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Volume 32 Issue 3
Jun.  2021
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Baojin Wu, Hanxiao Li, Michael M. Joachimski, Paul B. Wignall, Haishui Jiang, Jiaxin Yan, Lina Wang, Xianlang Wu, Xulong Lai. Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China. Journal of Earth Science, 2021, 32(3): 534-553. doi: 10.1007/s12583-020-1099-y
Citation: Baojin Wu, Hanxiao Li, Michael M. Joachimski, Paul B. Wignall, Haishui Jiang, Jiaxin Yan, Lina Wang, Xianlang Wu, Xulong Lai. Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China. Journal of Earth Science, 2021, 32(3): 534-553. doi: 10.1007/s12583-020-1099-y

Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China

doi: 10.1007/s12583-020-1099-y
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  • Focusing on the Shuixiakou Section (Xikou area, Zhen'an County, Shaanxi Province, southeastern Qinling region, China), the Roadian-Wordian conodonts are investigated. More than 2 000 conodont elements including 6 genera and 14 species have been obtained. Based on these materials, the Guadalupian Jinogondolella nankingensis and J. aserrata zones have been recognized. The Roadian-Wordian boundary is tentatively defined by the first occurrence of J. aserrata in the lower part of Unit Ⅲ in the Shuixiakou Formation. The sedimentary succession of Xikou area records similar sea-level changes to those observed in Laibin area (South China). The 40 m-thick bioclastic limestone of Unit Ⅳ in this section can be correlated with the reefs of Bed 114 in Laibin area. A temperature drop indicated by δ18Oapatite values suggests this Wordian interval coincides with a period of glaciation and global regression.
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  • Angiolini, L., Zanchi, A., Zanchetta, S., et al., 2015. From Rift to Drift in South Pamir (Tajikistan): Permian Evolution of a Cimmerian Terrane. Journal of Asian Earth Sciences, 102: 146-169. https://doi.org/10.1016/j.jseaes.2014.08.001 doi:  10.1016/j.jseaes.2014.08.001
    Anonymous, 1965. The 1: 200 000 Geological Map of Ankang Sheet. Regional Bureau of Ministry of Geology in Geological Survey, Northwest Institute of Geological Sciences (in Chinese)
    Behnken, F. H., 1975. Leonardian and Guadalupian (Permian) Conodont Biostratigraphy in Western and Southwestern United States. Journal of Paleontology, 49(2): 284-315. https://doi.org/10.2307/1303362 doi:  10.2307/1303362
    Behnken, F. H., Wardlaw, B. R., Stout, L. N., 1986. Conodont Biostratigraphy of the Permian Meade Peak Phosphatic Shale Member, Phosphoria Formation, Southeastern Idaho. Rocky Mountain Geology, 24(2): 169-190 http://rmg.geoscienceworld.org/content/24/2/169
    Biakov, A. S., 2015. Biogeography of the Permian Marine Boreal Basins Based on Bivalves. Paleontological Journal, 49(11): 1184-1192. https://doi.org/10.1134/s0031030115110040 doi:  10.1134/s0031030115110040
    Burrett, C., Udchachon, M., Thassanapak, H., et al., 2014. Conodonts, Radiolarians and Ostracodes in the Permian E-Lert Formation, Loei Fold Belt, Indochina Terrane, Thailand. Geological Magazine, 152(1): 106-142. https://doi.org/10.1017/s001675681400017x doi:  10.1017/s001675681400017x
    Chen, Z. -Q., George, A. D., Yang, W. R., 2009. Effects of Middle-Late Permian Sea-Level Changes and Mass Extinction on the Formation of the Tieqiao Skeletal Mound in the Laibin Area, South China. Australian Journal of Earth Sciences, 56(6): 745-763. https://doi.org/10.1080/08120090903002581 doi:  10.1080/08120090903002581
    Chen, Z. -Q., Jin, Y. G., Shi, G. -R., 1998. Permian Transgression-Regression Sequences and Sea-Level Changes of South China. Proceedings of the Royal Society of Victoria, 110: 345-367 http://www.researchgate.net/publication/290798729_Permian_transgression-regression_sequences_and_sea-level_changes_of_South_China
    Chen, B., Joachimski, M. M., Shen, S. Z., et al., 2013. Permian Ice Volume and Palaeoclimate History: Oxygen Isotope Proxies Revisited. Gondwana Research, 24(1): 77-89. https://doi.org/10.1016/j.gr.2012.07.007 doi:  10.1016/j.gr.2012.07.007
    Chen, B., Joachimski, M. M., Sun, Y. D., et al., 2011. Carbon and Conodont Apatite Oxygen Isotope Records of Guadalupian-Lopingian Boundary Sections: Climatic or Sea-Level Signal?. Palaeogeography, Palaeoclimatology, Palaeoecology, 311(3/4): 145-153. https://doi.org/10.1016/j.palaeo.2011.08.016 doi:  10.1016/j.palaeo.2011.08.016
    Cheng, C., Li, S. Y., Cao, T. L., 2017. Permian Conodonts at the Xikou Section, Zhen'an County, Shananxi Province, NW China. Acta Micropalaeontologica Sinica, 34(1): 16-32 (in Chinese with English Abstract) http://en.cnki.com.cn/Article_en/CJFDTOTAL-WSGT201701002.htm
    Cheng, C., Li, S. Y., Xie, X. Y., et al., 2019. Permian Carbon Isotope and Clay Mineral Records from the Xikou Section, Zhenʼan, Shaanxi Province, Central China: Climatological Implications for the Easternmost Paleo-Tethys. Palaeogeography, Palaeoclimatology, Palaeoecology, 514: 407-422. https://doi.org/10.1016/j.palaeo.2018.10.023 doi:  10.1016/j.palaeo.2018.10.023
    Chernykh, V. V., Chuvashov, B. I., Davydov, V. I., et al., 2006. Usolka Section (southern Urals, Russia): A Potential Candidate for GSSP to Define the Base of the Gzhelian Stage in the Global Chronostratigraphic Scale. Geologija, 49(2): 205-217. https://doi.org/10.5474/geologija.2006.015 doi:  10.5474/geologija.2006.015
    Ching, Y. K., 1960. Conodonts from the Kufeng Suite (Formation) of Lungtan, Nanking. Acta Palaeontologica Sinica, 8: 242-248 (in Chinese with English Abstract) http://en.cnki.com.cn/Article_en/CJFDTotal-GSWX196003002.htm
    Clark, D. L., 1972. Early Permian Crisis and Its Bearing on Permo-Triassic Conodont Taxonomy. Geologica et Palaeontòlogica, l: 147-158 http://www.researchgate.net/publication/281603830_Early_Permian_crisis_and_its_bearing_on_Permo-Triassic_conodont_taxonomy
    Clark, D. L., Behnken, F. H., 1979. Evolution and Taxonomy of the North USA Upper Permian Neogondolella Serrata Complex. Journal of Paleontology, 53(2): 263-275
    Clark, D. L., Ethington, R. L., 1962. Survey of Permian Conodonts in Western North America. Brigham Young University Geology Studies, 9(2): 102-114 http://www.researchgate.net/publication/312614490_Survey_of_Permian_conodonts_in_western_North_America
    Clark, D. L., Mosher, L. C., 1966. Stratigraphic, Geographic, and Evolutionary Development of the Conodont Genus Gondolella. Journal of Paleontology, 40(2): 376-394
    Clark, D. L., Wang, C. Y., 1988. Permian Neogondolellids from South China: Significance for Evolution of the Serrata and Carinata Groups in North America. Journal of Paleontology, 62(1): 132-138. https://doi.org/10.1017/s0022336000058972 doi:  10.1017/s0022336000058972
    Davydov, V. I., Biakov, A. S., Schmitz, M. D., et al., 2018. Radioisotopic Calibration of the Guadalupian (Middle Permian) Series: Review and Updates. Earth-Science Reviews, 176: 222-240. https://doi.org/10.1016/j.earscirev.2017.10.011 doi:  10.1016/j.earscirev.2017.10.011
    Ding, P. Z., Jin, T. A., Sun, X. F., 1983. The Marine Permian of Zhenan, Southern Shaanxi, Eastern Qinling Range. Bulletin of Xi'an Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, (6): 99-104 (in Chinese with English Abstract) http://en.cnki.com.cn/Article_en/CJFDTotal-XBFK198306008.htm
    Ding, P. Z., Jin, T. A., Sun, X. F., 1987. An Excursion Guide to Permian Geology of Xikou Area, Zhen'an County, Shananxi. Bulletin of Xi'an Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 15: 113-138 (in Chinese with English Abstract) http://ci.nii.ac.jp/naid/10006848287
    Ding, P. Z., Jin, T. A., Sun, X. F., 1989. The Marine Permian Strata and Its Faunal Assemblages in Xikou Area of Zhen'an County, South Shaanxi, East Qinling range. Bulletin of Xi'an Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, (25): 1-68 (in Chinese with English Abstract) http://en.cnki.com.cn/Article_en/CJFDTOTAL-XBFK198901000.htm
    Dong, Y. P., Santosh, M., 2016. Tectonic Architecture and Multiple Orogeny of the Qinling Orogenic Belt, Central China. Gondwana Research, 29(1): 1-40. https://doi.org/10.1016/j.gr.2015.06.009 doi:  10.1016/j.gr.2015.06.009
    Dzki, J., 1976. Remarks on the Evolution of Ordovician Conodonts. Acta Palaeontologica Polonica, 21: 395-455 http://ci.nii.ac.jp/naid/10019474740
    Eichenberg, W., 1930. Conodonten Aus Dem Culm des Harzes. Paläontologische Zeitschrift, 12(3/4): 177-182. https://doi.org/10.1007/bf03044446 doi:  10.1007/bf03044446
    Ellison, S., 1941. Revision of the Pennsylvanian Conodonts. Journal of Paleontology, 15(2): 107-143. https://doi.org/10.2307/1298938 doi:  10.2307/1298938
    Fielding, C. R., Frank, T. D., Birgenheier, L. P., et al., 2008. Stratigraphic Imprint of the Late Palaeozoic Ice Age in Eastern Australia: A Record of Alternating Glacial and Nonglacial Climate Regime. Journal of the Geological Society, 165(1): 129-140. https://doi.org/10.1144/0016-76492007-036 doi:  10.1144/0016-76492007-036
    Frank, T. D., Shultis, A. I., Fielding, C. R., 2015. Acme and Demise of the Late Palaeozoic Ice Age: A View from the Southeastern Margin of Gondwana. Palaeogeography, Palaeoclimatology, Palaeoecology, 418: 176-192. https://doi.org/10.1016/j.palaeo.2014.11.016 doi:  10.1016/j.palaeo.2014.11.016
    Glenister, B. F., Wardlaw, B. R., Lambert, L. L., et al., 1999. Proposal of Guadalupian and Component Roadian, Wordian, and Capitanian Stages as International Standards for the Middle Permian Series. Permophiles, 34: 3-11 http://www.researchgate.net/publication/285294760_Proposal_of_Guadalupian_and_component_Roadian_Wordian_and_Capitanian_stages_as_international_standards_for_the_Middle_Permian_Series
    Grossman, E. L., Yancey, T. E., Jones, T. E., et al., 2008. Glaciation, Aridification, and Carbon Sequestration in the Permo-Carboniferous: The Isotopic Record from Low Latitudes. Palaeogeography, Palaeoclimatology, Palaeoecology, 268(3/4): 222-233. https://doi.org/10.1016/j.palaeo.2008.03.053 doi:  10.1016/j.palaeo.2008.03.053
