Moler

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Outcrop of the Fur Formation on the coast of Fur Island

Moler (German: Mo-Ton ) is a very fine-grained silicate biogenic sedimentary rock similar to kieselguhr . It originated around 55 million years ago at the transition from the Upper Paleocene to the Lower Eocene and occurs in the Limfjord area in Denmark, especially on the islands of Fur and Mors and south of Thisted (Silstrup Hoved). "Mo" is the dialectal expression for (a certain kind of) sound . Lithostratigraphically , the moler-bearing strata of the Limfjord area is referred to as the Fur Formation according to its type locality on the island of Fur .

The fur formation is subdivided in various ways. One variant divides them into Knudeklit members (lower / older section, also called “negative series”, see below) and Silstrup members (upper / younger section, “positive series”). The upper part consists of about 65 wt.% From fossil skeletons of diatoms ( diatoms ) and about 35 wt.% Of clay minerals (predominantly montmorillonite ). The sediment, which is often finely stratified ( laminated ) , especially in the lower section of the stratification , also contains carbonate concretions (in Danish cementsten ) in certain levels , which may have grown together to form closed layers.

179 layers of volcanic ash are integrated into the moler layer sequence . These special horizons are numbered from −39 to +140. The approximately 30 m thick lower part of the sequence of layers (Knudeklit member) contains the 39 negatively numbered ash layers (hence also called the “negative series”), each of which is a maximum of 20 cm thick. The approx. 27 m thick upper part of the layer sequence (Silstrup member) contains the 140 positively numbered layers of ash (hence also called the "positive series"), each of which is a maximum of 15 cm thick, is therefore significantly richer in ash than the lower part. These ash layers can be found in many places in north-western Europe. The two most noticeable layers (−17 and +19) were even found in Germany during research drilling in the Wursterheide .

Fossil fish from the Fur formation

Moler is relatively rich in fossil plant and animal remains (insects, fish and other vertebrates). Of particular scientific interest are the land plants and insects found in some locations, as well as the few pieces of amber found in the same layers.

The raw material is used industrially for the production of light and insulating building materials as well as absorbent granulates (cat litter / oil binding agent).

literature

  • Kurt Hucke : Introduction to bed load research , Nederlandse Geologische Vereniging, Oldenzaal 1967
  • Steen Andersen & Steen Sjørring (Red.): Det nordlige Jylland (Geologisk set 3), Geografforlaget, 2nd edition Brenderup 1997
  • Stig Schack Pedersen, Gunver Krarup Pedersen & Per Noe: Moleret på Mors - Mors Kort og godt No. 1 . Morsø Lokalhistoriske Forlag 1994 (also in German and English)
  • Pedersen, SAS: Paleogene diatomite deposits in Denmark: geological investigations and applied aspects . In: Bulletin of Geological Survey of Denmark and Greenland . 15, 2008, pp. 21-24.
  • Marion Homann: The Diatoms of the Fur Formation (Old Tertiary) from the Limfjord area, North Jutland / Denmark (Geological Yearbook Series A, Issue 123), Hanover 1991

Web links

Individual evidence

  1. ↑ Outdated spelling Moe ; Stig Schack Pedersen, Gunver Krarup Pedersen & Per Noe: Moler on Mors. Mors Kort & godt-1 . Morsø Lokalhistoriske Forlag 1994.
  2. ↑ Gunver Krarup Pedersen: Anoxic events during sedimentation of a Palaeogene diatomite in Denmark. Sedimentology. Vol. 28, 1981, pp. 487-501, doi: 10.1111 / j.1365-3091.1981.tb01697.x
  3. ↑ Gunver Krarup Pedersen, Björn Buchardt: The calcareous concretions (cementsten) in the Fur Formation (Paleogene, Denmark): isotopic evidence of early diagenetic growth. Bulletin of the Geological Society of Denmark. Volume 43, 1996, pp. 78–86, 2dgf.dk (PDF; 560 kB)
  4. ^ Marion Homann: The Diatoms of the Fur Formation (Old Tertiary) from the Limfjord area, North Jutland / Denmark (Geological Yearbook Series A, Issue 123), Hanover 1991, p. 8.
  5. ↑ Marion Homann: The Diatoms of the Fur Formation (Old Tertiary) from the Limfjord area, North Jutland / Denmark , 285 pages, 3 figures, 8 tables, 57 photos, Geological Yearbook Series A, Issue 123, Hanover 1991, p. 12.
  6. ^ Sven Gisle Larsson: Baltic Amber - a Palaeobiological Study. Entomonograph Volume 1, Klambenborg (DK) 1978. ISBN 87-87491-16-8 .