Vol. 45 - N. 2 SUPPLEMENT Bollettino di Geofisica teorica ed applicata An International Journal of Earth Sciences Guest Editors: J. Carcione, F. Donda, E. Lodolo International Symposium on the Geology and Geophysics of the Southernmost Andes, the Scotia Arc and the Antarctic Peninsula Extended Abstracts of the GeoSur2004 International Symposium 22-23 November, 2004 Buenos Aires, Argentina Istituto Nazionale di Oceanografia ISSN 0006-6729 e di Geofisica Sperimentale Responsibility for all statements made in B.G.T.A. lies with the authors Cover design and typesetting: Nino Bon – OGS Printing: Centro Box SRL – Buenos Aires, Argentina Authorized by the Tribunale di Trieste, n. 242, September 17, 1960 INTERNATIONAL SYMPOSIUM International Symposium on the Geology and Geophysics of the Southernmost Andes, the Scotia Arc and the Antarctic Peninsula 22-23 November 2004 Buenos Aires, Argentina EXTENDED ABSTRACTS GEOSUR2004 22-23 NOVEMBER 2004 – BUENOS AIRES ORGANIZERS ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA SPERIMENTALE - OGS, TRIESTE, ITALY INSTITUTO DE GEOFÍSICA “DANIEL A. VALENCIO”, DEPARTAMENTO DE GEOLOGÍA, UNIVERSIDAD DE BUENOS AIRES, ARGENTINA SPONSORS ITALIAN EMBASSY IN ARGENTINA PROGRAMMA NAZIONALE DI RICERCHE IN ANTARTIDE (P.N.R.A.) EAGE-SEG Italian Section 4 GEOSUR2004 22-23 NOVEMBER 2004 – BUENOS AIRES SCIENTIFIC COMMITTEE G. BRANCOLINI - OGS, Trieste A. CAMERLENGHI - OGS, Trieste M. CANALS - University of Barcelona J.M. CARCIONE - OGS, Trieste A.H. COMÍNGUEZ - CONICET, University of La Plata I.W.D. DALZIEL - University of Texas at Austin E. DOMACK - Hamilton College, New York F. HERVÉ - University of Santiago R. LARTER - British Antarctic Survey S. MARENSSI - IAA, Buenos Aires G. PANZA - University of Trieste C. PARICA - CONICET, University of Buenos Aires V. RAMOS - University of Buenos Aires A. RAPALINI - INGEODAV, University of Buenos Aires G. RÉ - INGEODAV, University of Buenos Aires C. RODA - University of Udine M. RUSSI - OGS, Trieste D. VELIS - University of La Plata ORGANIZING COMMITTEE J.L. HORMAECHEA - EARG, Rio Grande H. LIPPAI - INGEODAV, University of Buenos Aires E. LODOLO - OGS, Trieste M. MENICHETTI - University of Urbino S. PERSOGLIA - OGS, Trieste J. RABASSA - CADIC, Ushuaia R. SEMENZATO - Italian Embassy, Buenos Aires A. TASSONE - INGEODAV, University of Buenos Aires J.F. VILAS - INGEODAV, University of Buenos Aires CONFERENCE SECRETARIAT ANGELA MARCHETTO - EAGE-SEG Italian Section 5 CONTENTS Session 1 - Regional Geology LATE JURASSIC BIRTH OF THE ROCAS VERDES BASIN AT THE SARMIENTO OPHIOLITIC COMPLEX: EVIDENCE FROM ZIRCON U-PB SHRIMP GEOCHRONOLOGY . 