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Sideritic ironstones as indicators of depositional environments in the Weald Basin (Early Cretaceous) SE England

Published online by Cambridge University Press:  07 December 2017

OLADAPO AKINLOTAN Open the ORCID record for OLADAPO AKINLOTAN [Opens in a new window]
OLADAPO AKINLOTAN*
Affiliation:
School of Environment and Technology, University of Brighton, Lewes Road, Brighton, BN2 4GJ, UK
*
*Author for correspondence: [email protected]; [email protected]
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Abstract

The Lower Cretaceous Wealden sideritic ironstones have a wide occurrence and great potential to aid the reconstruction of the depositional environments of the Weald Basin in SE England. However, mineralogical and geochemical datasets on the ironstones are scarce in the literature. Geochemical and mineralogical data on the sideritic ironstones are presented from the Wadhurst Clay Formation within the Weald Basin. The mineralogy of the ironstones was examined using a PANalytical X'Pert Pro X-ray diffractometer and PANalytical's HighScore Plus software. Elemental composition of the ironstones was measured using a PANalytical MiniPal2 ED-XRF (benchtop X-ray spectrometer). The examination of the mineralogy of the Wealden ironstones confirms the presence of early diagenetic siderites. The trace-element assemblage shows that the sideritic ironstones are chemically pure pointing to a freshwater origin. The sideritic ironstones reveal anoxic conditions and palaeo-salinity in the basin. More generally, it is suggested that the composition of the host rocks has significant controls on the composition of sideritic ironstones in sedimentary basins. This work reinforces the importance of the composition of sideritic ironstones as useful non-traditional data for understanding the depositional settings of sedimentary basins, especially when traditional datasets are not readily available or insufficient.

Keywords

sideritic ironstonesmineralogygeochemistryEarly Cretaceoussoutheast EnglandWeald Basin
Type
Original Articles
Information
Geological Magazine , Volume 156 , Issue 3 , March 2019 , pp. 533 - 546
Copyright
Copyright © Cambridge University Press 2017 

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References

Akinlotan, O. O. 2016. Porosity and permeability of the English (Lower Cretaceous) sandstones. Proceedings of the Geologists’ Association 127, 681–90.Google Scholar
Akinlotan, O. 2017a. Mineralogy and palaeoenvironments: the Weald Basin (Early Cretaceous), Southeast England. The Depositional Record 3, 187–200.Google Scholar
Akinlotan, O. O. 2017b. Geochemical analysis for palaeoenvironmental interpretations – a case study of the English Wealden (Lower Cretaceous, southeast England). Geological Quarterly 61, 227–38.Google Scholar
Akinlotan, O. O. 2017c. Multi-proxy approach to palaeoenvironmental modelling: the English Lower Cretaceous Weald Basin. Geological Journal, published online 8 February 2017. doi: 10.1002/gj.2893.Google Scholar
Allen, P. 1975. Wealden of the Weald: a new model. Proceedings of the Geologists’ Association 86, 389–437.Google Scholar
Allen, P. 1981. Pursuit of Wealden models. Journal of the Geological Society, London 138, 375–405.Google Scholar
Allen, P. 1989. Wealden research—ways ahead. Proceedings of the Geologists’ Association 100, 529–64.Google Scholar
Allen, P., Alvin, K. L., Andrews, J. E., Batten, D. J., Charlton, W. A., Cleevely, R. J., Ensom, P. C., Evans, S. E., Francis, J. E., Hailwood, E. A., Harding, I. C., Horne, D. J., Hughes, N. F., Hunt, C. O., Jarzembowski, E. A., Jones, T. P., Knox, R. W. O. B., Milner, A., Norman, D. B., Palmer, C. P., Parker, A., Patterson, G. A., Price, G. D., Radley, J. D., Rawson, P. F., Ross, A. J., Rolfe, S., Ruffell, A. H., Sellwood, B. W., Sladen, C. P., Taylor, K. G., Watson, J., Wright, V. P., Wimbledon, W. A. & Banham, G. H. 1998. Purbeck–Wealden (early Cretaceous) climates. Proceedings of the Geologists’ Association 109, 197–236.Google Scholar
