sediments in the western distribution area of ​​the chalk board can be further subdivided with the help of characteristically formed flint layers, the thickness of the Orsbach layers in the Aachen area decreases to a maximum of 25 to 30 m. The sequence of layers in the Aachen area is formed from an alternation between crumbly, soft white chalk limestone and very firm limestone, in which the 2–15 cm thick flint stones are embedded. Numerous macro fossils such as sea urchins, belemnites and brachiopods are common.

In some layer profiles in the Aachen area, for example on the Lousberg , the Orsbach limestone is completely absent. The sedimentation interruption is due to tectonic movements, combined with uplift and removal of sediments in certain areas of the chalk board at the beginning of the Maastrichtian. At Rijckholt and Valkenburg aan de Geul , the flint stones have been mined underground for the manufacture of tools since the Neolithic.

Some of the Orsbach limestones are deeply weathered . The insoluble remnants of the sequence of layers form the so-called flint weathered clay , which can be found in large parts of the Aachen forest and its surroundings.

Maastricht formation

Border between Gulpen and Maastricht Formations: The marl limestone of Lanaye at the base is transgressively overlaid by Valkenburg limestone. (Museum Het Land van Valkenburg, Limburg)

In the Aachen area, the chalky deposits of the Maastricht Formation form the youngest Upper Cretaceous sediments, while in the southern Limburg area the sedimentation continues more or less continuously up to the Cretaceous-Tertiary border . The failure of the most recent chalk layers in the Aachen area is related to tectonic movements in the Maastrichtium, which have led to a pronounced structure of floes on the western edge of the Lower Rhine Bay.

Vetschau member

The Vetschau limestone, which forms the lower Maastricht formation in the Aachen area, is characterized by an alternation between hard, yellowish-gray limestones and less solidified limestones that carry fossil debris. Lenses and slabs of brownish flint are embedded in the chalky layer sequence, which was the subject of Neolithic flint quarrying at Lousberg near Aachen, which - in contrast to the South Limburg quarries - was mined in an open pit. The calcareous rocks of the Vetschau strata were created in a strongly agitated, fully marine sediment environment near the coast.

The age classification of the strata sequence was carried out with the help of belemnites and foraminifera. According to the current stratigraphic structure, the rocks of the Vetschau layers were deposited during the Upper Maastrichtium. Further west, in the southern Limburg region, the Vetschau limestone is represented by the Kunrad limestone , which was formed further away from the coast and is characterized by the occurrence of limestone, which consists mainly of fine fossil rubble and is sporadically characterized by terrestrial additions.

Paleontological exploration

Ernst Heinrich von Dechen

The first fossils of the Aachen Chalk were described and illustrated by Ernst Heinrich von Dechen , Constantin von Ettingshausen & Matthias Debey, Ignaz Beissel, Eduard Holzapfel and Alfred Romer . In the period that followed, there were numerous controversies regarding the identification of different species, as a result of which new names were given for individual species not recognized by the authors. As a result, several names sometimes existed in parallel for a species.

Numerous works, individual and overview works on the macro and microfauna and flora supplemented the biostratigraphic research in the last decades (see: Felder & Bosch 2000). The current bio- and lithostratigraphic classification of the Cretan layer sequence can be found in the “LithoLex” of the Federal Institute for Geosciences and Raw Materials (BGR).

Current research projects, for example by the Augsburg Natural History Museum on silicified and limonitized plant remains with regard to paleocarpology , paleoecology , paleoclimate and biostratigraphy have been funded by the German Research Foundation.

Genesis of the Aachen flint stones

Brown flint

The genesis of flint has long been a very controversial topic in the geological literature. A complex, multi-stage chemical process is assumed for the formation of the Aachen flint. The chalk sediments consist to a large extent of organisms containing siliceous skeletons, such as sponge needles and diatoms . In the course of the solidification of the lime sludge, silica dissolves from the shells of the organisms and is transported with the pore water in the sediment.

