Yuping Qi

Carboniferous and Lower Permian sedimentological cycles and biotic events of South China

Abstract The sedimentary successions and four fossil groups, including rugose corals, brachiopods, fusulinaceans and conodonts, from the Carboniferous and Lower Permian of South China have been studied in order to reveal the sedimentary characteristics and evolutionary pattern of main biological groups in the East Tethyan region during the Late Palaeozoic Ice Age. The Lower Carboniferous lithology of South China is diverse, ranging from basinal and shelf carbonate rocks to coal measures and continental clastics, while the Upper Carboniferous and Lower Permian are composed mostly of shallow-marine carbonates. From uppermost Devonian to Lower Carboniferous, five major regression events are recognized at the topmost Devonian, middle and upper Tournaisian boundary, Tournasian–Viséan boundary, uppermost Viséan and the Mid-Carboniferous boundary in South China, separately. The Upper Carboniferous and Lower Permian shallow-water carbonate rocks consist of remarkable, high-frequency cyclothems. Moreover, another major sea-level fall is recognized and characterized by an extensive sedimentary hiatus at the Sakmarian–Artinskian boundary throughout South China. All of the sedimentary basins of South China were formed in extensional tectonic settings during this time; thus, multiple regressive events that occurred throughout South China should be primarily induced by glacio-eustatic drawdown. In addition, two biotic events characterized by a remarkable decline in the diversity of benthic biota and a turnover in the composition of fossil assemblages occurred, respectively, at the Mid-Carboniferous and Sakmarian–Artinskian boundaries, consistent with two major regressions, and were probably caused by the glaciations in Gondwana.

Late Visean – early Serpukhovian conodont succession at the Naqing (Nashui) section in Guizhou, South China

This study reports the conodont succession across the Visean–Serpukhovian (V/S) boundary interval at the Naqing section, South China. Continuous centimetre-scale sampling of the relatively deep-water section in recent years has provided new data for a more detailed biostratigraphy of conodonts across the Visean–Serpukhovian boundary. Three conodont zones were described in ascending order: the Gnathodus bilineatus , Lochriea nodosa and Lochriea ziegleri zones. The first appearance datum (FAD) of L. ziegleri has been moved down to 60.1 m above the base of the Naqing section. The correlation of the conodont succession across the Visean–Serpukhovian boundary in the Naqing section with other sections in Eurasia is discussed.

UPPER CARBONIFEROUS (PENNSYLVANIAN) CONODONTS FROM SOUTH GUIZHOU OF CHINA

This paper describes in detail che conodont sequence of che Upper Carboniferous (Pennsylvanian) and the upper and lower boundaries in this interval at the Nashui section in Luodian, South Guizhou. The following 23 conodont zones, in descending order, can be recognized: Streptognathodus isolatus , S. wabaunsensis, S. tenuialveus, S. firmus, S. nashuiensis, S. simulator, S. guizhouensis, S. gracilis-S. excelsus, S. cancellosus, S. clavatulus, S. nodocarinatus, Idiognathodus podolskensis, Mesogondolella clarki-Idiognathodus robustus, Diplognathodus orphanus-D. ellesmerensis, ldiognathoides ouachitensis, Streptognathodus expansus, Idiognathoides sulcatus parvus, Neognathodus bassleri-Idiognathodus primulus, N. symmetricus-Idiognathodus primulus, N. symmetricus, Idiognathoides corrugatus-I. pacificus, I. sinuatus, I. sulcatus sulcatus and Declinognathodus noduliferus zones. The first occurrences of Streptognathodus isolatus and Declinognathodus noduliferus afe recognized at the bases of che Permian and the Upper Carboniferous (Pennsylvanian), respectively. The Upper Carboniferous (Pennsylvanian) conodont sequences are discussed and based on these conodont sequences, correlations between Upper Carboniferous (Pennsylvanian) Stages in Chinese and Russian sections, as well as North America are discussed. Additionally, eight new conodont species are also described in this paper.

