Page 221 - Carbonate Platforms Facies, Sequences, and Evolution

N
In
the
·
last,
stone,
useful
this
monites.
. · .. .. ..... . ... ..
Vanneau
debelmasi,
DE
et
Pierre Jaune
... . ... . , . . .... .
region
Glandasse
at. ,
PIERRE
de
stratigraphic
(Fig.
JURA
1976;
5),
JAUNE
bioclastic
Orbitolino psis
NEUCHATEL
at the top) which contains
species
Neuchatel,
common in the early Aptian.
the
only small forms of this species.
Thieuloy,
have
Barremian of the southern Vercors
levels
fiandrini
tionally rich in benthic foraminifera,
limestone
appearing in the late Barremian,
1979)
been
Glandasse
and
of
which
whereas
the
The first, observed in the Glandasse bioclastic lime­
Paracos­
top of the late Barremian and the Urgonian lime­
by the Matheronites limentinus marly level (Arnaud­
In the carbonate facies, which are excep­
a large number of am­
Paracoskinolina reicheli, Eo palorbitolina charollaisi,
Valserina bronnimanni and Palorbitolina lenticular is.
two groups of
the
Barremian (Feraudi Zone at the base, Astieri Zone
late
identified.
marls. It includes Cribello psis thieuloyi, Orbitolino psis
bioclastic
kinolina? jourdanensis. The second group contains
contain
stone, has been found only below the M. limentinus
This association of the four species characterizes the
although the first two appear at the top of
is especially
limestone and the Urgonian limestone are separated
is
and,
early
Jura).
made.
which
(Fig. 6).
GLANDASSE
carbonate
confirmed
(1)
NORTHERN
BORNE
and the Jura
Ber.-Val.
Aptian,
by
probably,
The
decreases
In conclusion,
highlighted by
The Jura and northern Subal pine chains
a
the
platform
there
from
is
part
SUBALPINE
=
BIOCLASTIC
of
facies
no
BIOCLASTIC
foraminifera
the
Throughout this region,
CHAINS
examination
2000 m
steady
towards
of
typical
the
of
in the
LIMESTONE
the
wire-line
Jurassic-Cretaceous boundary; (2) Bypass margin of the Jura platform (Tithonian and early Berriasian); (3) Upper
late Barremian
a clear lithological boundary,
progradation
s
Fig. 4. Arrangement of the Hauterivian-Lower Aptian carbonate formations (Jura and northern sub-alpine chains). (1)
Valanginian and Lower Hauterivian outer shelf; (4) Hauterivian hemipelagic slope; (5) Lower Aptian hemipelagic slope.
Barremian of the northern Vercors, the Chartreuse
Barremian are found all through the Urgonian lime­
the Urgonian lime­
207
____ Qm
the Swiss Jura. In the Vercors, the absence of this
stone, from the Vercors to the Neuchiitel area (Swiss
to just a few metres to the northeast of the massif.
de Neuchatel dated to the Hauterivian. In the Jura,
In this region, two fundamental observations can be
Barremian are not found from the central Vercors to
are
a part of the late Hauterivian, the early Barremian
logs
of
missing between these two formations. Their absence
as
reduction in the thickness of the early Barremian
microfauna can be explained by a very substantial
early
southeast
the Jura where it is directly above the Pierre Jaune
stone always begins in the late Barremian, including
(2) The foraminifera which are typical of the late
Vocontian
between the Hauterivian and the ·