Page 203 - Carbonate Platforms Facies, Sequences, and Evolution

as
Fig.
The
ision
early
well
evaporite
as
of the
Outcrop data
in
0
0
1Q
clasts,
1804�
1':::
situ
___
MONTEJU_f'r
�
taining Solenopora,
northwestward
buildup
Kimmeridgian,
�
:!." -
J<
deeper-water limestone cap.
(API)
possibly
pI 1 ];; !
CALIPER
: \
� �� ,
1 +
cannot
stick-like
whilst
GAMMA RAY
S P (MV) 150
(J�-�'::!.§'_ S )__:�Q
1 00
·····································;·······
be
H---t---t<�-+-l..J...
continuation
derived
- ·
-� -
corals
-
� I118�Q
of
from
and
siliciclastic
the
CD
.,
)>
g
)>
.....
0
z
)>
0
:0
s:
)>
recognized
the
in
16. Log signature of the top of the salt structure
related buildup obtained from Campelos #1 showing the
as well as corals and stromato­
of a thin sequence of fossiliferous packstones con­
stromato­
sedimen­
Bolhos diapir to the northwest. The three-fold div­
cyclinid foraminifera, dasycladaceans and Cayeuxia,
tation occurred farther into the Bombarral Sub-basin.
well, where the overlying marine carbonates consist
of feldspathic sandstones. These also contain angular
this
well, so it seems possible that carbonate deposition
Ramalhal
rising
poroids, which are overlain by fine-grained, darker
wackestones containing gastropods, serpulids, large
poroids. The Abadia formation is not present in this
continued near tht'\ crest of the salt high during the
of
At
ing
but
and
east
thin
able
a
than
richly
along
of
poroids
the
mation.
(Guery,
appears
contrast
probably
Lourinha
Summary
that
the
Upper Jurassic carbonate buildups,
Ramalhal,
carbonates
In
to
Solenopora
diapir
150m
to
the
may extend
poroids and
Vimeiro
is
#1,
1984).
be
locally
the
the
grainstones
Jurassic (Fig. 3).
lateral
basinal locations
show
town
(Fig.
which
occur
development
6) at Montejunto.
fossiliferous
subsurface
in age
Portugal
only
form
of
of
with
Serra
2),
Montejunto formation
consists
and
packstones
and
into
Solenopora.
shallow-water
=
is
the
of
d'el
reached
Serra
Vimeiro-Caldas
locally
and
the
Montejunto
equivalents
associated
considerable
varied
the
Rei
d'el
abundant
outcrop
of
the deep-water cap appears
300m
Between the Bolhos diapir and
and
micrite-dominated
continued into the Kimmeridgian.
Abadia
framestones
with
At these outcrops,
500-600
of
carbonate
Upper
diapiric
Rei
m
the
up
P6,
area,
a
Ota
to be
developed
surface
intercalated
corals,
to
variations
sequence
the
framestones.
(Fig.
thick
sequences
thick,
in
formation
of
and,
4 m
Amaral
structure
To
limestone
during
3),
of
as
incorporating
buildups,
with
for­
sand­
ostracod­
to the south­
thick­
The coarsening-up trend from wackestones to grain­
Figure 17 shows an interpretative cross-section link­
Rei show no evidence of drowning, and it is prob­
The corals and stromato­
These are overlain by thick se­
stromato­
and
the
Upper Jurassic
Kimmeridgian
buildup is exposed at the surface at several locations
charophyte lime mudstones and arkosic sandstones.
ness, due to contemporaneous diapiric movement.
are
limestones (Ellis et al., 1987). This may be the site
confined to
stones is common to nearly all the sequences studied,
189
(Campelos #1, Ramalhal #1). In
a
well-defined reef zone or shelf-break facies did not
Ramalhal-Serra d'el Rei buildup described above.
Cabac;os
Upper
north, at Sobral de Lagoa and Dagorda, no more
the
in
a
the
Jurassic karst fill in the underlying Middle Jurassic
of limestones of Upper Kimmeridgian age that are
wiched between the Oxfordian carbonates and 150m
and oolitic packstones, with some minor amounts of
thick
quences of bioclastic, oolitic and oncolitic packstones
within the grainstones. The limestones at Serra d'el
the
sedimentation
a
The lower part of the Montejunto formation, as at
exposed, consisting chiefly of oncolitic wackestones
similar to the nerineid wackestone facies (association
rocks