Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-26T08:41:17.724Z Has data issue: false hasContentIssue false
  • English
  • Français

The geochemistry of the late Cambrian carbonate in North China: the Steptoean Positive Carbon Isotope Excursion (SPICE) record suppressed in a coastal condition?

Published online by Cambridge University Press:  08 March 2019

Jing Huang Open the ORCID record for Jing Huang [Opens in a new window] ,
Yali Chen ,
Xuelei Chu  and
Tao Sun
Jing Huang*
Affiliation:
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China CAS Center for Excellence in Comparative Planetology, China
Yali Chen
Affiliation:
Agro-Environmental Protection Institute/Key Laboratory for Environmental Factors Control of Agro-product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
Xuelei Chu
Affiliation:
Institute of Geology and Geophysics, Key Laboratory for Mineral Resources, Chinese Academy of Sciences, Beijing 100029, China University of Chinese Academy of Sciences, Beijing 100049, China
Tao Sun
Affiliation:
Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX 77005, USA
*
Email: hjmail@ustc.edu.cn
Get access Rights & Permissions [Opens in a new window]

Abstract

The Steptoean Positive Carbon Isotope Excursion (SPICE) is globally distributed in late Cambrian sedimentary records but controversially heterogeneous in its magnitudes. Here we use multiple geochemical proxies to investigate the late Cambrian carbonates from the Tangwangzhai section in North China, which were deposited in a shallow coastal environment with three depositional sequences (S1–S3). Each sequence comprises a transgressive systems tract (TST) and a highstand systems tract (HST). The REE + Y and trace element records are consistent with the depositional condition and indicate that terrigenous influence was more significant in the TST than HST. δ13Ccarb and δ34SCAS are low in the TST relative to HST, consistent with the scenario that terrigenous inputs were profoundly aggressive to seawater by introducing 13C-depleted and 34S-depleted materials. Within the TST of S2, the SPICE excursion shows a scaled-down δ13Ccarb positive shift (∼1.7 ‰) relative to its general records (∼4–6 ‰); the corresponding δ34SCAS show no positive excursion. This ‘atypical’ SPICE record is attributed to enhanced 13C-depleted and 34S-depleted terrigenous influence during the TST, which would reduce the amplitude of δ13Ccarb excursion, and even obscure δ34SCAS excursion. Meanwhile the subaerial unconformity at the base of TST would also cause a partially missing and a ‘snapshot’ preservation. Our study confirms significant local influence to the SPICE records, and further supports the heterogeneity and low sulphate concentrations of the late Cambrian seawater, because of which the SPICE records may be vulnerable to specific depositional conditions (e.g. sea-level, terrigenous input).

Keywords

carbon isotopesulphur isotopeterrigenous inputtrace element
Type
Original Article
Information
Geological Magazine , Volume 156 , Issue 10 , October 2019 , pp. 1805 - 1819
Copyright
© Cambridge University Press 2019 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ahlberg, PER, Axheimer, N, Babcock, LE, Eriksson, ME, Schmitz, B and Terfelt, F (2009) Cambrian high-resolution biostratigraphy and carbon isotope chemostratigraphy in Scania, Sweden: first record of the SPICE and DICE excursions in Scandinavia. Lethaia 42, 2–16.CrossRefGoogle Scholar
Álvaro, JJ, Ferretti, A, González-Gómez, C, Serpagli, E, Tortello, MF, Vecoli, M and Vizcaïno, D (2007) A review of the Late Cambrian (Furongian) palaeogeography in the western Mediterranean region, NW Gondwana. Earth-Science Reviews 85, 47–81.CrossRefGoogle Scholar