Carboniferous conodont biostratigraphy of the Dianzishang section, Zhenning, Guizhou, South China

A preliminary summary of the lower Visean to uppermost Moscovian (Carboniferous) conodont succession and biostratigraphy of the Dianzishang section in Zhenning, Guizhou, South China is presented. Eleven conodont zones, in ascending order, can be recognized: Gnathodus praebilineatus , Gnathodus bilineatus , Lochriea ziegleri , Declinognathodus noduliferus , Neognathodus symmetricus , ‘ Streptognathodus ’ expansus (primitive form), ‘ Streptognathodus ’ expansus , Mesogondolella donbassica – Mesogondolella clarki , Idiognathodus podolskensis , Swadelina fauna and Idiognathodus swadei zones. The first occurrences of Lochriea ziegleri at the base of the Serpukhovian Stage, Declinognathodus noduliferus noduliferus at the base of the Bashkirian Stage and ‘ Streptognathodus ’ expansus at the base of the Moscovian Stage are recognized. The definitions of these stage boundaries, as well as that of the base of the Kasimovian Stage are discussed. Correlations with the Naqing section in South China, Russian and North American sections, as well as other important sections in the world, are considered.

CONODONTS FROM THE WA’ERGANG SECTION, CHINA, A POTENTIAL GSSP FOR THE UPPERMOST STAGE OF THE CAMBRIAN

Furongian (upper Cambrian) conodonts from the Shenjiawan Formation, Wa’ergang section, Taoyuan County, Hunan Province, South China are described. The Wa’ergang section has been proposed as a potential GSSP for the base of the uppermost stage of the Cambrian System, at the first appearance of the agnostoid trilobite Lotagnostus americanus . The Shenjiawan Formation consists of limestone with intercalations of marlstone and shale. The conodont yielding is low and the preservation is moderate. The conodont fauna includes proto-, para- and euconodonts. Conodont taxa characteristic of North China, South China and Korea occur together with cosmopolitan taxa. The biostratigraphic distribution of conodonts is directly correlated with the agnostoid trilobite biozones, with the base of the Proconodontus posterocostatus Zone very close to the base of the Lotagnostus americanus trilobite Zone.

Strontium and carbon isotopic evidence for decoupling of pCO2 from continental weathering at the apex of the late Paleozoic glaciation

