ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

te Tertiary-Quaternary. In summary, tectonic extension
and strike-slip faulting during the neotectonic evolution of
south-central Turkey are the consequences of orogenic collapse
of thermally weakened and overthickened continental
crust in the upper plate of a north-dipping subduction
zone and the westward tectonic escape of the Anatolian
block following the collision of Arabia with Eurasia in the
Middle Miocene. The Central Anatolian «ova» province
and its unique geomorphology are thus an artifact of this
complex neotectonic evolution of an Alpine-style collision
orogen in south-central Turkey.
MICHELA DINI 1, GIUSEPPE MASTRONUZZI 2
& PAOLO SANSO 2
Morphogenetic effects of relative Holocene
sea level changes in Southern Apulia (Italy)
1Laboratorio di Geochimica Isotopica, Dip. Scienze della Terra,
Universita di Trieste, 34100 Trieste, Italy
2 Dipartimento di Geologia e Geofisica, Universita di Bari,
via Orabona 4,70125 Bari, Italy
Along the coast of Southern Apulia many marine and aeolian
landforms and deposits of Holocene age have been recognized.
Their study can allow to reconstruct the Holocene
evolution of the coastal area and to point out its tectonic
trend in recent times.
Apulia region represents part of the Apenninic foreland
and it is characterized by a 6 km thick Mesozoic carbonate
platform sequence overlaid by thin discontinuous Tertiary
and Quaternary deposits. The region was affected by uplift
since Middle Pleistocene (after Pliocene - Early Pleistocene
subsidence) probably due to the arrival of the Apulian
thick continental crust to the Apenninc hinge. However,
the rate of uplift is not uniform as transfer faults striking
oblique or perpendicular to the main WNW trending normal
faults break Apulia region in three main blocks with
different rate of uplift (Gargano, Murge & Salerno) divided
by areas characterized by relative subsidence (Tavoliere
and Brindisi-Taranto plain).
The coastal landscape of Southern Apulia is characterized
by a straircase of marine terraces, more or less evident.
Along the area close to present coastline the effects of relative
Holocene sea level changes are detectable both on
rocky coasts and on main beaches.
Some tracts of rocky coasts modelled on weak calcarenitic
deposits are characterized by raised shore platforms of impressive
width (up to 40 rn), placed at altitude ranging
between 1 and 3 m above sea level in same places bordered
landward by a well-developed notch. Furthermore, submarine
survey revealed the presence at about 4 m below sea
level of either a submerged platform or openings of sub-
150
merged sea caves. Good examples of these forms can be
recognized near Monopoli, Otranto and on the Cheradi
islands (Taranto).
The age of the emerged platforms can be inferred by
morphological considerations and from the regional geological
context. In fact, small patches of travertino and quarried
blocks encrusted by Vermetidae coming from the edge
of the present intertidal platform have been found on
their surface. The former yielded a radiocarbon age of
1,350±80 years B.P. and the latter dated a catastrophic wave
event occurred 2,060±50 years B.P. Furthermore, ancient
pottery encrusted by red algae was detected on the
Cheradi islands platform. On the other hand, the effects of
the youngest Tyrrhenian sea level stand are recognizable
along the coast of Southern Apulia at an altitude of about
8/10 m so that it seems reasonable to attribute the modelling
of the raised platforms to the Holocene.
Several tracts of coast shelter pocket beaches or are represented
by long beaches (i.e, along adriatic side from Torre
Canne to Rosa Marina, from San Cataldo to San Foca, and
near Alimini Lakes and along the Ionian side from Torre
Sgarrata to Torre Lapillo and from Torre San Giovanni to
Torre Vado). Their landward border is often characterized
by two main aeolian units represented by dune belts
behind the main long beaches or by small dune fields fed
by pocket beaches. Both the aeolian units are characterized
by pulmonate Gastropods (mainly Helix sp., Pomatia sp.,
Rumina sp.) which have been the object of numerous radiocarbon
age determinations.
The older aeolian unit is represented by grey or pale reddish
sands, partly cemented and showing a well-developed
high-angle cross lamination, which in Rosa marina locality
grades downward to beach deposits characterized by bioturbation
of Echinoids and placed at about 1 m above sea
level. Along the Adriatic side of southern Apulia this unit
constitutes the core of present dune belt and outcrops
along coastal tracts in severe erosion. On the contrary,
along the Ionian shoreline this aeolian dune shows the foot
1 m below present sea level and it is often cut by present
cliff. Several radiocarbon age determinations carried out
on samples coming from both the Adriatic and the Ionian
side of southern Apulia point out for this unit an age of
about 6,000 years.
The younger aeolian unit is made by brownish or greyish
loose sands characterized by the presence of numerous decimetric
levels of brownish soil. This unit often covers the
older Holocene aeolian unit by a thin brown paleosoil. Radiocarbon
age determinations yielded an age of about
2,500 years B.P. Small patches of younger aeolian deposits
have been recognized along several coastal tracts and radiometrically
aged to 500-800 y B.P.
The collected data suggest a relative high sea level stand in
mid-Holocene times. The altimetric position of forms genetically
linked to this sea level stand stresses the different
rates of uplift which characterize the four main structural
blocks recognized in southern Apulia, i.e. the Murge, the
Taranto and Brindisi plains, and the Salento peninsula.