Abstract
This study refines the biostratigraphic framework of the upper Zongshan Formation in southern Xizang (Tibet) by conducting a meticulous morphometric analysis of larger benthic foraminifera (LBF) from the Gamba area. Focusing on the genera Orbitoides and Omphalocyclus, we employed a comprehensive morphometric approach to delineate the stratigraphic transition within the formation. A total of 42 samples were collected across pivotal lithological intervals, leading to the identification of species groups that provide precise age constraints for the upper Zongshan Formation. Specifically, the O. tissoti–O. media group and Om. anatoliensis within Limestone II to Calcareous Marl II support a late Campanian age, while the presence of the O. megaloformis–O. gruenbachensis group and potential Om. cideensis in Limestone III suggest a younger age bracket extending into the early Maastrichtian. Our findings not only clarify the stratigraphic position of the upper Zongshan Formation but also contribute significantly to the ongoing investigations of final evolutionary stages of the eastern Neotethys.
References
- Baumfalk, Y.A. (1986) The evolution of Orbitoides media (Foraminiferida) in the Late Campanian. Journal of Foraminiferal Research, 16 (3), 293–312. https://doi.org/10.2113/gsjfr.16.4.293
- BouDagher-Fadel, M.K., Price, G.D., Hu, X.M. & Li, J. (2015) Late Cretaceous to early Paleogene foraminiferal biozones in the Tibetan Himalayas, and a pan-Tethyan foraminiferal correlation scheme. Stratigraphy, 12 (1), 67–91. https://doi.org/10.29041/strat.12.1.05
- Caus, E., Bernaus, J.M. & Gomez-Garrido, A. (1996) Biostratigraphic utility of species of the genus Orbitoides. Journal of Foraminiferal Research, 26 (2), 124–136. https://doi.org/10.2113/gsjfr.26.2.124
- Colpaert, C.P.A.M. & Li, G. (2021) Uppermost Jurassic to Lower Cretaceous benthic foraminiferal faunas of the Weimei and the Bandingsi localities of northern and southern parts of South Tibet—A preliminary analysis. Cretaceous Research, 124, 104785. https://doi.org/10.1016/j.cretres.2021.104785
- Drooger, C.W. (1993) Radial Foraminifera; morphometries and evolution. North-Holland, Amsterdam, 242 pp.
- Fang, P.Y., Xu, B., Mu, L., Zhu, Y.H. & Luo, H. (2020) New latest Coniacian to middle Campanian foraminiferal data from the lower Zongshan Formation in the Chaqiela section, Gamba, southern Tibet. Palaeoworld, 29 (1), 151–160. https://doi.org/10.1016/j.palwor.2019.05.011
- Gansser, A. (1964) Geology of the Himalayas. Interscience Publication John Wiley and Sons, New York, 289 pp.
- Hu, X.M., Jansa, L. & Wang, C.S. (2008) Upper Jurassic–Lower Cretaceous stratigraphy in south-eastern Tibet: a comparison with the western Himalayas. Cretaceous Research, 29 (3), 301–315. https://doi.org/10.1016/j.cretres.2007.05.005
- Li, G., Holbourn, A., Kuhnt, W., Fang, P.Y., Yao, J.X. & Willems, H. (2020) Occurrence of benthic foraminifers across the Jurassic/Cretaceous transition in Gyangze, southern Xizang (Tibet), China. Cretaceous Research, 105, 103931. https://doi.org/10.1016/j.cretres.2018.08.001
- Li, X.H., Wang, C.S. & Hu, X.M. (2005) Stratigraphy of deep-water Cretaceous deposits in Gyangze, southern Tibet, China. Cretaceous Research, 26 (4), 33–41. https://doi.org/10.1016/j.cretres.2004.11.004
- Liu, G.H. & Einsele, G. (1994) Sedimentary history of the Tethyan basin in the Tibetan Himalayas. Geologische Rundschau, 83 (2), 32–61. https://doi.org/10.1007/BF00211893
- Mu, E.Z., Yin, J.X., Wen, S.X. & Wang, Y.G. (1973) Stratigraphy of the mount Jolmo Lungma region in southern Tibet, China. Scientia Geologica Sinica, 1, 1–36. [In Chinese with English abstract]
- Özcan, E. (2007) Morphometric analysis of the genus Omphalocyclus from the Late Cretaceous of Turkey: new data on its stratigraphic distribution in Mediterranean Tethys and description of two new taxa. Cretaceous Research, 28 (4), 621–641. https://doi.org/10.1016/j.cretres.2006.09.002
- Özcan, E. & Özkan-Altiner, S. (1999) The genera Lepidorbitoides and Orbitoides: evolution and stratigraphic significance in some Anatolian basins. Geological Journal, 34 (3), 275–286. https://doi.org/10.1002/(SICI)1099-1034(199907/09)34:3<275::AID-GJ827>3.0.CO;2-J
- Rao, X., Sha, J.G., Pan, Y.H. & Cai, H.W. (2012) Bournonia from the Late Cretaceous Zongshan Formation of Gamba, Xizang, and the functional morphology of rudist bivalves. Acta Palaeontologica Sinica, 51 (4), 491–501. [In Chinese with English abstract]
- Tapponnier, P., Mercier, J.L., Proust, F., Andrieux, J., Armijo, R., Bassoullet, J.P., Brunel, M., Burg, J.P., Colchen, M., Dupré, B., Girardeau, J., Marcoux, J., Mascle, G., Matte, P., Nicolas, A., Li, T., Xiao, X., Chang, C., Lin, P., Li, G., Wang, N., Chen, G., Han, T., Wang, X., Den, W., Zhen, H., Sheng, H., Cao, Y., Zhou, J. & Qiu, H. (1981) The Tibetan side of the India—Eurasia collision. Nature, 294 (3), 405–410. https://doi.org/10.1038/294405a0
- Van Hinte, J.E. (1965) An approach to Orbitoides. Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, 68, 57–70.