    Golding, M. L., 2018. The Multielement Apparatuses of Guadalupian to Lopingian (Middle-Upper Permian) Sweetognathids from North America, and Their Significance for the Phylogeny of Late Paleozoic Conodonts. Bulletins of American Paleontology, 395/396: 115-125. https://doi.org/10.32857/bap.2018.395.09 doi:  10.32857/bap.2018.395.09
    Gullo, M., Kozur, H., 1992. Conodonts from the Pelagic Deep-Water Permian of Central Western Sicily (Italy). Neues Jahrbuchfure Geologie und Palaeontologie, 184(2): 203-234 http://www.researchgate.net/publication/284790280_Conodonts_from_the_pelagic_deep-water_Permian_of_central_Western_Sicily_Italy
    Henderson, C. M., 1981. Conodont Paleontology of the Permian Sabine Bay, Assistance and Trold Fiord Formations, Northern Ellesmere Island, Canadian Arctic Archipelago: [Dissertation]. University of British Columbia, Vancouver
    Henderson, C. M., 2018. Permian Conodont Biostratigraphy. Geological Society, London, Special Publications, 450: 119-142. https://doi.org/10.1144/sp450.9 doi:  10.1144/sp450.9
    Henderson, C. M., Mei, S. L., 2003. Stratigraphic versus Environmental Significance of Permian Serrated Conodonts around the Cisuralian-Guadalupian Boundary: New Evidence from Oman. Palaeogeography, Palaeoclimatology, Palaeoecology, 191(3/4): 301-328. https://doi.org/10.1016/s0031-0182(02)00669-7 doi:  10.1016/s0031-0182(02)00669-7
    Henderson, C. M., Mei, S. L., 2007. Geographical Clines in Permian and Lower Triassic Gondolellids and Its Role in Taxonomy. Palaeoworld, 16(1/2/3): 190-201. https://doi.org/10.1016/j.palwor.2007.05.014 doi:  10.1016/j.palwor.2007.05.014
    Isakova, T. N., 1998. Review of the Conodonts of the Sakmarian Stratotype Section (South Urals). Palaeontologia Polonica, 58: 261-271 http://www.palaeontologia.pan.pl/Archive/1998-58_261-271.pdf
    Joachimski, M. M., Breisig, S., Buggisch, W., et al., 2009. Devonian Climate and Reef Evolution: Insights from Oxygen Isotopes in Apatite. Earth and Planetary Science Letters, 284(3/4): 599-609. https://doi.org/10.1016/j.epsl.2009.05.028 doi:  10.1016/j.epsl.2009.05.028
    Kozur, H. W., 1975. Beitrage zur Conodont en Fauna des Perm. Geologische Palaontologische Mitteilungen Innsbruck, 5: 1-44 http://ci.nii.ac.jp/naid/10006849341
    Kozur, H. W., 1992. Dzhulfian and Early Changxingian (Late Permian) Tethyan Conodonts from the Glass Mountains, West Taxas. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 187(1): 99-114 http://ci.nii.ac.jp/naid/80007287021
    Kozur, H. W., 1995. Permian Conodont Zonation and Its Importance for the Permian Stratigraphic Standard Scale. Geologische Palaontologische Mitteilungen Innsbruck, 20: 165-205 http://www.researchgate.net/publication/265306630_Permian_conodont_zonation_and_its_importance_for_the_Permian_stratigraphic_standard_scale
    Kozur, H. W., Mostler, H., 1995. Guadalupian (Middle Permian) Conodonts of Sponge-Bearing Limestones from the Margins of the Delaware Basin, West Texas. Geologia Croatica, 48(2): 107-128
    Kozur, H. W., Wardlaw, B. R., 2010. The Guadalupian Conodont Fauna of Rustaq and Wadi Wasit, Oman and a West Texas Connection. Micropaleontology, 56(1/2): 213-231. https://doi.org/10.2307/40607082 doi:  10.2307/40607082
    Kutygin, R. V., 2015. Biogeographic Distribution and Relationship of Permian Ammonoid Communities of Verkhoyano-Okhotsk and Kolymo-Omolon Regions. Science Education, (2): 46-50 (in Russian)
    Lai, X. L., Wang, W., Wignall, P. B., et al., 2008. Palaeoenvironmental Change during the End-Guadalupian (Permian) Mass Extinction in Sichuan, China. Palaeogeography, Palaeoclimatology, Palaeoecology, 269(1/2): 78-93. https://doi.org/10.1016/j.palaeo.2008.08.005 doi:  10.1016/j.palaeo.2008.08.005
    Lambert, L. L., Bell, G. L. Jr, Fronimos, J. A., et al., 2010. Conodont Biostratigraphy of a more Complete Reef Trail Member Section near the Type Section, Latest Guadalupian Series Type Region. Micropaleontology, 56: 233-253. https://doi.org/10.2307/40607083 doi:  10.2307/40607083
    Lambert, L. L., Wardlaw, B. R., Henderson, C. M., 2007. Mesogondolella and Jinogondolella (Conodonta): Multielement Definition of the Taxa that Bracket the Basal Guadalupian (Middle Permian Series) GSSP. Palaeoworld, 16(1/2/3): 208-221. https://doi.org/10.1016/j.palwor.2007.05.017 doi:  10.1016/j.palwor.2007.05.017
    Lambert, L. L., Wardlaw, B. R., Nestell, M. K., et al., 2002. Latest Guadalupian (Middle Permian) Conodonts and Foraminifers from West Texas. Micropaleontology, 48(4): 343-364. https://doi.org/10.1661/0026-2803(2002)048[0343:lgmpca]2.0.co;2 doi:  10.1661/0026-2803(2002)048[0343:lgmpca]2.0.co;2
    Lindström, M., 1970. A Suprageneric Taxonomy of the Conodonts. Lethaia, 3(4): 427-445. https://doi.org/10.1111/j.1502-3931.1970.tb00834.x doi:  10.1111/j.1502-3931.1970.tb00834.x
    Ma, Q. F., Feng, Q. L., Caridroit, M., et al., 2016. Integrated Radiolarian and Conodont Biostratigraphy of the Middle Permian Gufeng Formation (South China). Comptes Rendus Palevol, 15(5): 453-459. https://doi.org/10.1016/j.crpv.2016.02.001 doi:  10.1016/j.crpv.2016.02.001
    Mei, S. L., Henderson, C. M., 2001. Evolution of Permian Conodont Provincialism and Its Significance in Global Correlation and Paleoclimate Implication. Palaeogeography, Palaeoclimatology, Palaeoecology, 170(3/4): 237-260. https://doi.org/10.1016/s0031-0182(01)00258-9 doi:  10.1016/s0031-0182(01)00258-9
    Mei, S. L., Henderson, C. M., 2002. Conodont Definition of the Kungurian (Cisuralian) and Roadian (Guadalupian) Boundary. Canadian Society of Petroleum Geologists, Memoir, 19: 529-551 http://www.researchgate.net/publication/303722461_Conodont_definition_of_the_Kungurian_Cisuralian_and_Roadian_Guadalupian_boundary
    Mei, S. L., Wardlaw, B. R., 1994. Jinogondolella: A New Genus of Permian Gondolellids. International Symposium on Permian Stratigraphy, Environments and Resources, Abstracts, Guiyang, China. 20-21
    Mei, S. L., Henderson, C. M., Jin, Y. G., 1999. Permian Conodont Provincialism, Zonation and Global Correlation. Permophiles, 35: 16
    Mei, S. L., Henderson, C. M., Wardlaw, B. R., 2002. Evolution and Distribution of the Conodonts Sweetognathus and Iranognathus and Related Genera during the Permian, and Their Implications for Climate Change. Palaeogeography, Palaeoclimatology, Palaeoecology, 180(1/2/3): 57-91. https://doi.org/10.1016/s0031-0182(01)00423-0 doi:  10.1016/s0031-0182(01)00423-0
    Mei, S. L., Jin, Y. G., Wardlaw, R. B., 1994. Succession of Conodont Zones from the Permian "Kuhfeng" Formation, Xuanhan, Sichuan and Its Implication in Global Correlation. Acta Palaeontologica Sinica, 33(1): 1-23 (in Chinese with English Abstract) http://europepmc.org/abstract/cba/274412
    Mei, S. L., Jin, Y. G., Wardlaw, B. R., 1998. Conodont Succession of the Guadalupian-Lopingian Boundary Strata in Labin of Guangxi, China and West Texas, USA. Palaeoworld, 9: 53-56 http://ci.nii.ac.jp/naid/10020145826
    Metcalfe, I., 1996. Gondwanaland Dispersion, Asian Accretion and Evolution of Eastern Tethys*. Australian Journal of Earth Sciences, 43(6): 605-623. https://doi.org/10.1080/08120099608728282 doi:  10.1080/08120099608728282
    Metcalfe, I., 2013. Gondwana Dispersion and Asian Accretion: Tectonic and Palaeogeographic Evolution of Eastern Tethys. Journal of Asian Earth Sciences, 66: 1-33. https://doi.org/10.1016/j.jseaes.2012.12.020 doi:  10.1016/j.jseaes.2012.12.020
    Mory, A. J., Redfern, J., Martin, J. R., et al., 2008. A Review of Permian-Carboniferous Glacial Deposits in Western Australia. Geological Society of America Bulletin, 441: 29-40. https://doi.org/10.1130/2008.2441(02) doi:  10.1130/2008.2441(02)
    Muttoni, G., Gaetani, M., Kent, D. V., et al., 2009. Opening of the Neo-Tethys Ocean and the Pangea B to Pangea A Transformation during the Permian. GeoArabia, 14(4): 17-48 http://www.researchgate.net/publication/228515990_Opening_of_the_Neo-Tethys_Ocean_and_the_Pangea_B_to_Pangea_A_transformation_during_the_Permian
    Nakrem, H. A., 1991. Conodonts from the Permian Succession of Bjornoya (Svalbard). Norsk Geologisk Tidsskr, 71: 235-248 http://www.researchgate.net/publication/281509015_Distribution_of_conodonts_through_the_Permian_succession_of_Svalbard
    Nicora, A., Baud, A., Henderson, C. M., et al., 2009. Distribution of Hindeoduswordensis Wardlaw, 2000 in Space and Time. ICOS2009 Abstracts, 1: 36
    Nishikane, Y., Kaiho, K., Henderson, C. M., et al., 2014. Guadalupian-Lopingian Conodont and Carbon Isotope Stratigraphies of a Deep Chert Sequence in Japan. Palaeogeography, Palaeoclimatology, Palaeoecology, 403: 16-29. https://doi.org/10.1016/j.palaeo.2014.02.033 doi:  10.1016/j.palaeo.2014.02.033
    Orchard, M. J., 1987. Conodonts from Western Canadian Chert: Their Nature, Distribution and Stratigraphic Application. In: Austin, R. L., ed., Conodonts: Investigative Techniques and Applications. British Micropaleontological Society, Ellis Horwood, Chichester. 94-119
    Orchard, M. J., Cordey, F., Rui, L., et al., 2001. Biostratigraphic and Biogeographic Constraints on the Carboniferous to Jurassic Cache Creek Terrane in Central British Columbia. Canadian Journal of Earth Sciences, 38(4): 551-578. https://doi.org/10.1139/e00-120 doi:  10.1139/e00-120
    Pucéat, E., Joachimski, M. M., Bouilloux, A., et al., 2010. Revised Phosphate-Water Fractionation Equation Reassessing Paleotemperatures Derived from Biogenic Apatite. Earth and Planetary Science Letters, 298(1/2): 135-142. https://doi.org/10.1016/j.epsl.2010.07.034 doi:  10.1016/j.epsl.2010.07.034
    Rexroad, C. B., Furnish, W. M., 1964. Conodonts from the Pella Formation (Mississippian), South-Central Iowa. Journal of Paleontology, 38: 667-676. https://doi.org/10.2307/1301445 doi:  10.2307/1301445
