Geochemistry of lower Silurian shale of Longmaxi Formation, southeastern Sichuan Basin, China: Implications for provenance and source weathering

Abstract

Lower Silurian Longmaxi Shale (SLS) in southeastern Sichuan Basin, China, was analyzed for major and selected trace elements, and their provenance, intensity of palaeoweathering of the source rocks were analyzed based on these elements. The results show that SiO₂, Al₂O₃ and Fe₂O₃, are dominant major elements with average contents of 60.59%, 15.91% and 5.87% in Upper Silurian Longmaxi Shale (USLS), and 65.14%, 13.24% and 4.68% in Lower Silurian Longmaxi Shale (LSLS). The TiO₂−Zr plot, Hf (ppm) versus La/Th discriminant diagram, and abundance of Cr and Ni suggest a dominantly felsic source for the Longmaxi sediments. Average chemical index of alteration (CIA), plagioclase index of alteration (PIA) values (64.05% and 72.86%, respectively) imply low-degree chemical weathering of the source material in early Longmaxi time, and average CIA, PIA values (68.44% and 80.35%, respectively) imply moderate chemical weathering of the source material in late Longmaxi time.

Keywords

trace elements / black shale / provenance / weathering / discriminant diagrams / Sichuan Basin

References

[1] BanerjeeS., DuttaS., PaikarayS., MannU.. Stratigraphy, sedimentology and bulk organic geochemistry of black shales from the Proterozoic Vindhyan Supergroup (central India) [J]. Journal of Earth System Science, 2006, 115(1): 37-47

[2] ShpirtM. Y., PunanovaS. A., StrizhakovaY. A.. Trace elements in black and oil shales [J]. Solid Fuel Chemistry, 2007, 41(2): 119-127

[3] PollackG. D., KrogstadE. J., BekkerA.. U-Th-Pb-REE systematics of organic-rich shales from the ca. 2.15 Ga Sengoma Argillite Formation, Botswana: Evidence for oxidative continental weathering during the great oxidation event [J]. Chemical Geology, 2009, 260(3): 172-185

[4] CurtisJ. B.. Fractured shale-gas systems [J]. AAPG bulletin, 2002, 86(11): 1921-1938

[5] LiD.-p., ChenY.-l., WangZ., LinY., ZhouJ.. Paleozoic sedimentary record of the Xing-Meng Orogenic Belt, Inner Mongolia: Implications for the provenances and tectonic evolution of the Central Asian Orogenic Belt [J]. Chinese Science Bulletin, 2012, 57(7): 776-785

[6] MondalM., WaniH., MondalB.. Geochemical signature of provenance, tectonics and chemical weathering in the Quaternary flood plain sediments of the Hindon River, Gangetic plain, India [J]. Tectonophysics, 2012, 566: 87-94

[7] NesbittH. W., YoungG. M.. Early Proterozoic climates and plate motions inferred from major element chemistry of lutites [J]. Nature, 1982, 299: 715-717

[8] FedoC. M., NesbittH. W., YoungG. M.. Unraveling the effects of potassium metasomatism in sedimentary rocks and paleosols, with implications for paleoweathering conditions and provenance [J]. Geology, 1995, 23(10): 921-924

[9] RazaM., AhamdA., ShamimM. K., KhanF.. Geochemistry and detrital modes of Proterozoic sedimentary rocks, Bayana Basin, north Delhi fold belt: implications for provenance and source-area weathering [J]. International Geology Review, 2012, 54(1): 111-129

[10] GarverJ. I., RoyceP. R., SmickT. A.. Chromium and nickel in shale of the Taconic foreland: A case study for the provenance of fine-grained sediments with an ultramafic source [J]. Journal of Sedimentary Research, 1996, 66(1): 100-106

[11] PaikarayS., BanerjeeS., MukherjiS.. Geochemistry of shales from the Paleoproterozoic to Neoproterozoic Vindhyan Supergroup: Implications on provenance, tectonics and paleoweathering [J]. Journal of Asian Earth Sciences, 2008, 32(1): 34-48

