IGCP Board; 10th session; Report of the ... - unesdoc - Unesco

stratigraphical researches on the Ordovician
sequences in the Caborca region, Sonora, Mexico;
collecting of Ordovician fossils in the
region of Oaxaca, Mexico.
WG 5 (Buenos Aires): Palaeomagnetic determinations
in the Lower Palaeozoic rocks in the
northern hills of Buenos Aires Province;
palaeomagnetic determinations in the Silurian-
Devonian rocks from the Somuncura Massif,
northern Patagonia.
WG 6 (La Plata): Geological mapping of the
Lower Palaeozoic sequences in the western slope
of the Precordillera of San Juan.
WG 7 (Buenos Aires): Investigations on the
microplankton in the Silurian sequences exposed
in the eastern flank of the Precordillera of San
Juan.
WG 8 (Buenos Aires): Palynological investigations
in the Ordovician sequences exposed in the
Precordillera of San Juan and in the Subandine
belt, in north-western Argentina. The Silurian
and Devonian sequences in the underground of
the Salta Province were included in these investigations.
In Bolivia, palaeogeographic investigations and
the study on the distribution of lithofacies in the
Lower Palaeozoic sequences were carried out
in connection with the researches on the structure
and evolution of the Hercynian belt. Palaeontological
and biostratigraphical researches on
Ordovician and Devonian brachiopods also were
made.
In Peru, an important contribution was made by
the French Geological Mission on the Cambrian
to Devonian stratigraphy and palaeogeography in
the areas between 9° 00'-10° 30' S; 12° 30'-14°0ff
and the 13° 00'-15° 30' S. G., in the Andean region.
A ^500 m thick Devonian sequence, which lies
transgressively over the Ordovician plutonio
rocks, was discovered at Sierra Almeida
(68° 30'W, 24° 15'S), Chile.
In Columbia, a sequence of Ordovician age was
discovered recently in the Amazonian region of
Columbia. The fossil-bearing beds contain a
fauna composed of Cruziana sp., and Skolithos
sp.
No. 53 ECOSTRATIGRAPHY
A.J. Boucot, Department of Geology, Oregon
State University, Corvallis, Oregon 97331, USA.
Description. A project for biochron correlation
at the ecosystem level, using the Wenlockian-
Gedinnian as a test sequence.
26
Summary of activities. 1981 was in many ways
the Project's most productive and exciting year
to date since its inception. The basis for this
statement is the Project Ecostratigraphy Plenary
Meeting organized by the Swedish Working Group
at the Allekvia Research Station on Gotland
22-28 August 1981. Seventy-one scientists from
16 countries participated in the meeting and 42
papers were given.
The indoor scientific programme had four main
topics: (1) Crossing the boundaries of the faciès
realms; (2) basin analyses of the Silurian "Baltic
Gulf" (the lithofacies subproject, final reports);
(3) Downtonian - Podlasian - Pridolian correlation;
(4) Ecostratigraphy in theory and practice.
During the three days indoors Project Ecostratigraphy
and the IUGS Subcommission on the Silurian
System held open business meetings. The
meeting was concluded by four days in the field.
The proceedings of the meeting were published
by the Geological Survey of Sweden (Laufeld 1981)
and a field guidebook had been prepared by Laufeld
and Martinsson (1981). Laufeld and Bassett
(1981) prepared a review of the Silurian of Gotland,
printed in "Episodes" and distributed free
by the IUGS to the meeting participants.
In addition, for the first time, a group of scientists
reviewed future plans and intentions of the
Project. It was agreed that the Project would
prepare a final report, with an initial draft by
the end of 1983. The final report will consist of
two parts. The first part will be a summary of
the activities and purposes of the Project. The
second part will be aglobal account of Wenlockian-
Gedinnian fossil communities.
It must be emphasized that this synthesis of community
information for a significant interval of
geologic time on a global basis is truly novel.
Nothing of this scope has ever been carried out
before. We all anticipate that the synthesis of the
anticipated wealth of community data will provide
a firm basis for a far more reliable basin analysis
capability during the Wenlockian-Gedinnian
time interval, and also for far more reliable biostratigraphic
correlations than have been available
previously. It then will be demonstrated to
the profession how fossils may be used with greater
facility in all parts of the Phanerozoic for
purposes of both biostratigraphic correlation and
basin analysis. Full attention will certainly be
paid to the everpresent biogeographic complications.
During the year under review, the Project activities
had advanced considerably in Austria,
Canada, China, Czechoslovakia, France, GDR,
Italy, Poland, Sweden, the UK, the USSR and
the USA, according to the annual reports received
from the relevant national working groups, as
well as in Rumania.
Activities planned. 1982 will be a busy year devoted
to the preparation of the Project's final report.