Misplaced Pages

#363636

37-595: The Emsian stratigraphy of the southern Rhenish Massif can be divided into two lithological units: the older slates of the Hunsrück-Schiefer and the younger sandstones of the Singhofener Schichten . Stratigraphically below the Hunsrück Slates is the (older) Taunus quartzite . All these metasedimentary rocks were originally deposited in the marine Rhenohercynian Basin , a back-arc basin south of

74-610: A brief period as benthic environments rapidly changed in the Cambrian. Chengjiang is the richest source of the Lobopodia , a group including many early panarthropods , with six genera represented: Luolishania , Paucipodia , Cardiodictyon , Hallucigenia (also known from the Burgess Shale), Microdictyon , and Onychodictyon . Perhaps the most important fossils from Chengjiang are eight possible members of phylum Chordata ,

111-535: A section of mudstone 50 metres (160 ft) thick in the Yuanshan Member of the Qiongzhusi Formation . The Yuanshan Member is extensive, covering multiple 10,000 square kilometres (3,900 sq mi) of eastern Yunnan Province, where there are many scattered outcrops yielding fossils. Studies of the strata are consistent with a tropical environment with sea level changes and tectonic activity. The region

148-473: A series of Early Cambrian sedimentary deposits in the Chiungchussu Formation, famous for their Konservat Lagerstätten , deposits known for the exceptional preservation of fossilized organisms or traces . The Maotianshan Shales form one of some forty Cambrian fossil locations worldwide exhibiting exquisite preservation of rarely preserved, non-mineralized soft tissue, comparable to the fossils of

185-526: A single sarcopterygian lobe-fin specimen are also known. Rhenopterus Probably misidentified remains of trilobites Chondrites Ichnotaxon Planolites Worm-like ichnotaxon Ctenopholeus Ichnotaxon Heliochone Ichnotaxon Protovirgularia Ichnotaxon, including fossils originally misidentified as Edestus Pteridichnites Ichnotaxon Endichnia Ichnotaxon [REDACTED] Media related to Hunsrück Lagerstätte at Wikimedia Commons Emsian The Emsian

222-800: Is believed to have been a shallow sea with a muddy bottom. The preserved fauna is primarily benthic and was likely buried by periodic turbidity currents , since most fossils do not show evidence of post-mortem transport. Like the younger Burgess Shale fossils, the paleo-environment enabled preservation of non-mineralized, soft body parts. Fossils are found in thin layers less than an inch thick. The soft parts are preserved as aluminosilicate films, often with high oxidized iron content and often exhibiting exquisite details. The Chengjiang beds are very deeply weathered, as evidenced by their low specific gravity (i.e., they are very lightweight). Trace fossils are abundant. The Chengjiang biota comprises an extremely diverse faunal assembly, with some 185 species described in

259-632: Is believed to have inhabited a delta front environment rich in oxygen, with high sedimentation rates and major fluctuations in salinity being the main environmental stressors. Located at the Yunnan Province of South China, the Guanshan biota are also Burgess shale-type fossils but slightly younger than the Chengjian biota, and is dated to 515–510 Myr falling within the Cambrian Stage 4 . Brachiopods are

296-488: Is described to be the earliest craniate -like chordate. This fish-like animal has many similarities to Y. lividum , but differs in several aspects: It has a discernible heart, dorsal and ventral aorta, gill filaments, and a notochord (neural chord). At present, there is no agreement as to the systematic placement of the Vetulicola , represented by seven species from Chengjiang. Originally described as crustacean arthropods,

333-675: Is locally termed Qiongzhusian , a stage correlated to the late Atdabanian Stage in Siberian sequences of the middle of the Early Cambrian . The shales date to ≤ 518  million years ago . The shales also contain the slightly younger Guanshan biota from Malong District in Yunnan, Kaili biota and Balang fauna in Guizhou, Shipai fauna in Hubei, and sponge faunas of Guizhou and Anhui. Along with

370-790: Is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan , 35 centimetres (14 in) above

407-620: Is the Haiyan Lagerstätte where hundreds of juvenile specimens have been found. This unique location offers insights into the development of most animal groups and as such is a unique deposit in the Cambrian. In respect of 'the Chengjiang fossils represent[ing] an uparalleled record of the fundamentally important rapid diversification of metazoan life in the early Cambrian', the International Union of Geological Sciences (IUGS) included

SECTION 10

#1733085675364

444-653: The Burgess Shale of British Columbia, Canada. They take their name from Maotianshan Hill ( Chinese : 帽 天 山 ; pinyin : Màotiānshān ; lit. 'Hat Sky Mountain') in Chengjiang County , Yunnan Province, China . The most famous assemblage of organisms are referred to as the Chengjiang biota for the multiple scattered fossil sites in Chengjiang. The age of the Chengjiang Lagerstätte