[12] JiaQ.-p., JiaD., LuoL., ChenZ.-x., LiY.-q., DengF., SunS.-s., LiH.-b.. Three-dimensional evolutionary models of the Qiongxi structures, southwestern Sichuan basin, China: Evidence from seismic interpretation and geomorphology [J]. Acta Geologica Sinica: English Edition, 2009, 83(2): 372-385

[13] JiangZ.-x., GuoL., LiangC.. Lithofacies and sedimentary characteristics of the Silurian Longmaxi Shale in the southeastern Sichuan Basin, China [J]. Journal of Palaeogeography, 2013, 2(3): 238-251

[14] JinY., FangN.-q., YangS.-y.. In situ gabbro geochemical characteristics and implications from the Southwest Indian Ocean Ridge [J]. Earth Sciece-Journal of China University of Geosciences, 2012, 37(1): 57-67

[15] CullersR. L.. The geochemistry of shales, siltstones and sandstones of Pennsylvanian-Permian age, Colorado, USA: implications for provenance and metamorphic studies [J]. Lithos, 2000, 51(3): 181-203

[16] TaylorS. R., MclennanS.The continental crust: Its composition and evolution [J], 1985Oxford, UKBlackwell349

[17] FloydP. A., LeveridgeB. E.. Tectonic environment of the Devonian Gramscatho basin, south Cornwall: Framework mode and geochemical evidence from turbiditic sandstones [J]. Journal of the Geological Society, 1987, 144(4): 531-542

[18] GhoshP., BhattacharyaS. K., DayalA. M., TrivediJ. R., EbiharaM., SarinM. M., ChakrabartiA.. Trace element and isotopic studies of Permo-Carboniferous carbonate nodules from Talchir sediments of peninsular India: Environmental and provenance implications [J]. Journal of Earth System Science, 2002, 111(2): 87-93

[19] Armstrong-AltrinJ. S., LeeY. I., VermaS. P., RamasamyS.. Geochemistry of sandstones from the upper Miocene Kudankulam Formation, southern India: Implications for provenance, weathering, and tectonic setting [J]. Journal of Sedimentary Research, 2004, 74(2): 285-297

[20] RoserB. P., KorschR. J.. Provenance signatures of sandstone-mudstone suites determined using discriminant function analysis of major-element data [J]. Chemical Geology, 1988, 67: 119-139

[21] HayashiK., FujisawaH., HollandH. D., OhmotoH.. Geochemistry of ~1.9 Ga sedimentary rocks from northeastern Labrador, Canada [J]. Geochimica et Cosmochimica Acta, 1997, 61(19): 4115-4137

[22] WronkiewiczD. J., CondieK. C.. Geochemistry of Archean shales from the Witwatersrand Supergroup, South Africa: Source-area weathering and provenance [J]. Geochimica et Cosmochimica Acta, 1987, 51(9): 2401-2416

[23] NesbittH. W., YoungG. M.. Prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations [J]. Geochimica et Cosmochimica Acta, 1984, 48(7): 1523-1534

[24] JohnssonM. J., StallardR. F., MeadeR. H.. First-cycle quartz arenites in the Orinoco River basin, Venezuela and Colombia [J]. The Journal of Geology, 1988, 94: 263-277

[25] NesbittH. W., FedoC. M., YoungG. M.. Quartz and feldspar stability, steady and non-steady-state weathering, and petrogenesis of siliciclastic sands and muds [J]. The Journal of Geology, 1997, 105(2): 173-192

[26] SrivastavaA. K., RandiveK. R., KhareN.. Mineralogical and geochemical studies of glacial sediments from Schirmacher Oasis, East Antarctica [J]. Quaternary International, 2013, 292: 205-216

[27] MoosaviradS. M., JanardhanaM. R., SethumadhavM. S., MoghadamM. R., ShankaraM.. Geochemistry of lower Jurassic shales of the Shemshak Formation, Kerman Province, Central Iran: Provenance, source weathering and tectonic setting [J]. Chemie der Erde-Geochemistry, 2011, 71(3): 279-288

[28] MclennanS. M., HemmingS., McdanielD. K., HansonG. N.. Geochemical approaches to sedimentation, provenance, and tectonics [J]. Special Papers-Geological Society of America, 1993, 284: 21-40