SOMMAIRE / SUMMARY / SUMARIO Page On the significance of transversal wrench-fault tectonics for the structuring of the southern Central Andes. 1 Andreas ABELS Proterozoi-Iower Paleozoic terrane evolution in western South America. 6 Florencio Gilberto ACENOLAZA, Hubert MILLER and Alejandro Jose TOSELLI Discrimination between the various AMS plunges for the location of magma Chambers beneath the doleritic dykes of 8 Magdalena island, Southern Chile. Tahar AIFA, Jean-Pierre LEFORT and Francisco HERVE Late cretaceous fore-arc extension in northwest Peru: geodynamic implications. 13 Antenor M. ALEMÄN Transtensive Tectonic complications in the westem border of the Ecuadorian Andes: The Example of MINDO. 17 A. ALVARADO, S. BES DE BERC, M. SEBRIER and O. BELLIER, J.F. DUMONT Aftershocks of Cariaco-Venezuela Earthquake (Mw=6.9), July 9, 1997: Seismological analysis using a local network 21 Patricia ALVARADO, Arturo BELMONTE, Michael SCHMITZ and Enrique GAJARDO Evolution of Domeyko Range, Northern Chile. 25 Alejandro AMILIBIA, Francesc SÄBAT, Guillermo CHONG, Josep Anton MUNOZ, Eduard ROCA and Antonio RODRIGUEZ-PEREA The epithermal AU-AG ore deposits in the cordillera Shila, Southern Peru: Fluid inclusions and microfissuration data. 30 Anne-Sylvie ANDRE, Jacques L. LEROY, coworkers ofthe Peru 97-98 metallogeny GdR mission The Liquine-Ofqui fault zone: A case of deformation partitioning at obliquely convergent transpressional plate boundaries 34 (Southern Chile). Gloria ARANCIBIA, Gloria LOPEZ, Jose CEMBRANO Lithospheric structures in the southern central Andes, preliminary results (38° - 42°S). 38 Manuel ARANEDA, Maria S. AVENDANO, Hans Jürgen GÖTZE, Sabine, SCHMIDT, Jorge MUNOZ, Michael SCHMITZ Shallow seismicity in the north-western part of Argentina and ist relation with tectonics. 42 Mario A. ARAUJO, Graciela TELLO, Angel M. PEREZ, Irene PEREZ, Carlos A. PUIGDOMENECH Induced seismic activity by a glacier in volcanic areas: application to north flank of Cotopaxi volcano, Ecuador. 47 Sebastiän ARAUJO, Jean-Philippe METAXIAN Sedimentary record of the Salar de Atacama: Palaeohydrological implications 52 Virginia C. ARRANZ, Juan Jose PUEYO, Conxita TABERNER, Carles AYORA, Ramon ARAVENA and Guillermo CHONG D. Clockwise block rotations along the eastern border of the Cordillera de Domeyko, between 22°45' and 23°30' (Chile). 56 Cesar ARRIAGADA, Pierrick ROPERCH, Constantino MPODOZIS Shape and intrusion style of the coastal batholith, Peru. 60 Michael P. ATHERTON and Michael HAERDERLE Structure of the Merida Andes, Venezuela: Facts and Models 64 Felipe E. AUDEMARD M. and Franck A. AUDEMARD M. Style and timing of deformation in the Oriente basin of Ecuador. 68 Patrice BABY, Marco RIVADENEIRA, Frederic CHRISTOPHOUL and Roberto BARRAGAN Magma evolution processes at the Tatara-San Pedro complex: 36°S, southern volcanic zone (SVZ), Chilean Andes. 73 Jenni BARCLAY, Andrea MARZOLI, Michael DUNGAN A cretaceous hot spot in the Ecuadorian Oriente Basin: Geochemical, Geochronological and Tectonic Indicator. 77 R. BARRAGAN and P. BABY Shear wave velocity in the lithospheric across the central Andes. 82 David BAUMONT, Anne PAUL, Helle PEDERSEN, George ZANDT and Susan BECK The cause of thick. Slow crust in the Altiplano, central Andes: Melt or Composition? 86 Susan BECK, Jennifer SWENSON and George ZANDT The tectonic evolution of the Mesozoic and Cenozoic auslral basin of southcrn South America. 