481-499: The Vetulicola were later erected as a new phylum of primitive deuterostomes by D.G. Shu et al. (Shu 2001). Another researcher places them with the urochordates, based on putative affinity with the phylum Chordata. They are thought to have been swimmers that either were filter feeders or detritivores. Some two dozen animals from the Chengjiang biota are problematic regarding phylogenetic assignment. Among these, ' Anomalocaris ' saron ,

518-750: The paleocontinent of Laurussia . The Hunsrück Slate roughly comprises the Sauerthal-Schichten , Bornich-Schichten and Kaub-Schichten . These are 408–400 Mya old, making them part of the Latest Pragian to Early Emsian stages of the Devonian. The Hunsrück slate was a source for Rhenish slate over several centuries. Archaeological finds in West Germany show that the slate was used in Roman times. The first documented case of mining in this area dates from

555-514: The 'Cambrian Chengjiang fossil site and lagerstätte' in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an 'IUGS Geological Heritage Site' as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.' The fossils occur in

592-526: The 14th century. The production continued with the Industrial Revolution at the end of the 1700s, but in 1846–49, the industry fell into crisis, resulting in poverty and misery in the mining areas. The economic upturn after the Franco-Prussian War of 1870-71 resulted in a renewed increase in slate production, where companies used more extensive pits. Production continued until the 1960s, when

629-638: The 1990s, Christoph Bartels and Günther Brassel have continued this work. The various fossil localities are quarries located mostly south of the River Mosel and west of the Rhine in western Germany . The biota of the Hunsrück Slate are commonly called "Bundenbach fossils" after the nearby German community of Bundenbach. More formally, the Hunsruck Slate is properly designated as a Konservat Lagerstätte due to

666-593: The Burgess Shale, the Maotianshan Shales are remarked as "our best window into the Cambrian 'explosion' ", especially on the origin of chordates . Although fossils from the region have been known from the early part of the 10th century, Chengjiang was first recognized for its exquisite states of preservation with the 1984 discovery of the naraoiid Misszhouia , a soft-bodied relative of trilobites . Since then,

703-478: The Hunsrück Slate. Many types of fishes have been described from the Hunsruck slate. Several genera of placoderm armoured fish have been recorded, including some preserved in three dimensions. Agnathan jawless fishes are the most commonly preserved vertebrates, particularly the flattened Drepanaspis , notable for its upwards-facing mouth, and the streamlined Pteraspis . Spines from acanthodii spiny sharks and

740-425: The Hunsrück Slate. The deposits occur in a strip some 15 km wide and 150 km long running from northwest to southeast. In the main depositional basins of Kaub, Bundenbach, and Gemünden, echinoderms are concentrated in the southwestern area around Bundenbach, with brachiopods predominating in the northeast. The presence of corals and trilobites with well-developed eyes and the rarity of plant fossils from

777-498: The alleged predatory terror of the early Cambrian, was the most famous, although that species is later reclassified to Houcaris saron and Innovatiocaris maotianshanensis . Shu (2006) recently described Stromatoveris psygmoglena as a possible bilateran missing link between Ediacaran fronds and Cambrian ctenophores . Cambrocornulitus had a tubicolous shell which probably was biomineralized. It shares some affinities with cornulitids and lophophorates. The Chengjiang biota

SECTION 20

#1733085675364

814-484: The animal groups found in the Burgess Shale; however, since it is ten million years older, it more strongly supports the deduction that metazoans diversified earlier or faster in the early Cambrian than does the Burgess Shale fauna alone. The preservation of an extremely diverse faunal assemblage renders the Maotianshan shale the world's most important for understanding the evolution of early multi-cellular life, particularly

851-474: The central basin areas suggest a shallow-water environment. Other animal fossils include sponges , corals, brachiopods, cephalopods , ctenophores , cnidarians , gastropods , and worm trace fossils . Trilobites and echinoderms are relatively abundant in some horizons. Crinoids and starfish are the predominant representatives of the echinoderms, although holothurians (sea cucumbers) are also represented. More than 60 species of crinoids are described from

888-494: The communities of Bundenbach and Gemünden. The slates were widely quarried in the past, mainly for roofing tiles from small pits, of which over 600 are known. Today, only a single quarry remains open in the main fossiliferous region of Bundenbach. There are also areas of the Hunsrück Slates where fossils are neither well preserved, nor pyritized, indicating that there also existed environments with shallow and fully oxygenated water. More than 260 animal species have been described from

925-485: The competition from cheaper synthetic or imported slate resulted in production decline. Only a single pit in the Bundenbach region was worked in the 1990s. Since 1999, slate imports from Spain , Portugal , Argentina and China caused the abandonment of local mining. Mining of Hunsrück slate was important for the discovery of fossils. Although not rare, fossils can only be found through extensive mining of slate. Many of

