| Lantian Formation | |
|---|---|
| Stratigraphic range: Ediacaran ~ | |
| Location | |
| Location | South China |
| Country |  China |
The Lantian Formation is a 150-meter-thick sequence of rocks deposited in Xiuning County, Anhui Province in southern China during a 90-million-year epoch in the Ediacaran period. [2] Its algal macrofossils (which have alternatively been interpreted as putative metazoans [3] ) are the oldest large and complex fossils known. [2]
The rocks were deposited in shallow seas, in the photic zone yet below storm wave base [ clarification needed ], [4] yet were deposited in predominantly anoxic conditions. The fossils are located on the bedding planes, and are randomly oriented. [2]
The lowest part of the formation consists of a cap dolomite, marking the end of the Marinoan glaciation and start of the Ediacaran. Above this is black shale containing the Lantian biota fossils. Above this are layers of dolomite, and shale followed by limestone. The highest part of the formation is black shale again. Above the formation is the Piyuancun formation consisting of silicious rock. The Lantian formation overlies diamictite from the Cryogenian. [5]
The fossils are preserved as carbonaceous films in a Burgess Shale type preservational fashion. [2] Anhuiphyton lineatum is one example of a fossil located in the site.
Originally presumed to be Cambrian in age, [2] the formation is now correlated with the Doushantuo formation, with an overlying formation also falling in the Ediacaran period. [4]
The Lantian biota has a maximum Re-Os age of 602 ± 7 million years ago. [1]
The Ediacaran Period is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is named after the Ediacara Hills of South Australia.
Pteridinium is an erniettomorph found in a number of Precambrian deposits worldwide. It is a member of the Ediacaran biota.
The Doushantuo Formation is a geological formation in western Hubei, eastern Guizhou, southern Shaanxi, central Jiangxi, and other localities in China. It is known for the fossil Lagerstätten in Zigui in Hubei, Xiuning in Anhui, and Weng'an in Guizhou, as one of the oldest beds to contain minutely preserved microfossils, phosphatic fossils that are so characteristic they have given their name to "Doushantuo type preservation". The formation, whose deposits date back to the Early and Middle Ediacaran, is of particular interest because it covers the poorly understood interval of time between the end of the Cryogenian geological period and the more familiar fauna of the Late Ediacaran Avalon explosion, as well as due to its microfossils' potential utility as biostratigraphical markers. Taken as a whole, the Doushantuo Formation ranges from about 635 Ma at its base to about 551 Ma at its top, with the most fossiliferous layer predating by perhaps five Ma the earliest of the 'classical' Ediacaran faunas from Mistaken Point on the Avalon Peninsula of Newfoundland, and recording conditions up to a good forty to fifty million years before the Cambrian explosion at the beginning of the Phanerozoic.
Hiemalora is a fossil of the Ediacaran biota, reaching around 3 cm in diameter, which superficially resembles a sea anemone. The genus has a sack-like body with faint radiating lines originally interpreted as tentacles, but discovery of a frond-like structure seemingly attached to some Heimalora has added weight to a competing interpretation: that it represents the holdfast of a larger organism.
Rangea is a frond-like Ediacaran fossil with six-fold radial symmetry. It is the type genus of the rangeomorphs.
Parvancorina is a genus of shield-shaped bilaterally symmetrical fossil animal that lived in the late Ediacaran seafloor. It has some superficial similarities with the Cambrian trilobite-like arthropods.
The Kaili Formation(凯里組) is a stratigraphic formation which was deposited during the Lower and Middle Cambrian. The formation is approximately 200 metres (660 ft) thick and was named after the city Kaili in the Guizhou province of southwest China.
The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.
The Burgess Shale of British Columbia is famous for its exceptional preservation of mid-Cambrian organisms. Around 69 other sites have been discovered of a similar age, with soft tissues preserved in a similar, though not identical, fashion. Additional sites with a similar form of preservation are known from the Ediacaran and Ordovician periods.
The Cambrian explosion, Cambrian radiation,Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately 538.8 million years ago in the Cambrian Period when practically all major animal phyla started appearing in the fossil record. It lasted for about 13 – 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well.
Eoandromeda is an Ediacaran organism consisting of eight radial spiral arms, and known from two taphonomic modes: the standard Ediacara type preservation in Australia, and as carbonaceous compressions from the Doushantuo formation of China, where it is abundant.
Ediacaran type preservation relates to the dominant preservational mode in the Ediacaran period, where Ediacaran organisms were preserved as casts on the surface of microbial mats.
The Haifanggou Formation, also known as the Jiulongshan Formation, is a fossil-bearing rock deposit located near Daohugou village of Ningcheng County, in Inner Mongolia, northeastern China.
Anhuiphyton lineatum is an extinct species of Neoproterozoic algae, known from several fossils from the Lantian formation of China, first described in 1994. It lived probably more than 580 million years ago. The thalli were of spherical to elliptical shape, made of thousands of flexible septated filaments. The whole organism was a few centimeters in size. Along with Flabellophyton, it is one of the few septated algae found in the assemblage.
The Dengying Formation is an upper Ediacaran fossiliferous geologic formation found in South China. It was deposited on a shallow marine carbonate platform.
Wutubus annularis is a tubular Ediacaran fossil from China. It is the only species in the genus Wutubus.Genus name was derived from the fossil locality near the village of Wuhe and from Latin tubus (tube), and the species epithet derived from Latin, annularis, with reference to the transverse annulae on the tube.
Orbisiana is an Ediacaran benthic organism formed out of series of agglutinated spherical or hemispherical chambers. It is believed to be a close relative of Palaeopascichnus.
Lenisambulatrix is a genus of extinct worm belonging to the group Lobopodia and known from the Lower Cambrian Maotianshan shale of China. It is represented by a single species L. humboldti. The incomplete fossil was discovered and described by Qiang Ou and Georg Mayer in 2018. Due to its missing parts, its relationship with other lobopodians is not clear. It shares many structural features with another Cambrian lobopodian Diania cactiformis, a fossil of which was found alongside it.
Shuhai Xiao is a Chinese-American paleontologist and professor of geobiology at Virginia Tech, Blacksburg, Virginia, U.S.A.