Triassic palynostratigraphy and palynofloral provinces: evidence from southern Xizang (Tibet), ChinaShow others and affiliations
2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, p. 67-86Article in journal (Refereed) Published
Abstract [en]
Palynological analysis was carried out on Middle to Upper Triassic strata from Tulong, Nyalam County, southern Xizang (Tibet), China. Well-preserved miospore (pollen and spore) assemblages and sparse acritarch occurrences were identified. We recognized four formal and one informal biozones based on stratigraphically important taxa and compositional changes through the succession, in ascending order: the Triplexisporites Interval Zone (Anisian), the Staurosaccites quadrifidus Taxon-range Zone (upper Anisian to lower Norian), the Striatella Interval Zone (lower Norian), the Craterisporites rotundus Taxon-range Zone (middle to upper Norian) and the informal ‘Dictyophyllidites harrisii zone’ (Rhaetian). The zonation was supported by marine fossils (e.g., ammonoids and conodonts), and compositional similarity between the zones was examined using non-metric multidimensional scaling (NMDS). Correlation with other representative palynological sequences across Gondwana was also conducted. The presence of miospore taxa not previously recovered from the Late Triassic North and South China palynofloral provinces (e.g., Ashmoripollis reducta, Craterisporites rotundus, Enzonalasporites vigens, Minutosaccus crenulatus, Samaropollenites speciosus and Staurosaccites quadrifidus) calls for a new province in southwestern China, i.e., the Southern Xizang Province. It is proposed here that the modern expression of the northern boundary runs along the Yarlung Zangbo Suture, the remnant of the Tethys that separated the Indian Plate (southern Xizang) and the Lhasa Block during the Late Triassic. This new palynofloral province comprises typical elements of the Onslow Microflora, indicating the need for an extension of this microflora in southern Xizang, China.
Place, publisher, year, edition, pages
Melbourne: Taylor & Francis, 2018. Vol. 42, p. 67-86
Keywords [en]
pollen and spores, phytogeography, Tulong, Southern Xizang Palynofloral Province, Onslow Microflora, Gondwana, non-metric multidimensional scaling
National Category
Other Earth Sciences
Identifiers
URN: urn:nbn:se:nrm:diva-3234DOI: 10.1080/03115518.2017.1370726OAI: oai:DiVA.org:nrm-3234DiVA, id: diva2:1276101
Funder
Swedish Research Council, 2015-04264
Note
This work was made possible by the support of the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB03010103), UNESCO grant IGCP 632, the Swedish Research Council, grant VR 2015-04264 and the China Scholarship Council (201504910609).
2019-01-012019-01-072025-02-07Bibliographically approved