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SHRIMP zircon U-Pb ages from coal beds across the Permian-Triassic boundary, eastern Yunnan, southwestern China

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Journal of Palaeogeography 2018年第2期7卷 117-129页

作者： Juan Wang long-yi shao Hao Wang Baruch Spiro David Large State Key Laboratory of Coal Resources and Safety Mining College of Geoscience and Surveying Engineering China University of Mining and Technology (Beijing) School of Resources and Environment Henan Polytechnic University Department of Mineralogy The Natural History MuseumLondon Faculty of Engineering University of Nottingham

The first SHRIMP zircon U e Pb ages from coal beds close to the end-Permian mass extinction are reported from the Ccoal seam in the Yantang Mine in Laibin Town, Xuanwei County, eastern Yunnan *** were extracted from kaolinite claystone layers, defined as tonsteins(volcanic ash deposits), in the subseam Band Bof the coal seam *** U-Pb ages are 252.0 ± 2.3 Ma and 250.3 ± 2.1 Ma for the sub-seam Band B, respectively. Within analytical uncertainties, these U-Pb ages include the time period of the onset of the mass extinction at 251.941 ± 0.037 Ma, which was obtained from the marine Meishan section in Zhejiang Province, ~1600 km away from the Yantang Mine. These new ages represent not only the first and closest ages to the PTB mass extinction in terrestrial coal beds, but also ages from the nearest site to the Emeishan volcanoes investigated so far. Therefore these new data provide the most accurate stratigraphic horizon of terrestrial facies of the end-Permian extinction in South China. The Emeishan volcanoes were likely the source of volcanic ash in the coal seams at the Xuanwei County and broader areas in South China. Furthermore, the minerals and geochemistry characteristics of the Ccoal seam also implied the influences of contemporaneous volcanic activities.

关键词： PTB mass extinction C1 coal seam SHRIMP U-Pb isotope age Xuanwei County Yunnan Province

Using geophysical logs to identify Milankovitch cycles and to calculate net primary productivity(NPP) of the Late Permian coals,western Guizhou,China

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Journal of Palaeogeography 2019年第1期8卷 31-42页

作者： Zhi-Ming Yan long-yi shao David Large Hao Wang Baruch Spiro College of Geoscience and Surveying Engineering China University of Mining and Technology (Beijing) Faculty of Engineering University of Nottingham Department of Earth Sciences Natural History MuseumLondon

Milankovitch periodicities of 123 kyr(eccentricity), 35.6 kyr(obliquity), and 21.2 kyr(precession) were identified in geophysical logs of three Late Permian coals: 17#, 18#, and 17 + 18#, from the Songhe mining area in western Guizhou Province. Based on the astronomic temporal framework, the periods of deposition of the 17#(5.6 m), 18#(6.4 m), and 17 + 18#(5.4 m) coals were constrained to 140.8–119.8 kyr, 160–136.2 kyr, and 135–114.9 kyr,respectively. The overall depositional period of the 18# coal of 160–136.2 kyr was further subdivided using the wavelet analysis method, into short and precise periods corresponding to the Milankovitch periodicities. It includes one eccentricity periodicity(123 kyr), three obliquity periodicities(35.6 kyr), and five precession periodicities(21.2 kyr). Different thicknesses of the subdivided coal sections, equivalent to the same time span of deposition, indicate different rates of coal deposition, i.e., thicker sections imply higher rates while the thinner sections represent lower rates. The combination of the measured average carbon concentration with the density of the coals gave rise to long-term average values of carbon accumulation rates for the Late Permian coals, in the range of 42.4–50.6 g?C?m^(-2)?a^(-1). This range corresponds to the long-term average carbon accumulation rates for the initial peat in the range of 60.6–72.3 g?C?m^(-2)?a^(-1). Based on the known quantitative relation between net primary productivity(NPP)values and long-term average carbon accumulation rates for the Holocene tropical peatlands, the range of NPP values for the Late Permian tropical peatlands was estimated as 242.4–433.8 g?C?m^(-2)?a^(-1).A comparison of existing information about peatland NPP levels of various ages and latitudes indicated that when conditions of high rain and high humidity prevail in the palaeo-peatland at given latitude, the NPP rates will vary with changes in atmospheric concentration of CO_2 and O_2. This relationship may le