90 C. Mike BELL , Rita DE LA CRUZ and Manuel SUÄREZ A grain-size Classification: igneous and metamorphic rocks under the Standard petrological T L. microscopc. 94 Ludwig BIERMANNS Nd + Pd isotopic composition of Paleozoic rocks of NW-Argentina and N-Chile: Crustal growth and dynamics in the 98 Andes from Ordovician to Permian times. B. BOCK, BAHLBURG, H.. WÖRNER, G., and ZIMMERMANN, U. Andean transpressive tectonics at the eastem edge of the Cordillera Oriental, Colombia. 103 Yannick BRANQUET, Alain CHEILLETZ, Peter R. COBBOLD, Patrice BABY, Bernard LAUMONIER, Gaston GIULIANI Tectonic Model of the North Subandean Zone, Ecuador. 106 A. BUITRON PEREZ Management of geoscientific information: The Website of the SFB267 110 Heinz BURGER, Michael ALTEN and Sabine MOHR Extension in the Southern Andes as evidenced by an Oligo-Miocene Age intra-arc basin. 115 W. Matthew BURNS and Teresa E. JORDAN Seismic swarm in Quito (Ecuador): Tectonic or volcani origin? 119 Alcinoe CALAHORRANO. Hugo YEPES, Bertrand GJUXIER, Mario RUIZ, Monica SEGOV1A, Darwin VILLAGÖMEZand Daniel ANDRADE Fluid inclusions study in Marte Porphyry Gold Deposit, Copiapo Chile. 123 Eduardo CAMPOS Characterization of fluid inclusions from zaldivar Porphyy Copper, Chile. 127 Eduardo CAMPOS and Jacques R. L. TOURET Post eocene deformational events in the north segment ofhe Precordilleran fault system, Copaquiri (21°S). 132 Pedro CARASCO, Hans-Gerhard W1LK.E and Heinz SGNE1DER. Last miocene-quarternary stratigraphy and tectonic of th eastem part of the Madre de Dios foreland basin (SE Peru). 136 Jose CARDENAS, Victor CARLOTTO, Darwin ROMBO, Waldir VALD1VIA, Wilber HERMOZA, Luis CERPA, Omar LATORRE, Miriam MAMANI Sedimentary and structural evolution of the Eocene-Oligocene Capas Rojas Basin: Evidence for a late Eocene lithospheric 141 delamination event in the southern Peruvian Altiplano. Victor CARLOTTO, Gabriel CARL1ER, Etienne JAILLARD, Thierry SEMPERE and Georges MASCLE GIS Andes: A metallogemc GIS of the Andes Cordillera 147 D. CASSARD Crustal-scale-pop-up structure at the Southern Andes plat boundary zone: A kinematic response to Pliocene transpression. 151 Jose CEMBRANO, Alain LAVENU, Gloria ARANCIBl, Gloria LOPEZ and Alejandro SANHUEZA Opposite thrust-vergencies in the Precordillera and westei cordillera in northern Chile and structurally linked cenozoic 155 paleoenvironmental evolution. Reynaldo CHARRJER, Gerard HERAIL, John FLYNN, lodrigo RIQUELME, Marcelo GARCIA, Darin CROFT and Andre WYSS Process of formation of the Au-Ag Shila-paula epithermal veins system (southern Peru) 159 Alain CHAUVET, Daniel CASSARD and Laurent BAILLY Ore and rock Lead isotope compositions witness geodynaimic events in the Ecuadorian Andes. 163 Massimo CHIARADIA and Lluis FONTBOTE Descrimination of eustatic and tectonic influences in the Ecuadorian Oriente Basin from Aptian to Oligocene times. 168 Frederic CHRISTOPHOUL, Patrice BABY and Celso DAVILA Multifractal analysis of the 1995 Antofagasta, Northern Chile earthquake. 172 D. COMTE, Aemando CISTERNAS, Louis DORBATH, Jaime CAMPOS, Jean Paul AMPUERO III