Due to the increasing sediment load, the pore water containing silica is forced to rise and is further enriched with silica. When the pore water is saturated with silica, silica gel precipitates on the sediment surface or in cavities close to the surface . This can lead to a simultaneous dissolution of lime and a precipitation of quartz from the silicic acid-containing pore water. It can therefore often be observed that there is still a remnant of a calcareous fossil inside a flint. If the silica gel falls flat on the surface - as u. a. am Lousberg - off, a flintstone is created. If, on the other hand, the silica gel fills cavities in the sediment, flint flints tend to form.

The solidification of the silica gel takes place over long periods of time with simultaneous release of water. Depending on the microorganisms involved , the parent and host rocks as well as the sedimentation conditions, flints are created that differ greatly from one another locally in their characteristics and thus make them identifiable. Axes from Lousberg could also be found in other areas. Numerous flint axes from the Lousberg have been found particularly along the rivers Rhine , Maas , Ruhr and Lippe . The maximum distance to a site is 280 km - this is a Neolithic stone ax from Neuenknick on the Weser .

use

Drinking cup, manufactured in Raeren in 1590

The deposits of Aachen chalk were used in many ways in the past. The Hergenrath -Tone formed especially from the 16th century, the basis for a nationally important ceramics production, with the center in Raeren.

The sands of the Aachen and Vaals Formations were used as local building material in the past. The solidified parts of the Upper Cretaceous sands and the Upper Cretaceous limestones have been used as building material on numerous buildings and in the city wall in Aachen and the surrounding area since Roman times.

In contrast to the use of Cretan limestone for the production of cement in South Limburg , near Sint Pietersberg , 't Rooth and Geulhem, such a use is not known in the Aachen area.

The flint stones in the Upper Cretaceous limestones of the Orsbach and Vetschau layers were the subject of mining in the late Neolithic at various locations in the vicinity of Aachen and in South Limburg. According to C14 data , the flint on the Lousberg was found 3500 to 3000 years ago. Dismantled. Lousberg flint was also used locally in the late Middle Paleolithic and Mesolithic . Cleaver blades were primarily made from the Lousberg flint.

literature

  • Ignaz Beissel: The foraminifera of the Aachen chalk. Schropp'sche Hof-Landkartenhandlung (JH Neumann), Berlin 1891 ( digitized version ).
  • Hans Breddin: About the deepest layers of the Aachen chalk as well as a senone leveling area and weathering bark on the northern slope of the High Fens . In: Cbl. Mineral. Geol. Paläontologie 1932, pp. 593-613.
  • Werner M. Felder: Geology van de St. Pietersberg bij Maastricht , Grondboor & Hamer, 52 (3), Heerlen 1998, 53-64
  • Werner M. Felder: Vuurstenen in de St. Pietersberg , Grondboor & Hamer, 52 (3), Heerlen 1998, 65-69
  • Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Geologie van Nederland, Deel 5, Delft / Utrecht, 2000, ISBN 90-6743-710-7
  • Werner M. Felder, Peter W. Bosch, Hans J. Albers: Aachen-Limburger Kreide, Tertiary and Quaternary . In: Excursion guide 130th Annual General Meeting DGG , Aachen 1978, pp. 123–177
  • Helmut Gottwald: Plants from the Aachen Chalk: Part 1: Silica. Publishing house Documenta Naturae, Munich 2000. ISBN 3865441319 .
  • Eduard Holzapfel : The mollusks of the Aachen chalk . In: Palaeontographica Volume 34, 1887, pp. 29-72.
  • Eduard Holzapfel: About some important molluscs of the Aachen chalk. In: Journal of the German Geological Society 36, 1884, pp. 454–484
  • Gangolf Knapp: Explanations of the geological map of the northern Eifel 1: 100,000 , Krefeld 1980.
  • Joseph Müller : Monograph of the petrefacts of the Aachen chalk formation . 3 parts. Henry & Cohen, Bonn 1847–1859 ( digitized part 1 ).
  • Karl-Heinz Ribbert: Geology in the Rhenish Slate Mountains. Part 1: Nordeifel , Krefeld 2010, ISBN 978-3-86029-934-0
  • Wolfgang Schmidt, Richard Wolters: Base clay of the Aachen chalk, old tertiary and fossil weathering on the northern edge of the Eifel . In: Geologisches Jahrbuch 66, 1952, pp. 661–670
  • Daniel Schyle: The Lousberg in Aachen. A Neolithic flint mine with ax blade production . (= Rhenish excavations 66). Zabern, Mainz 2010, ISBN 978-3-8053-4326-8
  • Ernst-Friedrich Vangerow, Walter Schloemer: Comparison of the Vetschau limestone of the Aachen chalk with the chalk profile of South Limburg on the basis of coccoliths . In: Geol. En Mijnb. 46, 1967, pp. 453-458.
  • Manfred Vigener: Schneeberg and Cyclops stones. A geological travel guide. Eupen 2003, ISBN 90-5433-167-4 .
  • Roland Walter : Aachen and the northern area . Geological Guide Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7
  • Roland Walter: Aachen geo-routes . Eupen 2012, ISBN 978-3-86712-058-6