Arnold, GL, Brunner, B, Müller, IA and Røy, H (2014) Modern applications for a total sulfur reduction distillation method – what’s old is new again. Geochemical Transactions 15, 4. doi: 10.1186/1467-4866-15-4.CrossRefGoogle Scholar
Arthur, MA (2000) Volcanic contributions of the carbon and sulfur geochemical cycles and global change. In Encyclopedia of Volcanoes (eds Sigurdsson, H, Houghton, B, McNutt, S, Rymer, H and Stix, J), pp. 1045–56. Amsterdam: Academic Press.Google Scholar
Bagnoli, G, Qi, YP, Zuo, JX, Du, SX, Liu, SC and Zhang, ZQ (2014) Integrated biostratigraphy and carbon isotopes from the Cambrian Tangwangzhai section, North China. Palaeoworld 23, 112–24.CrossRefGoogle Scholar
Bayon, G, Toucanne, S, Skonieczny, C, André, L, Bermell, S, Cheron, S, Dennielou, B, Etoubleau, J, Freslon, N, Gauchery, T and Germain, Y (2015) Rare earth elements and neodymium isotopes in world river sediments revisited. Geochimica et Cosmochimica Acta 170, 17–38.CrossRefGoogle Scholar
Berner, RA (2006) GEOCARBSULF: a combined model for Phanerozoic atmospheric O2 and CO2. Geochimica et Cosmochimica Acta 70, 5653–64.CrossRefGoogle Scholar
Canfield, DE (2004) The evolution of the Earth surface sulfur reservoir. American Journal of Science 304, 839–61.CrossRefGoogle Scholar
Censi, P, Sprovieri, M, Saiano, F, Di Geronimo, SI, Larocca, D and Placenti, F (2007) The behaviour of REEs in Thailand’s Mae Klong estuary: suggestions from the Y/Ho ratios and lanthanide tetrad effects. Estuarine, Coastal and Shelf Science 71, 569–79.CrossRefGoogle Scholar
Chen, J, Chough, SK, Han, Z, and Lee, J-H (2011) An extensive erosion surface of a strongly deformed limestone bed in the Gushan and Chaomidian formations (late Middle Cambrian to Furongian), Shandong Province, China: sequence-stratigraphic implications. Sedimentary Geology 233, 129–49.CrossRefGoogle Scholar
Chen, J, Chough, SK, Lee, J-H and Han, Z (2012) Sequence-stratigraphic comparison of the upper Cambrian Series 3 to Furongian succession between the Shandong region, China and the Taebaek area, Korea: high variability of bounding surfaces in an epeiric platform. Geosciences Journal 16, 357–79.CrossRefGoogle Scholar
Chough, SK, Lee, HS, Woo, J, Chen, J, Choi, DK, Lee, SB, Kang, I, Park, TY and Han, Z (2010) Cambrian stratigraphy of the North China Platform: revisiting principal sections in Shandong Province, China. Geosciences Journal 14, 235–68.CrossRefGoogle Scholar
Cowan, CA, Fox, DL, Runkel, AC and Saltzman, MR (2005) Terrestrial-marine carbon cycle coupling in ∼500-m.y.-old phosphatic brachiopods. Geology 33, 661–4.CrossRefGoogle Scholar
Dahl, TW, Boyle, RA, Canfield, DE, Connelly, JN, Gill, BC, Lenton, TM and Bizzarro, M (2014) Uranium isotopes distinguish two geochemically distinct stages during the later Cambrian SPICE event. Earth and Planetary Science Letters 401, 313–26.CrossRefGoogle ScholarPubMed
de Campos, FF and Enzweiler, J (2016) Anthropogenic gadolinium anomalies and rare earth elements in the water of Atibaia River and Anhumas Creek, Southeast Brazil. Environmental Monitoring and Assessment 188, 1–18.CrossRefGoogle ScholarPubMed
Derry, LA, Kaufman, AJ and Jacobsen, SB (1992) Sedimentary cycling and environmental change in the Late Proterozoic: evidence from stable and radiogenic isotopes. Geochimica et Cosmochimica Acta 56, 1317–29.CrossRefGoogle Scholar
Elderfield, H, Upstill-Goddard, R and Sholkovitz, ER (1990) The rare earth elements in rivers, estuaries, and coastal seas and their significance to the composition of ocean waters. Geochimica et Cosmochimica Acta 54, 971–91.CrossRefGoogle Scholar