A double-layered seismic zone in Arica, Northern Chile. 176 D. COMTE, Louis DORBATH, Mario PARDO, Tony MONFRET, Henri HAESSLER, Luis RIVERA, Michel FROGNEUX, Bianca GLASS, Carlos MENESES The Wadati-Benioff Zone around Copiapo, northern Chile using locally recorded data: Preliminary results. 180 Diana COMTE, Louis DORBATH, Bernard PONTOISE, Mario PARDO, Tony MONFRET, Henri HAESSLER, Yann HELLO, Yvan JOIN, Emilio LORCA, Alain LAVENU The crustal structure in the region of the 1997 Cariaco earthquake, eastern Venezuela, based on seismic refraction and 184 gravimetric data. Rommel CONTRERAS, Michael SCHMITZ, Leonardo ALVARADO, Jesus CASTILLO, Stefan LÜTH Quaternary deformations and seismic hazard at the Andean Orogenic Front (3 r-33°, Argentina): A Paleoseismological 187 Perspective. Carlos H. COSTA, Thomas K. ROCKWELL, Juan D. PAREDES, Carlos E. GARDINI Cenozoic deformation and tectonic style of the Puna Plateau (Northwestern Argentina, Central Andes). 192 Isabelle COUTAND, Peter COBBOLD, Annick CHAUVIN, Eduardo ROSSELLO, Oscar LOPEZ-GAMUNDI Age and Petrology of Tusaquillas plutonic complex on the evolution of Cretaceous rift in NW Argentina. 197 Chiara CRIST1ANI, Aldo DEL MORO, Massimo MATTEINI, Roberto MAZZUOLI, Ricardo OMARINI Neogene evolution ofthe main Ecuadorian fore-arc sedimentary basins and sediment mass-balance inferences. 201 Yann DENIAUD, Patrice BABY, Christophe BASILE, Martha ORDONEZ, Georges MASCLE and Galo MONTENEGRO Nevados de Chillän and Antuco volcanoes (Southern Andes) revisited: a remarkable example of magmatic differentiation 206 through closed-system crystal fractionation. Bernard DERUELLE and Leopoldo LÖPEZ-ESCOBAR Lower Holocene plinian eruptions of Cotopaxi volcano - Ecuador 210 DESMULIER, F., ROBIN, C. and MOTHES, P. A.

Evidence for the latest Ordovician / early Silurian glaciation in the Peruvian Altiplano: tectonic implications. 214 Enrique DIAZ-MARTINEZ, Harmuth ACOSTA, Rildo RODRIGUEZ, Victor CARLOTTO and Jose CARDENAS 207Pb/206Pb and59Ar/40Ar geochronology of metamorphic costal belt between 41° and 42°S in the Andes. 219 Paul DUHART, Jorge MUNOZ, Michael McDONOUGH, Mark MARTIN and Michael VILLENEUVE The Tatara-San Pedro volcanic complex (36°S, Chile): Implications for arc magma genesis and evolution in the southern 224 volcanic zone of the Andes. M.A. DUNGAN Volcanogenic Sedimentation model for the Miocene Farellones, Andean cordillera, Central Chile. 228 Sara ELGUETA, Reynaldo CHARRIER, Ramön AGUIRRE, Guy KIEFFER, Nicole VATIN-PERIGNON Monitoring geophysical and geochemical data at the volcano Galeras, Colombia. 232 E. FABER, S. GREINWALD, D. PANTEN, G. G. VALENCIA, D. M. GÖMEZ, R. A. TORRES, C. MORAN and A. O. ESTUPINAN The neogene transpressional architecture of the Santa Elena Peninsula, Ecuador: new insights from seismic data. 235 Fernando A. FANTIN, Patricio MALONE, Eduardo A. ROSSELLO and Muriel MILLER Origin of crystal clots and their orthopyroxene-titanomagnetite symplectites in lavas from the Lincancabur volcano, South- 240 Central Andes. Oscar FIGUEROA and Bemard DERUELLE Decompression at decreasing temperatures in eclogite-facies metapelites (El Oro Metamorphic Complex, SW-Ecuador): A 245 record of fast exhumation rates. Piercarlo GABRIELE, Michel BALLEVRE, Etienne JAILLARD and Jean HERNANDEZ Age and structure of the Oxaya Anticline: a major feature of the Miocene compressive structures of northernmost Chile. 249 Marcelo GARCIA, Gerard HERAIL, Reynaldo CHARRIER Oligo-Miocene ignimbritic volcanism of northern Chile (Arica region): stratigraphy and geochronology. 253 Marcelo GARCIA, Gerard HERAIL and Moyra GARDEWEG To what extent did the post 15 Ma aridisation of central South America modity the evolution of the crustal dynamics of the 257 Bolivian Andes? Reinhard GAUPP, Fritz SCHLUNEGGER, Thomas JAHR Fe and Cu-Fe±Au mineralizaiion in the coastal cordillera of Chanaral, northern Chile. 