Doushantuo-Pertatataka–type acanthomorphs and Ediacaran ecosystem stability

Geology ◽  
2020 ◽  
Vol 48 (7) ◽  
pp. 708-712
Author(s):  
Dmitriy Grazhdankin ◽  
Konstantin Nagovitsin ◽  
Elena Golubkova ◽  
Galina Karlova ◽  
Boris Kochnev ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
South China ◽  
Ecosystem Stability ◽  
Glacial Deposits ◽  
Resting Stages ◽  
Carbon Isotope Excursion ◽  
Globally Distributed ◽  
Stratigraphic Range ◽  
Northwestern Russia ◽  
Marked Stability

Abstract Large (100 to ∼700 µm diameter) spheroidal carbonaceous microfossils ornamented with regularly arranged spinose or branched processes are globally distributed in the Ediacaran (635–542 Ma). These microfossils, collectively known as the Doushantuo-Pertatataka–type acanthomorphs, have been variously interpreted as a polyphyletic assortment of resting stages of eukaryotes, including animals. The stratigraphic range of the acanthomorphs has long been thought to be restricted to the interval between the uppermost Cryogenian glacial deposits and the largest-known carbon isotope excursion in Earth’s history, the Shuram event. The mid-Ediacaran disappearance of the acanthomorphs was puzzling until they were discovered in younger strata in south China, in northwestern Russia, and in Mongolia. Here, we report Doushantuo-Pertatataka–type acanthomorphs coeval with Cambrian-type small skeletal fossils. It appears that neither the Shuram event nor the emergence of macro-organisms, eumetazoans, and biologically controlled mineralization significantly affected the acanthomorphs, suggesting a marked stability of Ediacaran ecosystems up to the very beginning of the Cambrian.

The geochemistry of the late Cambrian carbonate in North China: the Steptoean Positive Carbon Isotope Excursion (SPICE) record suppressed in a coastal condition?

2019 ◽  
Vol 156 (10) ◽  
pp. 1805-1819 ◽  
Author(s):  
Jing Huang ◽  
Yali Chen ◽  
Xuelei Chu ◽  
Tao Sun
Keyword(s):  
Sea Level ◽  
Carbon Isotope ◽  
North China ◽  
Coastal Environment ◽  
Sedimentary Records ◽  
Late Cambrian ◽  
Geochemical Proxies ◽  
Carbon Isotope Excursion ◽  
Globally Distributed ◽  
Shallow Coastal Environment

AbstractThe Steptoean Positive Carbon Isotope Excursion (SPICE) is globally distributed in late Cambrian sedimentary records but controversially heterogeneous in its magnitudes. Here we use multiple geochemical proxies to investigate the late Cambrian carbonates from the Tangwangzhai section in North China, which were deposited in a shallow coastal environment with three depositional sequences (S1–S3). Each sequence comprises a transgressive systems tract (TST) and a highstand systems tract (HST). The REE + Y and trace element records are consistent with the depositional condition and indicate that terrigenous influence was more significant in the TST than HST. δ13Ccarb and δ34SCAS are low in the TST relative to HST, consistent with the scenario that terrigenous inputs were profoundly aggressive to seawater by introducing 13C-depleted and 34S-depleted materials. Within the TST of S2, the SPICE excursion shows a scaled-down δ13Ccarb positive shift (∼1.7 ‰) relative to its general records (∼4–6 ‰); the corresponding δ34SCAS show no positive excursion. This ‘atypical’ SPICE record is attributed to enhanced 13C-depleted and 34S-depleted terrigenous influence during the TST, which would reduce the amplitude of δ13Ccarb excursion, and even obscure δ34SCAS excursion. Meanwhile the subaerial unconformity at the base of TST would also cause a partially missing and a ‘snapshot’ preservation. Our study confirms significant local influence to the SPICE records, and further supports the heterogeneity and low sulphate concentrations of the late Cambrian seawater, because of which the SPICE records may be vulnerable to specific depositional conditions (e.g. sea-level, terrigenous input).

A negative carbon isotope excursion defines the boundary from Cambrian Series 2 to Cambrian Series 3 on the Yangtze Platform, South China

2010 ◽  
Vol 285 (3-4) ◽  
pp. 143-151 ◽  
Author(s):  
Qingjun Guo ◽  
Harald Strauss ◽  
Congqiang Liu ◽  
Yuanlong Zhao ◽  
Xinglian Yang ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
South China ◽  
Yangtze Platform ◽  
Carbon Isotope Excursion

scholarly journals A global event with a regional character: the Early Toarcian Oceanic Anoxic Event in the Pindos Ocean (northern Peloponnese, Greece)

2011 ◽  
Vol 148 (4) ◽  
pp. 619-631 ◽  
Author(s):  
N. KAFOUSIA ◽  
V. KARAKITSIOS ◽  
H. C. JENKYNS ◽  
E. MATTIOLI
Keyword(s):  
Carbon Isotope ◽  
Passive Margin ◽  
Oceanic Anoxic Event ◽  
Northern European ◽  
Carbon Isotope Excursion ◽  
Anoxic Event ◽  
Considerable Controversy ◽  
Regional Character ◽  
Globally Distributed ◽  
Ammonite Zones

