MENICHETTI, M.

TASSONE, A.

English

Revistes CientÃ­fiques de la Universitat de Barcelona

GEOSUR: Mesozoic to Quaternary evolution of Tierra del Fuegoand neighbouring austral regions IIGeologica Acta,  Vol .6 ,  Nº  1 ,  March 2008,  1-3Avai lable onl ine at  www.geologica-acta.com© UB-ICTJA 1M. MENICHETTI and A. TASSONEIstituto di Scienze della Terra. Università di Urbino.Campus Scientifico Universitario. 61029 Urbino. Italy. E-mail: menichetti@uniurb.itCONICET-Instituto de Geofísica “Daniel A. Valencio” (INGEODAV). Departamento de Geología. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos AiresCiudad Universitaria. Pabellón 2. 1428 Ciudad Autónoma de Buenos Aires. Argentina. E-mail: atassone@gl.fcen.uba.arThis second thematic issue on Tierra del Fuego geo-logy and geophysics, as the first one (Menichetti andTassone, 2007) resulted from the new and profuse avail-able information presented at the November 2004 Geo-sur International Symposium (Buenos Aires, Argenti-na). The aim of the organizing committee of Geosur2004 was to provide sets of synthetic papers supplying acomprehensive review of the geological and geophysicalknowledge on the Tierra del Fuego region; and alsomore specific papers focused on subjects still understudy and debate, including original contributions fromTierra del Fuego and some neighbouring areas of thePatagonian Andes and Scotia plate.From the Chile trench to the transform boundaries ofthe western Scotia Sea, Tierra del Fuego Island shows acomplex geological and structural architecture. Its geo-dinamic history includes a Mesozoic extensional phasein the southern Gondwanaland margin that was followedby the Late Cretaceous collisional events that led to theAndean Cordillera upbuilding and the Magallanes andMalvinas foreland basin generation. The opening of theScotia Sea, with the separation from the AntarcticPeninsula and with superposition of important transformfaults, influenced largely on the Cenozoic evolution ofthis orogenic segment. The last glacial events modelledand contributed to the present landscape.The first thematic issue on Tierra del Fuego Mesozoicto Quaternay evolution contents contributions from awide disciplinary scope (Geodesy, Paleomagnetism,Gravimetry, bathymetric studies and Geomorphology) byauthors as Rappalini (2007),  Bujalesky (2007), Chávez etal. (2007), Del Cogliano et al. (2007), Lodolo et al.(2007), Polonia and Torelli (2007). This second issue alsopresents contributions from a variety of disciplinesincluding Petrology, Stratigraphy, Structural Geology andSeismostratigraphy.Olivero and Malumián (this issue) provide an updatedand exhaustive synthesis of the Mesozoic-CenozoicStratigraphy of the Fuegian Andes. Within the Creta-ceous-Cenozoic record the authors recognize distinct sed-imentary cycles in the northern cratonic areas of Tierradel Fuego and in the southern fold-and-thrust belt. In thecratonic areas four major sedimentary cycles evolved in ashallow marine platform setting mainly controlled byeustacy; whereas in the southern orogenic areas the prop-agation of the thrust front controlled the generation andmigration of successive depocenters in the inner, central,and outer fold belt.On the basis of new acquired and already publisheddata Menichetti et al. (this issue) present a comprehensivesynthesis of the structural geology of the Tierra del Fuego1 221Island. During the Mesozoic-Cenozoic evolution threecomplex tectonic stages are distinguished: extensional inthe Upper Jurassic, compressional in the Late Cretaceousonward, and left lateral strike-slip from the Oligoceneonwards, with the latter phase being superimposed andpossibly reactivating the oldest structures. The structuralcharacteristics and associated geodynamic events of eachstages are exhaustively reviewed. At the same time, theauthors detail a number of remaining topics related toTierra del Fuego geology, which require further work.The petrology, P-T evolution, geochronology and geo-dynamic meaning of the metamorphic complexes of thePatagonian and Fuegian Andes are presented in Hervè etal. (this issue). The authors distinguish metamorphic com-plexes located to the East of the Meso-Cenozoic SouthPatagonian Batholith and the so-called western complexes.The former correspond to the mostly low grade late Pa-leozoic Eastern Andes Metamorphic Complex (EAMC),which likely represents a passive margin metasedimenta-ry sequence, later locally submitted to Late Jurassic highmetamorphic conditions. The Cordillera Darwin Meta-morphic Complex could be a higher grade equivalent ofthe EAMC. The western accretionary complexes point tothe existence of a subduction zone environment near theTriassic - Jurassic boundary (Chonos Metamorphic Com-plex) up to the Middle Jurassic-Cretaceous (Diego deAlmagro Complex) at least. The former comprises bothallochtonous and autocthonous components, whereas thelatter would postdate the southward