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.............................................................................................................................. SDS Minutes 2006 .............................................................................................................................. Minutes of the SDS Business Meeting, Leicester, July 18th, 2006 1. Introduction and apologies for absence 2. Approval of the Minutes of the Business Meeting, Novosibirsk , 8th August 2005 5. Revision of Devonian Stage, Series and System Boundaries 5.2 Discussion of the Devonian-Carboniferous boundary
The SDS business meeting for 2006 took place during ICOS 2006, The First International Conodont Symposium, July 12th-30th, 2006.
Attendance The Chair (T. Becker), Vice-chair (A. El Hassani) & Secretary (J. Marshall), TM’s J. I. Valenzuela-Ríos, M. C. Perri, J. Over; CM’s J. A. Talent, Cheng-Yuan Wang , P. Bultynck, P. Sartenaer, B. Mistiaen, M. Ginter; Guests Jau-Chyn Liao, C. Martinez-Perez, S. Gouwy, C. Corradini, I. Boncheva, C. Randon, C. Girard, M. Sobstel, J. Sanz-López, J. Barrick, L. Jeppsson, K. Narkiewicz, H. Matyja, S. Kaiser, D. Sparling, L. Krystyn.
Documents were presented and numbered as follows:
1. Emsian sub-stages and the Daleje Event – a consideration of conodont, dacryoconarid, ammonoid and sea-level data by R.T. Becker. 2. The annulata and Dasberg Events (Famennian) in the Tafilalt and Maider (Eastern Anti-Atlas, SE Morocco) by S. Hartenfels and R.T. Becker. 3. A reference section for the neritic facies at the transition Late to Latest Famennian by M. Streel, N. Maziane-Serraj, J.E.A. Marshall and J. Thorez. 4. Comment on proposed uppermost Famennian “substage” by C.A. Sandberg.
1. Introduction and apologies for absence ã The meeting started at 20:48. The Chairman welcomed the large group of participants and noted how pleased we were to be in Leicester. Our hosts for ICOS 2006, Dick Aldridge and Mark Purnell were thanked for their assistance in arranging the meeting. The Chair noted that we were meeting in a late time slot and had a long agenda so participants had to be careful to keep the discussion focused. The SDS had planned a fieldtrip to the ORS to coincide with this meeting. This was to link in with our long term goal of correlation of the pelagic, neritic and terestrial environments. It was disappointing that there were not enough potential participants. It is planned to make this field trip to the Scottish ORS at a later date. Apologies: TMs Blieck, Casier, Hladil, Izokh, Ma, Mawson, Sandberg, Schindler, Tsyganko, Young; CMs Blake, Day, Hartkopf-Fröder, Garcia-Alcalde, Jansen, Klapper, Obukovskaya, Obut, Ovnatanova, Slavik, Spalletta, Streel, Troyols-Massoni, Turner, Ver Straeten, Yolkin.
2. Approval of the Minutes of the Business Meeting, Novosibirsk, 8th August 2005 ã A preliminary version of the minutes had been distributed by email. Following a number of minor corrections and clarifications the minutes were approved.
The tragic death in a traffic accident of Bill Oliver, our past SDS Chairman, was announced. The meeting stood in a minutes silence. There was a brief discussion about the need for an obituary for the Newsletter. The Chair then made a review of the previous year. The meeting at Novosibirsk had been a great success with a very good field excursion. This had been a joint meeting with IGCP 499 led by Peter Königshof. There had been a second IGCP 499 meeting with a workshop in Istanbul, Turkey. Peter Königshof also reported news of the situation with the IGCP programme. These had been under threat of closure and no new projects were being accepted whilst the programme was being reviewed. The IGCP programme would continue for present at a reduced rate. In addition there would be 1) an emphasis on an annually chosen special topic. 2) the focus would be on basic and applied programs. 3) the applied science included ‘global change and life evolution- evidence from the fossil record’ which is relevant to the SDS. IGCP 499 has future plans for 2006. Some 6 SDS members were known to be attending the Beijing 2nd IPC. In addition, there was going to be a joint meeting with CIMP in Prague from September 2nd to 6th. IGCP 499 was also going to have a joint meeting in Leon, 2006. Contact J. Valenzuela-Rios for details. Geochronology: The Chairman showed an overhead of the new compilation of Devonian dates by Kaufmann, 2006, Earth Science Reviews, 76: 175-190. http://www.uni-tuebingen.de/geo/gpi/mitarbeiter/kaufmann/devoniantimescale.pdf It considers all existing high precision zircon U/Pb age dates and gave age dates for the Devonian Period of 418-360.7 Ma. It considered the D-C boundary and reviewed the biostratigraphy. The age dates were calibrated using sediment thickness in homogenous facies. The Emsian was given a duration of 18 my and the Pragian shortened in duration. This time scale will be reproduced in the minutes and placed on the website. Other Devonian stages were now much shorter. The hemiansatus zone was now very short on this time scale but is known to be very thick in the Eifelian. The Secretary commented that the duration of the Eifelian now gave problems with the cyclostratigraphy. J. Valenzuela-Rios commented on problems with the base and the use of stratotypes and the placement of certain ash layers. However, the Chair did comment that each measurement took 6 months of work. Dale Sparling and Pierre Bultynck also discussed the position of the hemiansatus zone. The requirement for good phylogeny was noted.