Allen, P. & Wimbledon, W. A. 1991. Correlation of NW European Purbeck-Wealden (nonmarine Lower Cretaceous) as seen from the English type-areas. Cretaceous Research 12, 511–26.Google Scholar
Bahrig, B. 1989. Stable isotope composition of siderite as an indicator of the paleoenvironmental history of oil shale lakes. Palaeogeography, Palaeoclimatology, Palaeoecology 70, 139–51.Google Scholar
Baker, J. C., Kassan, J. & Hamilton, P. J. 1996. Early diagenetic siderite as an indicator of depositional environment in the Triassic Rewan Group, southern Bowen Basin, eastern Australia. Sedimentology 43, 77–88.Google Scholar
Batten, D. J. 1982. Palynofacies and salinity in the Purbeck and Wealden of southern England. In Aspects of Micropalaeontology (eds Banner, F. T. & Lord, A.R.), pp 278–308. London: George & Allen Unwin.Google Scholar
Booth, K. 2005. Geological Investigation of the Ashdown Beds at Fairlight, East Sussex. British Geological Survey Commercial Report CR/05/040N, 32 pp.Google Scholar
Browne, G. H. & Kingston, D. M. 1993. Early diagenetic spherulitic siderites from Pennsylvanian palaeosols in the Boss Point Formation, Maritime Canada. Sedimentology 40, 467–74.Google Scholar
Brumsack, H.-J. 2006. The trace metal content of recent organic carbon-rich sediments: implications for Cretaceous black shale formation. Palaeogeography, Palaeoclimatology, Palaeoecology 232, 344–61.Google Scholar
Chen, S., Wang, H., Wei, J., Lv, Z., Gan, H. & Jin, S. 2014. Sedimentation of the Lower Cretaceous Xiagou Formation and its response to regional tectonics in the Qingxi Sag, Jiuquan Basin, NW China. Cretaceous Research 47, 72–86.Google Scholar
Choi, K. S., Khim, B. K. & Woo, K. S. 2003. Spherulitic siderites in the Holocene coastal deposits of Korea (eastern Yellow Sea): elemental and isotopic composition and depositional environment. Marine Geology 202, 17–31.Google Scholar
Cope, J. C. W. 2008. Drawing the line: the history of the Jurassic—Cretaceous boundary. Proceedings of the Geologists’ Association 119, 105–17.Google Scholar
Cundy, A. B., Hopkinson, L. & Whitby, R. L. D. 2008. Use of iron-based technologies in contaminated land and groundwater remediation: a review. Science of the Total Environment 400, 42–51.Google Scholar
Curtis, C. D. & Coleman, M. L. 1986. Controls on the precipitation of early diagenetic calcite, dolomite and siderite concretions in complex depositional sequences. In Roles of Organic Matter in Sediment Diagenesis (ed. Gautier, D. L.), pp 23–33. Society of Economic Palaeontologists and Mineralogists 38.Google Scholar
Curtis, C., Pearson, M. & Somogyi, V. 1975. Mineralogy, chemistry and origin of a concretionary siderite sheet (clay-ironstone band) in the Westphalian of Yorkshire. Mineralogical Magazine 40, 385–93.Google Scholar
Curtis, C. & Spears, D. 1968. The formation of sedimentary iron minerals. Economic Geology 63, 257–70.Google Scholar
Dejax, J., Pons, D. & Yans, J. 2007. Palynology of the dinosaur-bearing Wealden facies in the natural pit of Bernissart (Belgium). Review of Palaeobotany and Palynology 144, 25–38.Google Scholar
Elbaz-Poulichet, F., Seidel, J. L., Jézéquel, D., Metzger, E., Prévot, F., Simonucci, C., Sarazin, G., Viollier, E., Etcheber, H., Jouanneau, J.-M., Weber, O. & Radakovitch, O. 2005. Sedimentary record of redox-sensitive elements (U, Mn, Mo) in a transitory anoxic basin (the Thau lagoon, France). Marine Chemistry 95, 271–81.Google Scholar
Feist, M., Lake, R. D. & Wood, C. J. 1995. Charophyte biostratigraphy of the Purbeck and Wealden of southern England. Palaeontology 38, 407–42.Google Scholar
