Skip to main content
SpringerLink
Log in

Crust-forming processes in the Hercynides of the Central Asian Foldbelt

  • Published:
Petrology Aims and scope Submit manuscript

Abstract

The paper reports data on the evolutionary history of magmatism, its conditions, and sources in the process of the development of the Southern Mongolian Hercynides during the pre-accretion, continental-margin, and rifting stages within the time span from the Silurian to Early Permian. The Hercynian continental crust in the southern Mongolian segment of the Central Asian Foldbelt (CAFB) was determined to have grown in the environment of ensimatic island arcs, backarc basins, spreading centers, and oceanic islands or plateaus, with material coming from the depleted and, perhaps, also enriched mantle sources in the open ocean that surrounded the Siberian paleocontinent on the side of the Caledonian margin. This made it possible to recognize the Early-Middle Paleozoic epoch of juvenile crustal growth in CAFB and the corresponding isotopic crustal province with a total area of more than 200 thousand km2. The principal differences between the composition and structure of the blocks surrounding the Hercynian regions (Caledonides in the Gobi Altai and Grenwillides in the South Gobi microcontinent) testify that the southern margin of the Caledonian Siberian continent and the Grenvillides of the South Gobi microcontinent had different geological histories and were spatially separated. The structural complex of the Paleoasian ocean, including the terranes of the South Gobi microcontinent, were transformed into a continental block in the latest Devonian-earliest Carboniferous, in relation with accretion processes, folding, metamorphism, and tectonic delamination along the boundaries of structurally heterogeneous domains. The subsequent recycling of the crust by magmatic processes was related to the development of an active continental margin (ACM). The development of an ACM in the Hercynides resulted from and was a continuation of the motions of the continental and oceanic lithospheric plates, i.e., processes that brought about the Hercynian accretion. The evolution history of the ACM was subdivided into two stages: early (a continental-margin stage proper) and late (rifting stage). The rocks of the early stage were produced at 350–330 Ma and compose a differentiated basalt-andesite-rhyodacite complex and related massifs of the granodiorite-plagiogranite and banatite (diorite-monzonite-granodiorite) associations. During the rifting stage at 320–290 Ma, a bimodal basalt-comendite-trachyrhyolite association was formed, along with accompanying alkali granite massifs. In the southern Mongolian segment of the Hercynides, the rocks of the rifting stage compose two subparallel rift zones: Gobi-Tien Shan, which extends along the boundaries of the South Gobi microcontinent, and the Main Mongolian lineament, which marks the boundaries between the Hercynides and Caledonides in the CAFB. The rift structures are made up of alkali granitoids and normal-alkalinity granitoids, which are atypical of rift zones. Their genesis is thought to have been related to crustal anatexis, a process that was triggered by rift-related magmas at an unusual combination of rifting and ACM tectonic setting. The basic rocks of the rift associations have geochemical signatures atypical of continental rifting. They show Ta and Nb minima and K and Pb maxima, as is typical of rocks generated at convergent plate boundaries. Nevertheless, the broad variations in the concentrations and ratios of some major and incompatible trace elements and in the Sr, Nd, and O isotopic composition of the rift basaltoids allowed us to distinguish their high-and low-Ti varieties, which were produced with the participation of three mantle sources: depleted mantle similar to the source of basalts in midoceanic ridges, enriched mantle like the source of basalts in oceanic islands, and the mantle material of the metasomatized mantle wedge. The origin of andesites in the rift zones is explained by the contamination of mantle basaltoid melts with sialic (predominantly sedimentary) material of the continental crust or the assimilation of anatectic partial granite melts.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Bao-fu Han, Shi-guang Wang, Bor-ming Jahn et al. “Depleted-Mantle Source for the Ulungur River A-type Granites from North Xinjiang, China: Geochemistry and Nd-Sr Isotopic Evidence, and Implications for Phanerozoic Crustal Growth,” Chem. Geol. 138, 135–159 (1997).

    Article  Google Scholar 

  2. G. Badarch, W. D. Cunningham, and B. F. Windley, “A New Subdivision for Mongolia: Implication for Phanerozoic Crustal Growth in Central Asia,” J. Asian Earth Sci. 21, 87 (2002).

