Posidonia Shale

Sachrang Formation
Stratigraphic range: Early-Late Toarcian[1][2]
~183–178 Ma
Possible Latest Pliensbachian records[3]
Posidonia Shale (Posidonienschiefer) Outcrop
TypeGeological formation
Unit of
Sub-units
UnderliesJurensismergel Formation (Germany)
Werkendam Formation (Netherlands)
Klaus Formation (Austria)
Marnes à Bifrons Formation (Luxembourg)
OverliesAmaltheenton Formation (Germany)
Aalburg Formation (Netherlands)
Scheibelberg Formation (Austria)
Lithology
PrimaryBlack shale
OtherLime mudstone, nodular claystone
Location
RegionWestern & Central Europe
Country Germany
 Netherlands
 Austria
 Switzerland
 France
 Luxembourg
Extent
Type section
Named forThe village of Sachrang, Bavaria
Named byJacobshagen
LocationBorder with Tyrol above Sachrang
Year defined1965
Coordinates47°41′N 12°14′W / 47.69°N 12.24°W / 47.69; -12.24[4]
Posidonia Shale is located in Germany
Posidonia Shale
Posidonia Shale (Germany)

Holzmaden, location of the main Outcrop

The Posidonia Shale (German: Posidonienschiefer, also called Schistes Bitumineux in Luxembourg) geologically known as the Sachrang Formation, is an Early Jurassic (Early to Late Toarcian) geological formation of southwestern and northeast Germany, northern Switzerland, northwestern Austria, southern Luxembourg and the Netherlands, including exceptionally well-preserved complete skeletons of fossil marine fish and reptiles.[5][6][7]

The Posidonienschiefer, the German translation, takes its name from the ubiquitous fossils of the oyster-related bivalve "Posidonia bronni" (synonym of Bositra buchii and Steinmannia bronni) that characterize the mollusk faunal component of the formation. The name Posidonia Shale has been used for more than a century, until revisions in 2016 proposed the Sachrang Formation as new name for the Germanic unit, in a same way Altmühltal Formation is the official name of the Solnhofen Limestone.[8] The Posidonia Shales where stablished as a valid vulgar name for this regions lower Toarcian Black Shales. The name Posidonienschiefer, while valid, represents another vulgar nomination, as Posidonia is an invalid genus and junior synonym of Bositra.[8] The type profile is still located on Dotternhausen.[8]

The formation comprises finely laminated layers of oil shales formed of fine-grained sediments intercalated with bituminous limestones and crops out in a number of locations in southwestern Germany, although most remains are from near the village of Holzmaden and Dotternhausen.[7] The European oil shales deposited on a sea floor during the Early Toarcian in the ancient Tethys Ocean are described as being deposited in an anoxic, or oxygen-depleted, deep water environment, although the details of the depositional environment are the subject of debate by researchers of the formation.[7][9]

  1. ^ Ruebsam, W.; Schmid-Röhl, A.; Al-Husseini, M. (2023). "Astronomical timescale for the early Toarcian (Early Jurassic) Posidonia Shale and global environmental changes". Palaeogeography, Palaeoclimatology, Palaeoecology. 623: 111619. Bibcode:2023PPP...62311619R. doi:10.1016/j.palaeo.2023.111619. S2CID 258545235. Retrieved 10 July 2023.
  2. ^ Burnaz, L.; Littke, R.; Grohmann, S. (2024). "Lower Jurassic (Pliensbachian–Toarcian) marine paleoenvironment in Western Europe: sedimentology, geochemistry and organic petrology of the wells Mainzholzen and Wickensen, Hils Syncline, Lower Saxony Basin". Int J Earth Sci (1). Bibcode:2024IJEaS.tmp....9B. doi:10.1007/s00531-023-02381-8.{{cite journal}}: CS1 maint: bibcode (link)
  3. ^ Neumeister, S.; Gratzer, R.; Algeo, T. J.; Bechtel, A.; Gawlick, H. J.; Newton, R. J.; Sachsenhofer, R. F. (2015). "Oceanic response to Pliensbachian and Toarcian magmatic events: Implications from an organic-rich basinal succession in the NW Tethys". Global and Planetary Change. 126: 62–83. Bibcode:2015GPC...126...62N. doi:10.1016/j.gloplacha.2015.01.007. Retrieved 12 December 2023.
  4. ^ "Typlokalität der Sachrang-Formation W von Sachrang" (PDF). Retrieved 31 January 2024.
  5. ^ Etter, Walter; Kuhn, Olivier (2000). "An Articulated Dragonfly (Insecta, Odonata) From The Upper Liassic Posidonia Shale Of Northern Switzerland". Palaeontology. 43 (5): 967–977. Bibcode:2000Palgy..43..967E. doi:10.1111/1475-4983.00157. ISSN 0031-0239. S2CID 140165815.
  6. ^ Henrotay, M.; Marques, D.; Paicheler, J. C.; Gall, J. C.; Nel, A. (1998). "Le Toarcien inférieur des régions de Bascharage et de Bettembourg (grand-duché du Luxembourg) : évidences paléontologiques et sédimentologiques d'environnements restreints proches de l'émersion" (PDF). Geodiversitas. 20 (2): 263–284.
  7. ^ a b c Clements, Thomas; Gabbott, Sarah (2022-04-13). "Exceptional Preservation of Fossil Soft Tissues". eLS: 1–10. doi:10.1002/9780470015902.a0029468. ISBN 9780470016176.
  8. ^ a b c Mönnig, Eckhard (2018). "Der Jura in der Stratigraphischen Tabelle von Deutschland (STD 2016)" (PDF). Newsletters on Stratigraphy. 41 (1–3): 253–261. doi:10.1127/0078-0421/2005/0041-0253. ISSN 0078-0421.
  9. ^ Brenner, K. (1978). "New aspects about the origin of the Toarcian Posidonia Shales". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 157 (3): 11–18. doi:10.1127/njgpa/157/1978/11.