might sharpen the further study of
these matters.
It was also suggested
that geologists on both sides of the
Atlantic should standardize or integrate
their use of such broad terms as Ta-
conic, Caledonian, Appalachian, and
others, so that all schools of geology
Meetings
Geology along the North Atlantic:
Gander Conference
Geologic relations on opposite sides
of the North Atlantic Ocean do not
prove the theory of continental drift
but most of them support the hypothesis. This was the informal conclusion
at an international conference held
24-31 August 1967, at Gander, New-
foundland. More than 50 papers were
presented to 114 participants, of whom
40 came from the United States, 31
from Great Britain, 30 from Canada,
and 13 from other countries. Several
field trips were made before, during,
and after the formal programs.
The papers fell into two main categories. Many were informative or discursive, describing the details of geologic
relations
Britain,
Canada,
the
and
rocks
maritime
northeastern
Greenland,
and
the
in
Great
provinces
United
islands
of
States,
of the
would have a common understanding
of the time and geographic significance of these terms. A portion of the
last session was devoted to such a synthesis and some of its inherent prob-
and tectonic structures. Differences
were discussed between the so-called
Atlantic and Pacific provinces of Newfoundland and Britain. Intercontinental
correlations
of
Cambro-Ordovician
rocks and graptolites were suggested.
Other sessions dealt with Silurian,
Devonian, and Carboniferous systems
of the North Atlantic region; trans-
current and other faulting, including
the thrust sheets of western Newfoundland; the relation of specific
formations, such as the Old Red Sandstone and various other conglomerates,
to general tectonic history and to particular structures; Arctic lands; geo-
physical and oceanographic relations;
and the synthesis of all of these details
into a composite pattern.
The subject of continental drift was
a
common
thread
running
through
most of the papers. Evidence bearing
upon drift fell into five types: (i) paleo-
lems were discussed without producing
any interregional agreement.
A number of unresolved problems
emerged in the course of the conference, such as the precise age of the
Dalradian rocks of Ireland and north-
ern Britain; the cause of certain anomalous radiometric dates, whether related
to subsequent cooling or produced by
the overprinting of subsequent events;
the whereabouts of the American Grenville rocks in the British Isles; the nature of the crust under Newfoundland;
the proper integration of American Taconic deformation with European Caledonian events; and the possible consan-
guinity of the Old Red Sandstone with
the American Catskill formation. Other
matters inviting more study were the
great rifts described in eastern Green-
land and the general dissimilarity of its
geologic history with that of the rest
of the North Atlantic province; the
possibility
of
residual
scars
on
the
North Atlantic. Other papers were ad-
geographic evidence based on_ intercontinental similarities during a single
nent comparisons or contrasts within
or between the several geographic re-
ocean floor resulting from the former
stand of vagrant continental blocks;
some revision of the reputed age dates
time periods; (iii) the physical congru-
gested correlation of the extinction of
certain foraminiferal genera with epochs
vocative or argumentative, noting pertigions, or pressing for specific inter-
pretations of structure or geologic history. Still others dealt with such particular processes as faunal relations,
oceanographic
and
geophysical
find-
ings, and geotectonic matters. A large
volume of detailed data was laid before the conference, in part summarizing known
information
and
in
part
suggesting new lines of research for
additional study.
The program commenced with several papers on the PreCambrian of
Scotland, Ireland, Newfoundland, and
time span; (ii) structural comparisons
of historical events during extended
ence of Atlantic coasts or the jigsaw
types of continental fit; (iv) specialized
interpretations such as polar wandering, magnetic reversals, seismic and
sea-floor data; and
(v)
faunal
and
radiometric similar‘ties. In general it
was agreed that the Canadian Maritime Provinces and the British Isles
are remarkably alike in many geologic
respects, with differences being less
prominent than their similarities. At
the same time there was some sentiment that Newfoundland is more like
Ireland than Labrador or the American mainland, while Ireland resembles
Newfoundland more than it does Scotland. There was no strong anti-drift
of various Atlantic islands; and a sug-
of magnetic reversals.
One speaker discussed the need to
analyze the types of evidence for continental drift, suggesting that a linear
variable which could be identified on
one side of the Atlantic and continued
on the other might be more impressive
and convincing than mere physical re-
semblances which could arise from a
common history without requiring ac-
tual proximity.
The field trip to New Worid Island,
40 miles north of Gander, was attend-
ed by most participants who examined
New England, with emphasis on the
radiometric age, structure, and metamorphism of such rocks as the Lewisian, Torridonian, Grenville, and early
Dalradian series. This discussion was
followed by similar regional analyses of
the Cambrian and Ordovician rocks
sentiment, although some items sup-
and volcanic rocks that were strongly
folded, variously intruded, thrust fault-
speakers took no stand pro or con.
ly
The suggestion was made that the
showed transcurrent movement. One of
cial emphasis on their similarities, geologic and faunal histories, magnetism,
resents the whole of the tectonic process involved, and that a better term
Atlantic continuation of one of the
around the North Atlantic, with spe-
1368
porting drift were questioned and many
term “continental drift” no longer rep-
Ordovician
and
Silurian
sedimentary
ed, and subsequently broken by steep-
dipping
faults
many
of
which
the latter is the Lukes Arm fault which
can be suspected of being 4 transSCIENCE, VOL. 158