    Article  Google Scholar 

  3. M. T. McCulloch and J. A. Gamble, “Geochemical and Geodynamical Constraints on Subduction Zone Magmatism,” Earth Planet. Sci. Lett. 102, 358–374 (1991).

    Article  Google Scholar 

  4. A. Demoux, A. Krener, E. Hegner, and G. Badarch, “Paleozoic Volcanic Arc Activity in Southern Mongolia: Constrains from U-Pb Zircon Ages and Geochemical Characteristics,” in Structural and Tectonic Correlation across the Central Asia Orogenic Collage: Implication for Continental Growth and Intracontinental Deformation Second International Workshop and Field Excursions for IGC Project 480 (2006), pp. 49–51.

  5. A. B. Dergunov, V. I. Kovalenko, S. V. Ruzhentsev, and V. V. Yarmolyuk, Tectonics, Magmatism, and Metallogeny of Mongolia (Routledge. Taylor and Francis Group, London-New York, 2001).

    Google Scholar 

  6. M. V. Durante, Paleobotanical Substantiation of the Carboniferous and Permian Stratigraphy of Mongolia (Nauka, Moscow, 1976) [in Russian].

    Google Scholar 

  7. Geology of Mongolian People Republic, Ed. by N. A. Marinova (Nedra, Moscow, 1973), Vol. 2 [in Russian].

    Google Scholar 

  8. O. Gerel, S. Myagmarsuren, S. Oyungerel, et al., “Granitoids of Mongolia and Related Metallogeny: Example on South Mongolia,” in Structural and Tectonic Correlation Across the Central Asia Orogenic Collage: Implication for Continental Growth and Intracontinental Deformation. Second International Workshop and Field Excursions for IGC Project 480, (2006), pp. 59–64.

  9. C. Helo, E. Hegner, A. Kroner, et al., “Geochemical Signature of Paleozoic Accretionary Complexes of the Central Asian Orogenic Belt in South Mongolia: Constraints on Arc Environments and Crustal Growth,” Chem. Geol. 227, 236–257 (2006).

    Article  Google Scholar 

  10. B. E. Khashgerel, R. O. Rye, J. W. Hedenquist, and I. Kavalieris, “Geology and Reconnaissance Stable Isotope Study of the Oyu Tolgoi Porhyry Cu-Au System, South Gobi, Mongolia,” Econ. Geol. 101, 503–522 (2006).

    Article  Google Scholar 

  11. D. V. Kovalenko and E. E. Chernov, “Paleomagnetism of the Carboniferous-Permian Magmatic Complexes from the Southern Mongolia,” Fizika Zemli, No. 4 (2008) (in press).

  12. V. I. Kovalenko, V. V. Yarmolyuk, V. P. Kovach, et al., “Sources of Phanerozoic Granitoids in Central Asia: Sm-Nd Isotope Data,” Geokhimiya, No. 8 (1996) [Geochem. Int. 34, 628–640 (1996)].

  13. V. I. Kovalenko, V. V. Yarmolyuk, V. P. Kovach, et al., “Magmatism as a Factor of Crust Evolution in the Central Asian Foldbelt: Sm-Nd Isotopic Data,” Geotektonika, No. 3, 21–41 (1999) [Geotectonics 33, 191–208 (1999)].

  14. V. I. Kovalenko, V. V. Yarmolyuk, V. P. Kovach, et al., “Isotope Provinces, Mechanisms of Generation and Sources of the Continental Crust in the Central Asian Mobile Belt: Geological and Isotopic Evidence,” J. Asian Earth Sci. 23, 605–627 (2004).

    Article  Google Scholar 

  15. V. I. Kovalenko, V. V. Yarmolyuk, E. B. Sal’nikova, et al., “Geology, Geochronology, and Geodynamics of the Khan Bogd Alkali Granite Pluton in Southern Mongolia,” Geotektonika, No. 6, 3–27 (2006) [Geotectonics 40, 450–466 (2006)].

  16. I. K. Kozakov, V. P. Kovach, E. V. Bibikova, et al., “Age and Sources of Granitoids in the Junction Zone of the Caledonides and Hercynides in Southwestern Mongolia: Geodynamic Implications,” Petrologiya 15, 133–159 (2007) [Petrology 15, 126–150 (2007)].

