Fiskeler
| Fiskeler Member | |
|---|---|
| Stratigraphic range: Danian ~[1] | |
The location of the fiskeler is indicated by the arrow | |
| Type | Geologic locality |
| Unit of | Rødvig Formation |
| Underlies | Cerithium Limestone Member |
| Overlies | Tor Formation |
| Thickness | 5 centimetres (2.0 in) to 10 centimetres (3.9 in) |
| Lithology | |
| Primary | Marl |
| Other | Iridium |
| Location | |
| Region | Zealand |
| Country | Denmark |
| Extent | Stevns Klint |
| Type section | |
| Named for | Abundance of preserved fish scales and teeth |
| Named by | Johan Georg Forchhammer |
| Year defined | 1826 |
The Fiskeler Member (lit. 'Fish Clay Member') of the Rødvig Formation is a notable geologic locality deposited during the Cretaceous–Paleogene boundary and the earliest part of the Danian (early Paleocene; c. 66.086 to 65 Ma).[1] It is known from exposures at Stevns Klint in Denmark.[2]
History
The fiskeler was discovered by Søren Abildgaard in 1759[3][4] and was named fiskeler by Johan Georg Forchhammer in 1826[5] before being described by Richard Taylor and Richard Phillips in 1827.[6] Charles Lyell noted the absence of fossils in 1835,[7] while Forchhammer was able to locate fossils at the site in 1849, using the name fiskeler for the first time in published literature.[8]
It was linked to the Cretaceous–Paleogene boundary during 1980 as a reference point for the stratigraphy and iridium content from the Chixculub impactor which struck Mexico.[2]
Geology
The dark marl layer of fiskeler, mainly five to ten centimeters thick, clearly marks the Cretaceous–Paleogene boundary[9] and overlies the Maastrichtian age Tor Formation as an unconformity.[10][11][12] The fiskeler is enriched in iridium, a fact used as an argument for the Alvarez hypothesis that the worldwide Cretaceous–Paleogene mass extinction was caused by the impact of an asteroid.[13] It also suggested that when the fiskeler was deposited, a sudden change in the local sea level occurred.[14]
It overlies the Cerithium Limestone Member which is Danian in age and contains Paleocene ammonites.[1][15]
Paleontology
The fiskeler contains fossils of animals directly killed by the Chixculub impactor, including an abundance of scales and teeth from fish (with most being microscopic in size),[1] with few other fossils of which include mussels and zoophytes.[5] The first chondrichthyan fossils (including thirty-one distinct species and one indeterminate specimen) from the fiskeler were described by Adolfssen & Ward (2014).[14] This suggested the fauna was similar to Maastrichtian Germany and Danian Sweden,[16][17] linking the fiskeler to the Tethys Ocean.[18]
Only one three-dimensional fish specimen has been found within the fiskeler, and it was described by Forchammer (1849).[8] It is missing the tail and head, and it probably belonged to Berycidae.[4]
References
- ^ a b c d Surlyk, F.; Damholt, T.; Bjerager, M. (2006). "Stevns Klint, Denmark: Uppermost Maastrichtian chalk, Cretaceous–Tertiary boundary, and lower Danian bryozoan mound complex". Bulletin of the Geological Society of Denmark. 54: 1–48. doi:10.37570/bgsd-2006-54-01.
- ^ a b Alvarez, L.W.; Alvarez, W.; Asaro, F.; Michel, H. V. (1980). "Extraterrestrial cause for the Cretaceous–Tertiary extinction". Science. 208 (4448): 1095–1108. Bibcode:1980Sci...208.1095A. CiteSeerX 10.1.1.126.8496. doi:10.1126/science.208.4448.1095. PMID 17783054. S2CID 16017767.
- ^ Abildgaard, S. (1759). Description of Stevns Klint and its natural oddities.
- ^ a b "The fish in the fish clay – an old mystery is unravelled (in Danish)". vidensdab.dk. 19 March 2017. Retrieved 21 October 2025.
- ^ a b Forchhammer, J. G. (1826). On the Geognostic Conditions in a Part of Zealand and the Neighboring Islands.
- ^ Taylor, R. & Phillips, R. (1827). The Philosophical magazine, or Annals of chemistry, mathematics, astronomy, natural history and general science. London : Richard Taylor (p. 99)
- ^ Lyell, C. (1835). On the Cretaceous and Tertiary Strata of the Danish Islands of Seeland and Moen.
- ^ a b Forchhammer, J. G. (1849). The Newer Chalk in Denmark.
- ^ "Stevns Klint". Den Store Danske (in Danish). Retrieved 23 June 2014.
- ^ NPD. "Tor Formation". NORLEX. Retrieved 25 August 2022.
- ^ British Geological Survey. "Tor Formation". The BGS Lexicon of Named Rock Units. Retrieved 26 August 2022.
- ^ Blinkenberg, K.H.; Anderskouv, K.; Sheldon, E.; Bjerrum, C.J.; Stemmerik, L. (2020). "Stratigraphically controlled silicification in Danian chalk and its implications for reservoir properties, southern Danish Central Graben". Marine and Petroleum Geology. 115. doi:10.1016/j.marpetgeo.2019.104134.
- ^ International Union on Conservation of Nature (March 2014). World Heritage Nomination - IUCN Technical Evaluation: Stevns Klint (Denmark) - ID No. 1416 (Report). UNESCO.
- ^ a b Adolfssen, J. S., & Ward, D. J. (2014). Crossing the boundary: An elasmobranch fauna from Stevns Klint, Denmark. Palaeontology, 57(3), 591–629. https://doi.org/10.1111/pala.12079
- ^ Machalski, Marcin; Heinberg, Claus (2005-12-01). "Evidence for ammonite survival into the Danian (Paleogene) from the Cerithium Limestone at Stevns Klint, Denmark". Bulletin of the Geological Society of Denmark. 52: 2005–12. doi:10.37570/bgsd-2005-52-08.
- ^ Herman, J. (1982b). Die Selachier-Zähne aus der Maastricht-Stufe von Hemmoor, Niederelbe (NW-Deutschland). Geologisches Jahrbuch A, 61, 129–159.
- ^ Siverson, M. (1993a). Late Cretaceous and Danian neoselachians from southern Sweden. Lund Publications in Geology, 110, 1–28.
- ^ Cappetta, H. (1980). Les sélaciens du Crétacé supérieur du Liban. I: Requins. Palaeontographica, Abteilung A, 168, 69–148.