关键词： Milankovitch cycle Coal deposition Peatland long-term average carbon accumulation rate Net primary productivity Late Permian Guizhou Province

Characteristics of Early Cretaceous wildfires in peat-forming environment, NE China

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Journal of Palaeogeography 2019年第3期8卷 238-250页

作者： Shuai Wang long-yi shao Zhi-Ming Yan Ming-Jian Shi Yun-He Zhang College of Geoscience and Surveying Engineering China University of Mining and Technology (Beijing)

Inertinite maceral compositions in coals from the Early Cretaceous Erlian, Hailar, and Sanjiang Basins in NE China are analyzed in order to reveal palaeowildfire events and palaeoclimate variations. Although huminite is the dominant maceral group in the studied basins, the inertinite group, as a byproduct of palaeowildfires, makes up a considerable proportion. Occurrence of inertinite macerals indicates that wildfires were widespread and frequent,and supports the opinion that the Early Cretaceous was a "high-fire" interval. Inertinite contents vary from 0.2% to 85.0%, mostly within the range of 10%–45%, and a model-based calculation suggests that the atmospheric oxygen levels during the Aptian and Albian(Early Cretaceous) were around 24.7% and 25.3% respectively. Frequent fire activity during Early Cretaceous has been previously related to higher atmospheric oxygen concentrations. The inertinite reflectance, ranging from 0.58%Ro to 2.00%Ro, indicates that the palaeowildfire in the Early Cretaceous was dominated by ground fires, partially reaching-surface fires. These results further support that the Cretaceous earliest angiosperms from NE China were growing in elevated O2 conditions compared to the present day.

关键词： Inertinite Coal Wildfire Palaeo-atmospheric oxygen level Angiosperm Early Cretaceous NE China

Application of channel-belt scaling relationship to Middle Jurassic source-to-sink system in the Saishiteng area of the northern Qaidam Basin,NW China

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Journal of Palaeogeography 2019年第2期8卷 181-197页

作者： Bing-Qiang Liu long-yi shao Xue-Tian Wang Ya-Nan Li Jie Xu College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing) School of Ocean Sciences China University of Geosciences(Beijing)

Palaeodrainage basin,as an important component of the source-to-sink system,contains critical information on provenance and *** studies indicate that the scaling relationships of source-to-sink system components generally follow power laws,and channel-belt thickness represents a reliable first-order proxy for the drainage *** this study,a database of borehole cores and geophysical well logs of the Jurassic coal measures from Saishiteng area in the northern Qaidam Basin was used to reconstruct the palaeogeography,and to identify single-story *** palaeochannels,namely,River A,River B and River C,were identified which were persistent throughout the Dameigou and Shimengou Formations during the Middle *** mean channel-belt thicknesses of River A,River B and River C in the Dameigou Formation were 9.8 m,8.9 m and 7.9 m,respectively,and those in the Shimengou Formation were 7.4 m,6.2 m and 5.4 m,*** estimate the drainage area of three major rivers by using scaling relationships between drainage area and channel-belt *** drainage areas of River A,River B and River C in the Dameigou Formation were 63.0×10~3 km^2,50.1×10~3 km^2 and 37.7×10~3 km^2,respectively,and those in the Shimengou Formation were 32.3×10~3 km^2,21.2×10~3 km^2 and15.3×10~3 km^2,*** drainage basin lengths of River A,River B and River C in the Dameigou Formation were 300.4 km,239 km and 180.2 km,respectively,and those in the Shimengou Formation were 154.3 km,101.3 km and 73.1 km,*** both the Dameigou and Shimengou Formations,River A showed the largest scale,followed by River B and River C succeedingly,which was mainly determined by the stretch direction of provenance in the southern Qilian *** variations of channel-belt thickness,drainage area and drainage basin length between Dameigou and Shimengou Formations are the response of source-to-sink system to the transformation from extension to compressio

