Organic carbon isotopes of the Sinian and Early Cambrian black shales on Yangtze Platform, China

1999 ◽  
Vol 42 (6) ◽  
pp. 595-603 ◽  
Author(s):  
Renwei Li ◽  
Jialan Lu ◽  
Shukun Zhang ◽  
Jiajin Lei
Keyword(s):  
Organic Carbon ◽  
Carbon Isotopes ◽  
Black Shales ◽  
Early Cambrian ◽  
Yangtze Platform ◽  
Organic Carbon Isotopes

Paleoceanographic Indicators for Early Cambrian Black Shales from the Yangtze Platform, South China: Evidence from Biomarkers and Carbon Isotopes

2012 ◽  
Vol 86 (5) ◽  
pp. 1143-1153 ◽  
Author(s):  
CHEN Lan ◽  
ZHONG Hong ◽  
HU Ruizhong ◽  
XIAO Jiafei ◽  
TSAI Louis Loung-Yie ◽  
...  
Keyword(s):  
Carbon Isotopes ◽  
South China ◽  
Black Shales ◽  
Early Cambrian ◽  
Yangtze Platform

Evaluating nitrogen isotopes as proxies for depositional redox conditions in shales: A case study from the Chang 7 Shale in the Ordos basin, North China.

2020 ◽  
Author(s):  
Ruiqian Chen ◽  
Guangdi Liu
Keyword(s):  
Organic Carbon ◽  
Carbon Isotopes ◽  
Total Nitrogen ◽  
Nitrogen Isotopes ◽  
Ordos Basin ◽  
Redox Conditions ◽  
Depositional Processes ◽  
Significant Difference ◽  
The Ordos Basin ◽  
Organic Carbon Isotopes

<p>Bulk sedimentary nitrogen isotopes (δ<sup>15</sup>N) have been used as an accurate redox proxy in well-preserved sedimentary systems, however, fewer studies of N-isotope have been performed in lacustrine shales.  In this paper, we report the first δ<sup>15</sup>N data from the Chang 7 Shale from a core drilled in the Ordos Basin. Bulk δ<sup>15</sup>N values are significantly higher in Zone A (the Chang 7<sub>3</sub> and the lower part of the Chang 7<sub>2</sub> submembers, average = 9.4 ± 1.3‰) than in Zone B (the upper part of the Chang 7<sub>2</sub> and the Chang 7<sub>1</sub> submembers, average = 5.4 ± 1.5‰). Given the lithological characteristics and previous geochemical measurements, we suggest that sediments within Zone A of the Chang 7 Shale were mainly deposited under suboxic bottom water conditions, whereas Zone B sediments show evidence of deposition under oxic deep water regimes. Additionally, organic carbon isotopes (δ<sup>13</sup>C<sub>org</sub>) and total nitrogen (TN) values were measured to characterize any processes that might control alteration of the bulk δ<sup>15</sup>N signal, including changes in organic matter source and post-depositional processes. Our results show that there is no significant difference in the organic carbon isotopes (δ<sup>13</sup>C<sub>org</sub>) and total nitrogen (TN) values between the two zones. In conclusion, we suggest that the difference in δ<sup>15</sup>N values through the Chang 7 Shale primarily reflects differences in the depositional redox conditions and δ<sup>15</sup>N values of shale can provide important details regarding the depositional history of unconventional resource plays.</p>

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