Earth’s penultimate icehouse (ca. 340–285 Ma) was a time of low atmospheric pCO2 and high pO2, formation of the supercontinent Pangaea, dynamic glaciation in the Southern Hemisphere, and radiation of the oldest tropical rainforests. Although it has been long appreciated that these major tectonic, climatic, and biotic events left their signature on seawater 87Sr/86Sr through their influence on Sr fluxes to the ocean, the temporal resolution and precision of the late Paleozoic seawater 87Sr/86Sr record remain relatively low. Here we present a high-temporal-resolution and high-fidelity record of Carboniferous–early Permian seawater 87Sr/86Sr based on conodont bioapatite from an open-water carbonate slope succession in south China. The new data define a rate of long-term rise in 87Sr/86Sr (0.000035/m.y.) from ca. 334–318 Ma comparable to that of the middle to late Cenozoic. The onset of the rapid decline in 87Sr/86Sr (0.000043/m.y.), following a prolonged plateau (318–303 Ma), is constrained to ca. 303 Ma. A major decoupling of 87Sr/86Sr and pCO2 during 303–297 Ma, coincident with the Paleozoic peak in pO2, widespread low-latitude aridification, and demise of the pan-tropical wetland forests, suggests a major shift in the dominant influence on pCO2 from continental weathering and organic carbon sequestration (as coals) on land to organic carbon burial in the ocean. INTRODUCTION Seawater 87Sr/86Sr has long been used as a tool for chronostratigraphic correlation (e.g., McArthur et al., 2012), and, in combination with global seawater δ13C, to constrain the timing and magnitude of tectonic events, continental weathering, and paleoclimate change (e.g., Kump and Arthur, 1997; Goddéris et al., 2017). For the middle to late Cenozoic, the highresolution seawater 87Sr/86Sr curve has provided robust chronostratigraphic constraints and insight into the interlinked processes of the Earth system during our modern icehouse (e.g., Zachos et al., 1999). The late Paleozoic ice age (LPIA, ca. 340–285 Ma) is one of two major icehouses of the Phanerozoic, and records the only greenhouse gas–forced transition from an icehouse with complex terrestrial ecosystems to a fully greenhouse world (Montañez and Poulsen, 2013). The LPIA was a time of very low atmospheric pCO2 (Montañez et al., 2016) and high pO2 (Glasspool et al., 2015), dynamic glaciation on Gondwana (Isbell et al., 2012), global tectonic reconfiguration (Veevers, 2013), and the evolution and radiation of the oldest tropical rainforests (DiMichele, 2014). The fingerprints of these events should have been recorded in seawater 87Sr/86Sr given they collectively influenced continental weathering, and thus Sr flux to the late Paleozoic oceans. The existing Carboniferous–early Permian seawater 87Sr/86Sr record derived using calcitic brachiopods (Bruckschen et al., 1999; Korte et al., 2006) remains only moderately resolved, reflecting stratigraphic uncertainties, relatively low temporal resolution, and possible diagenetic alteration. Here, we present a 87Sr/86Sr record of unprecedented temporal resolution (105 yr) for ~38 m.y. of the LPIA, built using conodont bioapatite from an open-water carbonate slope succession (Naqing, south China) of the eastern Paleo-Tethys Ocean (Fig. DR1 in the GSA Data Repository1). Our record refines the structure of the middle Mississippian to early Permian seawater 87Sr/86Sr curve and places more precise temporal constraints on the timing of major shifts and rates of change. Integrated conodont apatite 87Sr/86Sr and carbonate δ13C records provide insight into the relative roles of orogenic uplift, pan-tropical aridification, and the evolution of the paleo-tropical wetland rainforests on continental weathering and atmospheric pCO2 during Earth’s penultimate icehouse. GEOLOGIC SETTING AND METHODS During the Carboniferous–Permian, the South China Block was a nearly isolated terrain located at the interface of the Paleo-Tethys Ocean (west) and Panthalassic Ocean (east) (Fig. DR1). The Carboniferous– Permian Naqing succession in the Guizhou Province consists of thinbedded lime mudstones intercalated with intraclast-bearing bioclastic wackestones to packstones (Fig. 1), and contains abundant conodonts with complete evolutionary lineages (Qi et al., 2014). The succession records near-continuous, hemipelagic deposition on a carbonate slope episodically punctuated by turbidity currents and debris flows in the Qian-Gui Basin that defined an open-water seaway to the Paleo-Tethys Ocean (Buggisch et al., 2011; Chen et al., 2016). Sr was isolated from conodonts (n = 99) and carbonates (n = 22), collected from the Naqing section, using Eichrom exchange resin (50– 100 μm) in pipette-tip columns attached to a Watson Marlow 205U Peristaltic pump (detailed methods are provided in the Data Repository). The 87Sr/86Sr ratios were measured on a Nu Plasma HR (Nu032) multicollector–inductively coupled plasma–mass spectrometer (MC-ICPMS) at the University of California–Davis (USA). Analytical precision (2 standard deviations [SD] = ±0.000026) is based on repeated 87Sr/86Sr analysis of 1 GSA Data Repository item 2018128, analytical methods, age calibration, revision of pCO2 estimates, Figures DR1 and DR2, and Tables DR1 and DR2, is available online at http://www.geosociety.org/datarepository/2018/, or on request from editing@geosociety.org. *E-mail: jtchen@nigpas.ac.cn GEOLOGY, May 2018; v. 46; no. 5; p. 395–398 | GSA Data Repository item 2018128 | https://doi.org/10.1130/G40093.1 | Published online 1 March 2018

