Page 6 - Abate_ali_2003

20 8. Abate, G. Lo Cic<ro & L. Mont<VIari
fig. 6 .. Coneqnu.al physiographic mode1 (or the Eatly Liassic in the Pclorit~ni's :u·e:a: LG • Longi ~sin; GA, SMA, FZ, SI~ TA, GO. SA =
G-:tlati. S. Marco d'AiunUo, Fr:tz:c.anò, S. Pietro, T:torminoa, Gallodoro, S. Andrea carbon.ate platfonns or n.mps; AL= Ah gypsiferous
-.and carbonacic shdf; F-M = fondathelli·M:andraui·Mandanici zone; ASP e Asptomonte lone; NV • Rocca Novara zone. (modi(.
from C:areione et :al. 2003).
- In Maghrebides, until the Middle Lias, the Tri-
assic structure persisted with the presence of carbonate
platforms, ramps and relative sediments. Fcw emcrsions
occurred (one of these took piace in the Panormide, at
Mt. Gallo, with bauxites occupying the Early Lias-Early
Malm interv.l (Di Stefano 2002)).
- In the Peloritani, both the transgression over thc
basement and its continental-Triassic cover occurred later
(Lower Liassic). The correspondence between these two
zoncs concerning Lower Liassic sedime.ntation was later
reversed during two differeot times: at first the drowning
took piace by the Peloritan sector during Late Domer-
ian, then during che Toarcian in tbe Maghrebian one. The
latter occurred when the mainly carbonate sedimenta-
tion alternated with the radiolaritic-argillitic one. The
few affinities between the two depositional areas are in
the sporadic netitic occurrence at the top of the Jurassic
(EIIipsactinia-bearing limcstones in the Panormide, Cly-
peina-bearing limes tones in the N ovarese) and in the radi-
olaritcs both by the Imerese, Sicanian (Maghrebides) and
by the Alì (Peloritani) sequence. This resembles parental
relationships with the Sicilide rift, which was interposed
between Peloritani and Maghrebides in the Jurassic-Cre-
caceous nmes.
Simultaneous distinct physiographic s ituations
with different depositional typology, even to a small
scale, a.nd deep volcanism suggest a moderate structural
dynamics.
Updated generai models for the Gondwana-Laura-
sia boundaty during che Jurassic., which includcs the two
Sicilian rcalms (Stampfli & Mosar 1999; Stampfli et al.
2002), as well as of some Authors (Muttoni et al. 2000)
ones for the Gondwana sector, show widespread strike-
slip tectanics. T his laner one, foreseen by C atalano &
D 'Argenio ( 1982), may jus tify the contemporaneous
prescnce of adjacent structural ups and downs (push-
ups and rhombocasms) , even if of reduced dimensions.
On the base of these considerations and daLt, and
on the base of the mutua! position of domains whicb
were deforn1ed during Miocene (e.g. by Catalano et al.
2000 for che Maghrebides; Lentini et al. 2000; Carcione
et al. 2003 for Peloritani) wc can suggest four concep-
tual physiographic models, for the Early Liassic (cime
of carbonate platforms) or the Middlc Jurassic (time of
their dro,vning).
As for Maghrebides, excluding the Jurassic Sicilide,
the firs t t ime may indicate platforms and half-encircled
basins (Fig. 4), where the Hyblaean euxinic basin o f the
Streppenosa Fm. s uggests a potential indipendente of
Magbrebides from Apulia.
At the second time (Fig. 5) the development of
trnnscurre.nt strucrures owing to strike-slip tectonics