Science China Earth Sciences

, Volume 53, Issue 3, pp 356–367 | Cite as

Sedimentary geochemistry and provenance of the Lower and Middle Devonian Laojunshan Formation, the North Qilian Orogenic Belt

  • YaJun Xu
  • YuanSheng Du
  • JiangHai Yang
  • Hu Huang
Research Paper


The Laojunshan Formation is a suite of molasse formed during the rapid uplift of the North Qilian Orogenic Belt (NQOB). Forty-one samples of sandstone have been collected from the Sunan and Minle sections in the western sector and the Gulang and Jingyuan sections in the eastern sector of the NQOB belt. Geochemical analyses of those samples indicated: 1) The MgO+Fe2O3 T and Al2O3/SiO2 values are higher, and K2O/Na2O ratios are lower in the western sector than those in the eastern sector. 2) All of them are depleted in Nb and Ta elements. The samples from the western sector are depleted in Rb element and enriched with Sc, Co, Ni, V, and Cr elements in the Upper Crust-normalized patterns. However, those from the eastern sector are depleted in Sr without enrichments of Sc, Co, Ni, V, and Cr. 3) All of the samples display a right-inclined REE pattern after Chondrite-normalized REE pattern. But LaN/YbN and Eu/Eu* ratios of the samples from the western sector are lower than those of the samples from the eastern sector. These geochemical characteristics suggest the prominent input of mafic clast with minor granitic rocks into the Sunan area, felsic clast into the Gulang and Jingyuan area, and both mafic and felsic clast into the Minle area. The angular shapes of gravels imply that these ill-sorted sediments were deposited near their sources without recycling. Geochemical features above also demonstrated that no major chemical weathering occurred for the western provenance, but deposits in the eastern sector resulted from low or middle degree chemical weathering. Evidences combining tectonic discriminations and comparisons with potential provenances revealed that sediments in the Sunan area were derived mainly from the North Qilian Continental arc, whereas sediments in the Minle, Gulang, and Jingyuan areas were derived not only from the North Qilian Continental arc but also from the basement of the Middle Qilian block. Integrated with the characteristics of development of Silurian and Devonian, these imply that the orogeny of NQOB is diachronous in the trending direction due to the oblique collision.