Carboniferous integrative stratigraphy and time scale of China

The Carboniferous period lasted about 60 Myr, from ~358.9 Ma to ~298.9 Ma. According to the International Commission on Stratigraphy, the Carboniferous System is subdivided into two subsystems, i.e., Mississippian and Pennsylvanian, including 6 series and 7 stages. The Global Stratotype Sections and Points (GSSPs) of three stages have been ratified, the Tournaisian, Visean, and Bashkirian stages. The GSSPs of the remaining four stages (i.e., the Serpukhovian, Moscovian, Kasimovian, and Gzhelian) have not been ratified so far. This paper outlines Carboniferous stratigraphic subdivision and correlation on the basis of detailed biostratigraphy mainly from South China, and summarizes the Carboniferous chronostratigraphic framework of China. High-resolution biostratigraphic study reveals 37 conodont zones, 24 foraminiferal (including fusulinid) zones, 13 ammonoid zones, 10 brachiopod zones, and 10 rugose coral zones in the Carboniferous of China. The biostratigraphic framework based on these biozones warrants the precise correlation of regional stratigraphy of China (including 2 subsystems, 4 series, and 8 stages) to that of the other regions globally. Meanwhile, the Carboniferous chemo-, sequence-, cyclo-, and event-stratigraphy of China have been intensively studied and can also be correlated worldwide. Future studies on the Carboniferous in China should focus on (1) the correlation between shallow- and deep-water facies and between marine and continental facies, (2) high-resolution astronomical cyclostratigraphy, and (3) paleoenvironment and paleoclimate analysis based on geochemical proxies such as strontium and oxygen isotopes, as well as stomatal indices of fossil plants.

Mid-Carboniferous conodonts and their evolution: new evidence from Guizhou, South China

We studied details of the conodont assemblages in two deep-water sections spanning the mid-Carboniferous boundary at Guizhou, South China. Forty-six species/subspecies were identified belonging to 13 genera, including Lochriea, Gnathodus, Declinognathodus, Idiognathoides, Idiognathodus, Neognathodus, Neolochriea, Swadelina, ‘Streptognathodusii’, Cavusgnathus, Adetognathus, Rhachistognathus and Hindeodus. The evolutionary relationships among the species of Gnathodus, Neognathodus, Declinognathodus, Idiognathoides, Idiognathodus and Swadelina are discussed based on their P1 and P2 elements, as well as those of the species of Lochriea and Neolochriea. The early Pennsylvanian species of Declinognathodus are specifically studied with a focus on their taxonomy and evolution because of their biostratigraphical significance. These species can be distinguished as being part of the ridged or nodose groups by the parapet features of their P1 elements. The ridged group comprises D. praenoduliferus, D. bernesgae, D. lateralis, the newly recognized taxa D. tuberculosus sp. nov. and D. intermedius sp. nov., and D. cf. pseudolateralis. The nodose group includes D. inaequalis, D. noduliferus and D. japonicus. The number of rostral-ventral nodes of the Declinognathodus P1 elements are gradually reduced stratigraphically. Declinognathodus tuberculosus sp. nov. is considered to be the ancestor of the other ridged Declinognathodus species following a reduction in the number of rostral-ventral nodes; D. intermedius sp. nov. is a species that acts as a link within the lineage of the genera Declinognathodus and Swadelina via the development of an accessory lobe; D. cf. pseudolateralis is considered to be a morphotype that gave rise to the oldest Idiognathodus species, I. primulus, via D. lateralis with the shortening of its groove; and D. bernesgae is interpreted as the ancestor of the genus Idiognathoides following a transition wherein it loses its single node. The ancestry of the ridged group was probably derived from the ridged species Gnathodus postbilineatus. The nodose group may either be derived from D. tuberculosus sp. nov., or from G. girtyi simplex. The mid-Carboniferous boundary in the studied sections can be recognized by the first appearance datum of Declinognathodus tuberculosus sp. nov. Neognathodus is probably derived from Gnathodus girtyi simplex, while species of Neolochriea share a common ancestor with Lochriea commutata. http://zoobank.org/urn:lsid:zoobank.org:pub:C13DE4B7-9835-42E3-853F-5F9B533E797F

