Page 101 - Carbonate Platforms Facies, Sequences, and Evolution

in
92
as
a
tional
mitized.
0.4-1 m
lagoonal
thick
facies
Locally this
conglomerate;
beds,
lithological change to the
and
The main facies of the
(2)
facies
this
partially
F.
grades
the contact with the Rasquera Unit.
massive
Benifallet
to
grades
to
stones to grainstones, with cross-bedding.
with lime mudstones to oolitic grainstones.
totally
(line) and oolitic grainstones with cross-bedding (t).
La Riba Reef Unit
in the Rojals Unit, Upper Muschelkalk. Erosive base
Unit are:
upwards
Benifallet bioturbated limestones-dolomites unit
Ca/vet, M.E.
Fig. 14. Lower and middle part of a tidal channel sequence
usually dolomitized, and (3) oolitic-bioclastic pack­
dolo­
intraforma­
and
Gaia-Montseny Domain the upper boundary is a
the Prades Domain the upper boundary is a sharp
sharp contact with the Querol stromatolites unit. In
bioturbated grey, lime mudstones and wackestones,
(1)
there is also ferruginization and silicification close to
in the latter case. In the Baix Ebre- Priorat Domain
wackestones,
to
In the
Alcover Unit, with ferruginization and silicification
The lower part of the Benifallet Unit is interpreted
This unit, 20-SOm thick, is variable in lithofacies,
be
(2)
are:
This
were
0·4 m
strike
ramp.
higher
preted
eastern
the
Tucker,
phology
(1)
discrete,
of
Montseny
unit,
as
metre-scale
high)
framestone,
part.
the
result
and
energy
1988a)
apparently
of
tidal
with
The
coral
La Riba reefs unit
Tucker and J.M. Henton
dolomitic
2-12 m
domal
Domain
basin.
which
bipolar
packstones-grains
the dipping flank beds.
linear
isolated reefs,
deposits
only,
Querol stromatolites unit
thick,
mudstones-wackestones.
domal
sponges
are
huge stromatolite mounds.
deposits,
western part of the domain.
is
reefs are
Others
tones
and
framestone
and
bioturbation.
it
These
stromatolites.
sand shoals deposited in the sand
may
with
with
structures,
displaying
platy
lime mudstone, mostly micritic and
completely
The
present in
Lenses
have
5-60m in
cross-bedding;
facies
stromatolites
tidal
of
of
algae
the
this domain and they occur predominantly
are
main
(3)
lenticular
been
peloidal,
shoaling
height
is represented
such
( Thecosmillia up
se­
mor­
Gaia­
inter­
with a NE-SW orientation, parallel to the palaeo­
belt of a shallow
channels
quences. The oolitic grainstones are interpreted as
Prades Domain is the presence of reefs (Calvet &
(packstone-grainstone facies) located between the
type, 1-8m in wavelength and up to 2m in height;
facies and inter-reef facies (Fig. 16, Calvet & Tucker,
by
Archaeolithoporella (Esteban et al., 1977a; Calvet &
coarser,
lime
to
and
more
LLH-C
several hundred metres across (Fig. 15). Some reefs
1-2 km across,
facies
in the
number and size of the reefs decrease towards the
dolomitized
The main feature of the Upper Muschelkalk in the
(Tucker et al., 1989). The reefs are only present in
circular in plan view. The
towards the top of the mound core facies and within
as
The framework facies consists of coral-Tubiphytes
1988a). The mound core facies consists of massive
with
The reefs have a distinct facies zonation: mound
core, reef framework, reef-top bedded facies, flank
scattered skeletal grains such as molluscs and algae
more sandy skeletal-peloidal sediment occur in the
mound core. There is an increase in faunal diversity
( Tubiphytes). No framework is apparent, although
the core mudstone is commonly mottled; this could