    Rhodes, F. H. T., 1963. Conodonts from the Topmost Tensleep Sandstone of the Eastern Big Horn Mountains, Wyoming. Journal of Paleontology, 401-408. https://doi.org/10.2307/1301302 doi:  10.2307/1301302
    Ritter, S. M., 1986. Taxonomic Revision and Phylogeny of Post-Early Permian Crisis Bisselli-Whitei Zone Conodonts with Comments on Late Paleozoic Diversity. Geologica et Palaeontologica, (20): 139-165 http://ci.nii.ac.jp/naid/10012507031
    Rybalka, S. V., 1989. Conodonts and Some Problems of Paleozoic Stratigraphy of Primorye. Bulletin of Russian Academy of Natural Sciences, 64(2): 95-99 (in Russian)
    Sano, H., Orchard, M. J., 2004. Necoslie Breccia: Mixed Conodont Fauna-Bearing Neptunian Dyke in Carboniferous-Permian Seamount-Capping Oceanic Buildup (Pope Succession, Cache Creek Complex, Central British Columbia). Facies, 50(1): 133-145. https://doi.org/10.1007/s10347-004-0002-0 doi:  10.1007/s10347-004-0002-0
    Shen, S. Z., Zhang, H., Zhang, Y. C., et al., 2018. Permian Integrative Stratigraphy and Timescale of China. Science China Earth Sciences, 62(1): 154-188. https://doi.org/10.1007/s11430-017-9228-4 doi:  10.1007/s11430-017-9228-4
    Stampfli, G. M., Hochard, C., Vérard, C., et al., 2013. The Formation of Pangea. Tectonophysics, 593(3): 1-19. https://doi.org/10.1016/j.tecto.2013.02.037 doi:  10.1016/j.tecto.2013.02.037
    Sun, Y. D., Lai, X. L., Jiang, H. S., et al., 2008. Guadalupian (Middle Permian) Conodont Faunas at Shangsi Section, Northeast Sichuan Province. Journal of China University of Geosciences, 19(5): 451-460. https://doi.org/10.1016/s1002-0705(08)60050-3 doi:  10.1016/s1002-0705(08)60050-3
    Sun, Y. D., Lai, X. L., Wignall, P. B., et al., 2010. Dating the Onset and Nature of the Middle Permian Emeishan Large Igneous Province Eruptions in SW China Using Conodont Biostratigraphy and Its Bearing on Mantle Plume Uplift Models. Lithos, 119(1/2): 20-33. https://doi.org/10.1016/j.lithos.2010.05.012 doi:  10.1016/j.lithos.2010.05.012
    Sun, Y. D., Liu, X. T., Yan, J. X., et al., 2017. Permian (Artinskian to Wuchapingian) Conodont Biostratigraphy in the Tieqiao Section, Laibin Area, South China. Palaeogeography, Palaeoclimatology, Palaeoecology, 465: 42-63. https://doi.org/10.1016/j.palaeo.2016.10.013 doi:  10.1016/j.palaeo.2016.10.013
    Sungatullina, G. M., Davydov, V. I., 2015. New Data on Conodonts from the Kasimovian Stage of the Usolka Section, Southern Ural Mountains. Paleontological Journal, 49(10): 1142-1149. https://doi.org/10.1134/s0031030115110106 doi:  10.1134/s0031030115110106
    Wardlaw, B. R., 2000. Guadalupian Conodont Biostratigraphy of the Glass and Del Norte Mountains. Guadalupian Symposium, 32: 37-88. https://doi.org/10.5479/si.00810274.32.1 doi:  10.5479/si.00810274.32.1
    Wardlaw, B. R., 2015. Gondolellid Conodonts and Depositional Setting of the Phosphoria Formation. Micropaleontology, 61(4/5): 335-368
    Wardlaw, B. R., Collinson, J. W., 1979. Youngest Permian Conodont Faunas from the Great Basin and Rocky Mountain Regions. Brigham Young University Geology Studies, 26: 151-163 http://www.researchgate.net/publication/313516822_Youngest_Permian_conodont_faunas_from_the_Great_Basin_and_Rocky_Mountain_regions
    Wardlaw, B. R., Collinson, J. W., 1984. Conodont Paleoecology of the Permian Phosphoria Formation and Related Rocks of Wyoming and Adjacent Areas. Geological Society of America Special Paper, 196: 263-281 http://www.researchgate.net/publication/296061483_Conodont_paleoecology_of_the_Permian_Phosphoria_Formation_and_related_rocks_of_Wyoming_and_adjacent_areas
    Wardlaw, B. R., Collinson, J. W., 1986. Paleontology and Deposition of the Phosphoria Formation. Rocky Mountain Geology, 24(2): 107-142 http://www.researchgate.net/publication/259842943_Paleontology_and_deposition_of_the_Phosphoria_Formation
    Wardlaw, B. R., Nestell, M. K., 2010. Three Jinogondolella Apparatuses from a Single Bed of the Bell Canyon Formation in the Apache Mountains, West Texas. Micropaleontology, 56(1/2): 195-212. https://doi.org/10.2307/40607081 doi:  10.2307/40607081
    Wardlaw, B. R., Nestell, M. K., 2015. Conodont Faunas from a Complete Basinal Succession of the Upper Part of the Wordian (Middle Permian, Guadalupian, West Texas). Micropaleontology, 61: 257-292 http://smartsearch.nstl.gov.cn/paper_detail.html?id=ed85ced484e671199f4b3285fa742fff
    Wardlaw, B. R., Mei, S. L., 1998. A Discussion of the Early Reported Species of Clarkina (Permian Conodonta) and the Possible Origin of the Genus. Palaeoworld, 9: 33-52
    Wang, C. Y., 1995. A Conodont Fauna from the Lowermost Kufeng Formation (Permian). Acta Micropalaeontologica Sinica, 12(3): 293-298 (in Chinese with English Abstract) http://search.cnki.net/down/default.aspx?filename=WSGT503.006&dbcode=CJFD&year=1995&dflag=pdfdown
    Wang, C. Y., Ariunchimeg, Y. A., 2006. An Important Permian Conodont Species from Mongolia. Acta Micropalaeontologica Sinica, 23(3): 313-316 (in Chinese with English Abstract) http://manuscriptpro.com/profile/journal2/Wei-ti-gu-sheng-wu-xue-bao-=-Acta-micropalaeontologica-Sinica
    Wang, C. Y., Dong, Z. C., 1991. Permian Conodonts from Suoxiyu in Cili County, Hunan. Acta Micropalaeontologica Sinica, 8(1): 41-58 (in Chinese with English Abstract) http://en.cnki.com.cn/Article_en/CJFDTOTAL-WSGT199101003.htm
    Wang, C. Y., Ritter, S. M., Clark, D. L., 1987. The Sweetognathus Complex in the Permian of China: Implications for Evolution and Homeomorphy. Journal of Paleontology, 61(5): 1047-1057. https://doi.org/10.1017/s0022336000029395 doi:  10.1017/s0022336000029395
    Wang, C. Y., Wang, P., Li, W. G., 2004. Conodonts from the Permian Jisu Honguer (Zhesi) Formation of Inner Mongolia, China. Geobios, 37(4): 471-480. https://doi.org/10.1016/j.geobios.2003.06.003 doi:  10.1016/j.geobios.2003.06.003
    Wang, C. Y., Wu, J., Zhu, T., 1998. Permian Conodonts from the Penglaitan Section, Laipin County, Guangxi and the Base of the Wuchiapingian Stage (Lopingian Series). Acta Micropalaeontologica Sinica, 15(3): 225-235 (in Chinese with English Abstract) http://europepmc.org/abstract/cba/317991
    Wang, C. Y., Zhen, C. Z., Pen, Y. J., et al., 2000. A Conodont Fauna of Permian Northern Temperate Zone from the Fanjiatun Formation at Lijiayao, Jilin. Acta Micropalaeontologica Sinica, 17(4): 430-442 (in Chinese with English Abstract) http://www.researchgate.net/publication/286005524_A_conodont_fauna_of_Permian_Northern_temperate_Zone_from_the_Fanjiatun_Formation_at_Lijiayao_Jilin
    Wang, D. C., Jiang, H. S., Gu, S. Z., et al., 2016. Cisuralian-Guadalupian Conodont Sequence from the Shaiwa Section, Ziyun, Guizhou, South China. Palaeogeography, Palaeoclimatology, Palaeoecology, 457: 1-22. https://doi.org/10.1016/j.palaeo.2016.05.030 doi:  10.1016/j.palaeo.2016.05.030
    Wang, Z. H., 1978. Permian-Lower Triassic Conodonts of the Liangshan Area, Southern Shaanxi. Acta Palaeontologica Sinica, 17(2): 213-227 (in Chinese with English Abstract) http://www.researchgate.net/publication/312840646_Permian-Lower_Triassic_conodonts_of_the_Liangshan_area_southern_Shaanxi
    Wu, Q., Ramezani, J., Zhang, H., et al., 2017. Calibrating the Guadalupian Series (Middle Permian) of South China. Palaeogeography, Palaeoclimatology, Palaeoecology, 466: 361-372. https://doi.org/10.1016/j.palaeo.2016.11.011 doi:  10.1016/j.palaeo.2016.11.011
    Yao, Y., Yan, J. X., Li, A. Z., 2012. Sedimentary Features and Evolution of Mid-Permian Carbonates from Laibin of Guangxi. Earth Science-Journal of China University of Geosciences, 37(2): 184-194 (in Chinese with English Abstract)
    Yin, H. F., Huang, D. H., 1995. The Early Palaoeozoic Zhan'an-Xichuan Block and the Evolution of the Small Qinling Archipelagic Ocean Basin. Acta Geologica Sinica, 69(3): 193-204 (in Chinese with English Abstract) http://epub.cnki.net/grid2008/docdown/docdownload.aspx?filename=DZXE199503000&dbcode=CJFD&year=1995&dflag=pdfdown
    Yin, H. F., Peng, Y. Q., 1995. Evolution of the Phanerozoc Paleo-Ocean of Qinling. Earth Science-China University of Geosciences, 20(6): 605-611 (in Chinese with English Abstract) http://www.researchgate.net/publication/313618942_Evolution_of_the_Phanerozoic_paleo-ocean_of_Qinling
    Yin, H. F., Zhang, K. X., 1998. Evolution and Characteristics of the Central Orogenic Belt. Earth Science-China University of Geosciences, 23(5): 438-442 (in Chinese with English Abstract) http://ci.nii.ac.jp/naid/10026542178
    Youngquist, W. L., Miller, A. K., 1949. Conodonts from the Late Mississippian Pella Beds of South-Central Iowa. Journal of Paleontology, 23(6): 617-622. https://doi.org/10.2307/1299669 doi:  10.2307/1299669
    Yuan, D. X., Chen, J., Zhang, Y. C., et al., 2015. Changhsingian Conodont Succession and the End-Permian Mass Extinction Event at the Daijiagou Section in Chongqing, Southwest China. Journal of Asian Earth Sciences, 105(14): 234-251. https://doi.org/10.1016/j.jseaes.2015.04.002 doi:  10.1016/j.jseaes.2015.04.002
    Zhang, G. W., Dong, Y. P., Lai, S. C., et al., 2004. Mianlüe Tectonic Zone and Mianlüe Suture Zone on Southern Margin of Qinling-Dabie Orogenic Belt. Science in China Series D, 47(4): 300-316. https://doi.org/10.1360/02yd0526 doi:  10.1360/02yd0526
    Zhang, L. L., Zhang, N., Xia, W. C., 2007. Conodont Succession in the Guadalupian-Lopingian Boundary Interval (Upper Permian) of the Maoershan Section, Hubei Province, China. Micropaleontology, 53(6): 433-446. https://doi.org/10.2113/gsmicropal.53.6.433 doi:  10.2113/gsmicropal.53.6.433
    Zhang, N., Henderson, C. M., Xia, W. C., et al., 2010. Conodonts and Radiolarians through the Cisuralian-Guadalupian Boundary from the Pingxiang and Dachongling Sections, Guangxi Region, South China. Alcheringa, 34(2): 135-160. https://doi.org/10.1080/03115510903523292 doi:  10.1080/03115510903523292
    Zhao, Z., 1983. Conodont Sequences in Weixian and Xixia Stages of China. Xinjiang Petroleum Geology, 1: 38-61 (in Chinese)
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Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China