1-01 M. Calderón, F. Hervé, C.M. Fanning THE ITALIAN CONTRIBUTION TO THE DEVELOPMENT OF THE GEOLOGIC KNOWLEDGE OF ARGENTINA . 1-02 H.H. Camacho DEEP-SEISMIC IMAGING ACROSS LOS CHIHUIDOS ARCH, NEUQUEN BASIN, ARGENTINA (38° SL) . 1-03 A.H. Comínguez, J.R. Franzese REFLECTIONS ON THE SCOTIA ARC AT ITS CENTENNIAL . 1-04 I.W.D. Dalziel AEROGEOPHYSICAL IMAGING REVEALS A COMPOSITE TERRANE OVER PALMER LAND (ANTARCTIC PENINSULA) . 1-05 F. Ferraccioli, P. Jones, A.P.M. Vaughan, A. Dean, P.T. Leat THE CARIBBEAN PLATE CURRENT PROBLEMS: AN EXAMPLE FOR EVOLUTION OF SMALL PLATES . 1-06 G. Giunta THE WEST-DIRECTED SUBDUCTION ZONES OUTSIDE OF THE PACIFIC: SCOTIA, CARIBBEAN, TYRRHENIAN AND CARPATHIANS DOMAIN . 1-07 M. Guidarelli, O. Gonzalez, R. Raykova, T. Pinat, G.F. Panza NORTHERN ANTARCTIC PENINSULA – SOUTHERN PATAGONIA: A PRELIMINARY STRATIGRAPHIC FRAMEWORK FOR COMPARISON OF PALEOGENE EVENTS . 1-08 S.A. Marenssi GEOMETRIES, DEFORMATION STYLES AND KINEMATICS OF THE FUEGINAN ANDES AND MAGALLANES FOLD-AND-THRUST BELT (TIERRA DEL FUEGO ISLAND) . 1-09 M. Menichetti, M. Cenni, D. Gattini, A. Gaudio, M. Mattioli TECTONICS OF THE SOUTHERNMOST ANDES: A COMPARISON BETWEEN THE PATAGONIAN AND THE FUEGIAN CORDILLERAS . 1-10 V.A. Ramos SEISMIC IMAGING OF THE MAGALLANES-FAGNANO FAULT SYSTEM (TIERRA DEL FUEGO REGION) . 1-11 D. Yagupsky, A. Tassone, E. Lodolo, M. Menichetti, J.F. Vilas Session 2 - Geodynamic and Tectonics DEVELOPMENT OF ASYMMETRIC BASINS ALONG THE MAGALLANES-FAGNANO FAULT AND OTHER CONTINENTAL TRANSFORM FAULTS . 2-01 Z. Ben-Avraham, E. Lodolo PLATE KINEMATICS OF THE ANTARCTIC PENINSULA . 2-02 R. Dietrich, A. Rülke BREAKUP OF GONDWANA AND OPENING OF THE SOUTH ATLANTIC: REASSESSMENT BASED ON MAGNETIC ANOMALIES . 2-03 M.E. Ghidella, L.A. Lawver, L.M. Gahagan CRONOLOGY OF OROGENIC FRONT PROPAGATION IN THE FUEGUIAN FOLD-THRUST BELT . 2-04 M.C. Ghiglione, V.A. Ramos, E.B. Olivero 7 CONTENTS TECTONIC AND GEODYNAMIC EVOLUTION OF THE SOUTH SANDWICH ARC AND EAST SCOTIA SEA . 2-05 R.D. Larter AGULHAS PLATEAU, MAUD RISE AND NE GEORGIA RISE, PRODUCTS OF A TRIPLE JUNCTION? . 2-06 L.A. Lawver, L.M. Gahagan SOUTH AMERICA - ANTARCTICA PLATE MOTION AND TECTONICS OF THE SOUTHERNMOST ANDES, SCOTIA SEA AND ANTARCTIC PENINSULA . 2-07 R. Livermore, G. Eagles, P. Morris, A. Nankivell SPREADING REGIME AND TECTONICS IN THE WESTERNMOST SCOTIA SEA . 