Individual evidence

  1. ↑ Hans Breddin: About the deepest layers of the Aachen chalk as well as a senone leveling area and weathering bark on the northern slope of the High Fens : Cbl. Mineral. Geol. Paleont., 593-613. Stuttgart 1932, p. 593ff.
  2. ↑ Ignaz Beissel: The foraminifera of the Aachen chalk. Schropp'sche Hof map dealer (JH Neumann) 1891
  3. ^ Roland Walter: Aachen and the northern area . Geological Guides Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , pp. 18–37
  4. ^ Roland Walter: Aachen and the northern area . Geological Guide Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , p. 18
  5. ^ Roland Walter: Aachen and the northern area . Geological Guides Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , pp. 19-20
  6. ^ Karl-Heinz Ribbert: Geology in the Rhenish Slate Mountains. Part 1: Nordeifel , Krefeld 2010, ISBN 978-3-86029-934-0 , p. 27
  7. ^ A b Karl-Heinz Ribbert: Geology in the Rhenish Slate Mountains. Part 1: Nordeifel , Krefeld 2010, ISBN 978-3-86029-934-0 , p. 76
  8. ^ Roland Walter: Aachen and the northern area . Geological Guide Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , p. 20
  9. ^ Lithostratigraphic lexicon of the Federal Institute for Geosciences and Natural Resources, Hergenrath-Member ( Memento from March 4, 2016 in the Internet Archive ), accessed on May 23, 2012
  10. ^ Manfred Vigener: Schneeberg and Cyclops stones - A geological travel guide. Eupen 2003, ISBN 90-5433-167-4 , pp. 90f.
  11. ↑ Ignaz Beissel: The foraminifera of the Aachen chalk. Schropp'sche Hof map dealer (JH Neumann), 1891
  12. ↑ Eduard Holzapfel: About some important mollusks of the Aachen chalk. Job. Journal of the German Society for Geosciences ZDGG, Volume 36, Issue 3, 1884.
  13. ^ Lithostratigrafisches Lexikon: Aachen-Formation ( Memento of March 4, 2016 in the Internet Archive ), accessed on May 23, 2012
  14. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , p. 30.
  15. ↑ Ignaz Beissel: The Aachener Sattel and the thermal springs breaking out from the same. Aachen 1886, pp. 99-101.
  16. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , p. 30ff.
  17. ↑ Hans J. Albers: Fine stratigraphy, facies analysis and cycles of the Untercampan (Vaalser Grünsand = Hervien) from Aachen and the Dutch-Belgian Limburg . Geolog. Jahrbuch, A 34, Hannover 1976, pp. 3-68
  18. ^ Roland Walter: Aachen and the northern area . Geological Guide Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , p. 22
  19. ↑ Lithostratigrafisches Lexikon Vaals Formation  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , accessed on May 24, 2012@1@ 2Template: Toter Link / litholex.bgr.de  
  20. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , p. 50.
  21. ^ Karl-Heinz Ribbert: Geology in the Rhenish Slate Mountains. Part 1: Nordeifel , Krefeld 2010, ISBN 978-3-86029-934-0 , p. 77
  22. ^ Lithostratigrafisches Lexikon Gulpen-Formation ( Memento from March 4, 2016 in the Internet Archive ), accessed on May 24, 2012
  23. ↑ Hans Breddin et al. a .: The Aachen-NW sheet of the practical geological base map 1: 5 000. - Geol. Mitt., Heft 1, Aachen 1963, pp. 251–428
  24. ^ A b c Roland Walter: Aachen and northern surroundings . Geological Guide Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , p. 24
