Page 183 - Carbonate Platforms Facies, Sequences, and Evolution

© 1990 The International Association of Sedimentologists ISBN: 978-0-632-02758-3 James Lee Wilson, Paul D. Crevello, J. Rick Sarg, J. Fred Read 169 Carbonate Platforms: Facies, Sequences and Evolution Edited by Maurice E. Tucker, paper ups unique opportunity to study Atlantic margin build­ The proaches (Masson & Roberts, 1981) and in Portugal. & eastern Atlantic margin, including Morocco (Jansa 1978). Upper Jurassic buildups also occur along the opment is known from the Nova Scotian Shelf (Ehuk, (Schlee & Grow, 1982

a
both
at
distance
Wiedmann,
describes
of
Lusitanian
facies
In
outcrop
the
the
M.
1982),
over
Basin
and
the
latest
variation
of
in
the centre
1200 km
ELLIS*,
the
with
to
composition,
southern
R.
Portugal
'reef trend' lies under the
C.
Oxfordian-early
of the basin,
Georges
a
subsurface.
Western
structure
L.
eastern
described
provides
thin
Ap­
US
a
This
and
Bank
The Open University,
no distinct shelf break
Kimmeridgian,
of
a
that
from Portugal
facies,
the
also
and
sudden
geographic
WILSON* and R.
are
Saastrasse 21,
grainstone-dominated
from Portugal.
developed
Atlantic
in
relative
occur in
settings.
during
sea-level
the
Recent
D-6500 Mainz,
rise
late
well
R. LEINFELDER t
Mesozoic carbonate
Walton Hall, Milton Keynes MK7 6AA,
drowned
data
or
carbonate sequence of middle
dominated by grainstones and
bank
West Germany
Oxfordian.
from
UK; and
located to the northeast of a postulated short seg­
ment of an ocean ridge and associated major trans-
contrasting tectonic and palaeo­
Lusitanian Basin was not in an ocean margin location
The
at this time, but was situated to the east of the newly
1300 and 1500km wide (Jansa, 1986). The basin was
opened southern North Atlantic, which was between
the
developmental controls of four carbonate sequences
eastern US continental shelf are also described and
Figure 1 shows a palaeogeographic reconstruction
commented upon in the light of information gathered
form that displaced spreading southeastwards into
Tethys. Rifting that initiated the separation of Iberia
·