doi: 10.1007/s12583-020-1099-y

Abstract: Focusing on the Shuixiakou Section (Xikou area, Zhen'an County, Shaanxi Province, southeastern Qinling region, China), the Roadian-Wordian conodonts are investigated. More than 2 000 conodont elements including 6 genera and 14 species have been obtained. Based on these materials, the Guadalupian Jinogondolella nankingensis and J. aserrata zones have been recognized. The Roadian-Wordian boundary is tentatively defined by the first occurrence of J. aserrata in the lower part of Unit Ⅲ in the Shuixiakou Formation. The sedimentary succession of Xikou area records similar sea-level changes to those observed in Laibin area (South China). The 40 m-thick bioclastic limestone of Unit Ⅳ in this section can be correlated with the reefs of Bed 114 in Laibin area. A temperature drop indicated by δ18Oapatite values suggests this Wordian interval coincides with a period of glaciation and global regression.

Baojin Wu, Hanxiao Li, Michael M. Joachimski, Paul B. Wignall, Haishui Jiang, Jiaxin Yan, Lina Wang, Xianlang Wu, Xulong Lai. Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China. Journal of Earth Science, 2021, 32(3): 534-553. doi: 10.1007/s12583-020-1099-y
Citation: Baojin Wu, Hanxiao Li, Michael M. Joachimski, Paul B. Wignall, Haishui Jiang, Jiaxin Yan, Lina Wang, Xianlang Wu, Xulong Lai. Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China. Journal of Earth Science, 2021, 32(3): 534-553. doi: 10.1007/s12583-020-1099-y
  • During the Middle Permian, the Xikou area was located on the Zhen'an-Xichuan microblock of the small Qinling archipelagic ocean basin which was situated on the northeastern Paleo- Tethys (Fig. 1a; e.g., Dong and Santosh, 2016; Muttoni et al., 2009; Zhang et al., 2004; Yin and Zhang, 1998; Yin and Huang, 1995; Yin and Peng, 1995). At this time, the South China Block and the North China Block had not converged but the South Qinling and the North Qinling had merged to form the Qinling terrane (e.g., Dong and Santosh, 2016). The Xikou area was located within the southeastern Qinling region (Fig. 1b). The about 3 000 m thick carbonate strata, intercalated with mudstones, cherts and shales, were deposited from the Carboniferous to Triassic (e.g., Ding et al., 1989, 1987, 1983). Today the strata are exposed in a syncline which has the Jinji Ridge at its core (Fig. 1c; Ding et al., 1989, 1983). The studied Shuixiakou Section (GPS: 33°14′50.1″N, 109°28′15.7″E) is located in the southern slope of the syncline. The outcrops occur along a small river, parallel to a road near Shuixiakou Village and correspond to the western Xikou Section of Cheng et al. (2017; Fig. 1c). The Middle Permian strata at the Shuixiakou Section are highly fossiliferous, and are comprised of the Wulipo and Shuixiakou formations (Fig. 2). The bioclastic rocks increase from the Wulipo Formation, which consists of bioclastic limestone interbedded with mudstone, to the Shuixiakou Formation which has shale and a greater proportion of siliciclastic rocks (Figs. 2, 3, 4; Cheng et al., 2017; Ding et al., 1989, 1983).

    Figure 1.  (a) Middle Permian paleogeographic reconstructions of the South China Block, the North China Block and Qinling terrane (modified from Dong and Santosh, 2016; Muttoni et al., 2009; Zhang et al., 2004; Yin and Zhang, 1998; Yin and Huang, 1995; Yin and Peng, 1995); (b) simplified tectonic map of the Qinling orogenic belt within China (modified from Dong and Santosh, 2016), LWF. Lingbao-Lushan-Wuyang fault; LLF. Luonan-Luanchuan fault; SDS. Shangdan suture; MBXF. Mianlüe-Bashan-Xiangguang Mesozoic overthrust fault; (c) the strata distribution in the Xikou area was modified from the 1 : 200 000 Geological Map of Ankang Sheet (Anonymous, 1965) and Cheng et al. (2017).

    Figure 2.  Field photos showing the lithologic characteristic of the Roadian-Wordian interval in the Shuixiakou Section. The bioclastic limestone-dominated strata: (a) Unit Ⅰ, (c)–(d) Unit Ⅳ; mudstone and/or shale-dominated strata: (a)–(b) Unit Ⅱ, (c) Unit Ⅲ; marly limestone-shale intercalations: (e) Unit Ⅴ, (f) Unit Ⅵ.

    Figure 3.  Photomicrographs (a–h, j, l–q) and field photographs (i, k) showing the lithologic characteristics of the Roadian-Wordian interval in the Shuixiakou Section. (a) Bioclastic limestone (Sample SXK-1 of Unit Ⅰ); (b) thin-bedded marly limestone within mudstone (Sample SXK-5 of Unit Ⅱ); (c) hummocky cross bedding in thin-bedded, bioclastic, marly limestone within mudstone and shale (Sample SXK-8 of Unit Ⅲ); (d) thin-bedded, marly limestone within mudstone with abundant bioclast (Sample SXK-16 of Unit Ⅲ); (e) parallel bedding in the dark grey, thin-bedded, marly limestone within cherts with abundant sponge spicules (Sample SXK-36 of Unit Ⅴ); (f) abundant sponge spicules on the bedding plane of black cherts (Sample SXK-34 of Unit Ⅴ); (g) crinoids (Sample SXK-37 of Unit Ⅵ); (h, j) brachiopod (Sample SXK-38 of Unit Ⅵ; Sample SXK-28 of Unit Ⅳ); (l) coral (Sample SXK-16 of Unit Ⅲ); (m) echinoid (Sample SXK-14 of Unit Ⅲ); (n) trilobite (Sample SXK-37 of Unit Ⅵ); (o) gastropod (Sample SXK-4 of Unit Ⅱ); (p) bivalve (Sample SXK-16 of Unit Ⅲ); (q) ostracod (Sample SXK-16 of Unit Ⅲ); and (i) brachiopods, (k) solitary rugosas.

    Figure 4.  Diagram showing the lithology, fossil distributions (in thin sections), relative sea-level change and conodont distributions of the Roadian-Wordian interval in the Shuixiakou Section. Fu.z. fusulinids zones; Fm. formation; Litho. lithology; M. Mesogondolella; J. Jinogondolella; H. Hindeodus; Ps. Pseudohindeodus; Sw. Sweetognathus; Pu. Pustulognathus; C.Z. conodont zones.

  • A total of 38 samples (each one > 6 kg) were collected from six units in the Shuixiakou Section (Fig. 4). All samples were crushed into 1–2 cm3 fragments, dissolved in 8% acetic acid, and followed by heavy liquid separation. Conodont elements were picked from the residues using a stereoscopic microscope. Scanning electron microscope (SEM) was used for photography.

  • Conodont oxygen isotope analyses were performed using a TC-EA (high-temperature conversion-elemental analyzer) coupled online to a ThermoFinnigan Delta V Plus mass spectrometer. Conodonts samples of 0.5 to 1 mg were dissolved in HNO3 with the phosphate group precipitated as Ag3PO4 (Joachimski et al., 2009). The Ag3PO4 (0.2 to 0.3 mg) was weighed into silver foil and transferred to the sample carousel of the TC-EA. At 1 450 ℃, the phosphate is reduced and CO formed as the analyzed gas. CO was transferred in a helium stream through a gas chromatograph via a Conflo Ⅲ interface to the mass spectrometer. All δ18Oapatite values were reported in ‰ relative to VSMOW. Samples as well as standards were generally measured in triplicate. The measurements were calibrated by performing a two-point calibration using NBS 120c (21.7‰) and a commercial Ag3PO4 (9.9‰). A laboratory standard was used as a control standard (TueA) and processed together with the samples. External reproducibility, monitored by replicate analyses of samples as well as the laboratory standard, was 16.5‰±0.15‰ (1σ; n=4). Note the gap of 0.9‰ in the δ18Oapatite values between the Shuixiakou and Tieqiao sections, since the δ18O of NBS 120c was reported as 22.6‰ in the published Tieqiao Section (Chen et al., 2011). Paleotemperatures were calculated using the temperature equation for biogenic apatite published by Pucéat et al. (2010).

