Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China
Black shale of the Cryogenian Nantuo Formation, Shennongjia area, South China contains spheroids which co-occur with fossils of macroalgae. These three-dimensional structures occur sparsely as isolated specimens or abundantly as clusters which show different types of boundaries between individuals....
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ftchinacscnigpas:oai:ir.nigpas.ac.cn:332004/32067 2023-05-15T17:09:34+02:00 Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China Ye, Qin Tong, Jinnan Pang, Ke Tian, Li Hu, Jun An, Zhihui 2020-08-01 http://ir.nigpas.ac.cn/handle/332004/32067 https://doi.org/10.1016/j.precamres.2020.105759 英语 eng ELSEVIER PRECAMBRIAN RESEARCH http://ir.nigpas.ac.cn/handle/332004/32067 doi:10.1016/j.precamres.2020.105759 Carbonaceous spheroids Bubble impressions Biotic origin Cryogenian Nantuo Formation South China WATER-ESCAPE STRUCTURES EDIACARA-BIOTA SNOWBALL EARTH EXCEPTIONAL PRESERVATION VINDHYAN SUPERGROUP MACKENZIE MOUNTAINS ELECTRON-MICROSCOPY BONAHAVEN FORMATION CAP CARBONATES TAPHONOMY Geology Geosciences Multidisciplinary 期刊论文 2020 ftchinacscnigpas https://doi.org/10.1016/j.precamres.2020.105759 2020-10-30T01:05:17Z Black shale of the Cryogenian Nantuo Formation, Shennongjia area, South China contains spheroids which co-occur with fossils of macroalgae. These three-dimensional structures occur sparsely as isolated specimens or abundantly as clusters which show different types of boundaries between individuals. They are generally circular on bedding surfaces and elliptical on transecting sections, and range up to several millimeters in diameter. Both petrographic thin sections and scanning electron microscopy (SEM) reveal that these spheroids are mostly organic carbon in composition and exhibit sharp, well-rounded external margins composed of microcrystalline clay minerals. The carbonaceous nature of these spheroids and different elemental abundances between spheroids and matrix are also confirmed by Raman spectroscopy and energy dispersive X-ray spectroscopy (EDS). Organic carbon isotopic values of individual spheroids range from -28.55 parts per thousand to -28.83 parts per thousand, with an average of -28.72 parts per thousand, which show indistinguishable delta C-13(org) values with the surrounding sedimentary matrix but exhibit statistically significant difference to those of contemporaneous macroalgae. A range of physical origins for these spheroids-including concretions, fluid escape structures, raindrop impressions, or bubble impressions-are considered and cannot be entirely rejected. Alternatively, biogenic origin is also a possible interpretation from observations of their morphological, mineralogical, geochemical, and sedimentological characteristics. Although their nature remains unresolved, the documentation of these new carbonaceous spheroids from the Nantuo Formation of Shennongjia area adds to a growing list of fossil-like structure records in the Cryogenian Period. Report Mackenzie mountains Nanjing Institute of Geology and Palaeontology: NIGPAS OpenIR (Chinese Academy of Sciences) Precambrian Research 345 105759 |
institution |
Open Polar |
collection |
Nanjing Institute of Geology and Palaeontology: NIGPAS OpenIR (Chinese Academy of Sciences) |
op_collection_id |
ftchinacscnigpas |
language |
English |
topic |
Carbonaceous spheroids Bubble impressions Biotic origin Cryogenian Nantuo Formation South China WATER-ESCAPE STRUCTURES EDIACARA-BIOTA SNOWBALL EARTH EXCEPTIONAL PRESERVATION VINDHYAN SUPERGROUP MACKENZIE MOUNTAINS ELECTRON-MICROSCOPY BONAHAVEN FORMATION CAP CARBONATES TAPHONOMY Geology Geosciences Multidisciplinary |
spellingShingle |