The ICS informal committee had met for 2 days in Paris . They had received a report from the SDS. They congratulated the SDS on its achievements but noted the following, ‘the typological definition of standard stratigraphic units by means of boundary stratotypes, such as stage GSSP’s, should be extended downwards, below the stage level in the hierarchy.’ This means that sub-stages may require GSSP’s in future. The limit of sub-division is not yet reached since the more we learn the more we sub-divide. At this J. Valenzuela-Rios commented that we required more time for research before we started on the sub-division of the Lochkovian.
Document 1. This is a review by the chair, Thomas Becker, on the Emsian and had recognized 11 serious difficulties. Notably that the Daleje Event was not really global and that the mid Emsian conodonts show significant endemism. Thomas was unsure what to do to advance correlation. In Europe and North Africa, the icriodid evolution (entry of I. fusiformis-corniger ancestralis faunas) would allow a substage definition but the key species are absent in North America, large parts of Asia, and in Australia. There was discussion with P. Bultynck and J. Valenzuela-Rios. There was hope that new forthcoming data from the Senckenberg Group might prove invaluable. It was a difficult problem with an 18 my interval requiring to be sub-divided.
We had the results of the sub-stage ballot but several TMs had not yet given their votes (final outcome see forthcoming Newsletter)
For a Middle Givetian sub-stage at the base of the rhenanus/varcus Zone
For an Upper Givetian at the base of the hermanni Zone
We also have the result of the sub-stage ballot For a Middle Frasnian sub-stage at the base of the punctata or MN5 Zone
For an Upper Frasnian sub-stage at the first entry of Pa. semichatovae (~MN 11)
We now need to publish reviews and reference sections on all continents where these definitions can be recognized.
This has proved to be difficult. There is one formal proposal for the definition of an Upper Famennian sub-stage TM 8 yes, 1 against, 3 abstentions TM’s & CM’s 17 yes, 5 against, 5 abstentions Therefore there is clearly no decisive majority unlike the consensus for the Givetian and Frasnian sub-stages. An initial vote was taken on possible Middle and Upper Famennian sub-stages. The yes votes are:
Base Middle Famennian
Base Upper Famennian
There were also 2 new proposals The chair noted that we needed to rethink the Famennian sub-division. But it was also noted that the pattern of voting was inconsistent. There is a requirement for more data and a more thorough discussion so that all members understood the issues. This would take place in 2007 in Nevada and beyond. There would be a special Famennian session in Nevada.
Document 2: discussed the annulata and Dasberg Events in Morocco. Both were truly global and should be considered in the substage discussion. Data from conodonts and ammonoids suggest that there was no significant transgression or event at the base of the Lower expansa Zone in southern Morocco.
Document 3: was from M. Streel and colleagues. It showed the good high resolution data that was available from spores and acritarchs in eastern Belgium. The Chanxhe section is proposed as the regional reference section on the Ardenne Shelf for the Uppermost Famennian as defined by the base of the Upper expansa Zone. Thomas Becker commented on the spore record from the Refrath borehole (Germany) and the links to conodonts. Both in Morocco and Germany it is now clear that the Famennian V (Dasberg Stufe) begins very close to the boundary of the Lower/Middle expansa Zone or just above the upper range of Po. styriacus. The suggested significant transgression of the Lower expansa Zone in North America may be younger than currently thought since Po. styriacus is already lacking in the transgressive beds. The distribution of Bi. aculeatus, which defines the M. expansa Zone, may be controlled by facies influences. More data are needed.
