111 research outputs found
L'avventura italiana in Antartide
No full textIn video collegamento in diretta dall'Antartide con la Stazione italo-francese Concordia
Intervengono
Mauro Celussi, ricercatore Sezione di oceanografia, OGS
Franco Coren, direttore Sezione infrastrutture, OGS
Emanuele Lodolo, ricercatore Sezione di geofisica, OGS
Antoni Meloni, presidente CSNA Commissione Scientifica Nazionale per l'Antartide
modera
Fabio Pagan, giornalista scientific
Structure of the wedge-top and foredeep of the Magallanes-Malvinas basins between 62° W and 67° W (SW Atlantic Ocean)
No full textThis work analyzes the geometry and geodynamic development of the offshore sector (between 62° W and 67° W) of the south Magallanes and Malvinas basins wedge-top and foredeep, and associated orogenic wedge. It is based on the interpretation of more than 20,000 km of multichannel seismic profiles, along with bathymetric data. The fold-and-thrust belt front was mapped, and three structural domains were distinguished: western, transitional and eastern. A stepped foredeep characterizes the western domain with flower-structures that affect the basement, and by an intense erosion in the Miocene deposits. Towards the transitional domain, the erosion is less evident, and the wedge-top is more developed. This configuration is associated with the syn-deformational deposition and the generation of thrusts within an acoustically chaotic body in the transitional and eastern domains, deposited by processes of mass removal in the Oligocene. During the Oligocene/Miocene, the area was affected by compression/transpression, which generated an incipient tectonic inversion of the basement extensional faults, with the formation of anticlines associated with piggy-back basins in the wedge-top. The differences observed between the western and eastern domains would be related to the differential movement between the crustal blocks of Tierra del Fuego and Burdwood Bank, respectively, against the South American shelf since the Oligocene.Fil: Ormazabal, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Tassone, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Esteban, Federico Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Isola, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Cayo, Lubin Eric. Yacimientos Petrolíferos Fiscales; ArgentinaFil: Lozano, Jorge Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Menichetti, Marco. Università Degli Studi Di Urbino Carlo Bo; ItaliaFil: Lodolo, Emanuele. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; Itali
The central Fuegian fold and thrust belt in Tierra del Fuego: Strike‐slip tectonics superimposed onto compressional deformation
No full textThe boundary between South America and Scotia plates was established during Neogene times when a wrench tectonic regime was developed along the central area of Tierra del Fuego. This boundary includes the Magallanes–Fagnano fault system: a regional diffuse deformation zone, which involves the development of the satellite Yehuin–Chepelmut fault zone and a series of pull-apart basins overprinting the Fuegian fold and thrust belt. The analysis of regional seismic lines allowed to reconstruct and recognize the structure of the external fold and thrust belt. The interpreted structures were integrated into a regional transect and a 3D block diagram that display the different structural domains and, mainly, the wrench deformation associated with the Magallanes–Fagnano fault system. Geophysical data from gravity and magnetic anomaly maps provided further support for the location and development of the pull-apart basins along the plate boundary. The deformation of the external fold and thrust belt is characterized by an imbricated fan system with a Paleogene detachment surface, which was later cut across by the Yehuin–Chepelmut fault zone and the Magallanes–Fagnano fault system.Fil: Lozano, Jorge Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; ArgentinaFil: Bran, Donaldo Mauricio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Peroni, Javier Ignacio. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lodolo, Emanuele. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Menichetti, Marco. Università Degli Studi Di Urbino Carlo Bo; ItaliaFil: Cerredo, Maria Elena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Tassone, Alejandro Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentin
Gateways and climate: The Drake Passage opening
No full textThe Oligocene opening of the Drake Passage between the southern tip of South America and the Antarctic Peninsula, and the subsequent evolution of the Scotia plate, have definitively separated Antarctica from the other continental masses, and have created conditions for the development of the Antarctic Circumpolar Current. This annular water flow has had a profound influence on the global climate system because it has allowed the free transfer of water masses between the Pacific and Atlantic Oceans at mid to high southerly latitudes. The comparative seismic analysis of the passive margins of the western sector of the Scotia plate, represented by the Tierra del Fuego continental margin to the north, and by the Terror Rise to the south, has shown significant morphological and structural similarities between these two margins, supporting the interpretation that they were conjugate before the Drake Passage opened. Moreover, the identification of the oldest magnetic anomalies present at the base of the two margin pairs, corresponding to about 32 million years ago, has allowed the reconstruction, through time, of the relative positions of the two continental margins, and to constrain the events that occurred immediately after the break-up and opening of the Drake Passage. These timings correlate with events seen in the oxygen isotope record from benthic foraminera, and support the view that the Drake Passage opening was the trigger for abrupt Eocene-Oligocene climate deterioration and the growth of extensive ice sheets on the Antarctic continent.Fil: Lodolo, Emanuele. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Tassone, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Instituto de Geofísica "Daniel Valencio"; Argentin
sj-pdf-1-hol-10.1177_09596836211060496 – Supplemental material for Stratigraphic signature of the Perito Moreno ice-dammings during the Little Ice Age (southern Patagonia, Argentina)
No full textSupplemental material, sj-pdf-1-hol-10.1177_09596836211060496 for Stratigraphic signature of the Perito Moreno ice-dammings during the Little Ice Age (southern Patagonia, Argentina) by Mauro Caffau, Emanuele Lodolo, Federica Donda, Massimo Zecchin, Jorge G Lozano, Federica Nasi, Donaldo M. Bran, Alejandro Tassone and Andrea Caburlotto in The Holocene</p
ERT imaging of a shallow basin: eastern Lago Fagnano,Tierra del Fuego, Argentina
No full textTwo ERT (Electrical Resistivity Tomography) profiles were conducted at the eastern head of Lago Fagnano within the main deformation zone of the Magallanes-Fagnano Transform fault system (MFS) which represents the onland boundary between the SouthAmerica and Scotia plates. Results from the inversion models have provided new evidence of the presence and location at shallow depths of some strands of the MFS. Tomographic models showed significant resistivity contrasts across the inferred fault zones in the subsurface. The combination of ERT, geomorphic and outcrop structural data allowed us to interpret the stepped southwards subsidence of Tertiary and Quaternary units within the studied area. The Holocene development and evolution of a shallow deltaic basin at the mouth of Río Turbio, the eastern tributary of Lago Fagnano, was also interpreted from electrical imaging.Fil: Tassone, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Santomauro, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Menichetti, Marco. Istituto Di Scienze Della Terra; ItaliaFil: Cerredo, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Lodolo, Emanuele. Istituto Nazionale Di Oceanografia E Di Geofisica Speri; ItaliaFil: Remesal, Marcela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Lippai, Horacio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Hormaechea, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vilas, Juan Francisco A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentin
Bathymetric map of Lago Fagnano (Tierra del Fuego Island)
No full textWe present a general bathymetric map of Lago Fagnano, the largest ice-free lake of the Southern Hemisphere, located in the central part of the Tierra del Fuego Island. The map has been obtained compiling all the available bathymetric soundings and depth-converted high-resolution seismic profiles, collected in the course of several geophysical campaigns. The lake occupies a 110-km long, E-W trending tectonic depression within the southernmost tip of the Andean Cordillera, where the South America-Scotia plate boundary traverses the Tierra del Fuego Island. The map allows us to identify the main morpho-bathymetric features of Lago Fagnano. The lake floor is divided into two principal sectors of different water depths, separated by a main shoal located in the central part of the lake. Maximum water depth (206 m) is found in the eastern part, whereas water depths in the western half do not exceed 165 m. In this paper, we describe the geometry and the general morphological characteristics of the basin, which was generated by a combination of distinct tectonic processes, and later superposed by Late Quaternary glacial and glacio-lacustrine dynamic events.Fil: Zanolla, C.. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Lodolo, E.. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale ; ItaliaFil: Lippai, Horacio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Instituto de Geofísica "Daniel Valencio"; ArgentinaFil: Tassone, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Instituto de Geofísica "Daniel Valencio"; ArgentinaFil: Menichetti, M.. Università di Urbino; ItaliaFil: Baradello, L.. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Grossi, H. L.. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Hormaechea, Jose Luis. Estación Astronomica de Río Grande; Argentin
Post-LGM coastline evolution of the NW Sicilian Channel: Comparing high-resolution geophysical data with Glacial Isostatic Adjustment modeling