2-08 E. Lodolo, A.A. Schreider GEOLOGICAL CROSS-SECTION ACROSS THE FUEGINAN ANDES IN THE TIERRA DEL FUEGO ISLAND . 2-09 M. Menichetti DIFFERENT STYLES OF CONTINENTAL GROWTH AT THE CONVERGENCE ZONE OF SOUTHERN CHILE . 2-10 A. Polonia, M.-F. Loreto, L. Torelli, E. Vera NORTHWARD MOTION OF SOUTH AMERICA, SCOTIA SEA DEVELOPMENT, AND CARIBBEAN CONVERGENCE . 2-11 R. Somoza PALEOMAGNETISM FROM UPPER TRIASSIC-LOWER JURASSIC ROCKS IN THE DESEADO MASSIF: NEW INSIGHTS ON THE BEHAVIOR OF PATAGONIA DURING THE BREAKUP OF GONDWANA . 2-12 H. Vizán, R. Somoza, G. Taylor Session 3 - Earthquake Seismology EARTHQUAKE EPICENTRES IN TIERRA DEL FUEGO FROM MAY 1999 TO MARCH 2004 . 3-01 G. Connon, L. Barbero, C. Ferrer, J.L. Hormaechea, N. Sabbione, R. Pinciroli, C. Rastelli, M.P. Plasencia Linares LITHOSPHERIC STRUCTURES AND REGIONAL SEISMICITY IN THE SCOTIA SEA AREA: A REVIEW . 3-02 M. Guidarelli, M.P. Plasencia Linares, M. Russi, G.F. Panza THE 4 AUGUST 2003 EARTHQUAKE RECORDED BY ASAIN NETWORK IN ANTARCTICA AND TIERRA DEL FUEGO . 3-03 M.P. Plasencia Linares, B.G. Bukchin, M. Guidarelli, M. Russi, G.F. Panza FURTHER DEVELOPMENTS OF THE ASAIN NETWORK IN ANTARCTICA AND TIERRA DEL FUEGO . 3-04 M. Russi, M.P. Plasencia Linares, M. Guidarelli Session 4 - Magmatic Processes DISCOVERY OF ALKALI-BASALTS IN TIERRA DEL FUEGO . 4-01 R.D. Acevedo LITHOLOGIC TYPES OF THE JEU-JEPEN DIORITE ISLA GRANDE DE TIERRA DEL FUEGO . 4-02 R.D. Acevedo, C. Roig, M.L. Valín-Alberdi IRON SULFIDES RELATED TO FUMAROLIC VENTS IN DECEPTION ISLAND, ANTARCTICA . 4-03 A.T. Caselli, S.M. Tourn, C. Bengoa 8 CONTENTS EMPLACEMENT FABRICS OF THE CONCÓN DYKE SWARM, CENTRAL CHILE . 4-04 C. Creixell, M.A. Parada, P. Roperch, C. Arriagada, D. Morata METAMORPHIC P-T CONDITIONS OF RHYOLITES IN THE MAGALLANES FOLD AND THRUST BELT, PATAGONIAN ANDES . 4-05 F. Hervé, H.-J. Massonne, T. Theye, M. Calderón MONITORING MAGMATISM OF THE PATAGONIAN BATHOLITH THROUGH THE U-PB SHRIMP DATING OF DETRITAL ZIRCONS IN SEDIMENTARY UNITS OF THE MAGALLANES BASIN . 4-06 F. Hervé, E. Godoy, C. Mpodozis, M. Fanning THE PALEOCENE–EOCENE SEJONG FORMATION, BARTON PENINSULA, KING GEORGE ISLAND, ANTARCTICA: ERUPTIVE AND DEPOSITIONAL PROCESSES AND ENVIRONMENTS . 4-07 S.B. Kim, Y.K. Sohn, M.Y. Choe, J.I. Lee, S.D. Hur IMPLICANCES OF THE ACTIVITY OF FLUOR-RICH FLUIDS ON BASALTS AFFECTED BY VERY LOW GRADE METAMORPHISM IN CHAPELCO HILLS, NEUQUÉN, ARGENTINA . 4-08 C.I. Martínez Dopico, E. Gallegos, M.E. Vattuone MAGMATIC MUSCOVITE AND GARNET IN GRANITES OF THE SOUTHERN PATAGONIAN BATHOLITH . 