Document 4 discusses the relationship of Bispathodus ultimus, one of the index conodonts of the Upper expansa Zone, to the index foraminifera Quasiendothyra kobeitusana kobeitusana which has been considered in the past to mark the base of the Strunian and hence the uppermost Famennian sub-stage. TM Sandberg reported that this level at Anseremmes (Banc 28) contained conodonts that showed it was from the Middle expansa rather than Upper expansa Zone. (Banc 28). There was general discussion over the differences with the report of M. Streel and that either the the conodont or the foramifera had a late entry in one of the sections. The problem may be the difference between a first occurrence and an acme. M. Ginter had a discussion with Thomas Becker over the issues. It was decided to have, at the Nevada meeting in 2007, a special session dedicated to the Famennian. This forthcoming discussion requires not only conodont, spore and ammonoid data but also correlation with neritic groups, such as brachiopods.
5. Revision of Devonian Stage, Series and System Boundaries ã
J. Valenzuela-Rios discussed the problem of the base of the Emsian Stage. This was a continuation of the discussion with Yolkin in Novosibirsk . The solution was not known but there had to be a change in the definition of the P/E boundary to a much higher level. There is to be an SDS fieldtrip to Zinzilban, Uzbekistan in 2008. The discussion of the redefinition will be part of this meeting.
5.2 Discussion of the Devonian-Carboniferous boundary ã Messages from TM Sandberg and CM Spaletta have questioned whether SDS should deal with this topic. SDS can discuss the problems of the definition of the D-C boundary but has no power to change it. There had been a discussion with P. Heckel from the SCS and there would be further discussion at the forthcoming IGC in Norway in 2008. Eventually a new joint SDS/SCS working group may have to be formed. S. Kaiser introduced results from her restudy of the La Serre GSSP on a powerpoint slide. The first S. sulcata is, in fact, already found in Bed 85 (the current D/C boundary is higher at the base of Bed 89), with the first ?S. duplicata also in Bed 85. Beds 86 and 87 are now known to have typical S. sulcata. The boundary definition was intended to be fixed by the first occurrence of S. sulcata. Therefore, we either need to redefine the D-C boundary (from Bed 89 to Bed 85) or we must find a new stratotype. Thomas Becker commented on the original definition with the change in angle of twist in siphonodellids from Beds 88 to 90. La Serre was critizised at the Coutmacsherry meeting for not showing the entry of Gattendorfia, the traditional (1935 definition) index fossil of the Carboniferous. The new conodont data suggest that the La Serre GSSP falls in the upper part of the sulcata Zone or even in the duplicata Zone, above the entry of Gattendorfia in Germany. The current GSSP position places first Gattendorfia still in the Devonian, which is not acceptable and completely against the original intentions when the GSSP was decided. The best solution might be to bring the definition down from Bed 89 to Bed 85 but Bed 84 has no siphonodellids and very few conodonts. There is a long overlooked publication by Gong et al. (1991) that suggests that S. sulcata enters also earlier than originally thought at the Nianbiancun auxiliary stratotype in Guangxi. Both at La Serre and Nanbiancun, S. sulcata seem to enter just above a facies break and, therefore, there is no record of the praesulcata-sulcata transition that was originally decided to define the system boundary. Currently, there is no better section than La Serre. As an alternative the boundary could be even lowered to the base of the Upper praesulcata Zone.
There had been a meeting in Louvain (Belgium) from 1st to 5th September 2005 which would discuss future directions for the ICS. The meeting was attended by all SC chairs. The status of the time scale chronostratigraphic sub-division was discussed with the scheduled completion for the IGC in Norway . Progress has been made on the Pliensbachian, Ordovician and Triassic. The Ordovician GSSP’s are now defined first, followed by the names with some entirely new names introduced, e.g. Floian. The is a continuing debate about the Quaternary. There is now a new organisation, the International Association of Stratigraphic Geologists (IASG) with a new journal (Journal of Stratigraphy). The IGC has abandoned the fusion of geochronology and chronostratigraphy. Both time scales will remain. The will be a new IS code/guide. The SDS has made a 2000-2005 report for the ICS reviewing committee in Paris. SDS was selected as one of the SC to be used as an example for the quality and progress of work within ICS. Unfortunately, the chair could not attend the meeting himself but there was no criticism of the subcomission.
