Sedimentary geochemistry of the Early Cambrian Niutitang Formation to reconstruct the palaeo‐depositional environments and to evaluate the organic matter enrichment mechanism from the Yangtze Block, South China

2021 ◽  
Author(s):  
Rizwan Sarwar Awan ◽  
Chenglin Liu ◽  
Ashar Khan ◽  
Qibiao Zang ◽  
Yuping Wu ◽  
...  
Keyword(s):  
Organic Matter ◽  
South China ◽  
Depositional Environments ◽  
Early Cambrian ◽  
Yangtze Block ◽  
Sedimentary Geochemistry ◽  
Niutitang Formation

scholarly journals Elemental Geochemical Characterization of Sedimentary Conditions and Organic Matter Enrichment for Lower Cambrian Shale Formations in Northern Guizhou, South China

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 793
Author(s):  
Shuangbiao Han ◽  
Yuanlong Zhang ◽  
Jie Huang ◽  
Yurun Rui ◽  
Zhiyuan Tang
Keyword(s):  
Organic Matter ◽  
Deposition Rate ◽  
Black Shale ◽  
South China ◽  
Shale Gas ◽  
Geochemical Data ◽  
Shale Formations ◽  
Average Value ◽  
Geochemical Elements ◽  
Niutitang Formation

The black shale deposited in the Niutitang Formation and its adjacent strata is considered to be a favorable source rock in northern Guizhou of south China and has become a target horizon for shale gas exploration in recent years. Based on SQ-1 and CY-1 core samples, the organic matter properties and geochemical elements were obtained through experimental analysis. Provenance, paleoredox, paleoclimate, paleoproductivity and deposition conditions were analyzed, and the sedimentary effects on organic matter enrichment were discussed. The results show that total organic carbon (TOC) is between 0.22–10.10 wt.% in SQ-1, with an average of 2.60 wt.%, and TOC is between 0.23–7.7 wt.% in CY-1, with an average of 1.45 wt.%. The geochemical data of the samples indicate that the black shale of the Niutitang Formation and adjacent strata are deposited in the tectonic background of the passive continental margin. The provenance shows moderate weathering, with hot and humid paleoenvironmental characteristics and fast deposition rate. Using multiple ancient redox indicators, it is concluded that the formation has undergone changes in the oxidizing environment and anaerobic environment during deposition. According to the (La/Yb)N value (the average value of SQ-1 is 1.23 and the average value of CY-1 is 1.26), it shows a faster deposition rate of the two wells and shortens the residence time of organic matter in the microbial degradation zone. The Babio indicates that the bottom has a high paleoproductivity when deposited. Considering the influencing factors, the paleoproductivity mainly controls the organic matter enrichment, followed by ancient redox conditions and the deposition rate. The research results provide a reference for deepening sedimentary understanding and shale gas exploration in the study area.

scholarly journals Constraints on the Organic Matter Accumulation of Lower Cambrian Niutitang Shales in the Middle Yangtze Region, South China

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Xing Niu ◽  
Yini Liu ◽  
Detian Yan ◽  
Mingyi Hu ◽  
Zixuan Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
South China ◽  
Primary Productivity ◽  
Lower Cambrian ◽  
Hydrothermal Activity ◽  
Oxic Condition ◽  
Organic Matter Accumulation ◽  
Niutitang Formation ◽  
And Sea Level

Abstract The lower Cambrian Niutitang shales, as one of target intervals with the greatest potential for shale gas exploration and development, have attracted much attention. Nevertheless, the organic matter enrichment mechanisms of the lower Cambrian Niutitang shales need further study, especially in the hydrothermal active zone. In this study, samples from ND1 well in western Hubei Province, middle Yangtze region, South China, were investigated for the controlling factors of organic matter accumulation of Lower Cambrian Niutitang shales by detailed petrographic, mineralogic, and geochemical proxies. The results show that hydrothermal activity and sea level fluctuation controlled the redox conditions and paleoproductivity of seawater and ultimately controlled the organic matter accumulation of Niutitang formation. In the Niu-1 member, the intense hydrothermal events lead to a suboxic to anoxic environment, which is conducive to the organic matter preservation. However, low sea level strengthens the restriction of water mass and reduced nutrient upwelling into the shelf, leading to decreased marine primary productivity, which was ultimately responsible for depleted organic matter accumulation in the Niu-1 member. In the Niu-2 member, the anoxic-euxinic environment and high paleoproductivity, driven by continuous hydrothermal activity and rising sea level, were the main factors controlling the enrichment of organic matter. In the Niu-3 member, the dysoxic to oxic condition plus low primary productivity, caused by the disappearance of hydrothermal activities and sea-level fall, resulted in the unfavorable organic matter accumulation. The results of this paper enrich the model of organic matter enrichment in the lower Cambrian black shale in the middle Yangtze region.

