Page 208 - Carbonate Platforms Facies, Sequences, and Evolution

194
NW
1986).
The
area of
currence
Kurnubia
>
lagoon '
Bombarral
ammonites
in
Abadia marls.
Setting and age
top part
the
I
LIMESTONE
SOURCE AREA
Sub-basin
shelf
break
palastiniensis
CAP
characteristic
Amaral
in the Turcifal Sub-basin.
into
of
ON
1000 km 2 from the
Description and interpretation
of the Abadia
the
and the
the
5-10km
formation
SILICICLA STICS
of
Arruda
dasyclad
formation
The Amaral formation forms a thin ( =60
the
slope
tenuilobatum
P.M. Ellis, R. C. L.
PROGRADING
pseudomutabalis Zones which, together with the oc­
m) lime­
and packstones
contains
(Wilson, 1988, fig. 7) and is seen on seismic sections
age for the latter formation (Dolher in Leinfelder,
stone cap to the southward prograding slope marls
and silts of the Abadia formation. It extends over an
The Amaral formation represents a carbonate sheet
southern part of the
Sub-basin
and
Martins and Farta Pao formation overlying 900 m of
foram
Clypeina
jurassica clearly indicates an Upper Kimmeridgian
the distribution of facies associations described in Table 1.
�
neri neid wackestones
to
other
clastic
5 and
grades
consists
slope
toe of
7)
siliciclastic
biostromal
I
@
buildups
with sets up to
unit
oncolitic
vertically
in these sediments.
dominate,
Wilson and R.R. Leinfelder
and
sandstones
algal -microsolenid
in the
predominantly
deep
but
described
basi n
bi ndstone patch reef
-
of
LIMIT OF OUTCROP
and
packstones
centre
laterally
--
ooid
and
towards the top of the sequence.
in this
of
oyster
into
and Tubi phytes
the
wackestones @
---
paper
San Pedro limestone _J._-,---'-
water wackestones
grainstones
SE
sea -level
grainstones,
Arruda
coral-rich
mudstones (j)
(Table
ammonitic li m e
patch-reefs
up
30m of the Amaral formation consists of coral bind­
- �g�� a base
1).
bio­
sub­
Fig. 20. Interpretative cross-section of the Kimmeridgian-Berriasian buildup on the southwest side of the basin, showing
stones forming individual structures up to 10m thick.
sand and exhibits fewer facies associations than the
wackestones (association 6) occur in lagoonal areas.
High-energy grainstones and bioherms (associations
lower energy fossiliferous
Around the Torres Vedras-Montejunto high, and
These contain a diverse biota of baffling and massive
quartz-forming ooid nuclei increases upwards, and
to
wackestones. Significant amounts of ooids also occur
minor nerineid packstones and bioturbated bioclastic
with
basin. At outcrop, the grainstones are cross-bedded,
basinal shales and
In the centre of the Arruda Sub-basin, the basal
corals and stromatoporoids, with molluscs, echinoids
and encrusting algae and forams. This reefal facies
30m thick. This facies also occurs above the lower
in the Campelos and Ramalhal wells, the Amaral
2m thick are intercalated with the grainstones
10m thick. The amount of detrital
up