  25. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , p. 52.
  26. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , pp. 56-58.
  27. ^ Roland Walter: Aachen geo routes. Eupen 2012, ISBN 978-3-86712-058-6 , pp. 134f.
  28. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , pp. 62-70.
  29. ^ Roland Walter: Aachen and the northern area . Geological Guide Collection, Volume 101, Stuttgart 2010, ISBN 978-3-443-15087-7 , p. 23
  30. ^ Neolithic flint mining in Limburg , accessed on May 24, 2012
  31. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , pp. 71-101.
  32. ↑ Jürgen Weiner: Research History. In: Daniel Schyle: The Lousberg in Aachen. A Neolithic flint mine with ax blade production . Rheinische Ausgrabungen 66, Mainz 2010, pp. 4–10.
  33. ↑ Jürgen Weiner: Steel of the Stone Age. The Stone Age flint mine Lousberg in Aachen. In: The Rheinisches Landesmuseum Bonn. Reports from the work of Museum 3, Bonn 1989, pp. 36–42
  34. ^ Lithostratigrafisches Lexikon Maastricht-Formation ( Memento from March 4, 2016 in the Internet Archive ), accessed on May 23, 2012
  35. ^ Heinrich von Dechen: Orographic-geognostic overview of the administrative district of Aachen ; Aachen 1866
  36. ↑ Constantin von Ettingshausen, MH Debey: (1857) The primeval Thallophyten of the chalk mountains of Aachen and Maestricht . Meeting reports of the K. Akad. Wissensh., Berlin 1857, pp. 507-512
  37. ↑ Ignaz Beissel: The Aachen saddle and the thermal springs that break out of the same . Aachen 1886, p. 211.
  38. ^ Ignaz Beissel: The foraminifera of the Aachen chalk , revised by Eduard Holzapfel; Royal prussia. geol. L.-A., 3, Berlin 1891, p. 78
  39. ^ Eduard Holzapfel: The mollusks of the Aachen chalk. Paläontographica, 34, Stuttgart 1887, pp. 29–180
  40. ^ Eduard Holzapfel: The mollusks of the Aachen chalk. Part 2. Paläontographica, 35, Stuttgart 1889, pp. 139–268
  41. ↑ Holzapfel, Eduard: About some important mollusks of the Aachen chalk.
  42. ↑ LithoLex start page (interactive query)
  43. ↑ DFG funding application , accessed on May 24, 2012
  44. ↑ Daniel Schyle: The Lousberg in Aachen. A Neolithic flint mine with ax blade production. Rheinische Ausgrabungen 66, Mainz 2010, ISBN 978-3-8053-4326-8 , pp. 1-3
  45. ^ Roland Walter: Aachen geo routes . Eupen 2012, ISBN 978-3-86712-058-6 , pp. 84f
  46. ↑ Daniel Schyle: The Lousberg in Aachen. A Neolithic flint mine with ax blade production. Rheinische Ausgrabungen 66, Mainz 2010, ISBN 978-3-8053-4326-8 , pp. 108-109
  47. ^ Raeren ceramics: trade relations ( Memento from August 9, 2012 in the Internet Archive ), accessed on May 24, 2012
  48. ^ Roland Walter: Aachen geo routes . Eupen 2012, ISBN 978-3-86712-058-6 , pp. 132, 142
  49. ^ Werner M. Felder, Peter W. Bosch: Krijt van Zuid-Limburg . Delft / Utrecht 2000, ISBN 90-6743-710-7 , p. 130.
  50. ↑ Jürgen Weiner: The Lousberg in Aachen - flint mining 5500 years ago . In: Rheinische Kunststätten, issue 436, Neuss 1998, p. 5.
  51. ↑ Daniel Schyle: The Late Neolithic Beilproduktion on the Lousberg in Aachen - An extrapolation of supply and demand and draw conclusions about the late Neolithic population density. In: Archäologische Informations, 29/1 & 2, 2006, S. 35 pdf

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