Biostratigraphy of the Cambrian–Ordovician boundary beds at Kopet-Dagh, Iran
2015 (English)In: Stratigraphy, ISSN 1547-139X, Vol. 2, no 12, 40-47 p.Article in journal (Refereed) Published
A continuous succession comprising upper Cambrian (Furongian) to Lower Ordovician (Tremadocian) conodont biozones is reported for the first time from the Kopet-Dagh Region of northeastern Iran. Seven biostratigraphical units are recognized, including the Proconodontus tenuiserratus and Proconodontus posterocostatus zones; these two lowermost biostratigraphical units are defined by euconodont species which have not been previously reported from Iran and temperate latitude peri-Gondwana. The conodont diversity and abundance decreased significantly above the Eoconodontus notchpeakensis Zone; the conodont faunas of the succeeding Cordylodus proavus, Cordylodus lindstromi (sensu lato) and Cordylodus angulatus zones are characterised by oligotaxic to monotaxic associations dominated by species of Cordylodus. In the absence of diagnostic conodont species, the position of the lower boundary of the Ordovician System in the Kalat Valley Section can be placed somewhat below the first occurrence of the early planktonic graptolite Rhabdinopora flabelliformis, which approximately coincides with the onset of black shale deposition.
Place, publisher, year, edition, pages
2015. Vol. 2, no 12, 40-47 p.
Earth and Related Environmental Sciences
Research subject Earth Science with specialization in Historical Geology and Palaeontology
IdentifiersURN: urn:nbn:se:uu:diva-259592ISI: 000358762400006OAI: oai:DiVA.org:uu-259592DiVA: diva2:844861
FunderSwedish Research Council, 2009-4395, 2012-1658