Page 109 - Carbonate Platforms Facies, Sequences, and Evolution

5
an
the
the
ibly
&
time
level.
Mfs-2.
during
Arche,
Virgili,
marine
of
towards
responds
(Sopeiia,
Pyrenees
lines,
the
NATURE
Cantabrian
Prades
represented
angular
to
the
palaeohighs,
(J.
pers.
overlying
1987).
by
1979;
OF
IN
the
east
limestones
an
Anisian
suggests
Middle Muschelkalk.
paleosol
Gisbert,
a
comm.).
or
THE
Mountains
from
by
of the
siliciclastics
abrupt
unconformity
Buntsandstein
This
pers.
even
Upper Permian (Virgili et al. ,
lower
Sinemurian -Carixian
Perez-Arlucea
and
downlap
SEQUENCE
Related to
Upper
In the Iberian Range, there is
Marzo
above as a highstand systems tract.
&
age
lateral
during
TRIAS SIC
Boundaries of Depositional sequence 1
comm.)
lithological
Keuper
the
(1980).
(Garcia-Mondejar
sedimentation
evaporites
and
1974; Marzo,
(Lopez-Gomez,
(Giner,
Sopeiia,
change,
facies
In
et
disconformity-unconformity
Muschelkalk
in
of
geometry for
contact
be­
The lower boundary of depositional sequence 1 cor­
be­
formed during the Hercynian orogeny and then ex­
is a disconformity with Lower Liassic breccias, poss­
unconformity (a first-order unconformity) were de­
Marzo, 1980). The time represented by this uncon­
Alcover Unit beds is the maximum flooding surface,
BOUNDARIES
1987;
the
the Palaeozoic, whereas the Triassic upper boundary
1985;
in the Catalan Basin is an angular unconformity with
The lower boundary (Fig. 4) of the Triassic system
1980;
1986), there is a marked influx of siliciclastics at this
1980).
In the Iberian Range, the lower boundary is
tensively weathered and eroded (Virgili et al., 1974;
formity is post-Stephanian to Lower Triassic or even
upper part of the Upper Muschelkalk, interpreted
Perez-Arlucea, 1987). The upper boundary (Figs 4,
Salas, 1987). The Palaeozoic strata below the angular
Towards the Iberian Ranges and in association with
started
at. ,
the
tween the lutite-carbonate-evaporite unit and the
tween the carbonates of the Lower Muschelkalk and
the
into
a lateral passage
surface on the La Riba Reef that is onlapped by the
underlying dominantly siliciclastic Buntsandstein. In
the Catalan Basin, this is a paleosol horizon, termed
(A.
using
the
19) is a regional disconformity-unconformity
the unconformity
Ladinian
In
the
The
reefs.
The
buried
facies.
Lower
the
because
displays
naturally
complex.
subaerial
sequence
by
lower
an
the
water facies
Baix
mites above.
very extensive
Buntsandstein
overlying
Buntsandstein
onlap
occur
transgressive
with
and
exposure
downlap
Muschelkalk
Middle Triassic carbonate ramp systems, Spain
corresponds
1, situated
boundary
it
Capafons
is
Alcover
an
is
at
of
the
(> 100 km) in
Ebre-Priorat
surface
The transgressive surface
lutite-carbonate-evaporite
to the
Unit
the
surface
stone-dolomite facies of the
geometry
underlying clastics (Garcia-Gil,
an
Unit.
onlap
deposition
located
Lower
of
(the
unit
(Ts-2)
at
with
of
The
Domain,
contact
Boundaries of Depositional sequence 2
in
Depositional
last
the
the
unconformable
the
geometry
latter
the
regard
unit
top
where
upon
to
between
of
Muschelkalk
has
sequence
there is a laminated crust with tepees, erosion sur­
(Lopez­
fine clastic Middle Muschelkalk facies and the lime­
faces, supratidal stromatolites and collapse breccias.
ates the grey dolomites below from the white dolo­
systems tract. The Mfs-1 in the Catalan Basin separ­
deep­
Lower Muschelkalk and interpreted as phreatic in
areas close to palaeohighs in the Iberian Range, the
Possibly, the paleokarst described previously in the
gradational in the Catalan Range. However, in some
origin is related to this boundary which could be the
upper boundary (Fig.
the
paleokarst
is
flooding surface (Mfs-1) of Depositional sequence 1
the
(Ts-1) of Depositional
is a regional paraconformity. This surface, probably
upper
2
E-W direction, was
99
Upper Muschelkalk.
rich in ammonoids. In the Prades Domain·, Mfs-2 is
Gomez, 1987; Perez-Arlucea, 1987). The maximum
The TST-2 in the western part of the Iberian Range
the
sequence 2 is located at the boundary between the
boundary (Figs 4, 13 & 20) of Depositional sequence
4) of Depositional sequence 1. However, the upper
varies in nature according to the particular domain.
the
2 is difficult to define precisely in the Catalan Range
an
flooding surface (Mfs-2) of Depositional sequence 2
located between the La Riba-Benifallet Units and
of Depositional
highstand
Upper Muschelkalk) is transitional into the Keuper
1989). The maximum
of the
onlapping arrangement with respect to the La Riba
Rasquera Unit at a centimetre-thick condensed bed