Carbonaceous spheroids Bubble impressions Biotic origin Cryogenian Nantuo Formation South China WATER-ESCAPE STRUCTURES EDIACARA-BIOTA SNOWBALL EARTH EXCEPTIONAL PRESERVATION VINDHYAN SUPERGROUP MACKENZIE MOUNTAINS ELECTRON-MICROSCOPY BONAHAVEN FORMATION CAP CARBONATES TAPHONOMY Geology Geosciences Multidisciplinary Ye, Qin Tong, Jinnan Pang, Ke Tian, Li Hu, Jun An, Zhihui Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China |
topic_facet |
Carbonaceous spheroids Bubble impressions Biotic origin Cryogenian Nantuo Formation South China WATER-ESCAPE STRUCTURES EDIACARA-BIOTA SNOWBALL EARTH EXCEPTIONAL PRESERVATION VINDHYAN SUPERGROUP MACKENZIE MOUNTAINS ELECTRON-MICROSCOPY BONAHAVEN FORMATION CAP CARBONATES TAPHONOMY Geology Geosciences Multidisciplinary |
description |
Black shale of the Cryogenian Nantuo Formation, Shennongjia area, South China contains spheroids which co-occur with fossils of macroalgae. These three-dimensional structures occur sparsely as isolated specimens or abundantly as clusters which show different types of boundaries between individuals. They are generally circular on bedding surfaces and elliptical on transecting sections, and range up to several millimeters in diameter. Both petrographic thin sections and scanning electron microscopy (SEM) reveal that these spheroids are mostly organic carbon in composition and exhibit sharp, well-rounded external margins composed of microcrystalline clay minerals. The carbonaceous nature of these spheroids and different elemental abundances between spheroids and matrix are also confirmed by Raman spectroscopy and energy dispersive X-ray spectroscopy (EDS). Organic carbon isotopic values of individual spheroids range from -28.55 parts per thousand to -28.83 parts per thousand, with an average of -28.72 parts per thousand, which show indistinguishable delta C-13(org) values with the surrounding sedimentary matrix but exhibit statistically significant difference to those of contemporaneous macroalgae. A range of physical origins for these spheroids-including concretions, fluid escape structures, raindrop impressions, or bubble impressions-are considered and cannot be entirely rejected. Alternatively, biogenic origin is also a possible interpretation from observations of their morphological, mineralogical, geochemical, and sedimentological characteristics. Although their nature remains unresolved, the documentation of these new carbonaceous spheroids from the Nantuo Formation of Shennongjia area adds to a growing list of fossil-like structure records in the Cryogenian Period. |
format |
Report |
author |
Ye, Qin Tong, Jinnan Pang, Ke Tian, Li Hu, Jun An, Zhihui |
author_facet |
Ye, Qin Tong, Jinnan Pang, Ke Tian, Li Hu, Jun An, Zhihui |
author_sort |
Ye, Qin |
title |
Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China |
title_short |
Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China |
title_full |
Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China |
title_fullStr |
Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China |
title_full_unstemmed |
Fossils or sedimentary structures? Carbonaceous spheroids from the shale of the Cryogenian Nantuo Formation in Shengnongjia area, South China |
title_sort |
fossils or sedimentary structures? carbonaceous spheroids from the shale of the cryogenian nantuo formation in shengnongjia area, south china |
publisher |
ELSEVIER |
publishDate |
2020 |
url |
http://ir.nigpas.ac.cn/handle/332004/32067 https://doi.org/10.1016/j.precamres.2020.105759 |
genre |
Mackenzie mountains |
genre_facet |
Mackenzie mountains |
op_relation |
PRECAMBRIAN RESEARCH http://ir.nigpas.ac.cn/handle/332004/32067 doi:10.1016/j.precamres.2020.105759 |
op_doi |
https://doi.org/10.1016/j.precamres.2020.105759 |
container_title |
Precambrian Research |
container_volume |
345 |
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105759 |
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1766065690463174656 |