North Qilian Orogenic Belt (NQOB) Laojunshan Formation sedimentary geochemistry provenance orogeny 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    McLennan S M, Hemming S, McDaniel D K, et al. Geochemical approaches to sedimentation, provenance, and tectonics. Geol Soc Am Spe Paper, 1993, 284: 21–40Google Scholar
  2. 2.
    Rudnick R L, Gao S. Composition of the continental crust. In: Rudnick R L, ed. Treatise on Geochemistry. Vol. 3: The Crust. Amsterdam: Elsevier, 2003. 1–64Google Scholar
  3. 3.
    Hofmann A. The geochemistry of sedimentary rocks from the Fig Tree Group, Barberton greenstone belt: Implications for tectonic, hydrothermal and surface processes during mid-Archaean times. Precambrian Res, 2005, 143: 23–49CrossRefGoogle Scholar
  4. 4.
    Hegde V S, Chavadi V C. Geochemistry of late Archaean metagreywackes from the Western Dharwar Craton, South India: Implications for provenance and nature of the Late Archaean crust. Gondwana Res, 2009, 15: 178–187CrossRefGoogle Scholar
  5. 5.
    Li R W, Li S Y, Jin F Q, et al. Provenance of Carboniferous sedimentary rocks in the northern margin of Dabie Mountains, central China and the tectonic significance: Constraints from trace elements, mineral chemistry and SHRIMP dating of zircons. Sediment Geol, 2004, 166: 245–264CrossRefGoogle Scholar
  6. 6.
    McLennan S M, Hemming S R, Taylor S R, et al. Early Proterozoic crustal evolution: Geochemical and Nd-Pb isotopic evidence from metasedimentary rocks, southwestern North America. Geochim Cosmochim Acta, 1995, 59: 1153–1177CrossRefGoogle Scholar
  7. 7.
    Bhatia M R, Crook K A W. Trace element characteristics of gyay-wake and tectonic of sedimentary basins. Contrib Mineral Petr, 1986, 92: 181–193CrossRefGoogle Scholar
  8. 8.
    Nesbitt H W M, Young G M. Early Proterozoic climates and plate motions inferred from major element chemistry of lutites. Nature, 1982, 299: 715–717CrossRefGoogle Scholar
  9. 9.
    Long X P, Sun M, Yuan C, et al. Early Paleozoic sedimentary record of the Chinese Altai: Implications for its tectonic evolution. Sediment Geol, 2008, 208: 88–100CrossRefGoogle Scholar
  10. 10.
    Kasanzu C, Maboko M A H, Manya S, et al. Geochemistry of fine-grained clastic sedimentary rocks of the Neoproterozoic Ikorongo Group, NE Tanzania: Implications for provenance and source rock weathering. Precambrian Res, 2008, 164: 201–213CrossRefGoogle Scholar
  11. 11.
    Lambeck A, Huston D, Maidment D, et al. Sedimentary geochemistry, geochronology and sequence stratigraphy as tools to typecast stratigraphic units and constrain basin evolution in the gold mineralized Palaeoproterozoic Tanami Region, Northern Australia. Precambrian Res, 2008, 166: 185–203CrossRefGoogle Scholar
  12. 12.
    Li S Y, Li R W, Wang D X, et al. Geochemistry of the conglomerates and the tectonic setting of their provenance in Fenghuangtai Formation in the north margin of the Dabie Mountains (in Chinese). Acta Sediment Sin, 2005, 23: 380–388Google Scholar
  13. 13.
    Xu D R, Ma C, Nonna B C, et al. Petrological, mineralogical and geochemical characteristics of Ordovician volcanic-clastic sedimentary rocks in Bangxi area, northwest Hainan island, south China: Implication for provenance and tectonic setting (in Chinese). Geochimica, 2007, 36: 11–26Google Scholar
  14. 14.
    Zhou L, Gao S, Liu Y S, et al. Geochemistry and implications of clastic sedimentary rocks from the northern margin of Yangtze Craton (in Chinese). Earth Sci-J Chin Univ Geosci, 2007, 32: 29–38Google Scholar
  15. 15.
    Du Y S, Zhang Z, Zhou D H, et al. Silurian and Devonian Palaeogeography of the North Qilian-Hexi corridor and its sedimentary response to synorogenesis of the North Qilian Orogenic Belt (in Chinese). J Palaeogeogr, 2002, 4: 1–8Google Scholar
  16. 16.
    Zhang Q, Sun X M, Zhou D J. The characteristics of North Qilian ophiolites, forming settings and their tectonic significance (in Chinese). Adv Earth Sci, 1997, 12: 366–393Google Scholar
  17. 17.
    Feng Y M, He S P. Tectonics and Orogenesis of Qilian Mountains (in Chinese). Beijing: Geological Publishing House, 1996. 1–135Google Scholar
  18. 18.
    Xia L Q, Xia Z C, Xu X Y. Origin of Marine Volcanic Rocks in North Qilian Mountains (in Chinese). Beijing: Geological Publishing House, 1996. 1–153Google Scholar
  19. 19.
    Du Y S, Zhu J, Gu S Z, et al. Sedimentary geochemistry of the Cambrian-Ordovician cherts: Implication on archipelagic ocean of the North Qilian orogenic belt. Sci China Ser D-Earth Sci, 2007, 37: 1314–1329Google Scholar
  20. 20.
    Xu Z Q, Yang J S, Wu C L, et al. Timing and mechanism of formation and exhumation of the Northern Qaidam ultrahigh-pressure metamorphic belt. J Asian Earth Sci, 2006, 28: 160–173CrossRefGoogle Scholar
  21. 21.
