Archives
 
Year 2026
 
Vol 67, Issue 5, [10 - 2026]

Petrography, U–Pb zircon ages and zircon geochemistry of the Khanh Thien syenite complex and their tectonic implications for northeastern Vietnam during the Early Cambrian

DOI:10.46326/JMES.2026.67(5).08

  • Affiliations:

    1 Vietnam Department of Geology and Minerals, Hanoi, Vietnam
    2 Hanoi University of Mining and Geology, Hanoi, Vietnam
    3 Institute of Geological Sciences and Mineral Resources, Hanoi, Vietnam

  • *Corresponding:
    This email address is being protected from spambots. You need JavaScript enabled to view it.
  • Received: 20th-Jan-2026
  • Revised: 5th-July-2026
  • Accepted: 30th-July-2026
  • Online: 1st-Oct-2026
Pages: 95 - 112
Views: 19
View onlineView online
Downloads: 1
Downdload PDF
★★★★★Rating: , Total rating: 0
  • ★
  • ★
  • ★
  • ★
  • ★
Yours rating

Abstract:

The Khanh Thien syenite complex, exposed in the Yen Bai area, represents an important episode of alkaline magmatism during the Early Paleozoic tectonic evolution of the Northeastern Vietnam. The studied rocks are characterised by high K-feldspar contents, low proportions of plagioclase and quartz, and locally contain biotite ± hornblende. Zircon U–Pb dating yields a crystallisation age of 520.7 ± 1.5 Ma, indicating emplacement during the Early Cambrian. Petrographic features and zircon trace-element compositions, including (Ce/Ce*) > 1, (Eu/Eu*) < 1, low P contents and relatively high Hf concentrations, suggest highly oxidised magmatic conditions and strong feldspar fractionation, typical of fractionated A-type granitoid magmas. Zircon Nb/Hf, Th/U, Th/Nb and Hf/Th ratios, together with low εNd(t) values and relatively high ⁸⁷Sr/⁸⁶Sr ratios, are consistent with derivation from a slightly crustally enriched mantle source. These characteristics may reflect syenitic magmatism developed in a post-collisional extensional tectonic setting. The Khanh Thien syenites are interpreted to be related to deep lithospheric modification and reworking within an orogenic belt following the final assembly of the Gondwana supercontinent. This study provides new geochronological and zircon geochemical constraints on the Early Paleozoic tectonic framework of northeastern Vietnam and highlights the role of alkaline magmatism in regional lithospheric evolution.

How to Cite
Chu, D.Van, Tran, D.My, Le, T.Xuan, Trinh, H.Xuan and Ngo, T.Xuan 2026. Petrography, U–Pb zircon ages and zircon geochemistry of the Khanh Thien syenite complex and their tectonic implications for northeastern Vietnam during the Early Cambrian (in Vietnamese). Journal of Mining and Earth Sciences. 67, 5 (Oct, 2026), 95-112. DOI:https://doi.org/10.46326/JMES.2026.67(5).08.
References

Andersen, T. (2002). Correction of common lead in U–Pb analyses that do not report 204Pb. Chemical Geology, 192, 59-79.

Bonin, B. (2007). A-type granites and related rocks: Evolution of a concept. Lithos, 97, 1–29. https://doi.org/10.1016/j.lithos.2006.12.007.

Burnham, A. D., and Berry, A. J. (2017). Formation of Hadean granites by melting of igneous crust. Nature Geoscience, 10, 457–461. https://doi.org/10.1038/ngeo2942.

Cawood, P. A., Hawkesworth, C. J., and Dhuime, B. (2013). The continental record and the generation of continental crust. Earth-Science Reviews, 120, 77–93. https://doi.org/10.1016/j.earscirev.2012.08.002.

Chappell, B. W., and White, A. J. R. (1974). Two contrasting granite types. Pacific Geology, 8, 173–174.

Chu, V. D., Tran, M. D., and Ngo, X. T. (2026). Post-collisional extension during the Early Paleozoic in Northeast Vietnam: Evidence from syenitic complex. Proceedings of the International Symposium on Sustainable Critical Mineral Resource Development for Energy Transition (ISCMRDET 2026). ISBN: 978-604-76-3351-7.

Collins, A. S., and Pisarevsky, S. A. (2005). Amalgamating eastern Gondwana: The evolution of the Circum-Indian Orogens. Geology, 33, 821–824. https://doi.org/10.1130/G21300.1.

Eby, G. N. (1992). Chemical subdivision of the A-type granitoids: Petrogenetic and tectonic implications. Geology, 20(7), 641–644. https://doi.org/10.1130/0091-7613(1992)020<0641:CSOTAT>2.3.CO;2

Goodenough, K., Thomas, R. J., De Waele, B., et al. (2010). Post-collisional magmatism in the central East African Orogen: The Maevarano Suite of north Madagascar. Lithos, 116–117, 18–34.

Grimes, C. B., John, B. E., Kelemen, P. B., Mazdab, F. K., Wooden, J. L., Cheadle, M. J., Hanghøj, K., and Schwartz, J. J. (2007). Trace element chemistry of zircon from oceanic crust: A method for distinguishing detrital zircon provenance. Geology, 35, 643–646. https://doi.org/10.1130/G23603A.1

Grimes, C. B., Wooden, J. L., Cheadle, M. J., and John, B. E. (2015). Fingerprinting tectono-magmatic provenance using trace elements in zircon. Contributions to Mineralogy and Petrology, 170, 46. https://doi.org/10.1007/s00410-015-1199-3

Hoàng, T. S. và nnk. (1997). Địa chất và Khoáng sản nhóm tờ Đoan Hùng - Yên Bình, tỷ lệ 1:50.000. Lưu trữ Địa chất.