Elrick, M, Rieboldt, S, Saltzman, M and McKay, RM (2011) Oxygen-isotope trends and seawater temperature changes across the Late Cambrian Steptoean positive carbon-isotope excursion (SPICE event). Geology 39, 987–90.CrossRefGoogle Scholar
Fichtner, V, Strauss, H, Immenhauser, H, Buhl, D, Neuser, RD and Niedermayr, A (2017) Diagenesis of carbonate associated sulfate. Chemical Geology 258, 338–53.Google Scholar
Fike, DA and Grotzinger, JP (2008) Paired sulfate–pyrite δ34S approach to understanding the evolution of the Ediacaran–Cambrian sulfur cycle. Geochimica et Cosmochimica Acta 72, 2636–48CrossRefGoogle Scholar
Frimmel, HE (2009) Trace element distribution in Neoproterozoic carbonates as palaeoenvironmental indicator. Chemical Geology 463, 61–75.Google Scholar
Garrels, RM and Lerman, A (1981) Phanerozoic cycles of sedimentary carbon and sulfur. Proceedings of the National Academy of Sciences 78, 4652–6.CrossRefGoogle ScholarPubMed
Gill, BC, Lyons, TW and Frank, TD (2008) Behavior of carbonate-associated sulfate during meteoric diagenesis and implications for the sulfur isotope paleoproxy. Geochimica et Cosmochimica Acta 72, 4699–711.CrossRefGoogle Scholar
Gill, BC, Lyons, TW and Saltzman, MR (2007) Parallel, high-resolution carbon and sulfur isotope records of the evolving Paleozoic marine sulfur reservoir. Palaeogeography, Palaeoclimatology, Palaeoecology 256, 156–73.CrossRefGoogle Scholar
Gill, BC, Lyons, TW, Young, SA, Kump, LR, Knoll, AH and Saltzman, MR (2011) Geochemical evidence for widespread euxinia in the Later Cambrian ocean. Nature 469, 80–3.CrossRefGoogle ScholarPubMed
Glumac, B (2011) High-resolution stratigraphy and correlation of Cambrian strata using carbon isotopes: an example from the southern Appalachians, USA. Carbonates Evaporites 26, 287–97.CrossRefGoogle Scholar
Glumac, B and Mutti, LE (2007) Late Cambrian (Steptoean) sedimentation and responses to sea-level change along the northeastern Laurentian margin: insights from carbon isotope stratigraphy. Geological Society of America Bulletin 119, 623–36.CrossRefGoogle Scholar
Glumac, B and Spivak-Birndorf, ML (2002) Stable isotopes of carbon as an invaluable stratigraphic tool: an example from the Cambrian of the northern Appalachians USA. Geology 30, 563–6.Google Scholar
Guo, Q, Straus, H, Zhao, Y, Yang, X, Peng, J, Yang, Y and Deng, Y (2014) Reconstructing marine redox conditions for the transition between Cambrian Series 2 and Cambrian Series 3, Kaili area, Yangtze Platform: evidence from biogenic sulfur and degree of pyritization. Palaeogeography, Palaeoclimatology, Palaeoecology 398, 114–53.CrossRefGoogle Scholar
Haley, BA, Klinkhammer, GP and McManus, J (2004) Rare earth elements in pore waters of marine sediments. Geochimica et Cosmochimica Acta 68, 1265–79.CrossRefGoogle Scholar
Hayes, JM, Strauss, H and Kaufman, AJ (1999) The abundance of 13C in marine organic matter and isotopic fractionation in the global biogeochemical cycle of carbon during the past 800 Ma. Chemical Geology 161, 103–25.CrossRefGoogle Scholar
Hild, E and Brumsack, HJ (1998) Major and minor element geochemistry of Lower Aptian sediments from the NW German Basin (core Hohenegglesen KB 40). Cretaceous Research 19, 615–33.CrossRefGoogle Scholar
Hough, ML, Shields, GA, Evins, LZ, Strauss, H, Henderson, RA and Mackenzie, S (2006) A major sulphur isotope event at c. 510 Ma: a possible anoxiaextinction-volcanism connection during the Early–Middle Cambrian transition? Terra Nova 18, 257–63.CrossRefGoogle Scholar
Hurtgen, MT, Pruss, SB and Knoll, AH (2009) Evaluating the relationship between the carbon and sulfur cycles in the later Cambrian ocean: an example from the Port au Port Group, western Newfoundland, Canada. Earth and Planetary Science Letters 281, 288–97.CrossRefGoogle Scholar