Ferreira, N. N., Ferreira, E. P., Ramos, R. R. C. & Carvalho, I. S. 2016. Palynological and sedimentary analysis of the Igarapé Ipiranga and Querru 1 outcrops of the Itapecuru Formation (Lower Cretaceous, Parnaíba Basin), Brazil. Journal of South American Earth Sciences 66, 15–31.Google Scholar
Fisher, H. L. & Watson, J. 2015. A fossil insect egg on an Early Cretaceous conifer shoot from the Wealden of Germany. Cretaceous Research 53, 38–47.Google Scholar
Franchi, F., Rovere, M., Gamberi, F., Rashed, H., Vaselli, O. & Tassi, F. 2017. Authigenic minerals from the Paola Ridge (southern Tyrrhenian Sea): evidences of episodic methane seepage. Marine and Petroleum Geology 86, 228–47.Google Scholar
Garrels, R. M. 1960. Mineral Equilibria at Low Temperature and Pressure. New York: Harper, 254 ppGoogle Scholar
Garrido, A. C. & Salgado, L. 2015. Taphonomy and depositional environment of a Lower Cretaceous monospecific dinosaur bone assemblage (Puesto Quiroga Member, Lohan Cura Formation), Neuquén Province, Argentina. Journal of South American Earth Sciences 61, 53–61.Google Scholar
Gautier, D. L. 1982. Siderite concretions: indicators of early diagenesis in the Gammon Shale (Cretaceous). Journal of Sedimentary Research 52, 859–71.Google Scholar
Goldring, R., Pollard, J. E. & Radley, J. D. 2005. Trace fossils and pseudofossils from the Wealden strata (non-marine Lower Cretaceous) of southern England. Cretaceous Research 26, 665–85.Google Scholar
Hallam, A., Grose, J. A. & Ruffell, A. H. 1991. Palaeoclimatic significance of changes in clay mineralogy across the Jurassic–Cretaceous boundary in England and France. Palaeogeography, Palaeoclimatology, Palaeoecology 81, 173–87.Google Scholar
Hart, B., Longstaffe, F. & Plint, A. 1992. Evidence for relative sea level change from isotopic and elemental composition of siderite in the Cardium Formation, Rocky Mountain Foothills. Bulletin of Canadian Petroleum Geology 40, 52–9.Google Scholar
Haywood, A. M., Valdes, P. J. & Markwick, P. J. 2004. Cretaceous (Wealden) climates: a modelling perspective. Cretaceous Research 25, 303–11.Google Scholar
Hopson, P., Wilkinson, I. & Woods, M. 2008. A Stratigraphical Framework for the Lower Cretaceous of England. British Geological Survey, Research Report, RR/08/03.Google Scholar
Horne, D. J. 1995. A revised ostracod biostratigraphy for the Purbeck-Wealden of England. Cretaceous Research 16, 639–63.Google Scholar
Hubbard, C. R. & Snyder, R. L. 1988. RIR-measurement and use in quantitative XRD. Powder Diffraction 3, 74–7.Google Scholar
Huber, N. K. 1958. The environmental control of sedimentary iron minerals. Economic Geology 53, 123–40.Google Scholar
Hughes, N. F. 1955. Wealden plant microfossils. Geological Magazine 92, 201–17.Google Scholar
Isaack, A., Gischler, E., Hudson, J. H., Anselmetti, F. S., Buhre, S. & Camoin, G. F. 2017. Facies variations in response to Holocene sea-level and climate change on Bora Bora, French Polynesia: unravelling the role of synsedimentary siderite in a tropical marine, mixed carbonate-siliciclastic lagoon. Marine Geology 390, 1–22.Google Scholar
James, H. L. 1966. Chemistry of the Iron-Rich Sedimentary Rocks. Geological Survey Professional Paper 440–W. Washington: United States Government Printing Office, 61 ppGoogle Scholar
Jarzembowski, E. A. 1995. Early Cretaceous insect faunas and palaeoenvironment. Cretaceous Research 16, 681–93.Google Scholar
Jeans, C. V. 2006. Clay mineralogy of the Cretaceous strata of the British Isles. Clay Minerals 41, 47–150.Google Scholar
Jeans, C. V., Mitchell, J. G., Fisher, M. J., Wray, D. S. & Hall, I. R. 2001. Age, origin and climatic signal of English Mesozoic clays based on K/Ar signatures. Clay Minerals 36, 515–39.Google Scholar