    Data of conodont apatite from Jinogondolella (17) and from the mixture of Hindeodus, Pseudohindeodus and Sweetognathus (5) were obtained from six units in the Shuixiakou Section (Fig. 5; Table 1).

    Figure 5.  δ18Oapatite records of the Roadian-Wordian (Middle Permian) interval in the Shuixiakou Section, and its correlation with the Tieqiao Section (Chen et al., 2011). Note that the δ18Oapatite values of the Tieqiao Section (Chen et al., 2011) were corrected by -0.9‰ since δ18O of NBS 120c was reported as 22.6‰ (compared to 21.7‰ in this study).

    Sample Thickness (m) Conodont zone/stage Unit/formation δ18Oapatite (-J, ‰, VPDB) δ18Oapatite (-H, ‰, VPDB) T (℃)
    SXK-2 7.4 J. nankingensis/Roadian Unit I/Wulipo 19.8 19.9 27.1/26.7
    SXK-5 52.7 J. nankingensis/Roadian Unit Ⅱ/Wulipo 18.8 18.6 31.3/32.2
    SXK-6 91.2 J. aserrata/Wordian Unit Ⅲ/Shuixiakou 19.4 28.8
    SXK-10 121.8 J. aserrata/Wordian Unit Ⅲ/Shuixiakou 19.2 29.7
    SXK-12 126.2 J. aserrata/Wordian Unit Ⅲ/Shuixiakou 19.1 30.1
    SXK-15 134.8 J. aserrata/Wordian Unit Ⅲ/Shuixiakou 19.2 29.7
    SXK-16 137.3 J. aserrata/Wordian Unit Ⅲ/Shuixiakou 19.2 29.7
    SXK-17 138.6 J. aserrata/Wordian Unit Ⅲ/Shuixiakou 19.4 28.8
    SXK-26 174.8 J. aserrata/Wordian Unit Ⅳ/Shuixiakou 20.1 25.9
    SXK-27 176.9 J. aserrata/Wordian Unit Ⅳ/Shuixiakou 20.2 25.4
    SXK-28 178.2 J. aserrata/Wordian Unit Ⅳ/Shuixiakou 19.9 26.7
    SXK-34 189.7 J. aserrata/Wordian Unit Ⅴ/Shuixiakou 19.9 26.7
    SXK-36 192.5 J. aserrata/Wordian Unit Ⅴ/Shuixiakou 19.8 27.1
    SXK-37 234.8 J. aserrata/Wordian Unit Ⅵ/Shuixiakou 20 26.3
    SXK-38 250.3 J. aserrata/Wordian Unit Ⅵ/Shuixiakou 19.8 27.1
    -J. Jinogondolella; -H. Hindeodus, Pseudohindeodus and Sweetognathus. The temperatures in shade corresponding to the values of δ18Oapatite in shade.

    Table 1.  The δ18Oapatite records of the Roadian-Wordian interval in the Shuixiakou Section

  • In ascending order, the six units of the Middle Permian strata at the Shuixiakou Section can be described. Unit Ⅰ is dominated by grey, thin to thick, bioclastic limestones intercalated with mudstones containing shallow-water fossils including ostracods, gastropods and fusulinids, sponge spicules and burrows. Unit Ⅱ is dominated by mudstones intercalated with shale, chert and thin, bioclastic marly limestone, that contains shallow-water fossils including brachiopods, ostracods, gastropods and sponge spicules—the latter suggesting deeper waters. Unit Ⅲ is dominated by mudstones intercalated with shale and thin to medium bedded, bioclastic marly limestones containing a deep-marine fauna including abundant sponge spicules and rarer brachiopods in the lower part and a shallow water assemblage, including brachiopods, bivalves, solitary rugose corals, ostracods and echinoids, in the upper part. Unit Ⅳ is dominated by grey, thin to thick-bedded bioclastic limestone that contains brachiopods, ostracods, sponge spicules and crinoids. The lower part of Unit Ⅴ consists of black cherts with abundant sponge spicules, and the upper part of Unit Ⅴ is dominated by cherts intercalated with marly limestone. Unit Ⅵ is composed of marly limestone-shale intercalations containing shallow-marine brachiopods, crinoids, trilobites, ostracods, gastropods and sponge spicules (Figs. 3, 4).

    Burrows are observed in samples SXK-1, 2 of Unit I. Hummocky cross bedding appears in the thin-bedded, limestone from samples SXK-8 and SXK-13 within Unit Ⅲ and Sample SXK-25 within Unit Ⅳ (Fig. 3c), whilst planar lamination appears in thin-bedded, marly limestone of Sample SXK-6 in Unit Ⅲ and cherts from samples SXK-32 to 36 within Unit Ⅴ (Fig. 3e). In the thin to medium-bedded, bioclastic, marly limestones of units Ⅱ and Ⅲ, the carbonate matrix is a calcisiltite in samples SXK-4, 5, 15 to 17, microspar in samples SXK-8, 13, 14 and micrite in samples SXK-6, 7, 9 to 12. Abundant fossil shells that are embraced by fine bioclastic grains are well preserved in Sample SXK-9, 14, 28 (Fig. 3).

    The parallel bedding changes gradually into hummocky cross stratification and then into graded bedding (carbonate matrixes: from micrite/microspar to calcisiltite in upward) in the thin, bioclastic marly limestone beds of Unit Ⅲ. Ripple marks were reported in the limestone beds of the Wulipo and Shuixiakou formations in the Xikou area (Ding et al., 1989, 1983). These structures appear in units Ⅰ, Ⅳ and Ⅵ in the Shuixiakou Section. This range of evidences suggests deposition in the Shuixiakou Section was under storm influence. Unit Ⅰ and Unit Ⅳ are interpreted as mid-ramp facies while units Ⅱ, Ⅲ, Ⅴ and Ⅵ are interpreted as outer ramp or basinal facies.

  • More than 2 000 conodont elements including 6 genera and 14 species have been obtained (Table 2), and two conodont zones have been recognized (Fig. 4).

    1 2 5 6 9 10 11 12 13 14 15 16 17 18 21 24 26 27 28 29 31 34 37 38
    H. excavatus 1 19 1 2 2 3 1 9 3 1 1
    H. gulloides 1
    H. minutus 1 2 2 2 1
    H. wordensis 6 1 1 1 3 3
    J. nankingensis nankingensis 1 15 1 4 4 3 6 1
    J. nankingensis tenuis 199 4
    J. aserrata 5 3 7 2 9 1 1 3 5 18 96 1 2 1 1
    J. bitteri 13
    M. cf. lamberti 4
    Ps. cf. elliptica 2 1
    Ps. ramovsi 8 19 1 13 7 8 1
    Pu. vigilans 1
    Sw. hanzhongensis 3 2 6 3 3
    Sw. cf. subsymmetricus 1

    Table 2.  Statistics and distribution of conodont species (P1 element) of the Shuixiakou Section. H. Hindeodus; J. Jinogondolella; M. Mesogondolella; Ps. Pseudohindeodus; Pu. Pustulognathus; Sw. Sweetognathus.

  • Jinogondolella nankingensis Zone (Unit Ⅰ–lower Unit Ⅲ)

    The upper limit of this zone is defined by the first occurrence of Jinogondolella aserrata (Clark and Behnken, 1979) in the Sample SXK-6 of Unit Ⅲ. Jinogondolella nankingensis nankingensis, Hindeodus excavatus, H. gulloides, H. minutus, H. wordensis, Mesogondolella cf. lamberti, Pseudohindeodus ramovsi and Sweetognathus hanzhongensis co-occur in this interval (Fig. 4; Table 2). The lower limit of this zone has not been defined. Jinogondolella nankingensis nankingensis is the marker of the Roadian strata, and it has been reported from USA (e.g., Mei and Henderson, 2002; Kozur, 1995; Behnken et al., 1986; Clark and Behnken, 1979; Behnken, 1975; Clark and Mosher, 1966), Canada (Orchard et al., 2001; Orchard, 1987), Tajikistan (Angiolini et al., 2015), Japan (Nishikane et al, 2014), Norway (Nakrem, 1991), South China (e.g., Sun et al., 2017; Wu et al., 2017; Zhang et al., 2010; Ching, 1960) and southeastern Qinling region (Cheng et al., 2017). Both H. excavatus and H. minutus are cosmopolitan species and are common in the Middle Permian strata (e.g., Sun et al., 2017; Wang et al., 2016; Lai et al., 2008; Behnken, 1975). Hindeodus gulloides has been reported from the late Roadian strata in West Texas (Kozur and Mostler, 1995), the Kungurian strata in Northeast Thailand (Burrett et al., 2014) and the late Kungurian strata in South China (Sun et al., 2017). Hindeodus wordensis is known from the middle Roadian to early Capitanian strata in West Texas (e.g., Wardlaw and Nestell, 2015; Nicora et al., 2009; Wardlaw, 2000), the Wordian to Capitanian strata in Tajikistan (Angiolini et al., 2015), the Wordian strata in Japan (Nishikane et al., 2014). Pseudohindeodus ramovsi has been reported from the Kungurian to Capitanian strata in South China (e.g., Sun et al., 2017, 2010, 2008; Wang et al., 2016; Lai et al., 2008) and West Texas (e.g., Lambert et al., 2010; Wardlaw, 2000), the Roadian to Capitanian strata in Japan (Nishikane et al., 2014), the late Kungurian to early Roadian strata in Oman (Henderson and Mei, 2003) and the Kungurian strata in Tajikistan (Angiolini et al., 2015). Sweetognathus hanzhongensis has been reported from the Roadian to Wordian strata in Hanzhong area (Shaanxi Province, China; Wang, 1978), the late Kungurian to Capitanian strata in South China (e.g., Sun et al., 2017; Ma et al., 2016).

  • Jinogondolella aserrata Zone (upper Unit Ⅲ–Unit Ⅵ)

    The upper limit of this zone has not been recognized.

