Paleobiogeographic significance of Tethyan Lower Cretaceous Cecrops septemporatus Zone radiolarian faunas

• Published in: Palaeogeography, palaeoclimatology, palaeoecology Vol. 589; p. 110836
• Main Authors: Cui, Xiaohui, Li, Xin, Aitchison, Jonathan C., Luo, Hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2022
• Subjects: Paleobiogeography; Southern Tibet; Umbria–Marche Basin; Valanginian–Hauterivian; Vertical distribution; Valanginian–Hauterivian; Paleobiogeography; Vertical distribution; Southern Tibet; Umbria–Marche Basin
• ISSN: 0031-0182; 1872-616X
• DOI: 10.1016/j.palaeo.2022.110836

The Cecrops septemporatus Zone is widely applied in correlation of Valanginian to lower Hauterivian successions, but paleobiogeographic distributions of radiolarian fauna from this zone remain ambiguous. To address this issue this study compares radiolarian faunas from the Vispi Quarry section, Umbria–Marche Basin, central Italy with the Guigong section, southern Tibet. Similarity between these C. septemporatus Zone faunas suggests a close marine connection may have existed between western and eastern Tethys during Early Cretaceous time. Lithologies, depositional setting, associated fossil records, and paleomagnetic data from contemporaneous radiolarian occurrences in different areas globally are also assessed. The paleobiogeographic distribution of the C. septemporatus Zone fauna was mainly restricted to low latitudes in the Tethyan and Pacific regions, but also shows a significant migration from low latitudes in the Tethyan Realm to mid latitudes in the Boreal and Austral realms. Climatic and oceanographic conditions during the Weissert Event may have played important roles in the development of the paleobiogeographic distribution patterns observed for the C. septemporatus Zone faunas. [Display omitted] •Well-preserved Cecrop septemporatus Zone radiolarians were recovered.•A close marine connection between western and eastern Tethys.•Zonal fauna inhabits shallow water masses within a mesopelagic depth.•C. septemporatus Zone fauna is restricted in the Tethys realm and Pacific region.•C. septemporatus zonation has wide paleobiogeographical applicability.