Facies, magnetic susceptibility and timing of the Late Devonian Frasnian/Famennian boundary interval (Xom Nha Formation, Central Vietnam)
Königshof, Peter

Ellwood, Brooks B.
Nguyen, Thang C.
Luu, Phuong Lan T.
Doan, Dinh Hung
Munkhjargal, Ariuntogos
DOI: https://doi.org/10.1007/s12549-021-00506-y
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11069
Königshof, Peter; Senckenberg – Research Institute and Natural History Museum, Frankfurt am Main, Germany
Ellwood, Brooks B.; Department of Geology and Geophysics, Louisiana State University, Baton Rouge, USA
Nguyen, Thang C.; Department of Geomagnetic Institute of Geophysics, Vietnam Academy of Science and Technology, Hanoi, Vietnam
Luu, Phuong Lan T.; Department of Geomagnetic Institute of Geophysics, Vietnam Academy of Science and Technology, Hanoi, Vietnam
Doan, Dinh Hung; Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, Hanoi, Vietnam
Munkhjargal, Ariuntogos; Mongolian University of Science and Technology, Ulaanbaatar, Mongolia
Abstract
Upper Devonian carbonates deposited through the Frasnian/Famennian (F/F) stage boundary in the Xom Nha Formation, Central Vietnam, were studied. The section is mainly composed of fossiliferous, brecciated, and laminated limestone beds, while shale beds occur in a subordinate number. Microfacies generally suggests a hemipelagic setting on an outer shelf environment with low sedimentation rates. A sediment accumulation rate of 0.217 cm/kyrs for this section is calculated. The Xom Nha section does not exhibit characteristic black shales or black limestones through the F/F boundary, but instead shows a similar lithology in comparison to other F/F sections in Southeast Asia. The carbonates yielded abundant conodonts, which represent mainly cosmopolitan species but the section differs from most sections in Europe in showing relatively high numbers of Palmatolepis linguiformis species. Deposition through the F/F boundary interval reported here for the Xom Nha section appears to have occurred during a ~1.2 Ma, and shows well-defined climate cyclicity.