    Google Scholar 

  17. A. M. Kozlovsky, V. V. Yarmolyuk, V. I. Kovalenko, et al., “Trachytes, Comendites, and Pantellerites of the Late Paleozoic Bimodal Rift Association of the Noen and Tost Ranges, Southern Mongolia: Differentiation and Contamination of Peralkaline Salic Melts,” Petrologiya 15(3) (2007) [Petrology 15, 240–263 (2007)].

    Google Scholar 

  18. A. M. Kozlovsky, V. V. Yarmolyuk, E. B. Sal’nikova, et al., “Age of Bimodal and Alkali Granite Magmatism of the Gobi-Tien Shan Rift Zone, Tost Range, Southern Mongolia,” Petrologiya 13(2), 232–239 (2005) [Petrology 13, 197–203 (2005)].

    Google Scholar 

  19. A. M. Kozlovsky, V. V. Yarmolyuk, V. M. Savatenkov, and V. P. Kovach, “Sources of Basaltoid Magmas in Rift Settings of an Active Continental Margin: Example from the Bimodal Association of the Noen and Tost Ranges of the Late Paleozoic Gobi-Tien Shan Rift Zone, Southern Mongolia,” Petrologiya 14(4) (2006) [Petrology 14, 337–360 (2006)].

    Google Scholar 

  20. M. J. Le Bas, R. W. Le Maitre, A. Streckeisen, and B. Zanettin, “A Chemical Classification of Volcanic Rocks Based on the Total Alkali—Silica Diagram,” J. Petrol. 27, 745–750 (1986).

    Google Scholar 

  21. N. G. Markova, Stratigraphy of the Lower Paleozoic of Western Mongolia (Nauka, Moscow, 1975) [in Russian].

    Google Scholar 

  22. A. A. Mossakovskii, Orogenic Structures and Volcanism of Eurasia and Their Role in the Earth’s Crust Formation (Nauka, Moscow, 1975) [in Russian].

    Google Scholar 

  23. S. V. Ruzhentsev, G. Badarch, T. A. Voznesenskaya, and N. G. Markova, Evolution of Geological Processes and Metallogeny of Mongolia (Nauka, Moscow, 1990) [in Russian].

    Google Scholar 

  24. S. V. Ruzhentsev and I. I. Pospelov, “South Mongolian Variscan Fold System,” Geotektonika, No. 5 (1992).

  25. S. S. Sun and W. F. Donough, Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes: Magmatism in the Ocean Basins in Magmatism in the Ocean Basins, Ed. by A. D. Saunders and M. J. Norry, Geol. Soc. London Spec. Publ. 42, pp. 313–346 (1989).

  26. Tectonics of Mongolian People Republic, Ed. by A. L. Yanshina (Nauka, Moscow, 1974) [in Russian].

    Google Scholar 

  27. Treatise on Geochemistry (Elsevier, Amsterdam, 2003), Vol. 3.

  28. T. Wang, Ya. Zheng, G. E. Gehrels, and Z. Mu, “Geochronological Evidence for Existence of South Mongolian Microcontinent—A Zircon U-Pb Age of Granitoid Gneisses from the Yagan-Onch Hayrhan Metamorphic Core Complex,” Chin. Sci. Bull 146, 2005–2008 (2001).

    Article  Google Scholar 

  29. Wang Shiguang and Bao-fu Han, “Geochemistry and Tectonic Significance of Alkali Granites along Ulungur River, Xingan,” Sci. Geol. Sinica 29, 373–383 (1994).

    Google Scholar 

  30. M. Wilson, Igneous Petrogenesis (Unwin Hyman, London, 1989).

    Google Scholar 

  31. L. Xia, Z. Xia, X. Xu, et al., “Relationship between Basic and Silicic Magmatism in Continental Rift Settings: a Petrochemical Study of Carboniferous Post-Collisional Rift Silicic Volcanics in Tianshan, NW China,” Acta Geol. Sinica 79(5), 633–653 (2005).

    Google Scholar 

  32. V. V. Yarmolyuk, Upper Paleozoic Volcanogenic Associations and Structural-Petrological Features of Their Evolution (Nauka, Moscow, 1978) [in Russian].

    Google Scholar 

  33. V. V. Yarmolyuk, Late Paleozoic Volcanism of Continental Rift Structures of Central Asia (Nauka, Moscow, 1983) [in Russian].