962-585: The contact with the Madmon Formation . In North America the Emsian Stage is represented by Sawkill or Sawkillian time. During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after

999-623: The end of Early Devonian, before 391.9 mya ). Later agoniatitid ammonoids would die out in the Taghanic event in the upper middle Givetian . Goniatite ammonoids would give rise to further ammonoid orders, thus starting ammonoid dominance of marine fossils in further periods until their end at the Cretaceous-Paleogene mass extinction event . This geochronology article is a stub . You can help Misplaced Pages by expanding it . Maotianshan shales The Maotianshan Shales ( 帽天山页岩 ) are

1036-409: The fine fossils exhibited in museums today were originally found by the slate miners. The first scientific publication on these fossils comes from Ferdinand von Roemer (1862), who described starfish and crinoid fossils from Bundenbach. German paleontologists such as R. Opitz, F. Broili, R. Judge, and W. M. Lehmann studied many fossils between 1920 and 1959. Lehmann's death in 1959 and the decline of

1073-486: The fossil record. Phylum Porifera (sponges; 15 species) and Priapulida (16 species) are also well represented. Other phyla represented are Brachiopoda , Chaetognatha , Cnidaria , Ctenophora , Echinodermata , Hyolitha , Nematomorpha , Phoronida , and Chordata . Possible molluscs include Wiwaxia and Nectocaris . About one in eight animals are problematic forms of uncertain affinity, some of which may have been evolutionary experiments that survived for only

1110-518: The inherent beauty of the fossils. Pyritization is rare in the fossil record, and is believed to require not only rapid burial, but both burial in sediments low in organic matter, and high in concentrations of sulfur and iron. Such pyritization is also prevalent in the lower Cambrian fossils from the Maotianshan shales of Chengjiang, China, the oldest Konservat Lagerstätte of Cambrian time. The best localities for exceptionally preserved fossils are in

1147-428: The literature as of June 2006. Of these, nearly half are arthropods, few of which had the hard, mineral-reinforced exoskeletons characteristic of all later arthropoda; only about 3% of the organisms known from Chengjiang have hard shells. Most of those are the trilobites (of which there are five species), all of which have been found with traces of legs, antennae, and other soft body parts, an exceedingly rare occurrence in

Hunsrück Slate - Misplaced Pages Continue

1184-481: The locality has been intensively studied by scientists throughout the world, yielding a constant flow of new discoveries and triggering an extensive scientific debate surrounding the interpretation of discoveries. Over this time, taxa have been revised or reassigned to different groups. Interpretations have led to many refinements of the phylogeny of groups and even the erection of the new phylum Vetulicolia of primitive deuterostomes . The Chengjiang biota has all

1221-560: The many fossils that exhibit preservation of soft tissues. Hunsrück is one of the few marine Devonian Lagerstätte having soft tissue preservation, and in many cases fossils are coated by a pyritic surface layer. Preservation of soft tissues as fossils normally requires rapid burial in an anoxic (i.e., with little or no oxygen) sedimentary layer where the decomposition of the organic matter is significantly slowed. The pyritization found in Bundenbach fossils facilitated preservation and enhanced

1258-513: The members of phylum Chordata , which includes all vertebrates . The Chengjiang fossils comprise the oldest diverse metazoan assemblage above the Proterozoic - Phanerozoic transition and, thus, the fossil record 's best data source for understanding the apparently rapid diversification of life known as the Cambrian Explosion . One of the most intriguing locations of the Chengjiang biota

1295-409: The most abundant species, followed by trilobites. Other species belong to sponges, chancelloriids, cnidarians, ctenophores, priapulids, lobopodians, arthropods, anomalocaridids, hyoliths, molluscs, brachiopods, echinoderms, algae and vetulicolians. There are also the earliest-known eocrinoids, unidentified soft-bodied animals and abundant trace fossils. The Guanshan biota are regarded as successors of

1332-482: The phylum to which all vertebrates belong. The most famous is Myllokunmingia , possibly a very primitive agnathid (i.e., jawless fish ). Similar to Myllokunmingia is Haikouichthys ercaicunensis , another primitive fish-like animal. The enigmatic Yunnanozoon lividum is considered to be the earliest hemichordate , possessing many of the characteristic chordate features and providing an anatomical link between invertebrates and chordates. Haikouella lanceolata

1369-472: The slate industry caused a decline in fossil research. In 1970, Wilhelm Stürmer, a chemical physicist and radiologist at Siemens , developed a new method to examine the Hunsrück slate fossils using medium energy X-rays of 25-40 keV . He created high-resolution movies and stereoscopic images of unopened slates, which showed complex details of soft tissues that cannot be made visible with conventional methods. In

#363636