Ju, W. & Sun, W. 2016. Tectonic fractures in the Lower Cretaceous Xiagou Formation of Qingxi Oilfield, Jiuxi Basin, NW China part two: numerical simulation of tectonic stress field and prediction of tectonic fractures. Journal of Petroleum Science and Engineering 146, 626–36.Google Scholar
Khim, B.-K., Choi, K.-S. & Park, Y. 2000. Elemental composition of siderite grains in early-Holocene deposits of Youngjong Island (west coast of Korea), and its palaeoenvironmental implications. Proceedings in Marine Science 2, 205–17.Google Scholar
Kirkaldy, J. F. 1939. The history of the Lower Cretaceous period in England. Proceedings of the Geologists’ Association 50, 379–417, IN3–IN6.Google Scholar
Kirkaldy, J. F. 1947. The provenance of the pebbles in the Lower Cretaceous Rocks. Proceedings of the Geologists’ Association 58, 223–41.Google Scholar
Köhler, I., Konhauser, K. O., Papineau, D., Bekker, A. & Kappler, A. 2013. Biological carbon precursor to diagenetic siderite with spherical structures in iron formations. Nature Communications 4, 1741.Google Scholar
Lake, R. D. & Shephard-Thorn, E. R. 1987. Geology of the Country around Hastings and Dungeness. Memoir for 1:50,000 geological sheets 320 and 321 (England and Wales). London: HM Stationery Office, 81 pp.Google Scholar
Lake, R. D. & Thurrell, R. G. 1974. The Sedimentary Sequence of the Wealden Beds in Boreholes Near Cuckfield, Sussex. Report of the Institute of Geological Sciences CF74/02. London: HM Stationery Office, 60 pp.Google Scholar
Lake, R. D. & Young, B. 1978. Boreholes in the Wealden Beds of the Hailsham Area, Sussex. Report of the Institute of Geological Sciences CF78/23. London: HM Stationery Office, 22 pp.Google Scholar
Legarreta, L., Kokogián, D. A. & Boggetti, D. A. 1989. Depositional sequences of the Malargüe Group (Upper Cretaceous–lower Tertiary), Neuquén Basin, Argentina. Cretaceous Research 10, 337–56.Google Scholar
Li, J., Wen, X. Y. & Huang, C. M. 2016. Lower Cretaceous paleosols and paleoclimate in Sichuan Basin, China. Cretaceous Research 62, 154–71.Google Scholar
Li, X., Xu, W., Liu, W., Zhou, Y., Wang, Y., Sun, Y. & Liu, L. 2013. Climatic and environmental indications of carbon and oxygen isotopes from the Lower Cretaceous calcrete and lacustrine carbonates in Southeast and Northwest China. Palaeogeography, Palaeoclimatology, Palaeoecology 385, 171–89.Google Scholar
Lim, D. I., Jung, H. S., Yang, S. Y. & Yoo, H. S. 2004. Sequential growth of early diagenetic freshwater siderites in the Holocene coastal deposits, Korea. Sedimentary Geology 169, 107–20.Google Scholar
Loope, D. B., Kettler, R. M., Weber, K. A., Hinrichs, N. L. & Burgess, D. T. 2012. Rinded iron-oxide concretions: hallmarks of altered siderite masses of both early and late diagenetic origin. Sedimentology 59, 1769–81.Google Scholar
Milner, H. B. & Bull, A. J. 1925. The geology of the Eastbourne—Hastings Coastline: with special reference to the localities visited by the Association in June, 1925. Proceedings of the Geologists’ Association 36, 291–316, IN12–IN17.Google Scholar
Mirza, T. A., Mohialdeen, I. M. J. & Awadh, S. M. 2016. Iron mineralization in the Garagu Formation of Gara Mountain, Duhok Governorate, Kurdistan, NE Iraq: geochemistry, mineralogy and origin. Arabian Journal of Geosciences 9, 473.Google Scholar
Morter, A. A. 1984. Purbeck-Wealden Beds Mollusca and their relationship to ostracod biostratigraphy, stratigraphical correlation and palaeoecology in the Weald and adjacent areas. Proceedings of the Geologists’ Association 95, 217–34.Google Scholar
Mortimer, R. J. G., Coleman, M. L. & Rae, J. E. 1997. Effect of bacteria on the elemental composition of early diagenetic siderite: implications for palaeoenvironmental interpretations. Sedimentology 44, 759–65.Google Scholar
Mozley, P. S. 1989. Relation between depositional environment and the elemental composition of early diagenetic siderite. Geology 17, 704–6.Google Scholar