Rex Crick has stepped down. He is thanked for his great efforts on behalf of the Devonian and SDS. There are currently 21 TM’s. CM I Schülke has resigned on leaving geology The following new CM’s were proposed H. Matya for Poland, proposed by the chair, seconded by TM C. Perri S. Kaiser (Stuttgart) for conodonts and isotopes, proposed by the chair, seconded by the secretary C. Corradini, proposed by the chair, seconded by TMs J. Valenzuela-Rios and J. Over Ilyana Boncheva (Bulgaria) proposed by the chair and seconded by TM C. Perri TM T. Uyeno has declared his intention to resign. The Chair commented that we needed him to continue to represent Canada.
The Elsevier Devonian/Permo-Triassic volume ‘Developments in Sedimentology and Palaeontology’ 20 had been published. It included a sub-division of the linguiformis zone by Girard et al. and other important papers on the Frasnian-Famennian boundary, including an extensive review by TM Racki. 8.1 The next SDS Newsletter will be produced in late 2006/early 2007. Newsletter 21 will be available as a printed version but as yet no requests had been received. Newsletter 22: contributions are due end October with publication at the year end. It will be printed in Munster. 8.2 The House volume is in press. It is a Geological Society of London, Special Publication (No. 278). It is the first SP that will be available online. A contents list was circulated. 8.3 Sub-stages. These will be described and formally defined in an issue of Geological Quarterly. First drafts are due in March 2007 with the volume hopefully available before the Nevada meeting in September. The lead authors are
These lead authors will receive the volume guidelines and distribute to others.
8.4 A CFS volume is being published for the IGCP 499 meeting in Novosibirsk. At present there are 10 contributions from Russian colleagues with plus one on the Taghanic Event. More contributions were requested, deadline 15th November, details from P. Konigshof. 8.5 There is a Palaeo3 Middle Devonian volume in progress. The themes are sea-levels, sequence stratigraphy and stratigraphy. Details from TM C. Brett with the deadline of 31st December 2006.
This year, after severe cuts within IUGS, we only have $500 from ICS; $500 has been spent sponsoring attendance at Leicester based on a special ICS travel grant plus we have the Newsletter expenditure. The Leicester room hire ($90) has beeen funded from elsewhere.
Jeff Over made a brief presentation of the Nevada Meeting for September 2007. It will start in Las Vegas on the 7th September with a fieldtrip to Alamo and Eureka, followed by technical sessions from the 15-17th. It will be a joint meeting with IGCP 499. The themes of the meeting will be the Famennian, the Johnson Sea Level curve and global change. J. Valenzuela-Rios noted the excellent Lochovian/Pragian boundary which we needed to see. All SDS members were reminded to check US Visa requirements. They have changed. SDS members were reminded about the 16th Carboniferous and Permian Congress in Nanjing, China, June 21-24th 2007. Sessions included the the Frasnian/Famennian and the Mississippian recovery. SDS members were directed to fieldtrip C4 which was to the Devonian and Carboniferous marine sequence including the Nanbiancun D/C boundary auxiliary stratotype, a marine F/F section and the end Permian stratotype at Ching Yiang. IGCP 499 is having a meeting in San Juan, Argentina in the summer of 2007. SDS members were reminded about the SDS meeting at the IGC in Norway in 2008 (August 5-14th). We are obliged to meet at the IGC conferences. Proposals for IGC Symposia will be accepted until August 2006. At that meeting we will need to nominate a new SDS chair and officers. In September 2008 SDS hopes to visit Zinzilban and the Kitab Reserve in Uzbekistan. AOB. SDS now has no home page. It has been lost. A webmaster was urgently sought. The meeting closed at 23:25 and the somewhat diminished group repaired to the bar in time for last orders. John Marshall SDS Secretary February 2007 |
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