drifting of AntarcticPeninsula.On the basis of offshore multichannel seismic reflectionprofiles, combined with exploratory wells, the sedimentaryarchitecture of the southern Malvinas foreland basin andthe structural framework of its deformed inner and outerfront are presented (Tassone et al., this issue). The basininfilling and the structure imprint record the main tectono-stratrigraphic stages of the Fuegian Andes: the earliestJurassic to Cretaceous extensional tectonics, the main com-pressional phase related to the Andean orogeny since LateCretaceous, with the development of a thick-skinned tec-tonic style and the Mid-Tertiary to present influence ofstrike-slip activity, which has contributed to the subsidenceof the foredeep. Restricted Neogene pull-apart basinsformed by transcurrent motion occur superimposed to theMagallanes fold-and-thrust belt.Rossello et al. (this issue) present a summary of thehydrocarbon exploration history and petroleum potentialof Tierra del Fuego. Within the thick Late Cretaceous toTertiary sedimentary and volcanoclastic sequence of theAustral-Magellan Basin, the sandy levels of the SpringhillFormation host -in onshore as well as in offshore areas-productive hydrocarbon deposits.Original information on the submerged stratigraphyand structure along the Magellan Strait, which bounds theTierra del Fuego Island, is presented by Bartole et al. (thisissue). On the basis of multichannel seismic profiles theauthors distinguish three segments with specific sedimen-tary and tectonic architectures: the eastern Atlantic fore-land domain characterized by nearly undeformed verythick Cretaceous to Tertiary sedimentary package, thecentral fold-and-thrust belt province with seismic evi-dence of deformations of the foreland units and theCordillera province (Pacific segment) where the Magal-lanes-Fagnano transform fault exerts an important mor-pho-tectonic control that strongly conditions its bathymet-ric profile. Additionally, the seismic profiles alsohighlighted some depositional features of the glacialcycles in southernmost South America and present evi-dences of Miocene activity of the Magallanes-Fagnanofault in western Magellan Strait.Finally, the paper by Waldmann et al. (this issue)includes the first seismic reflection profiles of Lago Fag-nano that combined with sediment cores are presented ina preliminary succession of the depositional processes,which characterize the last deglaciation in Lago Fagnano.The authors recognize three major seismostratigraphicunits: the oldest corresponds to glacially derived sedi-ments; the overlying unit is interpreted as proglacial tur-bidite sequences that reflect sediment pulses released bythe retreating Fagnano glacier during the last deglacia-tion. A major environmental change occurred duringdeposition of the uppermost unit when the pelagic style ofsedimentation is interrupted by intercalated sequences ofdownslope mass flow events probably triggered by tec-tonic pulses along the Magallanes Fagnano system. Theauthors also provide important tools for the paleoclimatechange analysis.We would like to remind the readers that, as men-tioned in the first Geosur thematic issue (Menichetti andTassone, 2007), the terms Fuegian and Fueguian are syn-onymous and both are used as adjective meaning “ofTierra del Fuego” or “pertaining to Tierra del Fuego”.ACKNOWLEDGEMENTSMost of the articles presented in this volume have resultedfrom researches carried out in the last decade under the sponsor-ing and the financial support of Antarctic national scientific pro-grams jointly managed by Argentinean and Italian Institutions.The continuous scientific cooperation between Argentinean andItalian researchers was developed within the frame of severaljoint projects dealing with Tierra del Fuego geology and geo-physics (PNRA - FORTE Project), onshore/offshore geophysicaldata acquisition (PNRA - TESAC Project) and the installation inGEOSUR: Mesozoic to Quaternary evolution in Tierra del FuegoM. MENICHETTI and A. TASSONE2Geolog ica  Acta ,  Vo l .6 ,  Nº  1 ,  March 2008,  1-3GEOSUR: Mesozoic to Quaternary evolution in Tierra del FuegoM. MENICHETTI and A. TASSONE3Geolog ica  Acta ,  Vo l .6 ,  Nº  1 ,  March 2008,  1-3Alejandro A. Tassone graduated in 1989from the Buenos Aires University (Argen-tine) and in 1998 obtained his PhD fromBarcelona University (Spain). He ispresently a researcher of the CONICET,the national council of scientific andtechnological research of Argentine,working at the the D. Valencio Institute ofGeophysics of the Department of Geology(Buenos Aires University). His main research interest is related to theapplication of several geophysical methodologies (seismic reflection,gravimetry, magnetometry, etc.) in deciphering the tectonostratigraphicand geodynamic evolution of the Patagonian and Antarctic continentalmargins.Marco Menichetti received PhD in struc-tural geology from the University