Page 2 - FGamberi1992
P. 2

Seismic Data                         Marine Geology of Bologna carried out a
                                                         cruise collecting closely spaced seism ic
    Seismic data acqu ircd by the Italian Board          profiles over two of these basins. About 1000
                                                         km of seismic lines were acquired with a 30 kJ
o f lndustry in 1982 with a 3000 e.i. Airgun             sparker and a 24-channel strearner (Fig. 2).
and a 96-channel streamer are available in the
study area. In addition, in 1989 the Istitute fo r

    382500t11Or4=B=oo==~==~~~==~~~;;~;===~~==========='~222

                                                                o

                 1                                       20 km

    ~2

    .....__..... 3

    ~4

Fi~urc 4. Barhymcrric lll<IP wirh main strucwral clcmcnrs. Norc rhc most complex area of b:-tsin l is along its
nonhcrnmost sidc. B3sin 2 has rhc most complcx slfuctural setting along its southcmmost side. l : extensional
faulr: 2: conuactional fau lt: 3: anticlinc: 4: im·cncd extcnsional fau lt.

   Preliminary Results an d Interpretation               cxtensional faults (Fig. 4) having opposed
                                                         dips (1-ig. 5).
    A wcll markcd horizon. which scparates
two succcssions witll vcry diffcrcnt seismic                Thc centrai dcpocentre is bounded to thc
facics. is prcscnt on al\ scismic lines. This            cast by an extcns ional faul t striking NW-SE
rcrtcctor rcprcscnts thc rcgionally widcsprcad           and dipping NE. Depth of the basai
                                                         dctachmcnt is 2.8 sec. (Fig. 6).
crosional surfacc of thc base Plio-Qumemary
(Fig. 3).

lr

2                                                           Figure 5. Line G-36 illus!Iating an ex.tensional
                                                         fault which bounds basin l west of the island of
*...                                                     Marettimo. This NW-S E striking and NE dipping
                                                         faull caused the lowering of base Plio-Quaternary
.3..:                                                    from 0.3 s. offshore the island of Marettimo to 2.5
                                                         s. in the area near the extensional fault. Basai
Figure 3. Linc G-31 illuslrating a rellecror             detachment (arrow) at 3.5 s depth.
scparating two differen t scismic fac ies. This horizon
rcprescnts rhe rcgiona!ly widesprcad erosive surface        To the south there is a NNE-SSW trending
of base Plio-Qu:ncrnary.                                 fault, with a deepe r basai detachment and a
                                                         younger age (Fig. 7).
    Plio-Quatcrnary sedimenl thickness
indicates two basinal areas with NE-SW strike.
separated by a N-S - NW-SE structuraJ high.
Basin l. This 70 km long and 15 km wide

NW-SE trend ing basi n is Located west of the
Island of Marett imo. 1t has 3 separated

depocentres. The southemmost depocentre is
controlled by two NW-SE trending

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