Lagerstätte
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Lagerstätten (German; singular Lagerstätte; literally place of storage, resting place) are sedimentary deposits that exhibit extraordinary fossil richness or completeness. Palaeontologists distinguish two kinds.
Konzentrat-Lagerstätten (concentration lagerstätten) are deposits with a particular concentration of disarticulated organic hard parts, such as a bone bed or an oyster bed. These lagerstätten are less spectacular than the more famous Konservat-Lagerstätten.
Konservat-Lagerstätten (conservation lagerstätten) are deposits known for the exceptional preservation of fossilized organisms, where the soft parts are preserved in the form of impressions or casts. This is caused by incompleteness of biological recycling, for example where anoxic conditions, as in oxygen-free mud, has suppressed common bacterial decomposition long enough for the initial casts of soft body parts to register. The individual taphonomy of the fossils varies with the sites. Conservation lagerstätten are crucial in providing answers to important moments in the history and evolution of life, for example the Burgess Shale of British Columbia is associated with the Cambrian explosion, and the Solnhofen limestone with the earliest known bird, archeopteryx.
Lagerstätten preserve lightly sclerotized and soft-bodied organisms that are not otherwise preserved in the usual shelly and bony fossil record; thus they offer a more complete record of ancient biodiversity and enable some reconstruction of the paleoecology of ancient aquatic communities. In 1986 Simon Conway Morris calculated that only about 14% of genera in the Burgess Shale had possessed biomineralized tissues in life. The affinities of the shelly elements of conodonts were mysterious until the associated soft tissues were discovered near Edinburgh, Scotland, in the Granton Lower Oil Shale of the Carboniferous.[1] Information from the broader range of organisms found in lagerstätten have contributed to recent phylogenetic reconstructions of some major metazoan groups.
Lagerstätte still have preservational biases, i.e., certain fossils not showing up in the bed due to environmental conditions.
Contents |
[edit] Important Lagerstätten
Some of the world's major Lagerstätten include:
| Pre-Cambrian | ||
| Ediacara Hills | 700 mya | South Australia |
| Doushantuo Formation | 600–555 mya | Guizhou Province, China |
| Cambrian | ||
| Maotianshan shales (Chengjiang) | 525 mya | Yunnan Province, China |
| Emu Bay shale | 525 mya | South Australia |
| Sirius Passet | 518 mya | Greenland |
| Kaili Formation | 513-501 mya | Guizhou province, southwest China |
| House Range | Middle Cambrian | Western Utah, USA |
| Burgess Shale | 505 mya | British Columbia, Canada |
| Kinnekulle Orsten and Alum Shale | 500 mya | Sweden |
| Öland Orsten and Alum Shale | 500 mya | Sweden |
| Ordovician | ||
| Soom Shale | 435 mya | South Africa |
| Silurian | ||
| Wenlock Series | 420 mya | England |
| Devonian | ||
| Rhynie chert | 400 mya | Scotland |
| Hunsrück Slates | 390 mya | Rheinland-Pfalz, Germany |
| Canowindra, New South Wales | 360mya | Australia |
| Carboniferous | ||
| Bear Gulch Limestone | 320 mya | Montana, USA |
| Mazon Creek | 300 mya | Illinois, USA |
| Hamilton Quarry | 295 mya | Kansas, USA |
| Triassic | ||
| Karatau | 213–144 mya | Kazakhstan |
| Ghost Ranch | 185–155 mya | New Mexico, USA |
| Jurassic | ||
| Holzmaden | 160 mya | Württemberg, Germany |
| La Voulte-sur-Rhone | 160 mya | France |
| Solnhofen limestone | 145 mya | Bavaria, Germany |
| Cretaceous | ||
| Chaomidianzi Formation (Yixian Formation) | ca 135 mya | Liaoning, China |
| Crato Formation | ca 117 mya (Aptian) | northeast Brazil |
| Xiagou Formation | ca 110 mya | Gansu, China |
| Santana Formation | 108–92 mya | Brazil |
| Auca Mahuevo | 80 mya | Patagonia, Argentina |
| Eocene | ||
| Green River Formation | 50 mya | Colorado/Utah/Wyoming, USA |
| Monte Bolca | 49 mya | Italy |
| Messel Oil Shale | 49 mya | Hessen, Germany |
| London Clay | 54–48 mya | UK |
| Oligocene–Miocene | ||
| Dominican amber | 30–10 mya | Dominican Republic |
| Riversleigh | 25–15 mya | Queensland, Australia |
| Miocene | ||
| Clarkia fossil beds | 20–17 mya | Idaho, USA |
| Ashfall Fossil Beds | 10 mya | Nebraska, USA |
| Pleistocene | ||
| Rancho La Brea Tar Pits | 20,000 yrs bp | California, USA |
[edit] Notes
- ^ Briggs et al. 1983; Aldridge et al. 1993.
[edit] See Also
- List of fossil sites (with link directory)
[edit] References
- Fossil Lagerstätten. Department of Earth Sciences, University of Bristol (2003). Retrieved on November 21, 2005. — A catalogue of sites of exceptional fossil preservation produced by MSc palaeobiology students at University of Bristol's Department of Earth Sciences.
- Orr, Patrick J.; Derek E. G. Briggs, David J. Siveter and Derek J. Siveter (January 2000). "Three-dimensional preservation of a non-biomineralized arthropod in concretions in Silurian volcaniclastic rocks from Herefordshire, England". Journal of the Geological Society 157 (1): 173–186. Retrieved on 2006-10-26.
