Fossil Lagerstätte

Fossil Lagerstätte are sites of immense preservation and fossilisation. Are some creatures rapidly preserved or nearly instantly? For example the amazing remains of soft bodied animals at China's Qingjiang site.

German mining jargon for motherload or bonanza. However, usually used outside Germany for what is properly Fossil-Lagerstätten. Adolph Seilacher proposed two major types of Fossil-Lagerstätten:
Konzentrat-Lagerstätten: anomolously high amounts of fossil material
Konservat-lagerstätten: unusually well-preserved fossils (What is generally thought of by the term Lagerstätten)

Some Famous Lagerstätten: Burgess Shale, Hunsrückschiefer, Mazon Creek fauna, Holzmaden, Solnhofen Lithographic Limestone, Jehol Group
Lagerstätten - Taphonomy Making a Fossil Record | University of Maryland

fossil Lagerstätte

A sedimentary deposit may have experienced a mixing of noncontemporaneous remains within single sedimentary units via physical or biological processes; i.e. a deposit could be ripped up and redeposited elsewhere, meaning that a deposit may contain a large amount of fossils from another place (an allochthonous deposit, as opposed to the usual autochthonous).

Thus, a question that is often asked of fossil deposits is to what extent does the fossil deposit record the true biota that originally lived there? Many fossils are obviously autochthonous, such as rooted fossils like crinoids, and many fossils are intrisically obviously allocthonous, such as the presence of photoautotrophic plankton in a benthic deposit that must have sunk to be deposited.

A fossil deposit may thus become biased towards exotic species (i.e. species not endemic to that area) when the sedimentology is dominated by gravity driven surges, such as mudslides, or may become biased if there is very little endemic organisms to be preserved. This is a particular problem in palynology.
Mixing of fossils from different places - Taphonomy | Wikipedia

Lagerstätte (pl. Lagerstätten) A sedimentary deposit that is of value because of the fossils it contains. A fossil-Lagerstätte contains an abundance of fossils; a conservation-Lagerstätte is a stratum in which fossils are exceptionally well preserved; a concentration-Lagerstätte is a large accumulation of fossils of particular species, such as a shell bed. The term was introduced by Adolf Seilacher, from the German Lager, ‘stratum’, and Stätte, ‘place’.
Lagerstätte

Death assemblages or Lagerstätte

A Lagerstätte (German: [from Lager 'storage, lair' Stätte 'place'; plural Lagerstätten) is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. A number of taphonomic pathways may produce Lagerstätten. The following is an incomplete list:
Orsten-type and Doushantuo-type preservations preserve organisms in phosphate.
Bitter Springs-type preservation preserves them in silica.
Carbonaceous films are the result of Burgess Shale-type preservation
Pyrite preserves exquisite detail in Beecher’s trilobite-type preservation.
Ediacaran-type preservation preserves casts and moulds with the aid of microbial mats.
Preservation - Lagerstätten | Wikipedia

Burgess Shale–type fossil Lagerstätten provide the best evidence for deciphering the biotic patterns and magnitude of the Cambrian explosion. Here, we report a Lagerstätte from South China, the Qingjiang biota (~518 million years old), which is dominated by soft-bodied taxa from a distal shelf setting. The Qingjiang biota is distinguished by pristine carbonaceous preservation of labile organic features, a very high proportion of new taxa (~53%), and preliminary taxonomic diversity that suggests it could rival the Chengjiang and Burgess Shale biotas. Defining aspects of the Qingjiang biota include a high abundance of cnidarians, including both medusoid and polypoid forms; new taxa resembling extant kinorhynchs; and abundant larval or juvenile forms.
The Qingjiang biota—A Burgess Shale–type fossil Lagerstätte from the early Cambrian of South China

Lagerstätte

A wealth of ancient remains found by chance on the banks of a river in China are some of the most astoundingly preserved fossils now known on Earth. The 518-million-year-old site, called Qingjiang, joins just a few places around the world where fossil preservation is so extraordinary, it captures even soft-bodied animals. Called Lagerstätten, these special types of deposits include Canada's famous Burgess shale, which dates to 507 million years ago, and China's Chengjiang locality

“Most fossil localities throughout all of time are going to preserve the shelly things, the hard things ... [but] what these localities give you is anatomy,” says Harvard paleontologist Joanna Wolfe, an expert on Cambrian life who wasn't involved in the study. “These are the best of the best.”
Spectacular new fossil bonanza captures explosion of early life | National Geographic

Why are these not death assemblages?