关键词： Northern Qaidam Basin Middle Jurassic Source-to-sink system Drainage basin Channel-belt scaling relationship

Continental chemical weathering during the Early Cretaceous Oceanic Anoxic Event(OAE1b): a case study from the Fuxin fluvio-lacustrine basin, Liaoning Province,NE China

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Journal of Palaeogeography 2020年第2期9卷 246-266页

作者： Xiao-Tao Xu long-yi shao Bo Lan Shuai Wang Jason Hilton Jian-yi Qin Hai-Hai Hou Jie Zhao College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China Shandong Key Laboratory of Depositional Mineralization&Sedimentary Mineral Shandong University of Science and TechnologyQingdao 266590China Northeast China Coalfield Geology Bureau 107 Exploration Team Fuxin 123000China School of Geography Earth and Environmental SciencesUniversity of BirminghamEdgbastonBirmingham B152TTUK College of Mining Liaoning Technical UniversityFuxin 123000China.

This study focuses on Early Cretaceous mudstones from the Shahai and Fuxin formations in the Fuxin continental basin. We analyse chemical weathering, land surface temperatures and palaeoclimates based on chemical weathering indices, and emphasize the implications of continental chemical weathering on nutrient fluxes into lakes and *** to Cr and Ni abundance, Al2O3-TiO2, La/Sc-Th/Co and V-Ni-Th×10 plots, as well as rare earth element(REE)analysis, mudstone samples from the Shahai and Fuxin formations were derived from the same type of provenance comprising mainly felsic igneous rocks. Chemical weathering trends reflected by the Chemical Index of Alteration(CIA),Weathering Index of Parker(WIP) and the Mafic Index of Alteration for Oxidative weathering environments(MIA(O)) are consistent with each other and allow the geological succession to be divided into four stages. Land surface temperatures of the Shahai and Fuxin formations are estimated based on the linear relationship of CIA to temperature,and also can be divided into four stages consistent with those determined from chemical weathering trends. During Stage A(early part of the late Aptian) chemical weathering and land surface temperatures were relatively low and showed characteristic high fluctuations, while Stage B(latest Aptian) represented a transitional period where weathering rates and temperatures increased, and high amplitude fluctuations continued. Conditions changed markedly in Stage C(early Albian) with very high and stable weathering, and warm, humid climates, while in Stage D(middle and late Albian) conditions returned to low chemical weathering and land surface temperatures. These stages of chemical weathering and land surface temperature fluctuations represent responses to global climate fluctuations during the Early Cretaceous, with the early Albian high weathering intensities and warm, humid climates combining to create high nutrient levels that would have flushed through rivers int

关键词： Chemical weathering indices Land surface temperature Mudstone Greenhouse conditions Ocean Anoxic Event 1 b Black shales

Lithofacies palaeogeography of the Carboniferous and Permian in the Qinshui Basin, Shanxi Province, China

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Journal of Palaeogeography 2015年第4期4卷 387-413页

作者： long-yi shao Zhi-Yu Yang Xiao-Xu Shang Zheng-Hui Xiao Shuai Wang Wen-long Zhang Ming-Quan Zheng Jing Lu State Key Laboratory of Coal Resources and Safe Mining School of Geosciences and Surveying Engineering China University of Mining and Technology (Beijing) Hunan Provincial Key Laboratory of Shale Gas Resource Utilization Hunan University of Science and Technology No.105 Geological Brigade of Qinghai Administration of Coal Geology Fujian Institute of Geological Survey

