Page 294 - Carbonate Platforms Facies, Sequences, and Evolution

the
two
The
their
105
100
other
110
better
Fig. 29.
best
APTIAN
parts
ALBIAN
identification
relative
sub-units,
of
Lower
the
of the
113+--------1
palaeogeography
sea-level
u1
representative
expressed cyclicity
region
according to
in
In the west of the region
of the
is
resultant
the
U/) valid for the southwestern part of
Urgonian time is shown in Fig. 29.
ENTIRE
terms
variations
testimony
{no scale)
\,
sequences is developed because the
being
seven
\
of
PALAEOGEOGRAPHY
are
area
presence
Relative sea level changes
c
BASQUE -CANTABRIAN BASIN
the
of
presently
shown
u 3
sequences
u,
3
u 1
in­
u2
3
unconformities or their correlative conformities. The
curve of Hag et al. (1987), in order to make comparisons.
(centre and south), a
was less
Basque-Cantabrian
of depositional
of the units U2, U3 and U4 has been subdivided into
local
affected by the alpine tectonism and shows a greater
thickness of sediment and excellent outcrops. Each
in
phenomena that took place in the basin during the
Aptian-late Albian interval. These sequences and
major
in
vestigated, so that, for the moment, they appear as
the
NE
\
(no scale)
Basin
based
eustacy.
author's
order to
has been
on
Relative sea level changes
restoration.
conditioned
BASQUE-CANTABRIAN BASIN
constructed.
SOUTHWESTERN PART OF THE
field
by
shortening
coastline, as
Climate
Aptian-Albian carbonate episode, Spain
Each
of
data.
published
reconstruct
and
they
=
other influential factors.
map
The
tectonism
more
30 km
and,
shows
geological
is
a
(HAQ � 1987)
position
sedimentary
most
during the Aptian and Albian
of
accurately
GLOBAL SEA LEVEL VARIATIONS
was
the
the
constitute a central,
synthesis
Four palaeogeographic maps (Figs 30, 32,
calculated
processes
of
probably,
ferred source areas of one particular sequence.
100
108
113
105
110
Fig. 29. Urgonian depositional sequences (U 1- U4) valid for most parts of the region and depositional sub-sequences (U21-
deformed belt flanked by two thrusted areas. SW­
Arija­
clastic dispersal systems, axis of subsidence and in­
palaeo­
34 &
it. The corresponding relative sea-level changes are also shown as well as the eustatic
maintained at the present distance from
In
slightly
Nograro and Ramales sedimentary sectors (Fig. 23)
(Rat, 1959; Lotze, 1973; Soler et al., 1981), and the
275
geography, a palinspastic restoration has been made,
maps and sections
strongly
were
by
main lithological types, sedimentary environments,
the
38) representing the Urgonian sequences have been
At the beginning of the first Urgonian sequence
after