No full textSince about 20,000 years ago, the geography of the Earth has been profoundly modified by the gradual sea-level rise caused by the melting of continental ice sheets. Flat areas and regions characterized by very low gradients experienced, more than others, rapid flooding, with the progressive disappearance of vast coastal territories. Here we present a recon- struction of the late Quaternary coastline evolution of the north-western sector of the Sicilian Channel, constrained by high-resolution seismic profiles where the marker of the post-Last Glacial Maximum (LGM) marine transgression has been clearly identified and mapped. The locations of the post-LGM seismic horizon have been compared with predictions of a Glacial Isostatic Adjustment (GIA) model, which accounts for the migration of the shorelines in response to sea-level rise and for Earth’s rotational and deformational effects associated with deglaciation. We have verified that most of the points mapped through seismic data interpretation fall along the palaeo-coastline that the GIA model predicts for the 21 kyrs B.P. time frame. However, the model shows a misfit in the marine sector between Mazara del Vallo and Sciacca, where the available data indicate a Quaternary tectonic uplift. The analy- sis of the seismic profiles provides useful constraints to current GIA models. These add on existing histories of relative sea level in the Mediterranean Sea, allowing to gain new insight into the evolution of the palaeo-geography of the region of study and of the whole Sicilian Channel since the LGM, even in areas where direct geophysical observations are not avail- able yet. In this respect, one of the most attractive implications of the ancient coastline evo- lution is linked with the underwater archaeology. The sea-level rise heavily impacted the distribution of human settlements, possibly forcing site abandonment and migrations, and this is particularly relevant in the Mediterranean basin, the cradle of the western civilization. The underwater traces left by these ancient populations represent the fundamental proofs to reconstruct the early history of our precursors
Western Scotia Sea margins: Improved constraints on the opening of the Drake Passage
No full textWe present a revised tectonic interpretation (from ∼28 Ma to 3.2 Ma) of the western sector of the Scotia Sea, incorporating new multichannel seismic reflection profiles and magnetic anomaly identifications for the continental margin off the Tierra del Fuego Island, and available complementary data for the conjugate margin of the northwestern flank of the South Scotia Ridge. Seismic profiles show a remarkable diversity of the pair of conjugate passive margins of the western Scotia Sea in both their morphology and structural framework. The Tierra del Fuego continental margin can be related to a classic rifted passive margin, while the southwestern margin of the Scotia Sea is characterized by steep slopes mostly generated by subvertical faults that abruptly separate the continental crust of the South Scotia Ridge from the oceanic crust of the western Scotia Sea. This structural difference was caused by intense strike-slip tectonism, mostly concentrated along the modern South Scotia Ridge since the early development of the western Scotia Sea. We find evidence for a previously unrecognized magnetic anomaly 10 (∼28 Ma) at the foot of the Tierra del Fuego continental margin; the same anomaly is present at the conjugate northern flank of the South Scotia Ridge. The timing of events leading to the earliest development of the western Scotia Sea, which determined the opening of the Drake Passage is important because this gateway opening had a profound effect on global circulation and climate. The thickness and the distribution of the sedimentary cover overall in the abyssal plain off the two western Scotia Sea margins is different. This is due to the different regimes of the bottom-current flows which affected the western Scotia Sea, both in the past and in the present time.Fil: Lodolo, Emanuele. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Donda, Federica. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; ItaliaFil: Tassone, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentin
Episodic, rapid sea-level rises on the central Mediterranean shelves after the Last Glacial Maximum. A review
No full textSubmerged palaeo-shorelines on the central Mediterranean shelves, identified from high-resolution seismic profiles
and bathymetric data, mark distinct water depths at which sea level stationed for a period of time during the
relative sea-level rise that followed the Last Glacial Maximum (LGM). The shorelines are commonly represented
by palaeo-coastal cliffs and barrier-beaches that lie today at water depths between −100 m and −70 m, and
between −65 m and −40 m, in most places irrespective of the different tectonic contexts, even in the presence
of significant vertical rates. These morphological features are thought to have been drowned during melt-water
pulses 1A and 1B, which occurred between 15 and 10 ka. The evidence presented here confirms drowned shorelines
documented elsewhere at similar water depths and shows that melt-water pulses have punctuated the
post-glacial relative sea-level rise with rates up to 60 mm/yr. for a few centuries. The identification of morphological
features related to melt-water pulses in the central Mediterranean Sea has important implications to improve
our knowledge on episodes of rapid glacio-eustatic sea-level rise. This issue is critical to be able to forecast
future sea-level rises in the Mediterranean, which is characterized by densely populated coasts and important
coastal infrastructures
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