    Song S G, Niu Y L, Zhang L F, et al. Tectonic evolution of Early Paleozoic HP metamorphic rocks in the North Qilian Mountains, NW China: New Perspectives. J Asian Earth Sci, 2009, 35: 334–353CrossRefGoogle Scholar
  22. 22.
    Zuo G C, Wu H Q. A bisubduction-collision orogenic model of Early-Paleozoic in the middle part of North Qilian area (in Chinese). Adv Earth Sci, 1997, 12: 315–322Google Scholar
  23. 23.
    Geological Burean of Gansu Province. Lithostratigraphy of Gansu Province (in Chinese). Wuhan: China University of Geosciences Press, 1997. 1–314Google Scholar
  24. 24.
    Du Y S, Zhu J, Han X, et al. From the back-arc basin to foreland basin-Ordovician-Devonian sedimentary basin and tectonic evolution in the North Qilian orogenic belt (in Chinese). Geol Bull Chin, 2004, 23: 911–917Google Scholar
  25. 25.
    Du Y S, Xu Y J, Yang J H. Soft-sediment deformation structures related to earthquake from the Devonian of the Eastern North Qilian Mts. and Its tectonic significance. Acta Geol Sin, 2008, 82: 801–840Google Scholar
  26. 26.
    Du Y S, Zhou D H, Gong S Y, et al. Tempestite and its palaeogeographical significance of Devonian in Jingyuan and Jingtai County, Gansu province (in Chinese). J Mineral Petrol, 2001, 21: 69–73Google Scholar
  27. 27.
    Taylor S R, McLennan S M. The Continental Crust: Its Composition and Evolution. Oxford: Blackwell, 1985. 1–312Google Scholar
  28. 28.
    Gu X X. Geochemical characteristics of the Triassic Tethys-turbidites in the northwestern Sichuan, China: Implications for provenance and interpreta-tion of the tectonic setting. Geochim Cosmochim Acta, 1994, 58: 4615–4631CrossRefGoogle Scholar
  29. 29.
    McLennan S M, Taylor S R, McCulloch M T, et al. Geochemical and Nd-Sr isotopic composition of deep-sea turbidites: Crustal evolution and plate tectonic associations. Geochim Cosmochim Acta, 1990, 43: 375–388CrossRefGoogle Scholar
  30. 30.
    Fedo C M, Nesbtit H W. Unravelling the effects of potassium metasomatzsm in sedimentary rocks and Paleosoles, with implications for paleoweathing conditions and provenance. Geology, 1995, 23: 921–924CrossRefGoogle Scholar
  31. 31.
    Condie K C, Noll J P D, Conway C M. Geochemical and detrital mode evidence for two sources of Early Proterozoic sedimentary rocks from the Tonto Basin Supergroup, central Arizona. Sediment Geol, 1992, 77: 51–76CrossRefGoogle Scholar
  32. 32.
    Bock B, McLennan S M, Hanson G N. Geochemistry and provenance of the Middle Ordovician Austin Glen Member (Normanskill Formation) and the Taconian Orogeny in New England. Sedimentology, 1998, 45: 635–655CrossRefGoogle Scholar
  33. 33.
    She Z B, Ma C Q, Mason R, et al. Provenance of the Triassic Songpan-Ganzi flysch, west China. Chem Geol, 2006, 231: 159–175CrossRefGoogle Scholar
  34. 34.
    Taylor S R, McLennan S M. The geochemical evolution of the continental crust. Rev Geophys, 1995, 33: 241–265CrossRefGoogle Scholar
  35. 35.
    Cullers R L. The geochemistry of shales, siltstones and sandstones of Pennsylvanian-Permian age, Colorado, USA: Implications for provenance and metamorphic studies. Lithos, 2000, 51: 181–203CrossRefGoogle Scholar
  36. 36.
    Bhatia M R. Plate tectonics and geochemical composition of sandstone. J Geol, 1983, 91: 611–627CrossRefGoogle Scholar
  37. 37.
    Wan Y S, Yang J S, Xu Z Q, et al. Geochemical characteristics of the Maxianshan complex and Xinglongshan Group in the eastern segment of the Qilian orogenic belt. J Geol Soc China, 2000, 43: 52–68Google Scholar
  38. 38.
    Smith A D. The geochemistry and age of ophiolitic strata of the Xinglongshan Group: Implications for the amalgamation of the Central Qilian belt. J Asian Earth Sci, 2006, 28: 133–142CrossRefGoogle Scholar
  39. 39.
    Li W Y, Guo Z P, Wang W. Caledonian convergent transformation and metallogenetic response in the North Qilian Mountains (in Chinese). Geol Rev, 2005, 51: 120–127Google Scholar
  40. 40.
    Zuo G C, Liu Y K, Zhang C. Tectono-stratigraphic characteristics of continent crustal remnants in central-western sector of the North Qilian orogen (in Chinese). Sci Geol Sin, 2002, 37: 302–312Google Scholar
  41. 41.
    Qi X X, Zhang J X, Li H B, et al. Geochronology of the dextral strike ductile shear zone in south margin of the Northern Qilian Mountains and its geological significance (in Chinese). Earth Sci Front, 2004, 11: 469–479Google Scholar

Copyright information

© Science China Press and Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • YaJun Xu
    • 2
  • YuanSheng Du
    • 1
    • 2
  • JiangHai Yang
    • 2
  • Hu Huang
    • 2
  1. 1.Key Laboratory of Biogeology and Environmental Geology of China Education MinistryChina University of GeosciencesWuhanChina
  2. 2.State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhanChina

Personalised recommendations