The Qinshui Basin in the southeastern Shanxi Province is an important area for coalbed methane（CBM） exploration and production in China, and recent exploration has revealed the presence of other unconventional types of gas such as shale gas and tight sandstone gas. The reservoirs for these unconventional types of gas in this basin are mainly the coals, mudstones, and sandstones of the Carboniferous and Permian; the reservoir thicknesses are controlled by the depositional environments and palaeogeography. This paper presents the results of sedimentological investigations based on data from outcrop and borehole sections, and basin-wide palaeogeographical maps of each formation were reconstructed on the basis of the contours of a variety of lithological parameters. The palaeogeographic units include the depositional environments of the fluvial channel, flood basin（lake）, upper delta plain, lower delta plain, delta front, lagoon, tidal flat, barrier bar, and carbonate *** Benxi and Taiyuan Formations are composed mainly of limestones, bauxitic mudstones,siltstones, silty mudstones, sandstones, and economically exploitable coal seams, which were formed in delta, tidal flat, lagoon, and carbonate platform environments. The Shanxi Formation consists of sandstones, siltstones, mudstones, and coals; during the deposition of the formation, the northern part of the Qinshui Basin was occupied mainly by an upper delta plain environment, while the central and southern parts were mainly occupied by a lower delta plain environment and the southeastern part by a delta front environment. Thick coal zones occur in the central and southern parts, where the main depositional environment was a lower delta plain. The thick coal zones of the Taiyuan Formation evidently occur in the sandstone-rich belts, located mainly in the lower delta plain environment in the northern part of the basin and the barrier bar environments in the southeastern part of the basin. In contrast, the thick

关键词： palaeogeography Shanxi Province Qinshui Basin Shanxi Formation Taiyuan Formation coal measure coalbed methane Permian Carboniferous

Lacustrine basin evolution and coal accumulation of the Middle Jurassic in the Saishiteng coalfield, northern Qaidam Basin, China

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Journal of Palaeogeography 2016年第3期5卷 205-220页

作者： Meng Li long- yi shao Lei Liu Jing Lu Baruch Spiro Huai-Jun Wen Yong-Hong Li College of Geosciences and Survey Engineering China University of Mining and Technology Beijing 100083 China Institute of Resources and Environment Henan Polytechnic University Jiaozuo 454000 China Department of Mineralogy Natural History Museum London United Kingdom Qinghai Bureau of Coal Geological Exploration Xining 810000 China

Based on an extensive borehole survey of the Middle Jurassic coat-bearing sequences in the Saishiteng coalfield, northern Qaidam Basin （NQB）, a total of 20 rock types and 5 sedimentary facies were identified, including braided river, meandering river, braided delta, meandering river delta, and lacustrine facies. The distribution of rock types and sedimentary facies contributed to the reconstruction of three periods＇ sedimentary facies maps of the Middle Jurassic in the Saishiteng coalfield, namely, the Dameigou age, the early Shimengou age and the late Shimengou age. That also provided the basis for the development of a three-stage depositional model of the Middle Jurassic in the NQB, indicating the lacustrine basin of the NQB in the Dameigou age and early Shimengou age were corresponding to an overfill basin, and that in the late Shimengou age was related to a balanced-fill basin. The analysis of the stability and structure of coat seams based on sedimentary facies maps showed that the preferred coal-forming facies in the Saishiteng coalfield were inter-delta bay and interdistributary bay of lower delta plain in the Dameigou age. In particular, the swamps that developed on the subaqueous pataeohigh favored the development of thick coat seams. Thus, ruinable coal seams may also be found along the Pingtai pataeohigh in the western part of the Saishiteng coalfield.