4-09 H-J. Massonne, M. Calderon, F. Hervé EFFECTS OF METAMORPHISM ON MAGNETIC SUSCEPTIBILITY AND FERROMAGNETIC MINERALS IN THE SARMIENTO OPHIOLITE COMPLEX, SOURTHERN CHILE . 4-10 S. Singer, A. Rapalini, M. Calderón, F. Hervé THE ORIGIN OF PLATINUM IN TIERRA DEL FUEGO: GEOLOGICAL EVIDENCE . 4-11 E. Zappettini, L. Villar, S. Segal, A. Celeda, A. Romano, D. Acevedo Session 5 - Geomorphology and Geodesy REGIONAL GEOID DETERMINATION IN TIERRA DEL FUEGO INCLUDING GPS LEVELLING . 5-01 D. Del Cogliano, R. Dietrich, A. Richter, R. Perdomo, J.L. Hormaechea, G. Liebsch, M. Fritsche HORIZONTAL DISPLACEMENTS IN THE MAGALLANES-FAGNANO FAULT ZONE DETERMINED BY REPEATED GPS OBSERVATIONS . 5-02 J.L. Hormaechea, D. Del Cogliano, R. Perdomo, R. Dietrich, G. Liebsch, A. Richter, M. Fritsche GEOID UNDULATION ON THE ANDEAN CORDILLERA . 5-03 A. Introcaso, L.E. Lenzano, A.M. Robin, M.V. Mackern MORPHO-STRUCTURE OF LAGO FAGNANO (TIERRA DEL FUEGO) AND ADJACENT AREAS . 5-04 H. Lippai, E. Lodolo, A. Tassone, J.L. Hormaechea, M. Menichetti, J.F. Vilas, TESAC Party GEODETIC DETERMINATION OF RELATIVE PLATE MOTIONS AND CRUSTAL DEFORMATIONS DUE TO SOUTH AMERICA, SCOTIA AND ANTARCTIC PLATE INTERACTIONS . 5-05 R. Smalley Jr., E. Kendrick, M.G. Bevis, I.W.D. Dalziel, F. Taylor, E. Lauría, R. Barriga, G. Casassa, E. Olivero, E. Piana, A. Zakrajsek Session 6 - Marine Geology and Geophysics MORPHOLOGY AND SEDIMENTARY PROCESSES ON THE TERRACED ACCRETIONARY PRISM OF SOUTHERNMOST SOUTH AMERICA . 6-01 R. Bartole, D. Morelli, A. Cuppari SEISMOSTRATIGRAPHY AND RECENT SEDIMENTARY EVOLUTION OF AN ASYMMETRIC EXTENSIONAL BASIN AT THEWESTERN ARM OF THE MAGALLANES-FAGNANO TRANSFORM SYSTEM . 6-02 R. Bartole, W. Colautti, E. Colizza, C. Salvi, F. Tosoratti 9 CONTENTS MARINE GEOLOGY OF THE EREBUS AND TERROR GULF REGION, NW WEDDELL SEA . 6-03 E.W. Domack, E. Backman A GEOPHYSICAL STUDY ALONG THE EASTERN MARGIN OF THE ANTARCTIC PENINSULA . 6-04 W. Jokat, V. Helm, R. Krocker SEISMIC EXPRESSION OF THE WESTERN SCOTIA SEA CONTINENTAL MARGINS . 6-05 C. Sauli, E. Lodolo, N. Wardell, A. Tassone, A. Polonia 3D CRUSTAL VARIATIONS IN THE PHOENIX-ANTARCTIC RIDGE (P2 SEGMENT) . 6-06 E. Suriñach, E.L. Flores-Márquez, J. Galindo-Zaldivar, A. Maldonado 3D MODELLING OF THE SOUTH SCOTIA RIDGE PLATE BOUNDARY (ANTARCTICA) . 6-07 S. Susini, M. De Donatis, N. Zitellini GAS HYDRATES AND ACTIVE FLUID OUTFLOW NE OF THE SOUTH SHETLAND ISLANDS, ANTARCTIC PENINSULA . 6-08 U. Tinivella, F. Accaino, R.