Le Maitre, R. W. et al. (2002). Igneous Rocks: A Classification and Glossary of Terms. Cambridge University Press.

Li, L., Lin, S., Xing, G., Jiang, Y., and He, J. (2017). First direct evidence of Pan-African Orogeny associated with Gondwana assembly in the Cathaysia Block of Southern China. Scientific Reports, 7, 794. https://doi.org/10.1038/s41598-017-00950-x

Li, S. et al. (2017). Paleomagnetic constraints on the Mesozoic-Cenozoic paleolatitudinal and rotational history of Indochina and South China: review and updated kinematic reconstruction. Earth-Science Reviews, 171, 58–77.

Li, X. H. et al. (2008). Amalgamation between the Yangtze and Cathaysia blocks. Precambrian Research, 159, 79–94. https://doi.org/10.1016/j.precamres.2007.06.004

Li, Z. X., Bogdanova, S. V., Collins, A. S., Davidson, A., De Waele, B., Ernst, R. E., Fitzsimons, I. C. W., Fuck, R. A., Gladkochub, D. P., Jacobs, J., Karlstrom, K. E., Lu, S., Natapov, L. M., Pease, V., Pisarevsky, S. A., Thrane, K., and Vernikovsky, V. (2008). Assembly, configuration, and break-up history of Rodinia: A synthesis. Precambrian Research, 160, 179–210. https://doi.org/10.1016/j.precamres.2007.04.018

Loiselle, M. C., and Wones, D. R. (1979). Characteristics and origin of anorogenic granites. Geological Society of America Abstracts with Programs, 11(7), 468.

Ludwig, K. R. (2003). User's manual for a geochronological toolkit for Microsoft Excel (Isoplot/Ex version 3.0).

Lưu, H. H. (1998). Bản đồ địa chất tỷ lệ 1:50.000 nhóm tờ Bảo Yên [Bản đồ địa chất]. Liên đoàn Bản đồ Địa chất miền Bắc.

Nguyễn, T. C., và Nguyễn, T. D. (2009). Nguồn gốc syenit nephelin Đông Bắc Việt Nam. Tạp chí Các Khoa học về Trái Đất, 31(1), 73–84.

Nguyễn, V. Q. và nnk. (1992). Địa chất và Khoáng sản nhóm tờ Na Hang - Ba Bể F48-56A (Thomtchay), F48-56c (Ba Bể) 1:50.000. Lưu trữ Địa chất.

Pu, W., Gao, J. F., Zhao, K. D., Ling, H. F., and Jiang, S. Y. (2005). Separation method of Rb–Sr, Sm–Nd using DCTA and HIBA. Journal of Nanjing University (Natural Sciences), 41(4), 445-450.

Pu, W., Zhao, K., Ling, H., and Jiang, S. (2004). High precision Nd isotope measurement by means of Triton TI mass spectrometry. Acta Geoscientia Sinica, 271-274.

Roger, F., Leloup, P. H., Jolivet, M., Lacassin, R., Trinh, P. T., Brunel, M., and Seward, D. (2000). Long and complex thermal history of the Song Chay metamorphic dome (Northern Vietnam) by multi-system geochronology. Tectonophysics, 321, 449-466.

Sawaki, Y., Asanuma, H., Sakata, S., Abe, M., Ueda, H., Fujisaki, W., and Ohno, T. (2024). Zircon trace-element compositions in Cenozoic granitoids in Japan: Revised discrimination diagrams for zircons in I-type, S-type, and A-type granites. Island Arc, 33, e12539. https://doi.org/10.1111/iar.12539

Shellnutt, J. G., Pham, N. H. T., Denyszyn, S. W., et al. (2017). Timing of collisional and post-collisional Pan-African Orogeny silicic magmatism in south-central Chad. Precambrian Research, 301.

Tapponnier, P. et al. (1990). Extrusion tectonics in Asia. Geological publications.

Tran, V. T. (Ed.) (2023). Geology and Georesources of Việt Nam. Youth Publishing House, Hanoi.

Trần, V. T., và Vũ, K. (chủ biên) (2009). Địa chất và tài nguyên Việt Nam. Nhà xuất bản Khoa học Tự nhiên và Công nghệ, Hà Nội, 589 trang.

Trần, X. (1988). Địa chất và Khoáng sản 1:200.000 Nhóm tờ Bắc Quang - Mã Quang, Hà Tuyên (Hà Giang) F-48-XV và F-48-IX. Lưu trữ Địa chất.

Wang, and Burchfiel (2000). Structural and tectonic evolution of Asia.

Whalen, J. B., Currie, K. L., and Chappell, B. W. (2010). A-type granites and syenites. Lithos, 119, 1–23.

Yuan, H. L., Wu, F. Y., Gao, S., Liu, X. M., Xu, P., and Sun, D. Y. (2003). Determination of U-Pb age and rare earth element concentrations of zircons from Cenozoic intrusions in northeastern China by laser ablation ICP-MS. Chinese Science Bulletin, 48, 2411-2421.

Other articles