Page 275 - Carbonate Platforms Facies, Sequences, and Evolution

258
flysch
1981),
The
ferential
volcanism
and
(Rossy et al. ,
trough
1976; Pujalte,
Upper
in
which deepened
in
Garcia-Mondejar
Urgonian Complex.
1979;
et
the
subsidence
occurred
the
in
al.,
Mathey,
Albian
during
1985,
northeast
Jurassic-Lower
the
(Rat,
1982).
part
1986;
late
fault-bounded
of
1959;
the
Cretaceous
areas
J.
Pascal et
was subjected to a general extensional regime. Dif­
Garcia­
pression occurred at the end of the Triassic (Garcia­
al., 1983). Three short-lived episodes of minor com­
and widened during the late Cre­
suc­
took
During the Mesozoic and early Tertiary the basin
Jurassic-early Cretaceous (Garcia-Mondejar, 1979;
Mondejar et al. , 1986), in the Neocomian (Pujalte,
1981 ; Rat et al., 1983; Wiedmann et
basin,
place during the early Triassic and during the late
Mondejar, 1979). The Albian movements formed a
al.,
Cretaceous
sediments in the basin. This interval has traditionally
taceous and persisted into the early Tertiary. Basaltic
cession forms more than half of the total thickness of
been
origin
basin.
1979).
This
fluvial,
Garda-Mondejar
mentary
formities
spreading
dominantly
carbonate),
depositional
plexes' (Rat,
coastal,
within
subdivided
in the
deltaic,
the
Bay
into
Unconformities
environments
sequences.
marine
continental
reef,
(Supra-Urgonian).
A
and
and
three
The
talus
Urgonian
of Biscay
and Albian rudistid limestones.
clastic
platform
their
main
paper deals firstly with the
facies,
and
define
phase
units
Urgonian
which
four
or
of
'
Urgonian
palaeogeographic
correlative
(siliciclastic
was
·
Fig. 1. Simplified geological map of the Basque-Cantabrian region, showing areas of outcrop of the Aptian-Albian,
con­
d - e­
sedi­
'com­
It followed a. pre­
sedi­
(Montadert et al. ,
and
map
include
representative of each of them is included, showing
subject of this paper and consists mainly of Aptian
1959); the 'Wealden', 'Urgonian' and
clastic episode, ranging from fluvial to turbidite ;in
mentation (Wealden) and was succeeded by another
'Supra-Urgonian' successions. The Urgonian \s the
major
intra-platform
posited during the period when rifting gave way to