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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. Information from the broader range of organisms found in lagerstätten have contributed to recent phylogenetic reconstructions of some major metazoan groups. Lagerstätten are still subject to preservational biases, of course.
Important Lagerstätten Some of the world's major Lagerstätten include: Notes | ||||||||
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