Kampschulte, A and Strauss, H (2004) The sulfur isotopic evolution of Phanerozoic seawater based on the analysis of structurally substituted sulfate in carbonates. Chemical Geology 204, 255–86.CrossRefGoogle Scholar
Kaufman, AJ and Knoll, AH (1995) Neoproterozoic variations in the C-isotopic composition of seawater — stratigraphic and biogeochemical implications. Precambrian Research 73, 27–49.CrossRefGoogle ScholarPubMed
Kump, LR and Arthur, MA (1999) Interpreting carbon-isotope excursions: carbonates and organic matter. Chemical Geology 161, 181–98.CrossRefGoogle Scholar
Lawrence, M and Kamber, B (2006) The behaviour of the rare earth elements during estuarine mixing – revisited. Marine Chemistry 100, 147–61.CrossRefGoogle Scholar
Lee, J-H, Chen, J, Choh, S-J, Lee, D-J, Han, Z and Chough, SK (2014) Furongian (Late Cambrian) sponge–microbial maze-like reefs in the North China Platform. Palaios 29, 27–37.CrossRefGoogle Scholar
Lee, J-H, Chen, J and Chough, SK (2010) Paleoenvironmental implications of an extensive maceriate microbialite bed in the Furongian Chaomidian Formation, Shandong Province, China. Palaeogeography, Palaeoclimatology, Palaeoecology 297, 621–32.CrossRefGoogle Scholar
Lee, J-H, Chen, J and Chough, SK (2012) Demise of an extensive biostromal microbialite in the Furongian (late Cambrian) Chaomidian Formation, Shandong Province, China. Geosciences Journal 16, 275–84.CrossRefGoogle Scholar
Li, D, Zhang, X, Hu, D, Chen, X, Huang, W, Zhang, X, Li, M, Qin, L, Peng, S and Shen, Y (2018) Evidence of a large δ13Ccarb and δ13Corg depth gradient for deep-water anoxia during the late Cambrian SPICE event. Geology 46, 631–4.CrossRefGoogle Scholar
Loyd, SJ, Marenco, PJ, Hagadorn, JW, Lyons, TW, Kaufman, AJ, Sour-Tovar, F and Corsetti, FA (2012) Sustained low marine sulfate concentrations from the Neoproterozoic to the Cambrian: insights from carbonates of northwestern Mexico and eastern California. Earth and Planetary Science Letters 339–340, 79–94.CrossRefGoogle Scholar
Lyons, TW, Walter, LM, Gellatly, AM, Martini, AM and Blake, RE (2004) Sites of anomalous organic remineralization in the carbonate sediments of South Florida, USA: the sulfur cycle and carbonate-associated sulfate.In Sulfur Biogeochemistry: Past and Present (eds Amend, JP, Edwards, KJ & Lyons, KJ), pp. 161–76. Geological Society of America, Special Paper no. 379.Google Scholar
Maloof, AC, Porter, SM, Moore, JL, Dudás, FÖ, Bowring, SA, Higgins, JA, Fike, DA and Eddy, MP (2010) The earliest Cambrian record of animals and ocean geochemical change. Geological Society of America Bulletin 122, 1731–74.CrossRefGoogle Scholar
Marenco, PJ, Corsetti, FA, Hammond, DE, Kaufman, AJ and Bottjer, DJ (2008) Oxidation of pyrite during extraction of carbonate associated sulfate. Chemical Geology 247, 124–132.CrossRefGoogle Scholar
Ng, T-W, Botting, JP, Yuan, J-L and Lin, J-P (2015) New discoveries of Cambrian pelmatozoan echinoderm ossicles from North China. Palaeoworld 24, 438–44.CrossRefGoogle Scholar
Ng, T-W, Yuan, J-L and Lin, J-P (2014 a) The North China Steptoean positive carbon isotope event: new insights towards understanding a global phenomenon. Geobios 47, 371–87.CrossRefGoogle Scholar
Ng, T-W, Yuan, J-L and Lin, J-P (2014 b) The North China Steptoean positive carbon isotope excursion and its global correlation with the base of the Paibian Stage (early Furongian Series), Cambrian. Lethaia 47, 153–64.CrossRefGoogle Scholar
Nothdurft, LD, Webb, GE and Kamber, BS (2004) Rare earth element geochemistry of Late Devonian reefal carbonates, Canning Basin, Western Australia: confirmation of a seawater REE proxy in ancient limestones. Geochimica et Cosmochimica Acta 68, 263–83.CrossRefGoogle Scholar