ofPerugia, Italy, in 1991. He spent thepostdoctoral fellowship working on thecrustal seismic survey project in CentralApennines. From 1995 to 1997 he was aconsultant for oil and water companies.He joined Urbino University, Italy, in 1998 where he is currently incharge of the degree courses on Structural geology and Tectonics.His research interest focus on field geology and structural conceptsand methods for interpretation of mountain chains.1994 of the broad-band seismological network in the Scotia Arcregion, among other activities. We must express our deep grati-tude to all the colleagues and friends that in many differentways helped us in Tierra del Fuego during these years. We par-ticularly thank the Italian Embassy in Argentina for both theencouragement and the financial support in the organization ofthe Geosur 2004 International Symposium. The editors thankthe following colleagues and friends who kindly helped with thereviewing of the papers submitted to this second Geologica Actaissue: M. E. Cerredo (Argentina), R. Coccioni. (Italy), G.Fontolán (Italy), E. Lodolo (Italy), A. Massabie (Argentina), E.Oviedo (Argentina), E. Ramos (Spain), A. Rapalini (Argentina),N. Rubinstein (Argentina), F. Sàbat (Spain), J. Sellés Martínez(Argentina), B.L. Valero–Garcés (Spain), J. Vergés (Spain). Spe-cial acknowledgement is due to Lluís Cabrera and Ángeles San-tos (Scientific and Managing Editors of Geologica Acta, respec-tively) and also the whole managing scientific committee of thejournal for their constant support during the editorial process ofthis second thematic issue. Finally, thanks are also given to Prof.Miquel Canals who encouraged us to edit the sets of papersresulting from Geosur 2004 meeting.REFERENCESBartole, R., De Muro, S., Morelli, D., Tosoratti, F., 2008. Glaci-genic features and Tertiary stratigraphy of the Magellanstrait (Southern Chile). Geologica Acta, 6(1), 85-100.Bujalesky, G.G., 2007. Coastal geomorphology and evolution ofTierra del Fuego (Southern Argentina). Geologica Acta,5(4), 337-362.Chávez, R.E., Flores-Márquez, E.L., Suriñach, E., Galindo-Zaldívar, J.G., Rodríguez- Fernández, J.R., Maldonado, A.,2007. Combined use of the GGSFT data base and on boardmarine collected data to model the Moho beneath the PowellBasin, Antarctica. Geologica Acta, 5(4), 323-335.Del Cogliano, D., Dietrich, R., Richter, A., Perdomo, R.., Hor-maechea, J.L., Liebsch, G, Fritsche, M., 2007. Regionalgeoid determination in Tierra del Fuego including GPS lev-elling. Geologica Acta, 5(4), 315-322.Hervé, F., Calderón, M., Faúndez, V., 2008. The metamorphiccomplexes of the Patagonian and Fuegan Andes. GeologicaActa, 6(1), 43-53.Lodolo, E., Lippai, H., Tassone, A., Zanolla, C., Menichetti, M.,Hormaechea, J.L., 2007. Gravity map of the Isla Grande deTierra del Fuego, and morphology of Lago Fagnano. Geolo-gica Acta, 5(4), 307-314.Menichetti, M., Tassone, A. (eds.), 2007. GEOSUR 2004: Meso-zoic to Quaternary evolution of Tierra del Fuego and neigh-bouring austral regions I. Geologica Acta, 5(4), 283-286.Menichetti, M., Lodolo, E., Tassone, A., 2008. Structural geologyof the Fuegian Andes and Magallanes fold-and-thrust belt –Tierra del Fuego Island. Geologica Acta, 6(1), 19-42.Olivero, E.B., Malumián, N., 2008. Mesozoic-Cenozoic stratig-raphy of the Fuegian Andes, Argentina. Geologica Acta,6(1), 5-18.Polonia, A., Torelli, L., 2007. Antarctic/Scotia plate convergenceoff southernmost Chile. Geologica Acta, 5(4), 295-306.Rapalini, A.E., 2007. A paleomagnetic analysis of the PatagonianOrocline. Geologica Acta, 5(4), 287-294.Rossello, E.A., Haring, C.E., Cardinali, G., Suárez, F., Laffitte, G.A.,Nevistic, A.V., 2008. Hidrocarbons and petroleum geology ofTierra del Fuego, Argentina. Geologica Acta, 6(1), 69-83.Tassone, A., Lodolo, E., Menichetti, M., Yagupsky, D., Caffau,M., Vilas, J.F., 2008. Seismostratigraphic and structural set-ting of the Malvinas basin and its southern margin. (Tierradel Fuego Atlantic offshore). Geologica Acta, 6(1), 55-67.Waldmann, N., Ariztegui, D., Anselmetti, F.S., Austin Jr., J.A.,Dunbar, R., Moy, C.M., Recasens, C., 2008. Seismic strati-graphy of Lago Fagnano sediments (Tierra del Fuego, Argenti-na) - A potential archive of paleoclimatic change and tectonicactivity since the Late Glacial. Geologica Acta, 6(1), 101-110.

GEOSUR: Mesozoic to Quaternary evolution of Tierra del Fuego and neighbouring austral regions II

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GEOSUR: Mesozoic to Quaternary evolution of Tierra del Fuego and neighbouring austral regions II

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Revistes CientÃfiques de la Universitat de Barcelona

GEOSUR: Mesozoic to Quaternary evolution of Tierra del Fuego and neighbouring austral regions II

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Revistes CientÃ­fiques de la Universitat de Barcelona

Revistes CientÃfiques de la Universitat de Barcelona