Page 36 - Carbonate Platforms Facies, Sequences, and Evolution

IH
SA
?2_)
r===:J
�
PELAGIC
__ ,
�
I � II Ill IV SA R
shale or
li mestone
BKHA
+±+I] Marly lmst.
� I D
FACIES I

I
FA
Massiccio Limestone platform
CI
l � Early dolomite � � ·5.1. II IV TU Carbonate deposition during early rifting, Italy
NER
IT
ES
Nodular
I imestone
Nl
IC
A
with internal lagoons and asymmetric margins (Fig.
FA
the lack of terrigenous material are indicative of an
The vertical and laterai distribution of the facies and
isolated platform consisting of a wide tidal-fiat system
CI
E
Paleozoic
basement
that
S
and red beds
subsidence.
PL
carbonate
ATFORM
SC
dykes , sills
production
fillings, std.
� Breccias, karst
A
@
kept
®
FACI
up
ES
with
Dis. G.
A Buildups
NY
Tuscany: Stage I: Isolated platform established under arid climate on an inherited morphology (Botomian/Carnian­
drowning caused exposure of a number of blocks and resulted in karstic activity, slope breccias and neptunian dykes
facies formed on top of the more unstable blocks (Middle Cambrian-Lower Ordovician/Sinemurian-Pleinsbachian).
agani
�and l1mestone
faulting and differential subsidence (Upper Botomian-Toyonian/Hettangian). Stage III: Differential movements during
Rhaetian). Stage II: Isolated platform evolved under humid climate in an extensional tectonic regime which induced block
Fig. 12. Tectono-sedimentary evolution of the Cambrian and Upper Triassic-Liassic carbonate platforms of Sardinia and
(Middle Cambrian/Lower Sinemurian). Stage IV: Drowning of the platform and onlap of pelagic sediments. The nodular
(Boccaletti et al. , 1975). The platform interior main­
31
12 11), similar to the present situation in the Bahamas
tains throughout its growth, a non-cyclic, tidal-fiat,
irregular
internal-lagoon deposition. This behaviour suggests