Pasquier, V, Sansjofre, P, Rabineau, M, Revillon, S, Houghton, J and Fike, DA (2017) Pyrite sulfur isotopes reveal glacial-interglacial environmental changes. Proceedings of the National Academy of Sciences 114, 5941–5.CrossRefGoogle ScholarPubMed
Peng, S (1987) Early Late Cambrian stratigraphy and trilobite fauna of Taoyuan and Cili, Hunan. In Collection of Postgraduate Theses of the Nanjing Institute of Geology and Palaeontology, Academic Sinica, No.1. Jiangsu Science and Technology Publishing House, Nanjing, 53–134 (in Chinese with English summary).Google Scholar
Peng, S (2007) Historical review of trilobite research in China. In Fabulous Fossils – 300 Years of Worldwide Research on Trilobites (eds Mikulic, DG, Landing, E and Kluessendorf, J), pp. 171–92. Albany, New York: New York State Museum Bulletin.Google Scholar
Peng, S (2009 a) Review on the studies of Cambrian trilobite faunas from Jiangnan slope belt, south China, with notes on Cambrian correlation between south and north China. Acta Palaeontologica Sinica 48, 437–42.Google Scholar
Peng, S (2009 b) The newly-developed Cambrian biostratigraphic succession and chronostratigraphic scheme for South China. Chinese Science Bulletin 54, 4161–70.CrossRefGoogle Scholar
Peng, S, Babcock, LE, Robison, RA, Lin, H, Rees, MN and Saltzman, MR (2004) Global standard stratotype-section and point (GSSP) of the Furongian Series and Paibian Stage (Cambrian). Lethaia 37, 365–79.CrossRefGoogle Scholar
Peng, S, Babcock, LE, Zuo, J, Zhu, X, Lin, H, Yang, X, Qi, Y, Bagnoli, G and Wang, L (2012) Global Standard Stratotype-Section and Point (GSSP) for the Base of the Jiangshanian Stage (Cambrian: Furongian) at Duibian, Jiangshan, Zhejiang, Southeast China. Episodes 35, 462–77.CrossRefGoogle Scholar
Peng, Y, Bao, H, Pratt, LM, Kaufman, AJ, Jiang, G, Boyd, D, Wang, Q, Zhou, C, Yuan, X, Xiao, S and Loyd, S (2014) Widespread contamination of carbonate-associated sulfate by present-day secondary atmospheric sulfate: evidence from triple oxygen isotopes. Geology 42, 815–18.CrossRefGoogle Scholar
Prego, R, Caetano, M, Bernárdez, P, Brito, P, Ospina-Alvarez, N and Vale, C (2012) Rare earth elements in coastal sediments of the northern Galician shelf: influence of geological features. Continental Shelf Research 35, 75–85.CrossRefGoogle Scholar
Qi, YP, Bagnoli, G and Wang, ZH (2006) Cambrian conodonts across the pre-Furongian to Furongian interval in the GSSP section at Paibi, Hunan, South China. Rivista Italiana di Paleontologia e Stratigrafia 112, 177–90.Google Scholar
Rennie, VCF and Turchyn, AV (2014) The preservation of δ34SSO4 and δ18OSO4 in carbonate-associated sulfate during marine diagenesis: a 25 Myr test case using marine sediments. Earth and Planetary Science Letters 395, 13–23.CrossRefGoogle Scholar
Saltzman, MR, Cowan, CA, Runkel, AC, Runnegar, B, Stewart, MC and Palmer, AR (2004) The Late Cambrian Spice (δ13C) event and the Sauk II-SAUK III regression: new evidence from Laurentian Basins in Utah, Iowa, and Newfoundland. Journal of Sedimentary Research 74, 366–77.CrossRefGoogle Scholar
Saltzman, MR, Ripperdan, RL, Brasier, MD, Lohmann, KC, Robison, RA, Chang, WT, Peng, S, Ergaliev, EK and Runnegar, B (2000) A global carbon isotope excursion (SPICE) during the Late Cambrian: relation to trilobite extinctions, organic-matter burial and sea level. Palaeogeography, Palaeoclimatology, Palaeoecology 162, 211–23.CrossRefGoogle Scholar
