Page 1 - Abate_ali_2003

Rivisu ltali.tna di Paleomologi.t e Str.atignfia Jvolume no
SICILIAN JURASSIC PHYSIOGRAPHY ANO GEOLOGIC REALMS (ITALY)
BENEDETIO ABATE', GIOVANNA LO CICERO' & LORIS MONTANARI'
R~iwJ Octobrr JO, 2002; aa:quJ Nm.'t'ntbtrr 4, 10CJ
Key.uiOfdJ: Sidly. Jur;usie, palaeogrog~phy.
Abscr"cl.. Two tcctoncrsedinu:ntary domains. which wcre de-
(ormed during the Neogene ;:md e,·olvt'd into rwo large nrvctur.tl s«·
tors, cha.nctcri1.e the Sicili1n Juras~ic:: the Maghrcbides :and Pcloriu-
ni. A(rica m:..rgin scdimcnu, p:assing downward to Triassic succes:sions
2nd perh.-ps originali)' IO P.11t07.0ÌC' dcpositJ., characteriu the (ormcr.
The bncr belongs 10 the Europcan •ç:alabri.:an Are·. whcrc thcjur:t.ssic
transgrc"SSÌ\'cly resu on a eominent'al sub.«r.uc (i.c. thc crystalline Vt-
riscan b:asrment).
Thue domalns ilre ch~racteri.x.ed by rour .scdimem;ny facics:
sh:allow pl:atfom1-d.erivcd Jjmrstonc$: condcnscd s~mounHypc rcd
lime:stone.s; nodu.bt limestones with Otmmonites: deep ndiolaritu v.d
sbales. Thesc (:acies :~re illun.r.ucd in :a dozcn o( nr.nigro1phic logs.
The drowning of most Triusic-Li:~ssic carbonate pluforms
Ot ramps ;:md the deepeni.ng o( :adjac:em b;tsins c:&me with inferred
Jur:u.sie n rikc-sJjp ttctoni~:."i. connccted to the rdatÌ\•e movement of
Africa (Gol:'ldv.-3ni:~n p:an) vs. Europe (Uur:ui:~n p:.,n); the s:tmé' strike-.
slip tcctonics may have nust"d sc.1uered intrnpl.1te volcanic scamounts
found in Maghrcbide-s.
During thc Jur:usic the Maghrebide re.1.lm w:as char.acteriz-cd by
che interfingerin& of b:.,sins and c:arbon:ate platforms. During the Ear-
ly :md MiddJc Li:auic, carbon:atc pl:atfonn.s and ramps were dominant.
Since To:arei011'1 either r.\diobriu:s in some Msi.ns or AJ1Hnonite·beuing
ct~lcm:ous muds de\'elopcd with imcrvcning b.lsahic nows. :md were
:aoeompanied by condensed pdagic arbona.te-son the ensialic sc:amount·
typc highs.
The Jleloritani ~Jm display$ similar characteristiCJ. but with
latcr uansgrc.ssion on thc buemcnt, scvcnl strike-slip basins and with-
out :any volc:anoes.
Rfassunto. 11 Giurassico sicili:t.no s-i rlsconu'3 in due domini nrut·
turati deformni.si plit<1Uvamcncc dal Miocene secondo due catene or.a
s:ald~tc: il M:aghrcbidc c li Pdorit:.1no (Fig. 1). Uprimo~ form~to da sc-
dimemi marini di nurgine gondwaniano-afric:mo. in continuit1 dcPQsi-
l.ion:tle almeno daJ Triaso ll S«:ondo ~ form;uo cb sedimenti di margine
b.umsia.no-e-uropeo trugrc.sshti, sul b:lSamtnto varisieo e 1:. sua sottile
copcnur.:. contlnenu.le uiassK:o•infr:aliassia, solo nel Lias infC'riorc:.
1sedimc:mi giurassici di :ambc:duc i domini .sonoc:sprcui da quat-
tro tipo1ogi.c litologiche c: in un:t doz1.in-<1 di logstr:nigrafici cmblem:.1ici:
•C:&IC;1ti neritiei di pia.tt:aforma e di r:am?J; carbonatlCl; -calcari rossi di se·
dimcm:uionc: fX'I.~gic.:. condensar:~; -ca.IC'ari nodulari ros:.1ti (questi uhimi
l Oip:tnim. Geologi:a e: Gt:odest:. Uni\•ettit~ dj P.dermo. \~ An:hil'l.fi 22, I-90J23; Tel.+.390916230)11. E-m:til: bino@unip:a.it.lociccro@unipa.it.
2 CP 93 PPTI, via Roma, 90100 Palcnno, Td. + 393478S1659. E-maLI; lorismon@hotnu.il.it
no. l - ~p.l5·22 April2004
due assegnabili al "'Rosso Ammonitico•l.s): -ndiobriti cd .ugiUiU.
Nel Liu inferiore e medio i due domini erano suddivisibili nel
Ma~threbide s«:ondo pia.tuJorme e b.tcini interdigit:ni ercdh:tti dal Tri:as
c nd Pelorirano secondo pi.:auafonnt e rampe carbon~tiche circoncbnti
lncini probabilmente romboc:asmici.
Ovunque, tnnnt ratt ccc:ezioni, le pi:1.tt<1forme :subirono it noto
annegamento giur.usieo~ con ttndcn~i.:ale anticipo al Domcri:mo supe-
riore nd PcJoriuno e uno più nuuc.uo e diffuso al To:arciano nel M11·
ghrcbidc. Solo in que.s1'uhimo furono anivi vulcani sottomarini mc-
dio~iurassici .
lntroductlon
A palaeogcograpbic restoration of two Jurassic
crustal secrors, each otber fromal to tbe boundaries of
tbe suggested oceanic domain of the Alpine-Tctbys witb
lhe soutbern Neotethys one (cf. Stampni et al. 2002), is
bere offered. The southern crustal sector is supposed to
belong to Gondwana, from wbich the Magbrebide Chain
origina.ted. The nonhern sector is lnste.ad attributed to
J..aurasia, from whicb tbe materials of one or more micro-
continents derived. The latter, eventuallyassembled in the
Miocene, is bere considered to form rhe Calabrian Are,
wbose Sicilian part is tbe Peloritani region. This region is
bere assumed as an exotic "terrane• (Fig. l).
For rbe rwo Sicilian sectors, cb:~tacterized by a fold
~and .. rhrust sryle, a palinspastic reconstructìon is pro~
posed, not strictly takiog imo account their present po-
sition (as suggested by Castany 1956; Zappaterra 1994,
among tbc others), but considering, on tbe wbole, the
amount of sbortening occurred. The sedimentary char-
acters of them bave been individuated on the basis of the
research on the Sicilian Jurassic ca.rried out since mid XIX
century: namely the palaeontologicaland geologica! stud-
ies of G.G. Gemmellaro (Mid XIX century); Di Stefano
G. (1887); Di Stefano & Cortese (1891); Fucini ( 1921);