AbstractThe Early Toarcian (Early Jurassic, c. 183 Ma) was characterized by an Oceanic Anoxic Event (T-OAE), primarily identified by the presence of globally distributed approximately coeval black organic-rich shales. This event corresponded with relatively high marine temperatures, mass extinction, and both positive and negative carbon-isotope excursions. Because most studies of the T-OAE have taken place in northern European and Tethyan palaeogeographic domains, there is considerable controversy as to the regional or global character of this event. Here, we present the first high-resolution integrated chemostratigraphic (carbonate, organic carbon, δ13Ccarb, δ13Corg) and biostratigraphic (calcareous nannofossil) records from the Kastelli Pelites cropping out in the Pindos Zone, western Greece. During the Mesozoic, the Pindos Zone was a deep-sea ocean-margin basin, which formed in mid-Triassic times along the northeast passive margin of Apulia. In two sections through the Kastelli Pelites, the chemostratigraphic and biostratigraphic (nannofossil) signatures of the most organic-rich facies are identified as correlative with the Lower Toarcian, tenuicostatum/polymorphum–falciferum/serpentinum/levisoni ammonite zones, indicating that these sediments record the T-OAE. Both sections also display the characteristic negative carbon-isotope excursion in organic matter and carbonate. This occurrence reinforces the global significance of the Early Toarcian Oceanic Anoxic Event.

Marine Carbon-Sulfur Biogeochemical Cycles during the Steptoean Positive Carbon Isotope Excursion (SPICE) in the Jiangnan Basin, South China

2016 ◽  
Vol 27 (2) ◽  
pp. 242-254 ◽  
Author(s):  
Yang Peng ◽  
Yongbo Peng ◽  
Xianguo Lang ◽  
Haoran Ma ◽  
Kangjun Huang ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
South China ◽  
Biogeochemical Cycles ◽  
Carbon Isotope Excursion

Lowermost Cambrian acritarchs from the Yanjiahe Formation, South China: implication for defining the base of the Cambrian in the Yangtze Platform

2017 ◽  
Vol 154 (6) ◽  
pp. 1217-1231 ◽  
Author(s):  
SOO YEUN AHN ◽  
MAOYAN ZHU
Keyword(s):  
Carbon Isotope ◽  
South China ◽  
Yangtze Platform ◽  
Small Shelly Fossils ◽  
Temporal Relationships ◽  
Assemblage Zone ◽  
Stratigraphic Range

AbstractTheAsteridium–Heliosphaeridium–Comasphaeridium(AHC) acritarch assemblage is composed of common organic-walled microfossils in the basal Cambrian chert–phosphorite units in South China, indicating that the AHC assemblage can be a useful biostratigraphic tool for the Ediacaran–Cambrian boundary successions in the Yangtze Platform. To test the validity of the AHC acritarch assemblage as a biostratigraphic tool, the stratigraphic range of the AHC acritarch assemblage was confirmed, and its spatial and temporal relationships to other bio- and chemostratigraphic tools were analysed in the Yanjiahe Formation, Yangtze Gorges area, South China. The result shows that the AHC assemblage temporally correlates to theAnabarites trisulcatus–Protohertzina anabaricaAssemblage Zone, and spatially correlates to the large negative carbon isotope anomaly of the lowermost Cambrian (BACE) in the Yanjiahe Formation. This implies that the radiation of phytoplankton occurred slightly before the radiation of the small shelly fossils, and the AHC acritarch assemblage can be another important chronological reference to the lowermost Cambrian successions in South China, and potentially to global correlations.

scholarly journals Late Ediacaran occurrences of the organic-walled microfossils Granomarginata and flask-shaped Lagoenaforma collaris gen. et sp. nov.

2021 ◽  
pp. 1-22
Author(s):  
Heda Agić ◽  
Anette E.S. Högström ◽  
Sören Jensen ◽  
Jan Ove R. Ebbestad ◽  
Patricia Vickers-Rich ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Carbon Isotope Excursion ◽  
Kalahari Craton ◽  
Low Diversity ◽  
New Localities ◽  
Body Fossil ◽  
Microfossil Assemblage ◽  
New Occurrences ◽  
Stratigraphic Range ◽  
Cambrian System

Abstract New occurrences of flask-shaped and envelope-bearing microfossils, including the predominantly Cambrian taxon Granomarginata, are reported from new localities, as well as from earlier in time (Ediacaran) than previously known. The stratigraphic range of Granomarginata extends into the Cambrian System, where it had a cosmopolitan distribution. This newly reported Ediacaran record includes areas from Norway (Baltica), Newfoundland (Avalonia) and Namibia (adjacent to the Kalahari Craton), and puts the oldest global occurrence of Granomarginata in the Indreelva Member (< 563 Ma) of the Stáhpogieddi Formation on the Digermulen Peninsula, Arctic Norway. Although Granomarginata is rare within the assemblage, these new occurrences together with previously reported occurrences from India and Poland, suggest a potentially widespread palaeogeographic distribution of Granomarginata through the middle–late Ediacaran interval. A new flask-shaped microfossil Lagoenaforma collaris gen. et sp. nov. is also reported in horizons containing Granomarginata from the Stáhpogieddi Formation in Norway and the Dabis Formation in Namibia, and flask-shaped fossils are also found in the Gibbett Hill Formation in Newfoundland. The Granomarginata–Lagoenaforma association, in addition to a low-diversity organic-walled microfossil assemblage, occurs in the strata postdating the Shuram carbon isotope excursion, and may eventually be of use in terminal Ediacaran biostratigraphy. These older occurrences of Granomarginata add to a growing record of body fossil taxa spanning the Ediacaran–Cambrian boundary.

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