1 2 3 4 5 6 7 8 9 10 11 12 13
Microvertebrates can be recovered from beds of all lithological types with the use of mechanical means, acidLYES preparation especially acetic and formic, and with the use of the microwave oven (e.g., I 1990, TURNER 1991). In calcareous samples collected for conodont recovery vertebrate microremains and other phosphatic associates (e.g., phyllocarids, ostracodes) occur in around 20% of samples on average (VAN DEN B OOGAARD andTREEL others, pers. comm., pers. obs.). Fish microfossils come into their own in the less truly marine environments and complement spores both in freshwater and marine environments (S et al. 1987). BOUCOT & JANIS (1983)URNER , in press; B LIECK pointed out that conodonts are almost never recovered in Benthic Assemblage 1 whereas certain fish seem to thrive in such environments (T & JANVIER, in press). Even today truly marine fishes such as sharks commonly enter brackish or tidal freshwater environments to spawn or gain relief from parasitesARSHALL and diseases. This seems to have been a strong possibility in the Palaeozoic also. However, finding fish in a Palaeozoic, Old Red Sandstone-like series does not mean that the whole series was freshwater or marine in origin. For instance 1) the classically considered lacustrine freshwater deposits of the Orcadian Basin in Scotland (presently on- and off-shore) have recently yielded several marginal marine intercalated thin layers with acritarchs and scolecodonts (M et al. 1996); 2) the usually considered freshwater deposits of the ORS ofOUJET Spitsbergen were partly interpreted as marine influenced (G 1984, BLIECK 1985).
The final scientific report
The major aim of the last year of IGCP 328 activities has been to prepare a final scientific report (FSR) in the
form of global correlation charts for each Palaeozoic System. This was clearly announced in our original plans.ANSOM
It is quite evident that most results come from the Devonian System also known as "The Age of Fishes". This is why 16 papers are totally or partly devoted to it. However, all other systems are concerned with vertebrate microremains from the Upper Ordovician up to the Lower Permian, and particularly the Silurian (8 papers). Important contributions which include work carried out under the auspices of IGCP 328, from S et al.MITH (1996), S & SANSOM (1997), YOUNG (1997) and YOUNG et al. (1996), bode well for a futureERYCKE-KHATIR microvertebrate zonation of the Ordovician System. Likewise, work in train and especially on shark microremains (e.g., D 1994, DERYCKE , in press, DERYCKE et al. 1995, IVANOV 1996, IVANOV &INTER G 1996, LEBEDEV 1996, MADER & SCHULTZE 1987, TURNER 1993a, 1997a, WANG & TURNER 1995) areAMPE building up a potential zonation for the Carboniferous. H (1995) and SCHNEIDER (1996, also SCHNEIDER et al., this volume) have shown the enormous potential for zonation of the Permian System using xenacanth remains. Both marine and non-marine facies are treated, with only marine assemblages in Early Palaeozoic times, and more and more terrestrial assemblages in Late Palaeozoic times. The Devonian is at a major turn because of strong discussions on the nature of the Old Red Sandstone facies (ORS) all over the world. Better established correlations between marine and non-marine facies are exemplified in the East Gondwanan Realm (Australia-Antarctica) and in the more classical East Laureuropean (= Laurussian, Euramerican) Realm. Individual contributions on topics of special interest, deduced from new data, are also included in the FSR.
All these results are the conclusion of dynamic five-year collaborative activities between so-called developed and third world countries. Researchers representing over 50 countries participated in IGCP 328. The appended