- Wan, X.Q. (1985) Cretaceous strata and Foraminifera of Gangba region, Xizang. Contribution to the geology of the Qinghai-Xizang (Tibet) Plateau, 16, 203–228. [In Chinese with English abstract]
- Wan, X.Q. (1987) Cretaceous planktonic foraminifera zonation in Xizang (Tibet). Contribution to the geology of the Qinghai-Xizang (Tibet) Plateau, 18, 112–121. [In Chinese with English abstract]
- Wan, X.Q., Zhao, W.J. & Li, G.B. (2000) Restudy of the Upper Cretaceous in Gamba, Tibet. Geoscience, 14 (3), 281–285. [In Chinese with English abstract]
- Wang, C.S., Li, X.H., Hu, X.M., Wan, X.Q., Yin, J.R., Huang, Y.J., Huang, S.J. & Li, G.B. (2005) Sedimentary Geology and Continental Paleoceanography in Tethyan Himalayas. Geological Publishing House, Beijing, 373 pp. [In Chinese with English abstract]
- Wang, C.S., Xia, D.X., Zhou, X., Chen, J.P., Lu, Y., Wang, G.H., He, Z.W., Li, X.H., Wan, X.Q., Zeng, Q.G., Pubu, C. & Liu, Z.F. (1996) Field Trip Guide T121/T387, Geology between the Indus-Yarlung Zangbo Suture Zone and the Himalaya Mountains, Xizang (Tibet), China. Geological Publishing House, Beijing, 72 pp.
- Wang, Y.G., Sun, D.L. & He, G.X. (1980) New advances in the stratigraphy of the Chinese part of the Himalayas. Journal of Stratigraphy, 4 (1), 55–59. [In Chinese]
- Wen, S.X. (1974) Stratigraphy of the Mount Jolmo Lungma region: Cretaceous. In: Comprehensive Scientific Expedition Team to Xizang, Chinese Academy of Sciences (Ed.), A Report of the Scientific Expedition in the Mount Jolmo Lungma Region (1966–1968), Geology. Science Press, Beijing, pp. 148–183. [In Chinese]
- Wen, S.X., Lan, X., Chen, J.H., Zhang, Z.M., Chen, C.Z. & Gu, Z.W. (1976) Fossil Lamellibranchia from the Mount Jolmo Lungma region. In: Comprehensive Scientific Expedition to Xizang, Chinese Academy of Sciences (Eds), A Report of the Scientific Expedition in the Mount Jolmo Lungma Region (1966–1968), Paleontology (3). Scientific Press, Beijing, pp. 1–210. [In Chinese]
- Wendler, I., Willems, H., Gräfe, K.U., Ding, L. & Luo, H. (2011) Upper Cretaceous inter-hemispheric correlation between the Southern Tethys and the Boreal: chemo-and biostratigraphy and paleoclimatic reconstructions from a new section in the Tethys Himalaya, S-Tibet. Newsletters on Stratigraphy, 44 (2), 137–171. https://doi.org/10.1127/0078-0421/2011/0010
- Willems, H. (1993) Geoscientific investigations in the Tethyan Himalayas. Fachbereich Geowissenschaften der Universität Bremen, 183 pp.
- Willems, H., Zhou, Z., Zhang, B. & Gräfe, K.U. (1996) Stratigraphy of the Upper Cretaceous and Lower Tertiary strata in the Tethyan Himalayas of Tibet (Tingri area, China). Geologische Rundschau, 85 (3), 723–754. https://doi.org/10.1007/s005310050108
- Yin, A. & Harrison, T.M. (2000) Geologic evolution of the Himalayan-Tibetan orogen. Annual Review of Earth and Planetary Sciences, 28 (1), 211–280. https://doi.org/10.1146/annurev.earth.28.1.211
- Yu, G.M. & Wang, C.S. (1990) Sedimentary geology of the Xizang (Tibet) Tethys. Geological Publishing House, Beijing, 185 pp. [In Chinese with English abstract]