261 Sergio GELCICH Petrogenetic study of lavas erupted through the peristant explosive activity of the Nevado Sabancaya Volcano, Peru (1990 266 - 1998). Marie-C. GERBE and Jean -Claude THOURET The Alto Tunuyan Neogene foreland basin, Mendoza, Argentina. 269 L. GIAMBIAG1 Parameters Controlling the formation of the anomalous proportions of the Central Andes. 273 Peter GIESE, Klaus-J. REUTTER, Ekkehard SCHEUBER North-South structural evolution of the Peruvian subandean zone. 278 Willy G1L R., Patrice BABY, Rene MAROCCO, Jean Franfois BALLARD Structural Geology of the southern Sub-Andean thrust belt, Bolivia. A new deformational model. 283 Raul GIRAUDO, Rodrigo L1MACHI, Edgar REQUENA, Hugo GUERRA Diachronous deformation of the central and eastern Andean cordilleras of Colombia and syntectonic Sedimentation in the 287 Middle Magdalena Valley Basin. Elias GOMEZ and Teresa JORDAN , Kerry HEGARTY , Shari KELLEY The multiphase slip history of the Atacama fault system near Antofagasta, coastal cordillera, Northern Chile. 291 Gabriel GONZALEZ, Jaime CORTES, Dan DIAZ, Baeza CLAUDIA, Heinz SCHNEIDER The gravity field, isostasy and rigidity of the Central Andes. 296 Hans-Jürgen GÖTZE, Sabine SCHMIDT, Manuel ARANEDA, Guillermo CHONG D., Michael KÖSTERS, Ricardo OMARINI and Jose VIRAMONTE Deformation partitioning at subduction boundaries: an example from the northern Chilean Andes (26°S-30°S). 299 John GROCOTT, Graeme K. TAYLOR and Carlos E. AREVALO Steady long-period activity at Cayambe volcano, Ecuador. Location, spectral analysis and consequencies. 303 Bertrand GUILLIER, Pablo SAMANIEGO, Mario RUIZ, Jean-Luc CHATELAIN, Michel MONZIER, Hugo YEPES, Claude ROBIN and Francis BONDOUX Tectonic geomorphology of the Ambato block, Argentina. 307 Adolfo GUTIERREZ Fiat subduction beneath the Andes: SeismologicAL AND TOMOGRAPHIC CONSTRAINTS. 311 Marc-Andre GUTSCHER, Wim SPAKMAN, Härmen BIJWAARD Metallogeny and seismotectonic pattern in the central part of Andean, South America. 315 Vaclav HANUS, Jirf VANEK and Ales SPICÄK Subduction-related geochemical affinity of early cretaccus volcanism from Norther La Serena, Chile. 321 Laura B. HERNÄNDEZ, Osvaldo M. RABBIA and Aleandro H. DEMICHELIS Late Permian shrimp U-Pb detrital Zircon ages constrain the age of accretion of oceanic basalts to the Gondwana margin at 327 the Madre de Dios Archipelago, Southern Chile. Francisco HERVE, Mark FANNING, John BRADSHAW, Margaret BRADSHAW, Juan P. LACASSIE

Oblique thrusting, strike slip faulting and strain partitioning in the Boomerang Hills area, Andean foothills of Bolivia. 329 Ralph HINSCH, Christoph GAEDICKE, Charlotte KRAWCZYK, Gustavo REBAY, Raul GIRAUDO and Daniel DEMURO

Erosional control on thrust belt development in the Bolivian Andes. 334 Brian HORTON Cretaceous and Tertiary terrane accretion in the Cordillera Occidental of the Ecuadorian Andes. Richard A. HUGHES and 340 Luis F. PILATASIG

The Guayaquil seaway - linking the Pacific Ocean and the Ecuadorian Oriente in the Middle Miocene. 343 Dominik HUNGERBÜHLER, Wilfried WINKLER, Michael STEINMANN, Dawn PETERSON and Diane SEWARD V

Thermal Controls in compressive zones. An example from the Bolivian sub Andean zone. 347 Laurent HUSSON and lsabelle MORETT1