Saltzman, MR, Runnegar, B and Lohmann, KC (1998) Carbon isotope stratigraphy of Upper Cambrian (Steptoean Stage) sequences of the eastern Great Basin: record of a global oceanographic event. Geological Society of America Bulletin 110, 285–97.2.3.CO;2>CrossRefGoogle Scholar
Saltzman, MR, Young, SA, Kump, LR, Gill, BC, Lyons, TW and Runnegar, B (2011) Pulse of atmospheric oxygen during the late Cambrian. Proceedings of the National Academy of Sciences 108, 3876–81.CrossRefGoogle ScholarPubMed
Schiffbauer, JD, Huntley, JW, Fike, DA, Jeffrey, MJ, Gregg, JM and Shelton, KL (2017) Decoupling biogeochemical records, extinction, and environmental change during the Cambrian SPICE event. Science Advances 3, e1602158.CrossRefGoogle ScholarPubMed
Sial, AN, Peralta, S, Toselli, AJ, Ferreira, VP, Frei, R, Parada, MA, Pimentel, MM and Pereira, NS (2013) High-resolution stable isotope stratigraphy of the upper Cambrian and Ordovician in the Argentine Precordillera: carbon isotope excursions and correlations. Gondwana Research 24, 330–48.CrossRefGoogle Scholar
Taylor, SR and McLennan, SM (1985) The continental crust: its composition and evolution. Oxford: Blackwell Scientific Publications.Google Scholar
Tribovillard, N, Algeo, TJ, Lyons, T and Riboulleau, A (2006) Trace metals as paleoredox and paleoproductivity proxies: an update. Chemical Geology 232, 12–32.CrossRefGoogle Scholar
Veizer, J, Holser, WT and Wilgus, CK (1980) Correlation of 13C/12C and 34S/32S secular variations. Geochimica et Cosmochimica Acta 44, 579–87.CrossRefGoogle Scholar
Walker, JCG (1986) Global geochemical cycles of carbon, sulfur and oxygen. Marine Geology 70, 159–74.CrossRefGoogle ScholarPubMed
Webb, GE and Kamber, BS (2000) Rare earth elements in Holocene reefal microbialites: a new shallow seawater proxy. Geochimica et Cosmochimica Acta 64, 1557–64.CrossRefGoogle Scholar
Woods, MA, Wilby, PR, Leng, MJ, Rushton, AWA and Williams, M (2011) The Furongian (late Cambrian) Steptoean Positive Carbon Isotope Excursion (SPICE) in Avalonia. Journal of the Geological Society 168, 851–62.CrossRefGoogle Scholar
Wotte, T, Shields-Zhou, GA and Strauss, H (2012 a) Carbonate-associated sulfate: experimental comparisons of common extraction methods and recommendations toward a standard analytical protocol. Chemical Geology 326–327, 132–44.CrossRefGoogle Scholar
Wotte, T and Strauss, H (2015) Questioning a widespread euxinia for the Furongian (Late Cambrian) SPICE event: indications from δ13C, δ18O, δ34S and biostratigraphic constraints. Geological Magazine 152, 1085–103.CrossRefGoogle Scholar
Wotte, T, Strauss, H, Fugmann, A and Garbe-Schönberg, D (2012 b) Paired δ34S data from carbonate-associated sulfate and chromium-reducible sulfur across the traditional Lower–Middle Cambrian boundary of W-Gondwana. Geochimica et Cosmochimica Acta 85, 228–53.CrossRefGoogle Scholar
Zhang, W-T (2003) Cambrian correlation between North America and China based on trilobite and conodont faunas. Acta Palaeontologica Sinica 42, 305–16 (in Chinese and English bilingual).Google Scholar
Zhang, W-T and Jell, PA (1987) Cambrian trilobites of North China: Chinese Cambrian trilobites housed in the Smithsonian Institution. Beijing: Science Press, pp. 1–322.Google Scholar
Zhou, Z-C, Willems, H, Li, Y and Luo, H (2011) A well-preserved carbonate tempestite sequence from the Cambrian Gushan Formation, eastern North China Craton. Palaeoworld 20, 1–7.CrossRefGoogle Scholar
Zhu, M-Y, Zhang, J-M, Li, G-X and Yang, A-H (2004) Evolution of C isotopes in the Cambrian of China: implications for Cambrian subdivision and trilobite mass extinctions. Geobios 37, 287–301.CrossRefGoogle Scholar
Zhu, Z-L and Wittke, HW (1989) Upper Cambrian trilobites from Tangshan, Hebei Province, North China. Palaeontologia Cathayana 4, 199–259.Google Scholar