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ATLAS OF THE MARINE AND TRANSITIONAL HOLOCENE TERRACES - EASTERN STRAITS OF THE MAGELLAN COASTS – PATAGONIA AND TIERRA DEL FUEGO (CHILE)
No full textPrevious studies, carried out by the “Trieste and Cagliari University”, within the Italian "Programma
Nazionale di Ricerche in Antartide" on the Straits of Magellan were mainly directed at
sedimentological research on the sea bottoms and coastal belt of the eastern section (Atlantic
opening). Subsequent research along the coastal belt was carried out in greater detail with mapping
of morpho-sedimentologicalogical units. During this second phase, greater attention was given to the
study of palaeo-shorelines and different terrace orders of presumed marine and transitional origin
(Brambati et alii 1993, De Muro et alii 1995). On the basis of the initial geomorphological, and
sedimentological results obtained, we made a zoning of the coastal belts along the Atlantic opening of
the Straits which enabled us to print 12 sheets on a scale of 1:50,000 (De Muro et alii 2004).
Morphogenesis of the area was strictly controlled by the processes associated with the advance and
retreat of the Magellano Glacier and, subordinately, by the main morphodynamic event represented
by post deglaciation marine ingression. The Holocene paleogeographic evolutionary picture of the
Patagonia-Tierra del Fuego area is mainly controlled by the imposing phenomenon of glacio-isostasy,
though it cannot be ruled out that the morphogenesis subsequent to deglaciation may have been
affected by mild neo-tectonic movements. The Atlas provides a zoning of the area distribution of the
most significant Holocene marine and transitional deposits processes and forms relating to the
coastal belt between P.ta Dungeness and Cabo Frowar
Notes on the Geomorphological map of the area between Capo Testa and Punta di li Francesi (Northern Sardinia - Italy);(+1:25.000 scale map)
No full textDynamics of the bar and trough zone between Capo Testa e Punta di li Francesi (Northern Sardinia - Italy)
No full textSubmerged coastlines in the sector between capo Testa and Punta di li Francesi (Northern Sardinia, Italy): geomorphological and sedimentological aspects
No full textCoastal mapping of the Quaternary marine deposits in the Strait of Magellan (Chile)
No full textDuring the last glacial cyclc, glaciers drained north-eastward into the Strait of Magellan. The timing
of the last advances has been amhiguous but the older dates of 16,590-15,800 up to 10,050 yr for
deglaciation have been reported.
This paper focuses on the Strait of Magellan where, after the last glacial cycle, the marine ingression
is well defied.
Along the coasts of the eastern Atlantic side of the Straits, it is possible to observe at least four orders
of terraces, prevalently marine lying on a meso-Tertiary sedimentary basement or on glacial and
glaciofluvial deposits, linked to the last Quaternary main glacial stages.
The four main ordcrs of terraced sequences have been mapped, described and dated using 14C. Their
stratigraphic position and their radiocarbon dating, refer to the Lower Holocene. This time period
connects them to the isostasy rebound.
The First and oldest Order, were found regularly between altitudes of 18 and 25 metres. The Second
Order is distributed between 6 and I I metres, and is mainly represented by fossiliferous gravel
deposits; sands and silts are also present. It regularly covers most of the coastal stretch and extcnds in
the backland.
The age of formation of the marine deposits, by C14 dating, is comprised on average between 6,000
and 7,000 years B.P.
The Third Order is following the present-day beach, between altitudes of 3 and 5 metres, at the foot
of the Second Order terrace. It is made up of gravels and sands and refers preferrably to a marine
environment. At a slightly lower elevation, lies the Fourth Order marine tcrrace, distribuited between
1.5 and 3 metres.
All terraces present well-preserved characteristics of paleobeach environments (berms, spits and
ridges).
The First Order terrace belongs to the palaeogeography, which was evolved during the first phase of
the last deglaciation. The other orders are connected with subsequent stages of the last deglaciation,
but the influences of the tectonics in their evolution cannot be excluded
Abrasion of beach sands: a laboratory predictive model for Northern Adriatic Sea beaches
No full textSediment resuspension induced by clam fishing with hydraulic dredges in the Gulf of Venice (Adriatic Sea). A preliminary experimental approach.
No full textMORPHOLOGY AND SEISMOSTRATIGRAPHY OF THE PROXIMAL SHELF BETWEEN CAPO TESTA AND PUNTA DI LI FRANCESI (NORTHERN SARDINIA). PRELIMINARY RESULTS
No full textThe last marine ingression in central Magellan Straits, southernmost Chile: geological and geochemical evidences
No full textDuring the last glacial cycle, glaciers drained north-eastward into the Strait of Magellan. The timing of the last advances has been ambiguous but the older dates of 16,590-15,800 up to 10,500 yr for deglaciation is known in the literature.
This presentation focuses the Strait of Magellan, where after the last glacial cycle, the marine ingression is well defined.
Along the coasts, located on the eastern Atlantic side of the Straits, it is possible to observe at least four orders of terraces, prevalently marine lying on a meso-tertiary sedimentary basement or on glacial and glacifluvial deposits, linked to the last Quaternary main glacial stages.
The four main orders of terraced sequences have been mapped, described and dated using 14C. Because of there stratigraphic position and by radiocarbon dating, these four order terraces were referred to the Lower Holocene and connected to the isostasy rebound.
The First, and oldest Order, was found regularly between altitudes of 18 and 25 metres. The Second Order, is distributed between 6 and 11 metres, and is mainly represented by fossiliferous gravel deposits; sands and silts are also present. It regularly covers most of the coastal stretch and extends in the backland.
The age of formation of the marine deposits, by C14 dating, is on average between 6,000 and 7,000 years B.P.
The Third Order is following strictly the present beach, between altitudes of 3 and 5 metres, at the foot of the Second Order terrace. It is made up of gravels and sands and refers preferably to a marine environment. At a slightly lower elevation, there is the Fourth Order marine terrace distribuited between 1.5 and 3 metres.
All terraces, present well-preserved characteristics of paleobeach environments (berms, spits and ridges).
The First Order terrace belongs to the palaeogeography, which was evolved during the first phase of the last deglaciation. The other orders are connected with subsequent stages of the last deglaciation, but the influences of the tectonics in their evolution cannot be excluded
Sediments and sedimentological processes in the Ross Sea continental shelf (Antarctica): results and preliminary conclusions
No full textA zoning on the basis of the sediment textural characteristics has led to a distinction between the inner and outer shelf: the first, where coarse grained sediments prevail, is subjected to terrigenous input from present glaciers; the latter is dominated by the reworking of ancient sediments. -from Author
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