    Google Scholar 

  34. V. V. Yarmolyuk and V. I. Kovalenko, Rift Magmatism of Active Continental Margins and Its Ore Potential (Nauka, Moscow, 1991) [in Russian].

    Google Scholar 

  35. V. V. Yarmolyuk, V. I. Kovalenko, V. P. Kovach, et al., “Nd-Isotopic Systematics of Western Transbaikalian Crustal Protoliths: Implications for Riphean Crust Formation in Central Asia,” Geotektonika, No. 4, 3–20 (1999a) [Geotectonics 33, 271–286 (1999)].

  36. V. V. Yarmolyuk, V. I. Kovalenko, V. P. Kovach, et al., “Isotopic Composition, Sources of Crustal Magmatism, and Crustal Structure of Caledonides of the Ozernaya Zone, Central Asian Foldbelt,” Dokl. Akad. Nauk 387, 387–392 (2002) [Dokl. Earth Sci. 387, 1043–1047 (2002)].

    Google Scholar 

  37. V. V. Yarmolyuk, V. P. Kovach, V. I. Kovalenko, et al., “Isotopic Composition of the Hercynian Crust of Southern Mongolia: Substantiation of the Hercynian Juvenile Crust-Forming Event,” Dokl. Akad. Nauk 416, 804–809 (2007) [Dokl. Earth Sci. 416, 1178–1182 (2007)].

    Google Scholar 

  38. V. V. Yarmolyuk, V. I. Kovalenko, E. B. Sal’nikova, et al., “U-Pb Age of Syn-and Postmetamorphic Granitoids of South Mongolia: Evidence for the Presence of Grenvillides in the Central Asian Foldbelt,” Dokl. Akad. Nauk 404, 84–89 (2005) [Dokl. Earth Sci. 404, 986–990 (2005)].

    Google Scholar 

  39. V. V. Yarmolyuk, V. I. Kovalenko, E. B. Sal’nikova, et al., “Geochronology of Igneous Rocks and Formation of the Late Paleozoic South Mongolian Active Margin of the Siberian Continent,” Stratigr. Geol. Korrelyatsiya 16(2), 59–80 (2008) [Stratigr. Geol. Correlation 16, 162–181 (2008)].

    Google Scholar 

  40. V. V. Yarmolyuk, V. S. Samoilov, V. G. Ivanov, et al., “Composition and Sources of Basalts in the Late Paleozoic Rift System of Central Asia: Geochemical and Isotopic Data,” Geokhimiya, No. 10, 1027–1042 (1999b) [Geochem. Int. 37, 921–935 (1999)].

  41. L. P. Zonenshain, O. D. Suetenko, L. Zham’yandamba, and G. Eenzhin, “Structure of the Axial Part of the Southern Mongolian Eugeosyncline and Dzolen Ridge,” Geotektonika, No. 4 (1975).

Download references

Author information

Authors and Affiliations

  1. Institute of the Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 119017, Russia

    V. V. Yarmolyuk, V. I. Kovalenko, A. M. Kozlovsky, D. V. Kovalenko & E. A. Kudryashova

  2. Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034, Russia

    V. P. Kovach, E. B. Sal’nikova & A. B. Kotov

  3. Tuva Institute for Complex Research of Natural Resources, Siberian Branch, Russian Academy of Sciences, ul. Internatsional’naya 117a, Kyzyl, 667007, Russia

    V. I. Lebedev

  4. Institute of Geology and Mineral Resources, Mongolian Academy of Sciences, Ulan-Bator, 210357, Mongolia

    G. Eenzhin

Authors
  1. V. V. Yarmolyuk
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. V. I. Kovalenko
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. A. M. Kozlovsky
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. V. P. Kovach
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. E. B. Sal’nikova
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. D. V. Kovalenko
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. A. B. Kotov
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. E. A. Kudryashova
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. V. I. Lebedev
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. G. Eenzhin
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to A. M. Kozlovsky.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Yarmolyuk, V.V., Kovalenko, V.I., Kozlovsky, A.M. et al. Crust-forming processes in the Hercynides of the Central Asian Foldbelt. Petrology 16, 679–709 (2008). https://doi.org/10.1134/S0869591108070035

Download citation

  • Received:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1134/S0869591108070035

Keywords

Search

Navigation