Study of the crust on the Peruvian section from gravity data and Geoid undulations. 352 Antonio INTROCASO, Rosalia CABASS1 Central Andes: the gravity signal from the subdueting slab. 356 Carlos IZARRA, Nick KUSZNIR and Huw DAVIES Late Paleozoic - early Mesozoic plutonism and related rifting in the Eastern Cordillera of Peru. 358 Javier JACAY, Thierry SEMPERE, Gabriel CARLIER, Victor CARLOTTO Hercynian deformation and metamorphism in the Eastern cordillera of Southern Bolivia. 364 Volker JACOBSHAGEN, Joachim MÜLLER, Hans AHRENDT and Klaus WEMMER Structural and isostatic modelling of Serrania del interior Thrust Belt and Monagas Foreland Basin Eastern Venezuela. 367 M.I. JACOME, N. KUSZNIR and S. FL1NT Continental Triassic in Argentina: Response to tectonic activity 372 Uwe JENCHEN, Ulrich Rosenfeld Microgravity and GPS at Galeras Volcano, Colombia: Establishment of a new network and first measurements. 377 Gerhard JENTZSCH, Marta CALVACHE, Arturo BERMUDEZ and Milton ORDONEZ Structural styles ofthe folded Bogota Segment, Eastern Cordillera ofColobia. 381 A. KAMMER Changing slab dip and the Neocene magmatic/tectonic evolution of the Central Andean Are. 385 Suzanne Mahlburg KAY Metasomatism of the mantle wedge below the Southern Andes. 389 Rolf KILIAN, Christoph FRANZEN, Mario KOCH, Charles R. STERN, Rainer ALTHERR Petrogenesis of a mafic to felsic plutonic complex (Complejo lgneo Pocitos) and ist host rocks in the southern Puna of NW- 393 Argentina. T. KLEINE, U. ZIMMERMANN, K. MEZGER, H. BAHLBURG ,B. BOCK Tectonic evolution of the eastern cordillera in Carboniferous to Recent time, 23-24°, 396 NW Argentina. Jonas KLEY, Henning KOCKS, Patricio SILVA, Cesar R. MONALDI Erosive mass transfer at convergent margins: Constraints from analog models and applications of Coulomb Wedge 400 analysis. Nina KUKOWSK1, Jürgen ADAM, Jo LOHRMANN Is BSR occurrence in Lima basin offshore central Peru an indication for methan produetion below the gas hydrate stability 404 zone? Nina KUKOWSKI and Ingo A. PECHER New contrains for the age of the cretaceous compressional deformation in the Andes of northern Chile (Sierra de Moreno, 407 21°-22°10'S) Marco LADINO, Andrew TOMLINSON and Nicolas BLANCO P. From compressional to extensional tectonic regime at the front of the Patagonian Andes 46°S - 47°S: A response to the 411 subduetion of the Chile spreading ridge? Yves LAGABRIELLE, Jacques BOURGOIS, Manuel SUAREZ, Rita De La Cruz, Erwan GAREL, Olivier DAUTEUIL, Marc-Andre GUTSCHER. Volcanism and tectonics of the Pleistocene-Holocene volcanic arc, southern Andes 417 (40.5°-41.5°S) Luis LARA, Hugo MORENO, Alain LAVENU Structural setting and age of the Colombian emerald deposits: implications for the tectonic evolution of the Cordillera 422 Oriental. Bernard LAUMONIER, Yannick BRANQUET, Alain CHEILLETZ, Gaston GIULIANI Quatemary extensional deformation and recent vertical motion along the Chilean coast. 424 Alain LAVENU, Carlos MARQUARDT, Diana COMTE, Mario PARDO, Luc ORTLIEB, Tony MONFRET V 1

Competition between magma flow and subduction related stresses in a doleritic dyke eomplex located close to the 428 subduction of the Chile Ridge (Patagonia). An AMS and structural study. Jean-Pierre LEFORT, Tahar AlFA and Francisco HERVE-ALLAMAN Electrical conductivity beneath the Tuzgle Volcano and ist surrounding shoshonic volcanic centers, NW Argentina, 433 P. LEZAETA and H. BRASSE Antuco Volcano: One of the isotopically most primitive stratovolcano of the southern Andes 437 (37°25'S). Silke LOHMAR, Leopoldo LÖPEZ-ESCOBAR, Hugo MORENO and Bernard DERUELLE Basic to intermediate Middle Jurassic volcanism in the NorthPatagonian Massif: dyke swarms of the Sierra de Mamil 441 Choique. Mönica G. LOPEZ DE LUCHI and Augusto E. RAPALIN1 Thermochronological evolution of a deformed tonalite of the North Patagonian batholith, Southern Andean margin. 