Lagerstätten: Extraordinary Fossil Localities

Lagerstätten: extraordinary fossil localities

Konzentrat-Lagerstätten:

Concentration deposits—deposits are remarkable because the fossils are abundant
Examples include bone beds, coquinas, etc.
Usually collect over a long interval of time, represent time-averaging
Preservationally skewed towards durable organically produced materials

Konservat-Lagerstätten:

Conservation deposits—deposits are remarkable because of exceptional preservation, normally of “soft” organics that are typically destroyed during death, decay, decomposition, biostratinomic processes, and diagenesis.
Usually represent a catastrophic event that induces both death, and subsequently enhances preservation
Examples include articulated multipartic fossils, and fossilized soft tissues
Konservat-Lagerstätten give us a more transparent view through the taphonomic filter of pre-death paleobiology than any other type of deposit.
Often referred to as a “taphonomic window”
Typical environments enhancing “Konservat” formation include:
Microbial mats (e.g. Ediacaran biota)
Episodic sedimentation on submarine slopes and fans without significant deep bioturbation
Episodic sedimentation in highly bioproductive, fluctuating saline waters of lagoons and bays of the upper delta plain.
Shallow restricted marine basins in tropical, semiarid regions enhancing formation stratified water bodies and sediment/water interfacial microbial mats
Lacustrine deposits in stratified water, again with sediment/water interfacial microbial mats (usually Cenozoic due to preservational potential)
Plant Resinal interment—amber inclusions
Impregnation by hydrocarbons in seeps, bogs, etc.
Authigenic minerals form quickly in decay-prone tissues
Often induced by microbial decomposition, may preserve tissues as molds produced by petrifaction of encasing bacteria. Limits resolution of structure to size of bacteria sheathing the tissues
Concretionary preservation results from steep biogeochemical gradients around organisms through authigenic mineral formation
May be induced through anaerobic steep chemical gradients around organism
Minerals include apatite, clay minerals, pyrite, opalline silica, and calcite

Important Lagerstatten:

3450-3470 Ma, Apex Chert of the Warawoona Group, Western Australia
Lakhanda Formation (mudstone), 1000Ma, (eu- and prokaryota)
Doushantuo Formation, China, 570 Ma nodular cherts with actritarchs and prokaryotes in lower carbonaceous shales, and overlying phosphorites with colonial algae and Ediacaran biota.
Chengjiang, China, Lower Cambrian, phosphatic and pyritized in mudstones
Soom Shale, South Africa, Upper Ordovician
Rhynie Chert, Scotland, Lower Devonian
Hunsrück Slate, western Germany, Lower Devonian
La Voulte-sur Rhône, France, Upper Middle Jurassic (e.g. pyritized squid)
Santana Formation, Lower Cretaceous, Brazil, concretionary phosphatic, fish
La Huérguina Limestone Formation of the Las Hoyas basin, Spain, Lower Cretaceous, lacustrine
PrincetonChert, British Columbia, Canada, Middle Eocene flora, lacustrine
Dominican Amber, 15-40 Ma, produced by Hymenaea protera, a Leguminosae, 490 genera and 372 families
Burgess Shale, Mt. Stephan, British Columbia, Canada, Middle Cambrian
Solnhofen Limestone, Bavaria, Jurassic
Francis Creek Shale (Mazon Creek), southern Illinois, Carboniferous
Messel Oil Shale, Eocene, near Frankfurt, Germany
Barstow Formation, Miocene, BarstowCalifornia, insects