Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform

The discovery of hydrocarbon in the Pagoda Formation in South China has received attention from the petroleum industry. This research paper identifies the discontinuity surface underlying the Pagoda Formation. The Upper Ordovician strata were correlated in different regions using the conodont biostr...

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Main Authors: Xueying Ma, Shenghui Deng, Yuanzheng Lu, Ru Fan, Fenglian Zhang, Yanqi Sun, Xu Li, Zhengyang Qu
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-10-01
Series:Frontiers in Earth Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/feart.2023.1220173/full
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author Xueying Ma
Shenghui Deng
Yuanzheng Lu
Ru Fan
Fenglian Zhang
Yanqi Sun
Xu Li
Zhengyang Qu
author_facet Xueying Ma
Shenghui Deng
Yuanzheng Lu
Ru Fan
Fenglian Zhang
Yanqi Sun
Xu Li
Zhengyang Qu
author_sort Xueying Ma
collection DOAJ
description The discovery of hydrocarbon in the Pagoda Formation in South China has received attention from the petroleum industry. This research paper identifies the discontinuity surface underlying the Pagoda Formation. The Upper Ordovician strata were correlated in different regions using the conodont biostratigraphy, and δ13C and δ18O isotope stratigraphy. The biostratigraphic result illustrates that three conodont zones can be established in each study section, and one to three conodont zones are missing in the lower Pagoda Formation and the strata underlying the Pagoda Formation of the Upper Yangtze Platform. Moreover, the chemostratigraphic result highlighted that the development of the lower δ13C isotope positive excursion events in the Xiaogangwan and Liangcun areas was less complete than that in the Jiaodingshan area. Combined with the cyclostratigraphic results, the development of the δ13C isotope positive excursion is not complete. The development of the δ13C excursion event is more complete in the south and east than in the center and north. This demonstrates that the Pagoda Formation began its deposition at different times and the transgression process may have advanced from the southeast to the north and that the contact between the Pagoda Formation and the underlying formation is not conformable. It is proposed that the Late Ordovician in the South China Plate was affected by the tectonic movement and the cooling paleoclimate at that time, which resulted in the discontinuity between the Pagoda Formation and the underlying strata. The unconformity could be the channel for hydrocarbon migration or for the high-quality oil and gas reservoirs being developed and preserved under the unconformity surface.
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spelling doaj.art-874838769fa646258557743d80d1dede2023-10-26T05:09:57ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632023-10-011110.3389/feart.2023.12201731220173Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze PlatformXueying Ma0Shenghui Deng1Yuanzheng Lu2Ru Fan3Fenglian Zhang4Yanqi Sun5Xu Li6Zhengyang Qu7Research Institute of Petroleum Exploration and Development, PetroChina, Beijing, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing, ChinaSchool of Ocean Sciences, China University of Geosciences, Beijing, Beijing, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing, ChinaNo.4 Gas Production Plant, PetroChina Changqing Oilfield Company, Ordos, Shanxi, ChinaNo.4 Oil Production Plant, PetroChina Changqing Oilfield Company, Yinchuan, Ningxia, ChinaThe discovery of hydrocarbon in the Pagoda Formation in South China has received attention from the petroleum industry. This research paper identifies the discontinuity surface underlying the Pagoda Formation. The Upper Ordovician strata were correlated in different regions using the conodont biostratigraphy, and δ13C and δ18O isotope stratigraphy. The biostratigraphic result illustrates that three conodont zones can be established in each study section, and one to three conodont zones are missing in the lower Pagoda Formation and the strata underlying the Pagoda Formation of the Upper Yangtze Platform. Moreover, the chemostratigraphic result highlighted that the development of the lower δ13C isotope positive excursion events in the Xiaogangwan and Liangcun areas was less complete than that in the Jiaodingshan area. Combined with the cyclostratigraphic results, the development of the δ13C isotope positive excursion is not complete. The development of the δ13C excursion event is more complete in the south and east than in the center and north. This demonstrates that the Pagoda Formation began its deposition at different times and the transgression process may have advanced from the southeast to the north and that the contact between the Pagoda Formation and the underlying formation is not conformable. It is proposed that the Late Ordovician in the South China Plate was affected by the tectonic movement and the cooling paleoclimate at that time, which resulted in the discontinuity between the Pagoda Formation and the underlying strata. The unconformity could be the channel for hydrocarbon migration or for the high-quality oil and gas reservoirs being developed and preserved under the unconformity surface.https://www.frontiersin.org/articles/10.3389/feart.2023.1220173/fullcarbon and oxygen isotopeconodontunconformityPagoda FormationUpper OrdovicianUpper Yangtze Platform
spellingShingle Xueying Ma
Shenghui Deng
Yuanzheng Lu
Ru Fan
Fenglian Zhang
Yanqi Sun
Xu Li
Zhengyang Qu
Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform
Frontiers in Earth Science
carbon and oxygen isotope
conodont
unconformity
Pagoda Formation
Upper Ordovician
Upper Yangtze Platform
title Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform
title_full Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform
title_fullStr Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform
title_full_unstemmed Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform
title_short Using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the Upper Ordovician Pagoda Formation in the Upper Yangtze Platform
title_sort using chemostratigraphy and biostratigraphy methods to define the unconformity underlying the upper ordovician pagoda formation in the upper yangtze platform
topic carbon and oxygen isotope
conodont
unconformity
Pagoda Formation
Upper Ordovician
Upper Yangtze Platform
url https://www.frontiersin.org/articles/10.3389/feart.2023.1220173/full
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