446 Gloria LOPEZ , Dave PRIOR, Simon KELLEY A chaos of Lead in the basement of the Central Andes (18°-27°S)? 450 Friedrich LUCASSEN, Raul BECCHIO, Russell HARMON and Gerhard FRANZ Isotopic composition of late Mesozoic mafic rocks from the Andes (23° - 32°S) - How heterogeneous is the mantle source? 454 Friedrich LUCASSEN, Monica ESCAYOLA, Rolf L. ROMER, Jose V1RAMONTE, Gerhard FRANZ Contribution of Seif-Potential and soil-temperaturesuneys for the investigation of structural limits and hydrothermal 458 system on Ubinas Volcano (Peru). MACEDO Sänchez O., FINIZOLA A„ GONZALES K.., and RAMOS D. The Raspas metamorphic eomplex (southern Ecuador): Remnant of a late Jurassic-Early Cretaceous accretionary prism. 462 Geochemical and isotopic constraints. Jean-Louis MALFERE , Delphine BOSCH, Henriette LAP1ERRE, Etienne JA1LLARD, Richard ARCULUS and Patrick MON1E Stratigraphic characterization of the Ancön group from seismic data (Santa Elena Peninsula, Ecuador). 467 Patricio A.MALONE, Fernando A. FANTIN, Eduardo A.ROSSELLO and Murie) MILLER M. MAMBERTI et al, see at the end of the summary Petrography and geochemistry of the Dona Juana Volcanic Complex, SW Colombia. 472 MARIN, M., MOLINA, M„ ORDÖNEZ.O. and WEBER, M. Quatemary brittle deformation in the Caldera area, Northern Chile (27°S) 476 Carlos MARQUARDT and Alain LAVENU Recent vertical motion and Quaternary marine terraces in Caldera area. 482 Carlos MARQUARDT, Luc ORTLIEB, Alain LAVENU, Nury GUZMAN The Central Atlantic continental flood basalt province and possible relationship with Triassic-Jurassic magmatism in the 488 Andes. Andrea MARZOLI , Paul R. RENNE, Enzo M. P1CCIRILLO, Marcia ERNESTO New insights into the strueture of the Upper Palaeozoic / Mesozoic accretionary wedge complex of the Coastal Cordillera 492 of Central and Southern Chile Hans-J. MASSONNE, Lydia HUFMANN, Paul DUHART, Francisco HERVE,Arne P. W1LLNER Exploration of the northern part of the southern Patagonian batholith, southern Chile, combining spectral and hyperspectral 496 satellite data with ground thruthing methods Hans-J. MASSONNE, Jörg-U. MOHNEN, Hans-Georg KLAEDTfCE, Alfred fCLEUSBERG and Francisco HERVE Geophysical studies of Cotopaxi volcano, Ecuador: seismicity, strueture and ground deformation. 499 Jean Ph. METAXIAN, Mario RUIZ, Alexandre NERCESSIAN, Sylvain BONVALOT, Patricia MOTHES, Germinal GABALDA, Francis BONDOUX, Pierre BRIOLE, Jean-Luc FROGER and Dominique REMY Geomorphology, pattem recognition of textures, tectonic lineation analysis and material Classification using optical satellite 505 imagery on the southern Patagonian batholith, southern Chile Jörg-U. MOHNEN, Hans-Georg K.LAEDTKE and Hans-J. MASSONNE Phanerozoic paleography and geologic evolution of Colombia. 507 Jairo MOJ1CA Normal faulting and major rocks slides in the north Pampean Ranges of Argentina. Ricardo MON Geochemistry and tectonics at the southern termination of the northern volcanic zone (Riobamba volcanoes, Ecuador): Preliminary results. M. MONZ1ER, C. ROBIN, M.L. HALL, J. COTTEN and P. SAMANIEGO Geochemistry of the Triassic volcanic rocks in the coastal ränge, central Chile. Diego MORATA, Luis AGUIRRE, Marcela OYARZÜN and Mario VERGARA Cretaceous to Paleogene Geology of the Salar de Atacama Basin, northern Chile: A reappraisal of the Purilactis Group stratigraphy. Constantino