关键词： Sedimentary facies Middle Jurassic Northern Qaidam Basin Lacustrine basin evolution Coalaccumulation

Terrestrial records of the early Albian Ocean Anoxic Event:Evidence from the Fuxin lacustrine basin,NE China

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Geoscience Frontiers 2022年第1期13卷 138-157页

作者： Xiao-Tao Xu long-yi shao Kenneth A.Eriksson Bo Pang Shuai Wang Cheng-Xue Yang Hai-Hai Hou College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China Shandong Key Laboratory of Depositional Mineralization&Sedimentary Mineral Shandong University of Science and TechnologyQingdao 266590China Department of Geosciences Virginia TechBlacksburgVA 24061USA Liaoning Province Geology and Minerals Group Energy Geology Co. Ltd.Shenyang 110000China Institute of Earth Sciences China University of Geosciences(Beijing)Beijing 100083China College of Mining Liaoning Technical UniversityFuxin 123000China

The early Albian Oceanic Anoxic Event 1 b(OAE 1 b) is well documented in the Tethys, Pacific and North Atlantic, but few studies have evaluated whether or not terrestrial records of OAE 1 b exist. In order to identify terrestrial records of the early Albian OAE 1 b and to infer possible driving mechanisms, an integrated multi-proxy study from the late Aptian to Albian in the Fuxin lacustrine basin was conducted,including thick, organic-rich black mudstones, total organic carbon(TOC), organic carbon isotopes(d13 Corg), mercury concentration(Hg) and results from pyrolysis analyses(S2, Tmaxand HI). Results show three distinct short-term negative d13 Corgexcursions corresponding with relatively high TOC values,which could be counterparts of the Kilian, Paquier and Leenhardt sub-events of the early Albian OAE1 b. Atmospheric CO2 concentration(p CO2) recovered from C3 plant d13 Corgcompositions indicates an increasing trend in Unit C during the early Albian, and there are three short-term increases of p CO2 corresponding to the three sub-events of OAE 1 b at this time interval. We infer that a trend of increasing p CO2 during the Kilian sub-event in the study area is closely related to volcanism. Continental weathering calculated using chemical weathering indices(CIA, WIP and MIA(O)) show an increasing trend during the OAE 1 b interval, likely resulting from warmer and more humid conditions. Mixed sources of terrestrial plants and lacustrine plankton demonstrated by pyrolysis analyses(HI vs. Tmaxand S2 vs. TOC), indicate a terrestrial contribution to the organic-rich sediments of the Kilian, Paquier and Leenhardt sub-events of OAE 1 b. We suggest that a CO2-forced greenhouse effect during the early Albian might have triggered the relatively warm and humid palaeoclimatic conditions, and intensified chemical weathering that combined to create high nutrient and organic matter levels that were flushed into lakes contributing to eutrophication and anoxia in lacustrine and in c

关键词： Fuxin Basin Early Albian Organic carbon isotopes Ocean Anoxic Event 1b Terrestrial records

Characteristics and evolution of inertinite abundance and atmospheric pO_(2) during China's coal-forming periods

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Journal of Palaeogeography 2021年第2期10卷 259-283页

作者： Dong-Dong Wang Lu-Sheng yin long-yi shao Da-Wei Lyu Hai-Yan Liu Shuai Wang Guo-Qi Dong College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Coal, especially the inertinite in it, is highly sensitive to climate changes, showing an obvious response to paleoclimate conditions, in particular, to paleo-oxygen concentration(pO_2 ). In this study, the inertinite abundance data of typical coal-forming periods in China were systematically collected and analyzed. Its characteristics and control factors were studied, and its evolution was established. Based on inertinite abundance data, pO_2 evolution curves of various coal-forming periods in China were established, which fluctuated between 15% and 30% during the entire Phanerozoic. The inertinite abundance in coal deposits during Paleozoic in China was basically consistent with that of other areas of the world, while it was quite different globally from the Mesozoic to the Cenozoic. The results show that the inertinite abundance in coal deposits is controlled by pO_2 and other factors including climatic zones, plant differentiation, sedimentary environments, and tectonic activities. The inertinite abundance in coal deposits in China during the Jurassic was high, suggesting dry paleoclimate of inland China.

关键词： Inertinite abundance pO_2 Paleoclimate Sedimentary environment Coal-forming period Comparative analysis China