MsoDockBottom

1 2 3 4 5 6 7 8 9 10 11 12 13

7

final publication list of IGCP 328 includes 975 references (563 directly relevant to IGCP 328) of refereed papers (553 / 279), abstracts including those given at IGCP 328 sponsored meetings or at relevant ones (384 / 262), collective and authors' books and symposia volumes (38 / 22). Numberings are given in table 1 and figure 1. Articles, newsletters (Ichthyolith Issues) and book reviews have also been produced (see Appendix 2).

The Silurian-Devonian vertebrate zonations

As pointed out here above, more detailed results have been obtained for the Silurian and Devonian Systems. These results are tentatively summarised, with regard to the standard conodont zonation, on figures 2 and 3 for the Old Red Sandstone Continent. A single, generalised vertebrate scale is defined for the Silurian while several scales are proposed for the Devonian. These different scales are related to different lithofacies, and problems of correlation to the conodont zonation are not fully solved (see references in figs. 2-3, and in this volume).
When placed within the radiochronological timescale of FORDHAM(1992), conodont zones are of various durations. [This is also true if they are placed within the schemes of ODIN(1994) or G RADSTEIN& OGG(1996), which are different from F ORDHAM's one.] The vertebrate zones also correspond to various time spans. A better apparent precision is obtained for the Wenlock-Ludlow, lower Lochkovian (fig. 2), Eifelian and Givetian/Frasnian boundary (fig. 3) time slices. However, a lower resolution is obtained for the Llandovery, Lochkovian/Pragian boundary (fig. 2), and Givetian (fig. 3) times.
Most stage basal boundaries do not correspond to vertebrate zones boundaries, with exceptions: 1) for the Sheinwoodian Stage (Wenlock Series) which is defined by the Loganellia avoniazone (fig. 2; TURNERthis volume); 2) for the Lochkovian Stage (Silurian/Devonian boundary) which is defined by the Turinia pageizone (fig. 2; BLIECKet al. 1995).
The Frasnian/Famennian boundary, which is important as concerned with bio-events (e.g., WALLISER1996), is still badly defined by vertebrate zones mainly because of poor correlations of the macrovertebrate assemblages to the standard conodont scale (B LIECKet al. in press), and because of still incomplete data on microvertebrates (C1-C2, fig. 3). If the proposed correlation of figure 3 is correct, thus the last psammosteids (heterostracan pteraspidomorphs, C3, fig. 3) disappear before the Frasnian/Famennian boundary. This means that the last armoured agnathans of the "Age of Fishes" ("ostracoderms" sensuJ ANVIER1996b) disappeared before the F/F biological crisis.
Silurian - Devonian microvertebrate assemblages with potential zonal fossils for East Gonwana with possible extension to south China are proposed here (fig. 4; see also YOUNG & TURNERthis volume). In the Australasian region (East Gondwana and some neighbouring terranes, e.g., Irian Jaya, New Zealand, S. China), taxonomic research on microvertebrates is in its infancy. YOUNG(1995) put forward the first assessment of taxa ranges and probable assemblages based on data from work in train. Several new taxa have been defined since and clarification of their stratigraphic ranges is in progress; problems arise from the lack of measured sections and well-dated conodont-bearing horizons in much of Australia. Here one of us (ST) has utilised mainly endemic taxa as potential zone fossils. Ranges are given against the standard SDS scheme with modifications for the



		7
final publication list of IGCP 328 includes 975 references (563 directly relevant to IGCP 328) of refereed papers (553 / 279), abstracts including those given at IGCP 328 sponsored meetings or at relevant ones (384 / 262), collective and authors' books and symposia volumes (38 / 22). Numberings are given in table 1 and figure 1. Articles, newsletters (Ichthyolith Issues) and book reviews have also been produced (see Appendix 2).
	The Silurian-Devonian vertebrate zonations
As pointed out here above, more detailed results have been obtained for the Silurian and Devonian Systems. These results are tentatively summarised, with regard to the standard conodont zonation, on figures 2 and 3 for the Old Red Sandstone Continent. A single, generalised vertebrate scale is defined for the Silurian while several scales are proposed for the Devonian. These different scales are related to different lithofacies, and problems of correlation to the conodont zonation are not fully solved (see references in figs. 2-3, and in this volume). When placed within the radiochronological timescale of FORDHAM(1992), conodont zones are of various durations. [This is also true if they are placed within the schemes of ODIN(1994) or G RADSTEIN& OGG(1996), which are different from F ORDHAM's one.] The vertebrate zones also correspond to various time spans. A better apparent precision is obtained for the Wenlock-Ludlow, lower Lochkovian (fig. 2), Eifelian and Givetian/Frasnian boundary (fig. 3) time slices. However, a lower resolution is obtained for the Llandovery, Lochkovian/Pragian boundary (fig. 2), and Givetian (fig. 3) times. Most stage basal boundaries do not correspond to vertebrate zones boundaries, with exceptions: 1) for the Sheinwoodian Stage (Wenlock Series) which is defined by the Loganellia avoniazone (fig. 2; TURNERthis volume); 2) for the Lochkovian Stage (Silurian/Devonian boundary) which is defined by the Turinia pageizone (fig. 2; BLIECKet al. 1995). The Frasnian/Famennian boundary, which is important as concerned with bio-events (e.g., WALLISER1996), is still badly defined by vertebrate zones mainly because of poor correlations of the macrovertebrate assemblages to the standard conodont scale (B LIECKet al. in press), and because of still incomplete data on microvertebrates (C1-C2, fig. 3). If the proposed correlation of figure 3 is correct, thus the last psammosteids (heterostracan pteraspidomorphs, C3, fig. 3) disappear before the Frasnian/Famennian boundary. This means that the last armoured agnathans of the "Age of Fishes" ("ostracoderms" sensuJ ANVIER1996b) disappeared before the F/F biological crisis. Silurian - Devonian microvertebrate assemblages with potential zonal fossils for East Gonwana with possible extension to south China are proposed here (fig. 4; see also YOUNG & TURNERthis volume). In the Australasian region (East Gondwana and some neighbouring terranes, e.g., Irian Jaya, New Zealand, S. China), taxonomic research on microvertebrates is in its infancy. YOUNG(1995) put forward the first assessment of taxa ranges and probable assemblages based on data from work in train. Several new taxa have been defined since and clarification of their stratigraphic ranges is in progress; problems arise from the lack of measured sections and well-dated conodont-bearing horizons in much of Australia. Here one of us (ST) has utilised mainly endemic taxa as potential zone fossils. Ranges are given against the standard SDS scheme with modifications for the