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applied to the solution of geological problems: biostratigraphy in all systems of the Palaeozoic has been
investigated; assemblages have been defined and biozonation deduced therefrom across certain time ranges;ILSON correlation of marine-non-marine sequences has been enhanced (complementing standard conodont and palynological scales, especially in the Devonian). The data derived has also been applied to gain insights into palaeoenvironments, palaeogeography and distribution (vicariant or otherwise) of the main taxa. Concomittant controlling factors and processes such as climatic changes, geographic changes such as sea level rise and fall, catastrophic events, and palaeoenvironment adaptation have been assessed.
Our meetings have been times of stimulating and often heated discussion, mainly when regarding hotly debated problems such as conodont-vertebrate relationships, original environments of the ORS, stratigraphical correlations to the standard conodont scales within Devonian siliciclastics, nature of palaeotissues in teeth and scales (and their homology through the whole vertebrate taxa), etc.
Through workshops, poster sessions at other conferences, and field work we believe that the aims we set and chief directive of the scientific committee to educate have been fulfilled and that the process to utilise microvertebrate remains in geology will continue. To this end students, from undergraduate to doctorate level have been trained and microvertebrate studies are extending.
"IGCP 328 has lived, welcome to IGCP 406." The latter is considered as partial successor of the former. However, IGCP 406 focus on both micro- and macro-vertebrates from mainly Ordovician to Devonian series. It is devoted to the Circum-Arctic areas where numerous problems have to be solved and where IGCP 328 carried out two successful field seasons in 1994 and 1995 (W 1997, IVANOV et al. 1997). For instance, what haveEIST been the palaeogeographical relationships of the Timan-Pechora region (TPR) in Early Palaeozoic times? Recent re-investigations of geological and palaeontological data indicate affinities with either northern Baltica or with Siberia, although it seems clear that the TPR was linked to the Old Red Sandstone Continent in Devonian times. Vertebrates have a major role to play in this debate which has been initiated during the 1996 Silurian and Tallinn workshops.
In 1996 a further IGCP project on Gondwana was proposed to UNESCO and participants from IGCP 328 were invited to contribute ( F & TALENT 1997). IGCP Project 421 was accepted in 1997 with co-leaders, Dr.EIST Raimund F (France) and Pr. John A. TALENT (Australia). Symposia held in that year included several contributions on Palaeozoic microvertebrates from Gondwana.
Finally we must consider that endemic freshwater macrofish-bearing deposits could hardly be correlated in age (see, e.g., the long lasting difficulties in correlating some Early Devonian ORS and ORS-like sediments). However ,the IGCP 328 results clearly confirm that many Palaeozoic fish-bearing deposits can be correlated on a regional, palaeocontinental or even worldwide scale. The papers presented in this volume summarise that position from many parts of the world. Work is still underway and further refinements can be expected towards more unified schemes.
Acknowledgements : It has been a great experience to coordinate activities of so many enthusiastic scientists under the banner of the
UNESCO/I.U.G.S./International Geological Correlation Programme. Dr. Gavin C. Y OUNG (formerly of the Australian Geological Survey
Organisation; now in the Australian National University) was instrumental in the formulation of the initial proposal. He co-ran the project