    The lower limit is defined by the first occurrence of Jinogondolella aserrata in Sample SXK-6 of Unit Ⅲ (Fig. 4). Jinogondolella aserrata, J. bitteri, J. nankingensis nankingensis, J. nankingensis tenuis, Hindeodus excavatus, H. minutus, H. wordensis, Pseudohindeodus cf. elliptica, Ps. ramovsi, Pustulognathus vigilans, Sweetognathus hanzhongensis and Sw. cf. subsymmetricus all co-occur in this interval (Fig. 4; Table 2). Jinogondolella aserrata is the most cosmopolitan conodont species of the Wordian Stage, and is considered as the good marker for this interval. It has been reported from Canada (Sano and Orchard, 2004), USA (e.g., Wardlaw and Nestell, 2010; Clark and Behnken, 1979), Oman (Kozur and Wardlaw, 2010), South China (e.g., Sun et al., 2017; Wang et al., 2016; Mei et al., 1994), North China (Wang et al., 2004), Tajikistan (Angiolini et al., 2015) and Russia (Rybalka, 1989). Jinogondolella bitteri was found in the late Wordian to Capitanian strata in USA (Wardlaw and Collinson, 1979), Canada (Henderson, 1981), and Oman (Henderson, 2018; Kozur and Wardlaw, 2010). Jinogondolella nankingensis tenuis is known from the Roadian to Wordian strata in West Texas (Wardlaw, 2015; Wardlaw and Nestell, 2015), and it is the first described outside of Texas here. Pustulognathus vigilans was reported from the Wordian to Wuchiapingian strata in Canada (Golding, 2018).

  • The Global Stratotype Section and Point (GSSP) for the boundary between the Roadian and Wordian stages is defined by the first appearance datum (FAD) of the conodont Jinogondolella aserrata at Getaway Ledge in Texas (Glenister et al., 1999). The Roadian-Wordian boundary in the Tieqiao Section was tentatively placed in Bed 112 of the Maokou Formation (Sun et al., 2017). In the Shuixiakou Section, the conodont J. nankingensis Zone and fusulinid Pseudodoliolina-Cancellina Zone co-occur in the former formation (Cheng et al., 2017; Ding et al., 1989; this study). The fusulinid Neomisellina-Yabeina Zone was recognized in the Shuixiakou Formation and the Roadian-Wordian boundary is placed at the FAD of the conodont Jinogondolella aserrata (at ~51 m below the base of lower Unit Ⅳ) in the lower part of Unit Ⅲ (Fig. 4).

  • The relative sea-level changes in the Shuixiakou Section (Xikou area, southeastern Qinling region) appear similar to those recorded in the Tieqiao Section (Laibin area, South China; Fig. 4; Yao et al., 2012; Chen et al., 2009, 1998). During the Jinogondolella nankingensis Zone, the deepening from Unit Ⅰ mid-ramp limestones upwards into the outer ramp facies of units Ⅱ to Ⅲ in the Shuixiakou Section is similar to the synchronous sea-level changes from Bed 111 to beds 112 and 113 in Tieqiao Section (Yao et al., 2012; Chen et al., 2009, 1998). Though the upper limit of J. aserrata Zone in the Shuixiakou Section has not been recognized, similar relative sea-level changes in J. aserrata Zone appeared in both the Shuixiakou and Tieqiao sections. In the J. aserrata Zone, the water depths underwent a shift from the deep outer ramp facies of Unit Ⅲ to shallow mid-ramp facies of Unit Ⅳ, then to deep basin or outer ramp facies of units Ⅴ to Ⅵ again, which is similar to the sea-level changes from beds 112 and 113 to Bed 114, then to Bed 115 in Tieqiao Section (Yao et al., 2012; Chen et al., 2009, 1998).

    The conspicuous 40 m-thick bioclastic limestone of Unit Ⅳ in the Shuixiakou Section (Xikou area, southeastern Qinling) and the synchronous reef limestone of Bed 114 in Tieqiao Section (Laibin area, South China) indicate a sea-level drop. Coincidentally, the carbonate buildup that heavily recrystallized and dolomitized of the upper part of the Appel Ranch Menber in Glass Mountains, West Texas, USA suggests subaerial exposure and shallow deposition (Wardlaw, 2000). It seems like a global Wordian regression.

  • The δ18Oapatite values from the Roadian-Wordian stages of the Shuixiakou Section fluctuate around 19.5‰±0.5‰ (1σ, n=17) which gives calculated seawater temperatures around 28.2± 2.0 ℃ (1σ, n=17; Fig. 5, Table 1). In units Ⅰ, Ⅱ and Ⅲ, the δ18Oapatite values from Jinogondolella (19.3‰±0.4‰; 1σ, n=5) are similar to the δ18Oapatite values from the mixture of Hindeodus, Pseudohindeodus and Sweetognathus (19.2‰±0.5‰; 1σ, n=5). The average paleotemperature estimate of 26.8 ℃ (δ18Oapatite: 19.9‰±0.1‰, 1σ, n=4; Fig. 5, Table 1) in units Ⅴ to Ⅵ is slightly lower than the sea water temperatures around 27.5 ℃ from Bed 115 of the equatorial Tieqiao Section (Laibin area, South China; Chen et al., 2013, 2011). The δ18Oapatite values increase from 19.3‰±0.4‰ (1σ, n=10) in units Ⅰ, Ⅱ and Ⅲ to 20.0‰±0.2‰ (1σ, n=7) in units Ⅳ, Ⅴ and Ⅵ. As the appearance of the 40 m-thick bioclastic limestone of Unit Ⅳ, the seawater temperature decreased from 29.4 to 26.5 ℃ in the Jinogondolella aserrata Zone (Fig. 5, Table 1). It suggests that the Wordian regression may be related to a temperature decreasing.

    According to the diversity and taxonomic composition of bivalve and lack of ammonoid, the P3 glacial event began in Roadian and ended in the late Wordian (Davydov et al., 2018; Biakov, 2015; Kutygin, 2015). Due to the extreme cooling, the P3 event corresponds with the disappearance of ammonoids and conodonts in the upper Roadian and Wordian in high- latitudes regions, i.e., N-E Russia, Russian and Canadian Arctic and Australia (Davydov et al., 2018). Furthermore, the calibration of Braxton Formation and Muree Sanstone linked to the P3 glaciation in the eastern Australia was in Wordian (Davydov et al., 2018; Mory et al., 2008). Hence, the temporal coincidence among the P3 glaciation in the eastern Australia, the Wordian regression and the seawater temperature decreasing in Shui- xiakou Section suggests it possible that the temperature decreasing in Shuixiakou Section and the Wordian regression regions may be related to the P3 glacial event.

  • Class: Conodonta Eichenberg, 1930

    Order: Ozarkodinida Dzki, 1976

    Family: Anchignathodontidae Clark, 1972

    Genus: Hindeodus Rexroad and Furnish, 1964

    Type species: Hindeodus cristulus (Youngquist and Miller, 1949)

    Hindeodus wordensis Wardlaw, 2000

    Pl. 5, Figs. 1, 2

    2000  Hindeodus wordensis Wardlaw, pl. 3-4, figs. 24, 25; pl. 3-12, figs. 1, 2

    2014  Hindeodus wordensis Wardlaw, Nishikane et al., pl. III, figs. 2, 4

    2015  Hindeodus wordensis Wardlaw, Wardlaw and Nestell, pl. 14, figs. 5, 10, 16–19

    2017  Hindeodus cf. wordensis Wardlaw, Sun et al., pl. 4, fig. 17

    Description: P1 elements with large cusps are characterized by the denticles increasing in width and decreasing in height posteriorly except the last three. The last three denticles may be subequal or decreasing in width and height posteriorly.

    Remarks: Wardlaw (2000) described the apparatus of Hindeodus wordensis. Nicora et al. (2009) discussed its distribution in space and time. Basal cavities of Hindeodus are not as greatly expanded as Pseudohindeodus (Sun et al., 2017). The small denticles in front blade and larger cusp distinguish H. gulloides from H. wordensis. The subequal denticles (except the last one) distinguish H. minutus from H. wordensis. The denticles increasing in width and decreasing in height posteriorly (except the last three) distinguish H. wordensis from H. minutus.

    Occurrence: From Wulipo Formation (Sample SXK-5 in Unit Ⅱ) and Shuixiakou Formation (samples SXK-10-13, 16 in Unit Ⅲ; Sample SXK-37 in Unit Ⅵ), and range from the late Roadian to Wordian strata in the Shuixiakou Section (Table 2).

    Family: Gondolellidae Lindström, 1970

    Genus: Jinogondolella Mei and Wardlaw, 1994

    Type species: Gondolella nankingensis (Ching, 1960)

    Remarks: The genus Jinogondolella was named in memory of Yu-Gan Jin who named the first species Gondolella nankingensis (Ching, 1960) which is now assigned to the genus as its type species: Jinogondolella nankingensis (Lambert et al., 2007; Mei and Wardlaw, 1994; Ching, 1960). The presence of serrations on the anterior platform margins was used as a synapomorphic character of Guadalupian Jinogondolella (partly previously known as Mesogondolella), which distinguishes it from Mesogondolella (previously known as Gondolella and Neogondolella; Lambert et al., 2007; Mei et al., 1994; Clark and Wang, 1988; Clark and Mosher, 1966). Wang et al.(2004, 1998) questioned the application of Jinogondolella because the absence of serrations is ubiquitous. For example, some Jinogondolella species or partial specimens of the same species have no serrations on the anterior platform (e.g., J. aserrata, J. postserrata and J. altudaensis; Kozur and Wardlaw, 2010; Mei et al., 1998; Kozur, 1992; Clark and Behnken, 1979). Furthermore, a series of Middle Permian gondolellid conodonts with serrations in Jilin Province and Inner Mongolia Autonomous Region were assigned to Mesogondolella (Wang et al., 2006, 2004, 2000). In general, though with occasional exceptions, the Middle Permian gondolellid conodonts generally have serrated anterior platforms, and Jinogondolella is a valid and widely accepted genus (e.g., Henderson, 2018; Kozur and Wardlaw, 2010; Wardlaw and Nestell, 2010; Lamberti et al., 2007; Mei and Wardlaw, 1994).

    Permian conodont provincialism has been widely discussed. Equatorial warm-water gondolellids are characterized by small cusps and high, fused anterior denticles, while relatively cool- water taxa in mid-latitude regions are characterized by larger cusps and lower, discrete anterior denticles (e.g., Henderson and Mei, 2007, 2003; Mei and Henderson, 2002, 2001; Mei et al., 1999; Kozur, 1995). Jinogondolella was restricted to warm water environments (Henderson and Mei, 2007; Mei and Henderson, 2001). Lamberti et al. (2007) revised the diagnosis of Jinogondolella and showed that serrations are usually present on the anterior platform of P1 adult specimens based on the study of the multi-apparatus of genus. They also concluded that Jinogondolella primarily inhabited warm, shallower water masses in the Permian pan-tropical belt whilst Mesogondolella predominantly inhabited cold water masses in shallow mid-latitude settings and deeper tropical settings. Kozur and Wardlaw (2010) also noted that Jinogondolella has a limited distribution largely in the tropical basins of North America and China. There are some provincialism-related morphological variations in different conodonts distribution provinces and different water depth of settings, but these differences are not added to the diagnosis of Jinogondolella (distinguishing from Mesogondolella) here. Their Middle Permian gondolellid conodonts of the Xikou Section (western of the Shuixiakou) had been assigned to Mesogondolella by Cheng et al. (2017), and instead belong to Jinogondolella (Cheng et al., 2019).

