Devonian-Carboniferous boundary sections in Iran
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ORIGINAL PAPER
Devonian-Carboniferous boundary sections in Iran Peter Königshof 1
&
Ali Bahrami 2 & Sandra I. Kaiser 3
Received: 5 April 2019 / Revised: 4 March 2020 / Accepted: 24 June 2020 # The Author(s) 2020
Abstract Many sections are known from Iran which exhibit sediments across the Devonian-Carboniferous (D-C) boundary. In contrast to the majority of published D-C sections worldwide from pelagic/hemipelagic environments, successions in Iran are mainly composed of shallow-water sediments. Correlation with hemipelagic or pelagic palaeoenvironments remains difficult due to biostratigraphic uncertainties in most sections and/or hiatuses. On the other hand, a limited number of sections dealing with shallow-water facies settings in Iran at this particular time period are known and further research is necessary. Several sections in the Alborz Mountains provide an excellent opportunity to study successions across the D-C boundary in shallow-water facies. In Iran, protognathoids are represented by Protognathodus meischneri and Protognathodus collinsoni. The two biostratigraphically important protognathoids (Protognathodus kuehni and Protognathodus kockeli) were not reported or did not occur for the first time in the Late Tournaisian. Early siphonodellids were described instead. In the frame of an Iranian/German research project, we study different palaeoenvironments to reduce serious palaeoenvironmental and palaeogeographical sampling bias which may limit our knowledge on the Hangenberg Event particularly in shallow-water facies. We present a summary on published D-C sections in Iran (Ghale-Kalaghu, Howz-e-Dorah 1, Howz-e-Dorah 2 and Shahmirzad) and sections which are under study (Mighan, Chelcheli and Khoshyeilagh) at the time of this writing. Keywords Hangenberg Crisis . Shallow-water palaeoenvironments . Conodonts . Alborz Mountains . Shotori Range
Introduction Based on recent discussions on climate change, the study of extinction events, dynamics and reasons for environmental and climate changes in Earth’s history is of fundamental importance. The Devonian-Carboniferous (D-C) transition is one This article is a contribution to the special issue “Global review of the Devonian-Carboniferous Boundary”. * Peter Königshof [email protected] Ali Bahrami [email protected] Sandra I. Kaiser [email protected] 1
Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, 60325 Frankfurt am Main, Germany
2
Department of Geology, Faculty of Science, University of Isfahan, Isfahan, Iran
3
State Museum of Natural History Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
of the most interesting time slices in Earth’s history as this period was characterised by extreme climate and faunal changes which led to the end-Devonian biodiversity crisis. Based on the ecological severity index by McGhee et al. (2013), the end-Devonian extinction is known as the fourth severe mass extinction in Earth’s history. This first-order mass extinction eliminated nearly 20% of marine invertebr
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