Page 10 - Carbonate Platforms Facies, Sequences, and Evolution

© 1990 The International Association of Sedimentologists ISBN: 978-0-632-02758-3 James Lee Wilson, Paul D. Crevello, J. Rick Sarg, J. Fred Read 9 * Deceased. arid suggests the shifting of the continental plates from continental break-up connected with the opening of quences Bernoulli opening phases quences The sedimentary evolution of early Mesozoic se­ and then other pelagic deposits (Fig. 2). after drowning was buried by red, nodular limestones platform depositional ized by sequences which show a similar

of
of
Cambrian
et al.,
of
with
Tethys
developed
continental
evolution.
1979).
in Tuscany has
of Sardinia are
on
limestones.
rifting
whereas
Carbonate Platforms: Facies, Sequences and Evolution Edited by Maurice E. Tucker,
(Bernoulli
In both
related
southwestern
&
to
siliciclastic
cases,
been related
Persistence
associated
to
Sarqinia
of
Jenkins,
The subsequent
deposits
and
with
the latter evolved
early stages
The Lower Palaeozoic se­
a carbonate
1974;
and
the
of
the
the early
COCOZZA*
evolution
shallow-water
and
1
2
into an open
A.
University of Siena,
bonate
to
drowned
ocean.
deposition
humid
under
demonstrate that:
platforms
a
GANDIN
of
in Sardinia gave way
documents
tropical
a
areas
Sardinia
folding (Vai & Cocozza, 1986).
as
that resulted in pull-a-part basins
continuous
and
Climatic changes occurred
Nodular lime­
during
balance
of the basins reflects the different geodynamic
synsedimentary tectonic
to oblique transform
Via delle Cerchia 3, 53100 Siena, Italy
Tuscany
related to early stages of intra-cratonic rifting;
divergent movements during continental rifting.
the Cambrian of Sardinia and the
The aim of this paper is to compare the sedimen­
the Lower Palaeozoic and Lower Mesozoic car­
the climatic change from arid to humid conditions
regime
a consequence of
recorded within the platform stage of both sequences
were
rifting
and local gentle
tological characters of the two sequences in order to
the Iapetus Ocean. However, this extensional phase
tilted, isolated platforms, established, developed and