    Jinogondolella nankingensis nankingensis (Ching, 1960)

    Pl. 1, Figs. 5–14

    1960  Gondolella nankingensis Ching, pl. 2, figs. 5–8

    1962  Gondolella serrata Clark and Ethington, pl. 1, figs. 10, 11, 15, 19; pl. 2, figs. 1, 5, 8, 9, 11–14

    1966  Gondolella serrata Clark and Ethington, Clark and Mosher, pl. 47, figs. 14, 15

    1975  Neogondolella serrata serrata (Clark and Ethington), Behnken, pl. 2, figs. 21–24, 37

    1979  Neogondolella serrata (Clark and Ethington), Clark and Behnken, pl. 1, fig. 12

    1986  Neogondolella serrata (Clark and Ethington), Behnken et al., 1986, figs. 5.20, 5.21, 5.23–5.31

    1988  Neogondolella serrata (Clark and Ethington), Clark and Wang, fig. 3-3

    1994  Mesogondolella nankingensis (Ching), Mei et al., pl. I, figs. 1–3, 18

    1995  Mesogondolella nankingensis (Ching), Kozur, pl. 4, figs. 2–4

    1995  Mesogondolella nankingensis (Ching), Kozur and Mostler, pl. 1, figs. 4–9, 12–17; pl. 2, figs. 1–5, 7–13

    1998  Mesogondolella nankingensis (Ching), Mei et al., pl. 2, fig. 5

    2000  Mesogondolella nankingensis (Ching), Wardlaw, pl. 3–10, figs. 8–10

    2001  Jinogondolella nankingensis (Ching), Orchard et al., pl. 1, figs. 13

    2003  Jinogondolella nankingensis nankingensis (Ching), Henderson and Mei, pl. 2, figs. 1, 5, 12

    2007  Jinogondolella nankingensis (Ching), Lambert et al., figs. 4a–4c, 6h, 7j, 7t–7u

    2008  Jinogondolella nankingensis (Ching), Sun et al., pl. 1, figs. 2–5

    2014  Jinogondolella nankingensis (Ching), Nishikane et al., pl. I, figs. 2, 5

    2017  Mesogondolella nankingensis (Ching), Cheng et al., pl. III, figs. 12–28

    2017  Jinogondolella nankingensis (Ching), Sun et al., pl. 5, figs. 2, 9

    Description: The P1 element is characterized by typical bamboo leaf-shaped or tongue-shaped, slightly arched platform, well-developed and deep serrations on the anterior half or whole of the platform and moderate sized cusp. In the early stage, there are only ~8 denticles on the short platform and well-developed, deep serrations occur over half of the platform (Pl. 1, Figs. 5, 6). In the adult stage, the denticles on the long, thick platform can be as many as 19, serrations occupy the anterior half of the platform, and the posterior changes from narrow-rounded to broadly rounded (Pl. 1, Figs. 13, 14).

    Remarks: Jinogondolella nankingensis is the senior synonym of J. serrata, which is widely recognized (Lambert et al., 2007). Lambert et al. (2007) considered the characteristic serrations on the platform margins of the original specimen illustration (a camera lucida-based drawing, Ching, 1960) were over-emphasized. Wang (1995) re-examined the species (with a rounded posterior) from the base of the Kufeng Formation and selected a neotype. We attribute the serrations distribution change (from whole or over half of the anterior platform to the half of the anterior platform) and the posterior shape change (from narrow-rounded to rounded) to ontogenetic changes from the early to the adult stage. The well-developed and deep serrations, typical bamboo leaf-shaped or tongue- shaped and moderate cusp of the typical adult features distinguish J. nankingensis nankingensis from other Jinogondolella species.

    Occurrence: From Unit Ⅰ (Sample SXK-2), Unit Ⅱ (Sample SXK-5) of Wulipo Formation and Unit Ⅲ (samples SXK-9, 10, 13, 15, 16, 17) of Shuixiakou Formation, and range from Roadian to Early Wordian strata in the Shuixiakou Section, southeastern Qinling region (Table 2).

    Jinogondolella nankingensis tenuis Wardlaw, 2015

    Pl. 2, Fig. 9; Pl. 3, Figs. 1–7

    2015  Jinogondolella nankingensis tenuis n. subsp. Wardlaw, pl. 1, figs. 1–3, 6, 9, 10; pl. 2, figs. 2–9, 11, 13, 14; pl. 5, figs. 12

    2015  Jinogondolella nankingensis tenuis Wardlaw, Wardlaw and Nestell, pl. 15, figs. 10a, 10b

    Description: A subspecies of Jinogondolella nankingensis characterized by a large cusp which is 3 times the size of the posterior denticles, 3–4 tall and strong anterior denticles, low, discrete or partly fused middle denticles, well-developed to weak serrations on the anterior platform and deep furrows on the slender and arched platform. In the juvenile stage, the large cusp is fused from the last two denticles (Pl. 3, Figs. 1b–2), and ~10 low and separated denticles in front of the large cusp developed on the slender platform where serrations occupy more than half of the platform (Pl. 3, Fig. 1). In the adult stage, serrations occupy the anterior half of the platform, and the anterior denticles, with fused lower part, gradually become tall and strong (except at the front end, Pl. 3, Figs. 2–4). In mature specimens, the tall and strong anterior denticles are more fused, with the middle denticles fused into a low ridge, serrations occupying the anterior third of the platform and the platform is more thickly developed (Pl. 2, Fig. 8; Pl. 3, Figs. 5–7).

    Remarks: This subspecies was reported in West Texas (Wardlaw, 2015; Wardlaw and Nestell, 2015). Three to four tall and strong anterior denticles, the large cusp and the low ridges fused with the middle denticles distinguish J. nankingensis tenuis from J. nankingensis nankingensis. Though the platform of J. nankingensis tenuis widen and thicken from the young to the adult stage, it is always narrower than J. nankingensis nankingensis species at the similar stage.

    Occurrence: From Shuixiakou Formation (samples SXK-37, 38 in Unit Ⅵ), and range from the Wordian strata in the Shuixiakou Section (Table 1).

    Jinogondolella aserrata (Clark and Behnken, 1979)

    Pl. 2, Figs. 1–8

    1979  Neogondolella aserrata Clark and Behnken, pl. 1, figs. 1–11

    1994  Mesogondolella aserrata (Clark and Behnken), Mei et al., pl. 1, figs. 4–7, 11, 13

    1998  Mesogondolella aserrata (Clark and Behnken), Mei et al., pl. 2, fig. 9

    2000  Mesogondolella aserrata (Clark and Behnken), Wardlaw, pl. 3-3, figs. 1–16; pl. 3-5, figs. 1–7; pl. 3-10, figs. 11–17

    2004  Mesogondolella aserrata (Clark and Behnken), Wang et al., figs. 3, 6–22

    2004  Mesogondolella cf. aserrata (Clark and Behnken), Sano and Orchard, 2004, figs. 6.9, 6.10

    2008  Jinogondolella aserrata (Clark and Behnken), Sun et al., pl. 1, figs. 1, 19

    2010  Jinogondolella aserrata (Clark and Behnken), Kozur and Wardlaw, pl. 1, figs. 1–11, 13

    2010  Jinogondolella aserrata (Clark and Behnken), Wardlaw and Nestell, pl. 1, figs. 10–18; pl. 2, figs. la–1b, 3a–3b, 12, 13a–13b, 15a–15b; pl. 3, figs. la–1b, 3a–3b, 12, 13a–13b, 15a–15b; pl. 4, figs. 5, 7–8, 10–12, 14–16, 19, 23–24, 27; pl. 5, figs. 4–6, 8–9, 24–26, 29; pl. 6, figs. 1–3, 8, 16, 18–22, 26–28

    2016  Jinogondolella aserrata (Clark and Behnken), Wang et al., pl. 4, figs. 3, 4; pl. 7, figs. 2–13

    2016  Jinogondolella aserrata (Clark and Behnken), Ma et al., figs. 3.6–3.9

    2017  Jinogondolella aserrata (Clark and Behnken), Sun et al., pl. 5, fig. 12

    Description: Jinogondolella aserrata is characterized by a typical drop-shaped or wedge-shaped, symmetrical or asymmetrical platform that is widest in the middle-posterior. There are weak or no serrations on the anterior platform. The cusp is small to moderate in size. In the earliest stage, there are only ~8 denticles on the small, drop-shaped or wedge-shaped platform (Pl. 2, Figs. 1, 2). In the adult stage, the denticles on the thick platform can be as many as 19, and the denticles become fused in the posterior portion with an increase in size anteriorly (Pl. 2, Figs. 6–8).

    Remarks: The narrow platform with marked anterior narrowing and somewhat subparallel posterior platform in Jinogondolella postserrata (Wardlaw, 2000; Behnken, 1975) is different from the drop-shaped or wedge-shaped platform in J. aserrata (Clark and Behnken, 1979). The distinctive, drop- shaped or wedge-shaped platform and weak or no serrations on the anterior platform also distinguish J. aserrata (Clark and Behnken, 1979) from other Middle Permian gondolellid conodont species.

    Occurrence: From the Shuixiakou Formation including Unit Ⅲ (samples SXK-6, 10, 14, 15, 16), Unit Ⅳ (samples SXK-18, 21, 24, 26, 27, 28, 29), Unit Ⅴ (samples SXK-31, 34) and Unit Ⅵ (Sample SXK-37), and range from the Wordian strata of the Shuixiakou Section (Table 2).

    Jinogondolella bitteri (Kozur, 1975)

    Pl. 3, Figs. 8–12

    1975  Gondolella bitteri Kozur, p. 19–20

    1979  Neogondolella bitteri (Kozur), Wardlaw and Collinson, pl. 1, figs. 8–33

    1981  Neogondolella bitteri (Kozur), Henderson, pl. 7, figs. 1–8

    1984  Neogondolella bitteri (Kozur), Wardlaw and Collinson, pl. 3, figs. 15–17

    1986  Neogondolella bitteri (Kozur), Wardlaw and Collinson, fig. 17-5

    1986  Neogondolella wilcoxi Clark and Behnken, Wardlaw and Collinson, fig. 17-6

    1998  Pseudoclarkina bitteri (Kozur), Wardlaw and Mei, pl. 1, figs. 1–27; pl. 3, figs. 9, 11, 13–19, 26

    2010  Mesogondolella bitteri (Kozur), Kozur and Wardlaw, pl. 3, figs. 11, 20

    Description: P1 elements are characterized by a blunt posterior platform and brim, with abrupt narrowing in the anterior third or quarter of its length, weak serrations on the anterior platform, a low cusp of circular cross section and low denticles on the carina. Denticles are laterally compressed, becoming high and larger anteriorly, and discrete to partially fused in the middle.