Mozley, P. S. 1996. The internal structure of carbonate concretions in mudrocks: a critical evaluation of the conventional concentric model of concretion growth. Sedimentary Geology 103, 85–91.Google Scholar
Mozley, P. S. & Wersin, P. 1992. Isotopic composition of siderite as an indicator of depositional environment. Geology 20, 817–20.Google Scholar
Naish, D. & Sweetman, S. C. 2011. A tiny maniraptoran dinosaur in the Lower Cretaceous Hastings Group: evidence from a new vertebrate-bearing locality in south-east England. Cretaceous Research 32, 464–71.Google Scholar
Oertel, G. & Curtis, D. C. 1972. Clay-ironstone concretion preserving fabrics due to progressive compaction. Geological Society of America Bulletin 83, 2597–606.Google Scholar
Paredes, J. M., Foix, N., Colombo Piñol, F., Nillni, A., Allard, J. O. & Marquillas, R. A. 2007. Volcanic and climatic controls on fluvial style in a high-energy system: the Lower Cretaceous Matasiete Formation, Golfo San Jorge basin, Argentina. Sedimentary Geology 202, 96–123.Google Scholar
Parkes, A. S. 1993. Dinosaur footprints in the Wealden at Fairlight, East Sussex. Proceedings of the Geologists’ Association 104, 15–21.Google Scholar
Postma, D. 1983. Pyrite and siderite oxidation in swamp sediments. Journal of Soil Science 34, 163–82.Google Scholar
Pott, C., Guhl, M. & Lehmann, J. 2014. The Early Cretaceous flora from the Wealden facies at Duingen, Germany. Review of Palaeobotany and Palynology 201, 75–105.Google Scholar
Pye, K., Dickson, J. A. D., Schiavon, N., Coleman, M. L. & Cox, M. 1990. Formation of siderite-Mg-calcite-iron sulphide concretions in intertidal marsh and sandflat sediments, north Norfolk, England. Sedimentology 37, 325–43.Google Scholar
Radley, J. D. & Allen, P. 2012. The Wealden (non-marine Lower Cretaceous) of the Weald Sub-basin, southern England. Proceedings of the Geologists’ Association 123, 245–318.Google Scholar
Richiano, S. 2014. Lower Cretaceous anoxic conditions in the Austral basin, south-western Gondwana, Patagonia Argentina. Journal of South American Earth Sciences 54, 37–46.Google Scholar
Rippen, D., Littke, R., Bruns, B. & Mahlstedt, N. 2013. Organic geochemistry and petrography of Lower Cretaceous Wealden black shales of the Lower Saxony Basin: the transition from lacustrine oil shales to gas shales. Organic Geochemistry 63, 18–36.Google Scholar
Robinson, S. A., Scotchman, J. I., White, T. S. & Atkinson, T. C. 2010. Constraints on palaeoenvironments in the Lower Cretaceous Wealden of southern England, from the geochemistry of sphaerosiderites. Journal of the Geological Society, London 167, 303–11.Google Scholar
Rodrigues, A. G., De Ros, L. F., Neumann, R. & Borghi, L. 2015. Paleoenvironmental implications of early diagenetic siderites of the Paraíba do Sul Deltaic Complex, eastern Brazil. Sedimentary Geology 323, 15–30.Google Scholar
Rollin, K. E. 1995. A simple heat-flow quality function and appraisal of heat-flow measurements and heat-flow estimates from the UK Geothermal Catalogue. Tectonophysics 244, 185–96.Google Scholar
Sladen, C. P. 1983. Trends in Early Cretaceous clay mineralogy in NW Europe. Zitteliana 10, 57.Google Scholar
Sladen, C. P. 1987. Aspects of the clay mineralogy of the Wealden and upper Purbeck rocks. In Geology of the Country around Hastings and Dungeness (eds Lake, R. D. & Shephard-Thorn, E. R.), pp. 71–2. Memoir for 1:50,000 geological sheets 320 and 321 (England and Wales). London: HM Stationery Office.Google Scholar
Sladen, C. P. & Batten, D. J. 1984. Source-area environments of late Jurassic and early Cretaceous sediments in Southeast England. Proceedings of the Geologists’ Association 95, 149–63.Google Scholar
Spiro, B., Gibson, P. J. & Shaw, H. F. 1993. Eogenetic siderites in lacustrine oil shales from Queensland, Australia, a stable isotope study. Chemical Geology 106, 415–27.Google Scholar
