SGURapporter och meddelanden 128 Rapporter och meddelanden 128 WOGOGOB 2007 9th meeting of the Working Group on Ordovician Geology of Baltoscandia Field guide and Abstracts Jan Ove Ebbestad, Linda Wickström & Anette Högström (eds.) WOGOGOB2007 9th– meeting the of Working Groupon Ordovician Geology Baltoscandia of Rapporter och meddelanden 128 WOGOGOB 2007 9th meeting of the Working Group on Ordovician Geology of Baltoscandia IGCP503 Ordovician Palaeogeography and Palaeoclimate Regional Meeting 2007 August 17th–20st, Rättvik, Sweden Field guide and Abstracts Jan Ove R. Ebbestad, Linda M. Wickström & Anette E.S. Högström (eds.) Sveriges geologiska undersökning 2007 ISSN 0349­2176 ISBN 978­91­7158­788­6 Cover photo: Composite photo showing (upper part, photo by J.O.R. Ebbestad) the east flank of the Osmundsberget quarry in the Siljan District, Dalarna with the Kullsberg Limestone to the right, followed by transition beds of the Fjäcka Shale equivalent, and the flank facies Boda Limestone to the left; (lower part, photo by L.M. Wickström), river section at Sladderforsen, River Långan, with folded and thrusted beds of ramp facies sediments (Isön Limestone). WOGOGOB 2007 logo: The design follows the WOGOGOB 2004 layout, with the text and trilobite motif added by J.O.R. Ebbestad. The outline represents the cranidium of the trilobiteTetralichas planifrons (Ange­ lin, 1854) from the Katian Kullsberg Limestone in the Siljan District, Dalarna, Sweden. © Sveriges geologiska undersökning Layout: Jeanette Bergman Weihed, SGU Tryck: Elanders Tofters, Östervåla 2007 Contents Preface ............................................................................................................................................................... 5 WOGOGOB – How it began ................................................................................................................................ 6 Maurits Lindström Ordovician of the Siljan District, Sweden......................................................................................................... 7 Jan Ove R. Ebbestad & Anette E.S. Högström Structural setting ........................................................................................................................................................ 7 Earliest history of research ........................................................................................................................................ 7 The stratigraphic succession...................................................................................................................................... 9 The Ordovician conodont biostratigraphy in the Siljan region, south-central Sweden: a brief review of an international reference standard .............................. 26 Stig M. Bergström Previous conodont studies in the Siljan region ................................................................................................... .28 Conodont biostratigraphy in upper Darriwilian–Hirnantian sections ......................................................... .30 13 Relations to δ C chemostratigraphy .................................................................................................................... .39 Concluding remarks ................................................................................................................................................. .41 Ordovician of the Storsjön Area ...................................................................................................................... 41 Linda M. Wickström Previous work ............................................................................................................................................................ 41 Geological setting .................................................................................................................................................... 42 Faunas ................................................................................................................................................................... 43 The Lockne crater .................................................................................................................................................. 45 Maurits Lindström Stratigraphic succession ..................................................................................................................................... 49 Linda M. Wickström, Åsa M. Frisk & Maurits Lindström Locality descriptions, the Siljan District ........................................................................................................ 52 Jan Ove R. Ebbestad & Anette E.S. Högström Stop 1. Amtjärn quarry ............................................................................................................................................ 52 Stop 2. “Fjäckan” ..................................................................................................................................................... 54 Stop 3. Osmundsberget .......................................................................................................................................... 54 Stop 4. Solberga ....................................................................................................................................................... 57 Stop 5. Jutjärn .......................................................................................................................................................... 58 Locality descriptions, the Storsjön Area ....................................................................................................... 58 Linda M. Wickström, Åsa M. Frisk & Peter Dahlqvist Stop 6. Lockne crater (crater trail) ........................................................................................................................ 58 Stop 7. Brunflo area................................................................................................................................................. 60 Stop 8. Rannåsen ..................................................................................................................................................... 60 Stop 9 Österulvsås, Kälom ...................................................................................................................................... 61 Acknowledgements ............................................................................................................................................. 62 Contact details of contributing authors (in alphabetical order) .......................................................... 63 References ............................................................................................................................................................. 63 Abstracts ............................................................................................................................................................. 79 The organizing committee warmly thanks the following: Preface Last year WOGOGOB (WOrking Group on Ordovician Geology of Baltoscandia) turned 20 years, and the 9th meeting this year in Rättvik in the Siljan District celebrates this occasion. WOGOGOB was instigated by Maurits Lindström in 1986, and the history is chronicled briefly below. The meeting has over the years developed into one of the more important forums for integrated Baltoscandian research and collaboration, along with The Baltic Stratigraphic Conference and Lundadagarna. WOGOGOB 2007 is a field meeting, with excursions in the Siljan District and the Östersund area. The reason behind the choice of Rättvik and Östersund as the place for this gathering is twofold. Firstly the Sil­ jan District has a central place in Ordovician geology of Baltoscandia and indeed world wide. We are here thinking of reference sections for units in Sweden, standard conodont zones and even global palaeoclimate changes (e.g. the Boda event). Jämtland is central in WOGOGOB’s history as the area served as a meeting place for the intial meeting in 1986, and more recently renewed stratigraphical and sedimentological studies have demonstrated the importance of this area in regional geology. WOGOGOB 2007 is unique in that it brings together palaeontologists, sedimentologists, geochemists and stratigraphers with research efforts directed at the Ordovician of Baltoscandia primarily, but also with wider ramifications for Ordovician geology. The meeting is held in collaboration with, and is a contribution to IGCP project 503, Ordovician Palaeogeography and Palaeoclimate, which aims to develop a better under­ standing of the environmental changes that influenced the Ordovician biodiversification, the end­Ordovician extinction and the Silurian radiation (http://sarv.gi.ee./igcp503). WOGOGOB 2007 also serves as the Baltic regional team meeting for IGCP 503. Jan Ove R. Ebbestad, Linda M. Wickström, and Anette E.S. Högström (Editors) Rapporter.&.meddelanden.128 5 WOGOGOB – How it began Maurits Lindström WOGOGOB was born at 18.00 hrs on May 31, 1985. Although it was declared dead by a couple of truly knowledgeable people a few days before and after this date, its survival into a third decade may be due, among other things, to the circumstance that a sufficient number of people would not just let such a quaint acronym expire. It stands for Working Group on Ordovician Geology of Baltoscandia. The idea of WOGOGOB was presented to a meeting of Palaeontologisk Klub (DGF) in Copenhagen on