    Remarks: As a Middle Permian gondolellid conodont with weak serrations, Mesogondolella bitteri is tentatively assigned to Jinogondolella, in this study. Kozur and Wardlaw (2010) stated that gondolellid species with faint serrations may be separated from Mesogondolella bitteri and named M. siciliensis. The abrupt narrowing in the anterior third or quarter of its length in Jinogondolella bitteri distinguishes it from Mesogondolella siciliensis. Jinogondolella bitteri is distinguished from other Middle Permian gondolellid species by weak serrations, a blunt posterior platform and the abrupt narrowing in the anterior third or quarter of its length. It ranges from the late Wordian to Capitanian stages (Henderson, 2018).

    Occurrence: From the Shuixiakou Formation (Sample SXK-31 in Unit Ⅴ), and range from the Wordian strata of the Shuixiakou Section (Table 2)

    Family: Sweetognathidae Ritter, 1986

    Genus: Pseudohindeodus Gullo and Kozur, 1992

    Type species: Pseudohindeodus ramovsi Gullo and Kozur, 1992

    Pseudohindeodus ramovsi Gullo and Kozur, 1992

    Pl. 4, Figs. 8, 10, 11

    1992  Pseudohindeodus ramovsi Gullo and Kozur, figs. 4A–4H

    1995  Pseudohindeodus ramovsi Gullo and Kozur, Kozur and Mostler, pl. 1, figs. 3, 10, 11; pl. 2, fig. 6

    2000  Pseudohindeodus ramovsi Gullo and Kozur, Wardlaw, pl. 3-1, figs. 5–24

    2002  Pseudohindeodus ramovsi Gullo and Kozur, Mei and Henderson, pl. 7, fig. 7

    2003  Pseudohindeodus ramovsi Gullo and Kozur, Henderson and Mei, pl. III, fig. 10

    2008  Pseudohindeodus ramovsi Gullo and Kozur, Sun et al., pl. 1, fig. 23

    2008  Pseudohindeodus ramovsi Gullo and Kozur, Lai et al., pl. 1, fig. 23

    2010  Pseudohindeodus ramovsi Gullo and Kozur, Sun et al., pl. 2, figs. 5, 6

    2010  Pseudohindeodus ramovsi Gullo and Kozur, Lambert et al., pl. 1, figs. 9, 10

    2014  Pseudohindeodus ramovsi Gullo and Kozur, Nishikane et al., pl. III, figs. 1, 3, 5

    2015  Pseudohindeodus ramovsi Gullo and Kozur, Wardlaw and Nestell, pl. 15, figs. 5–9

    2016  Pseudohindeodus ramovsi Gullo and Kozur, Wang et al., pl. 9, fig. 9

    2017  Pseudohindeodus ramovsi Gullo and Kozur, Sun et al., pl. 4, fig. 14

    Description: The cusp of P1 element is high and narrow. The compressed denticles increase in width and decrease in height posteriorly until a slight hump. The followed, uncompressed denticles decrease in width and height posteriorly. The expanded basal cavity is near triangular and decorated with a surface apron.

    Remarks: Generally, Pseudohindeodus elements have small, round outside and large basal cavity. Pseudohindeodus ramovsi is widely distributed in the Middle Permian strata.

    Occurrence: From the Wulipo Formation (Sample SXK-5 in Unit Ⅱ), Shuixiakou Formation (samples SXK-10 to SXK-12 in Unit Ⅲ, Sample SXK-28 in Unit Ⅳ, samples SXK-37, 38 in Unit Ⅵ), and range from the Roadian to Wordian strata of the Shuixiakou Section (Table 2).

    Genus: Pustulognathus Golding and Orchard, 2018

    Type species: Pustulognathus monticola Golding and Orchard, 2018

    Pustulognathus vigilans Golding, 2018

    Pl. 4, Fig. 12

    2002  Iranognathus? sp. nov. A, Mei et al., figs. 13.14–13.16

    2016  Diplognathodus movschovitschi Kozur and Pjatakova, Wang et al., pl. 6, figs. 6, 7

    2018  Pustulognathus vigilans Golding and Orchard, text-figs. 2.1–2.11

    Description: The P1 elements are characterized by a single line of completely fused denticles on the top of the carina and an unornamented, elongate, sub-elliptical basal cavity. The anterior blade composed by two to four unfused denticles increasing in size towards the anterior is separated from the single line of completely fused denticles by a small notch. After the single line of completely fused denticles, there are two or three weakly fused denticles decreasing in size.

    Remarks: Golding (2018) described the apparatus of Pustulognathus genus and the diagnosis of Pustulognathus vigilans. The basal cavity of Pustulognathus is larger than Iranognathus and Sweetognathus.

    Occurrence: From the Shuixiakou Formation (Sample SXK-28 in Unit Ⅳ), and range from the Wordian strata of the Shuixiakou Section (Table 2).

    Genus: Sweetognathus Clark, 1972

    Type species: Sweetognathus whitei (Rhodes, 1963)

    Sweetognathus hanzhongensis (Wang, 1978)

    Pl. 4, Figs. 3–5

    1978  Gnathodus hanzhongensis Wang, pl. I, figs. 33–35, 40–41

    1991  Sweetognathus hanzhongensis (Wang), Wang and Dong, pl. III, figs. 6–8

    2002  Sweetognathus iranicus hanzhongensis (Wang), Mei et al., figs. 10.6–10.12

    2016  Sweetognathus iranicus hanzhongensis (Wang), Ma et al., figs. 10.12, 10.13

    2017  Sweetognathus hanzhongensis (Wang), Sun et al., pl. 3, figs. 15–18; pl. 7, figs. 9, 10

    Description: The anterior 1/3 of P1 elements developed a near-rectangular blade (lateral view), and the posterior 2/3 developed a relatively elongated, two way pointed ovate basal cup (aboral view). The widest of P1 element was in the middle or slightly in front. The lower edge of the unornamented, thin basal cavity is often broken. There are four to six fused denticles on the blade. The denticles on the moderately high carina in the middle of P1 elements are almost completely fused.

    Remarks: Wang (1978) illustrated many specimens of the P1 element. Then, this species was described by Mei et al. (2002) and Sun et al. (2017).

    Occurrence: From the Wulipo Formation (Sample SXK-2 in Unit I, Sample SXK-5 in Unit Ⅱ), Shuixiakou Formation (Sample SXK-16 in Unit Ⅲ, Sample SXK-28 in Unit Ⅳ), and range from the Roadian to Wordian strata of the Shuixiakou Section (Table 2).

  • A detailed conodont biostratigraphic and taxonomic study of the Middle Permian strata including the Wulipo and Shuixiakou formations at Shuixiakou Section has been concluded. More than 2 000 conodont elements including 6 genera and 14 species have been obtained. The samples from southeastern Qinling region have enabled recognition of two main conodont zones including Jinogondolella nankingensis and Jinogondolella aserrata zones.

    The relative sea-level changes in the studied interval reveal substantial fluctuations with a major, but short-lived fall characterized by a 40 m-thick bioclastic limestone of Unit Ⅳ in the Shuixiakou Formation in the J. aserrata Zone. It maybe the phenomenon of Wordian regression in southeastern Qinling region. The seawater temperature decreased from 29.4 to 26.5 ℃ in the Jinogondolella aserrata Zone of Shuixiakou Section maybe related to a Wordian regression and the P3 glacial event.

    Figure Plate 1.  SEM images of Shuixiakou conodonts—genera Mesogondolella and Jinogondolella. 'a' oral view; 'b' lateral view; and 'c' aboral view. 1–4. Mesogondolella cf. lamberti (Mei and Wardlaw, 1994); 1. SXK-1-2; 2. SXK-2-4; 3. SXK-1-4; 4. SXK-1-5. 5–14. Jinogondolella nankingensis nankingensis (Ching, 1960); 5. SXK-2-4; 6. SXK-5-2; 7. SXK-5-14; 8. SXK-5-10; 9. SXK-5-9; 10. SXK-13-5; 11. SXK-13-2; 12. SXK-15-1; 13. SXK-10-4; 14. SXK-16-1.

    Figure Plate 2.  SEM images of Shuixiakou conodonts—genus Jinogondolella. 1–8. Jinogondolella aserrata (Clark and Behnken, 1979), 1. SXK-28-7-17; 2. SXK-28-7-35; 3. SXK-28-7-45; 4. SXK-27-7; 5. SXK-28-7-39; 6. SXK-6-1; 7. SXK-28-7-7; 8. SXK-28-2-10. 9. Jinogodolella nankingensis tenuis Wardlaw, 2015, SXK-38-1.

    Figure Plate 3.  SEM images of Shuixiakou conodonts—genus Jinogondolella. 1–7. Jinogodolella nankingensis tenuis Wardlaw, 2015; 1. SXK-37-15; 2. SXK-37-6; 3. SXK-37-19; 4. SXK-37-10; 5. SXK-37-13; 6. SXK-37-17; 7. SXK-37-1. 8–12. Jinogondolella bitteri (Kozur, 1975); 8. SXK-31-8; 9. SXK-31-16; 10. SXK-31-15; 11. SXK-31-9; 12. SXK-31-8.

    Figure Plate 4.  SEM images of Shuixiakou conodonts—genera Sweetognathus, Hindeodus, Pseudohindeodus and Pustulognathus. 1. Sweetognathus cf. hanzhongensis (Wang, 1978), SXK-6-1; 2. Sweetognathus cf. subsymmetricus (Wang et al., 1987), SXK-6-5. 3–5. Sweetognathus hanzhongensis (Wang, 1978); 3. SXK-16-2-10; 4. SXK-2-2-10; 5. SXK-28-2-7. 6, 7, 9. Pseudohindeodus cf. elliptica Sun, 2017; 6. SXK12-2-6; 7. SXK-34-2-1; 9. SXK-12-2-11. 8, 10, 11. Pseudohindeodus ramovsi Gullo and Kozur, 1992; 8. SXK-31-4; 10. SXK-28-7-345; 11. SXK-28-7-342. 12. Pustulognathus vigilans Golding and Orchard, 2018, SXK-28-2-1; 13, 16. Hindeodus excavatus (Behnken, 1975); 13. SXK-13-2-9; 16. SXK-38-2-2. 14, 15, 17, 18. Hindeodus minutus (Ellison, 1941); 14. SXK-12-2-12; 15. SXK-11-2-1; 17. SXK-5-23; 18. SXK-27-9.

    Figure Plate 5.  1–2. Hindeodus wordensis Wardlaw, 2000; 1. SXK-5-2-10; 2. SXK-12-2-9. 3. Hindeodus gulloides Kozur and Mostler, 1995, SXK-2-2-1.

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