Stewart, D. J. 1978. Ophiomorpha: a marine indicator? Proceedings of the Geologists’ Association 89, 33–41.Google Scholar
Stewart, D. J. 1981a. A field guide to the Wealden Group of the Hastings area and the Isle of Wight. In Field Guides to Modern and Ancient Fluvial Systems in Britain and Spain (ed. Elliott, T.), pp 3.1–3.32. International Fluvial Conference, University of Keele.Google Scholar
Stewart, D. J. 1981b. A meander-belt sandstone of the Lower Cretaceous of Southern England. Sedimentology 28, 1–20.Google Scholar
Stewart, D. J. 1983. Possible suspended-load channel deposits from the Wealden Group (Lower Cretaceous) of Southern England. In Modern and Ancient Fluvial Systems (eds Collinson, J. D. & Lewin, J.), pp 369–84. International Association of Sedimentologists Special Publication 6. Oxford: Blackwell Publishing.Google Scholar
Sweeting, G. S. 1925. The geology of the country around Crowhurst, Sussex. Proceedings of the Geologists’ Association 36, 406–18, IN2–IN4.Google Scholar
Tang, F., Luo, Z. X., Zhou, Z. H., You, H. L., Georgi, J. A., Tang, Z. L. & Wang, X. Z. 2001. Biostratigraphy and palaeoenvironment of the dinosaur-bearing sediments in Lower Cretaceous of Mazongshan area, Gansu Province, China. Cretaceous Research 22, 115–29.Google Scholar
Taylor, J. H. 1963. Sedimentary features of an ancient deltaic complex: the Wealden rocks of southeastern England. Sedimentology 2, 2–28.Google Scholar
Taylor, K. G. 1990. Berthierine from the non-marine Wealden (Early Cretaceous) sediments of south-east England. Clay Minerals 25, 391–9.Google Scholar
Taylor, K. G. 1991. Phosphatic concretions in the Wealden of South-East England. Proceedings of the Geologists’ Association 102, 67–70.Google Scholar
Taylor, K. G. 1992. Non-marine oolitic ironstones in the Lower Cretaceous Wealden sediments of southeast England. Geological Magazine 129, 349–58.Google Scholar
Watson, J. & Alvin, K. L. 1999. The cheirolepidiaceous conifers Frenelopsis occidentalis Heer and Watsoniocladus valdensis (Seward) in the Wealden of Germany. Cretaceous Research 20, 315–26.Google Scholar
Wedepohl, K. 1971. Environmental influences on the chemical composition of shales and clays. Physics and Chemistry of the Earth 8, 305–33.Google Scholar
Wedepohl, K. 1991. The composition of the upper earth's crust and the natural cycles of selected metals. Metals in natural raw materials. In Metals and their Compounds in the Environment. Occurrence, Analysis, and Biological Relevance (ed. Merian, E.), pp. 3–17. New York: VCH Weinheim.Google Scholar
Westaway, R., Maddy, D. & Bridgland, D. 2002. Flow in the lower continental crust as a mechanism for the Quaternary uplift of south-east England: constraints from the Thames terrace record. Quaternary Science Reviews 21, 559–603.Google Scholar
Wooldridge, S. W. & Goldring, F. 1953. The Weald. London: Collins, 276 pp.Google Scholar
Worssam, B. C. 1972. Iron ore workings near Horsham, Sussex, and the sedimentology of Wealden clay ironstone. Proceedings of the Geologists’ Association 83, 37–55.Google Scholar
Xu, G., Hannah, J. L., Bingen, B., Georgiev, S. & Stein, H. J. 2012a. Digestion methods for trace element measurements in shales: paleoredox proxies examined. Chemical Geology 324–325, 132–47.Google Scholar
Xu, L., Lehmann, B., Mao, J., Nägler, T. F., Neubert, N., Böttcher, M. E. & Escher, P. 2012b. Mo isotope and trace element patterns of Lower Cambrian black shales in South China: multi-proxy constraints on the paleoenvironment. Chemical Geology 318–319, 45–59.Google Scholar
Yans, J., Gerards, T., Gerrienne, P., Spagna, P., Dejax, J., Schnyder, J., Storme, J.-Y. & Keppens, E. 2010. Carbon-isotope analysis of fossil wood and dispersed organic matter from the terrestrial Wealden facies of Hautrage (Mons Basin, Belgium). Palaeogeography, Palaeoclimatology, Palaeoecology 291, 85–105.Google Scholar