Locating the BACE of the Cambrian: Bayan Gol in southwestern Mongolia and global correlation of the Ediacaran–Cambrian boundary

Topper, Timothy P.; Betts, Marissa J.; Dorjnamjaa, D.; Li, Guoxiang; Li, Luoyang; Altanshagai, Gundsambuu; Enhkbaatar, Bakthuyag; Skovsted, Christian B.

doi:10.1016/j.earscirev.2022.104017

Cited by 34 publications

(39 citation statements)

References 200 publications

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“…536 Ma (updated after Bowyer et al 2023b;Nelson et al 2023), and overlaps in time with cloudinids of the Nama assemblage (e.g. Topper et al 2022).…”

Section: Redefinition Of the Nama Assemblagementioning

confidence: 99%

New Ediacaran biota from the oldest Nama Group, Namibia (Tsaus Mountains), and re-definition of the Nama Assemblage

Wood,

Bowyer,

Alexander

et al. 2023

Geol. Mag.

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The Nama Group, Namibia (≥550.5 to <538 million years ago, Ma), preserves one of the most diverse metazoan fossil records of the terminal Ediacaran Period. We report numerous features that may be biological in origin from the shallow marine, siliciclastic, lowermost Mara Member (older than ca. 550.5 Ma) from the Tsaus Mountains. These include forms that potentially represent body fossils, Beltanelliformis and an indeterminate juvenile uniterminal rangeomorph or arboreomorph frond, plug trace fossils, Bergaueria, as well as sedimentary surface textures, which are possibly microbially induced. These are the oldest documented macrofossils in the Nama Group. They represent taxa that persist from the Avalon or White Sea assemblages prior to the later appearance of new biota, including calcified metazoans, calcified and soft-bodied tubular taxa including all cloudinids, as well as more complex trace fossils. Using a new age model that allows more accurate stratigraphic placement of major Ediacaran macrofossil morphogroups and taxa, we propose a re-definition of the Nama Assemblage following the practice for Phanerozoic evolutionary faunas to include only new morphogroups of soft-bodied tubular, calcified taxa and complex trace fossils, defined by first appearance of Cloudina, which postdates deposition of the Kanies and lower Mara members and first appears ca. 550 Ma and persists until at least 539 Ma. Finally, the Tsaus Mountain environment is pristine, unspoilt by geologists and naturalists. Following World Heritage Convention, we suggest a pledge of non-destructive excavation that all future scientists should be able to make in publications of work that involve research in this area.

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“…536 Ma (updated after Bowyer et al 2023b;Nelson et al 2023), and overlaps in time with cloudinids of the Nama assemblage (e.g. Topper et al 2022).…”

Section: Redefinition Of the Nama Assemblagementioning

confidence: 99%

New Ediacaran biota from the oldest Nama Group, Namibia (Tsaus Mountains), and re-definition of the Nama Assemblage

Wood,

Bowyer,

Alexander

et al. 2023

Geol. Mag.

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“…However, recent discoveries of typical Cambrian SSFs (e.g., Anabarites, Rugatotheca) in the siliceous rocks of the Daibu Member in the Xiaotan Section of Yongshan County from northeast Yunnan, indicate that it may be better correlated with the lower Kuanchuanpu Formation in south Shaanxi and the lower Maidiping Formation in south Sichuan (Yang et al, 2014(Yang et al, , 2016Steiner et al, 2020;Yang and Steiner., 2021). Therefore, the base of siliceous strata of the basal Daibu Member has commonly been taken as the base of Cambrian at least in China (Yang and Steiner., 2021;Topper et al, 2022).…”

Section: Geological Background Stratigraphymentioning

confidence: 99%

“…The Meishucun Section in Jinning County of Kunming, eastern Yunnan of Southwest China was originally a candidate for the stratotype section for the international Ediacaran-Cambrian boundary in China. The exact location of the Ediacaran-Cambrian boundary in eastern Yunnan however, is not fully resolved, despite much discussion (e.g., Peng, 2008;Geyer, 2019;Zhu et al, 2019Zhu et al, , 2021Bowyer et al, 2022;Topper et al, 2022). In general, "marker A" in the Meishucun Section, as defined by the first appearance datum of Small Shelly Fossils (SSFs), is most commonly regarded as the base of Cambrian in China (Qian et al, 2002;Zhu et al, 2001Zhu et al, , 2003, and this is also supported by a recent U-Pb Zircon age (Zhu et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Late Ediacaran cavity-dwelling filamentous microorganisms accommodated in a valve-like organism from the uppermost Dengying Formation in eastern Yunnan of South China

Fang

Liang

Chen

et al. 2022

Precambrian Research

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“…Thus, tectonic models need better paleontological underpinning. The Neoproterozoic–lower Cambrian successions and faunas of the Zavkhan terrane are relatively well studied (e.g., Voronin et al, 1982; Wood et al, 1993; Brasier et al, 1996; Smith et al, 2016; Yang et al, 2020; Steiner et al, 2021; Topper et al, 2022). In contrast, our knowledge of facies and fossils from other former tectonic zones is still almost in its infancy.…”

Section: Introductionmentioning

confidence: 99%

New trilobite assemblage from the lower Cambrian (upper Stage 4) of the Lake Zone, western Mongolia

et al. 2023

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The western Mongolian Lake Zone was a Neoproterozoic to early Paleozoic volcanic arc where tuffs, lavas, fossiliferous siliciclastics, and carbonates accumulated during the early Cambrian. An uppermost Cambrian Series 2 (upper Stage 4) trilobite assemblage is described here from the Burgasutay Formation representing a continuous lower Cambrian succession at the Seer Ridge of the Great Lake Depression. The new assemblage is dominated by dorypygids and consists of 13 trilobite genera belonging to nine families including Catinouyia heyunensis new species. These fossils comprise the youngest and richest lower Cambrian trilobite assemblage in Mongolia. The composition of the Lake Zone fauna suggests its biogeographic affinity with the Siberian Platform and Altay-Sayan Foldbelt, but the presence of inouyiids also implies a connection of this region with East Gondwana. UUID: http://zoobank.org/fb0ebe23-144f-46ed-9543-7df9eea85fbc

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Locating the BACE of the Cambrian: Bayan Gol in southwestern Mongolia and global correlation of the Ediacaran–Cambrian boundary

Cited by 34 publications

References 200 publications

New Ediacaran biota from the oldest Nama Group, Namibia (Tsaus Mountains), and re-definition of the Nama Assemblage

New Ediacaran biota from the oldest Nama Group, Namibia (Tsaus Mountains), and re-definition of the Nama Assemblage

Late Ediacaran cavity-dwelling filamentous microorganisms accommodated in a valve-like organism from the uppermost Dengying Formation in eastern Yunnan of South China

New trilobite assemblage from the lower Cambrian (upper Stage 4) of the Lake Zone, western Mongolia

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