Controls on organic matter accumulation on the early-Cambrian western Yangtze Platform, South China

2020 ◽  
Vol 111 ◽  
pp. 75-87 ◽  
Author(s):  
Chengsheng Jin ◽  
Chao Li ◽  
Thomas J. Algeo ◽  
Shiyong Wu ◽  
Meng Cheng ◽  
...  
Keyword(s):  
Organic Matter ◽  
South China ◽  
Early Cambrian ◽  
Yangtze Platform ◽  
Organic Matter Accumulation

Climatic-oceanic forcing on the organic accumulation across the shelf during the Early Cambrian (Age 2 through 3) in the mid-upper Yangtze Block, NE Guizhou, South China

2017 ◽  
Vol 134 ◽  
pp. 365-386 ◽  
Author(s):  
Rumana Yeasmin ◽  
Daizhao Chen ◽  
Yong Fu ◽  
Jianguo Wang ◽  
Zenghui Guo ◽  
...  
Keyword(s):  
South China ◽  
Early Cambrian ◽  
Yangtze Block ◽  
Oceanic Forcing

Submarine hydrothermal/hot spring deposition of Early Cambrian Niutitang Formation in South China

2010 ◽  
Vol 21 (S1) ◽  
pp. 40-43 ◽  
Author(s):  
Li Lin ◽  
Yanchun Pang ◽  
Liyan Ma ◽  
Yongjun Yang ◽  
Deliang Li
Keyword(s):  
South China ◽  
Hot Spring ◽  
Early Cambrian ◽  
Niutitang Formation

Factors controlling organic matter enrichment in the Lower Cambrian Niutitang Formation Shale on the eastern shelf margin of the Yangtze Block, China

2017 ◽  
Vol 5 (3) ◽  
pp. T399-T410 ◽  
Author(s):  
Xianglu Tang ◽  
Zhenxue Jiang ◽  
Zhuo Li ◽  
Lijun Cheng ◽  
Ye Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Lower Cambrian ◽  
Vertical Section ◽  
Hydrothermal Activity ◽  
Yangtze Block ◽  
Anoxic Conditions ◽  
Eastern Shelf ◽  
Niutitang Formation ◽  
Shelf Margin ◽  
Water Contents

The degree of organic matter (OM) enrichment in shale determines its oil and gas potential. To understand the factors controlling this OM enrichment, we have used petrological and geochemical analyses to study the Lower Cambrian Niutitang Formation Shale in the eastern shelf margin of the Yangtze Block. Our results reveal that the total organic carbon (TOC) content of the Niutitang Formation Shale varies significantly throughout the vertical section. The lower part of the Niutitang Formation has a high TOC content, likely due to its formation in a dysoxic/anoxic environment with intense upwelling that favored OM enrichment. The middle part of the Niutitang Formation has the highest TOC content, which can be attributed to its formation in an environment with more hydrothermal activity, moderately upwelling, high paleosalinity, dysoxic/anoxic conditions, and moderately restricted water contents. Finally, the upper part of the Niutitang Formation records the lowest TOC contents because it likely formed in an oxic to dysoxic environment with weakly restricted hydrographic conditions that did not favor the preservation of OM. Therefore, these data demonstrate that the factors controlling OM enrichment in the Niutitang Formation Shale on the shelf margin include intense upwelling, greater amounts of hydrothermal activity, high paleosalinity, dysoxic/anoxic conditions, and moderately restricted water contents.

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