Carbon-Isotope Excursions Recorded in the Cambrian System, South China: Implications for Mass Extinctions and Sea-Level Fluctuations

Cambrian carbonates with abundant fossils of agnostoid trilobites deposited on the southern slope (Jiangnan slope belt) of the Yangtze Platform and in the Jiangnan deepwater basin are well exposed in the Wangcun Section of western Hunan, South China, and in the Duibian A Section of western Zhejiang, southeastern China, respectively. To better understand the response of carbon-isotope excursions to depositional environment changes, mass extinctions and eustatic events, we collected 530 carbonate samples in fresh roadcut exposures of the two measured sections for analysis of carbon and oxygen isotopic compositions. Data of δ13C from the Wangcun Section, western Hunan, South China, demonstrate that the Cambrian carbon-isotope profile includes three remarkable positive excursions CPEwc-1, 2, 3 in the Upper Series 2, in the Lower and in the Middle Furongian Series. Three distinctive negative excursions CNEwc-1, 2, 3 were separately tested in the Lower Terreneuvian Series, Lower Series 3 and in the Upper Furongian Series. Similarly, in the corresponding horizons in the Duibian A Section, Zhejiang Province, southeastern China, three positive excursions CPEdb-1, 2, 3 and three negative excursions CNEdb-1, 2, 3 also have been discovered. We interpret these significant carbon-isotope excursions as being associated with enhanced biogenic productivity, mass extinctions and eustatic events.

Revised conodont and fusuline biostratigraphy of the Bamchi Formation (Pyongan Supergroup) at the Bamchi section, Yeongwol and the Carboniferous–Permian boundary in South Korea

Wang, Q., Wang, Y., Qi, Y., Wang, X., Choh, S.J., Lee, D.C. & Lee, D.J., November 2017. Yeongwol and the Carboniferous–Permian boundary in South Korea. Alcheringa 42, 245–258. ISSN 0311-5518 Six conodont and one fusuline zones are recognized on basis of a total of 25 conodont and 13 fusuline species (including seven unidentified species or species given with cf. or aff. in total) from the Bamchi Formation, Yeongwol, Korea. The conodont zones include the Streptognathodus bellus, S. isolatus, S. cristellaris, S. sigmoidalis, S. fusus and S. barskovi zones in ascending order, which can be correlated with the conodont zones spanning the uppermost Gzhelian to Asselian Age of the Permian globally. The fusuline zone is named the Rugosofusulina complicata–Pseudoschwagerina paraborealis zone. The co-occurrence of the conodont Streptognathodus isolatus (the Global Boundary Stratotype Section and Point index for the base of Permian) and Pseudoschwagerina (a Permian inflated fusuline) indicates that the Carboniferous–Permian boundary can be placed in the lower part of the Bamchi Formation in South Korea. Qiulai Wang* [qlwang@nigpas.ac.cn] CAS Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, East Beijing Road 39, Nanjing 210008, PR China; Yue Wang* [yuewang@nigpas.ac.cn] LPS, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, East Beijing Road 39, Nanjing 210008, PR China; Yuping Qi* [ypqi@nigpas.ac.cn] Xiangdong Wang* [xdwang@nigpas.ac.cn] CAS Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, East Beijing Road 39, Nanjing 210008, PR China; Suk-Joo Choh [sjchoh@korea.ac.kr] Department of Earth and Environmental Sciences, Korea University, Seoul 02841, Republic of Korea; Dong-Chan Lee [dclee@chungbuk.ac.kr] Department of Earth Sciences Education, Chungbuk National University, Cheongju 28644, Republic of Korea; Dong-Jin Lee [djlee@andong.ac.kr] Department of Earth and Environmental Sciences, Andong National University, Andong 36729, Republic of Korea. *Also affiliated with: University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, PR China.