MPODOZIS, Cesar ARRIAGADA, Pierrick ROPERCH Oligocene-Early Miocene coastal magmatic belt in south-central Chilean Andes (37°-44°S). Jorge MUNOZ, Rosa TRONCOSO, Paul DUHART, Pedro CRIGNOLA, Lang FARMER, Charles STERN Tectonophysics of the Andes region: relationships with heat flow and the thermal structure. Miguel MUNOZ Anomalies of the geomagnetic Variation field in the Andes (30°-40°S) and their tectono-physical significance. M. MUNOZ, E. BORZOTTA, 1.1. ROKITYANSKY, H. FOURNIER, M. MAMANI Heatflow, temperature and bathymetry of Lago General Carrera and Lago Cochrane, southern Chile. Ruth E. MURDIE, David T. PUGH and Peter STYLES, Miguel MUfiOZ New constraints on the Cretaceous-Tertiary deformation in Sierra de Moreno, Precordillera of the Segunda region de Antofagasta, Northern Chile. Claudio NICOLAS, Hans-G. WILKE, Heinz SCHNEIDER, Friedrich LUCASSEN Geochemical evolution of Neocomian volcanism S of Vallenar, Chile. Ana NOVA, M.E. CISTERNAS Tectonic style, deformation and active processes at the Central Andean Margin - Constraints from ANCORP'96. Onno ONCKEN and ANCORP Research Group New U-Pb ages and Sr-Nd data from the frontal cordillera composite batholith, Mendoza: Implications for magma source and evolution. Helen M. ORME, Michael P. ATHERTON Episodic silicic volcanism in Patagonia and the Antarctic Peninsula: Plume and subduction influences associated with the break-up of Gondwana. R.J. PANKHURST, T.R. RILEY, C.M. FANNING and S. P. KELLEY Thermochronology of the lower cretaceous Caleu pluton in the coast ränge of central Chile: Tectono - Stratigraphic implications. Miguel A. PARADA and Paula LARRONDO The Punitaqui earthquake of 14 October 1997 (Ms=6.8): A destructive intraplate event in Central Chile. M. PARDO, D. COMTE, T. MONFRET Whitnesses of an accreted oceanic terrane in early Eocene deposits of northern Peru: Tectonic implications. Laurence PECORA, Etienne JAILLARD and Henriette LAPIERRE Mechanism and consequences of tectonic erosion in the forearc of Northern Chile (20-22°S). Klaus PELZ and Onno ONCKEN Geomorphic evolution of salinas Grandes-Quebrada de Humahuaca, in relation with tectonics setting and climate, NW Argentina. Fernando X. PEREYRA and TCHILINGUIRIAN, Pablo The volcanic series of the cordillera de Las Yaretas, frontal cordillera, (34°S) Mendoza, Argentina. Daniel J. PEREZ and Lidia I. KORZENIEWSKI Last interglacial volcanic sediments at the coast of Valvidia, south of Chile. Mario PINO Q. VIII

Sedimentary register of the cenozoic deformation of the western border of the Altiplano in the northern Chile (Region of Tarapaca, 19°00' - 19°30'). Luisa PINTO, Gerard HERA1L and Reynaldo CHARRIER Rapid tectonic uplift as revealed by pedologic changes: The Ona Massif, southern part of central Ecuador. 597 Jeröme POULENARD, Theofilos TOULKERID1S and Pascal PODWO.IEWSKI Relationships between earthquak.es and the Peninsulas in the Biobio region, South Central Chile. 600 Jorge QUEZEDA FLORY Mammal fossils in the region of Cuzco. 603 Jose Angel RAMIREZ PAREJA The Andes of Neuquen (36°-38°S): Evidnce of Cenozoic transtension along the arc. 606 RAMOS, Victor A„ FOLGUKRA. Andrs Preliminary paleomagnetic evidence for a very large counterclockwise rotation of the Madre de Dios Archipelago, southern 610 Chile. Augusto E. RAPALIN1, Francisco HERVE and Victor A. RAMOS Models for subduction erosion of northern Chile. 614 C. REICHERT, CINCA Working Group

Andean deformation mechanism in the easfcm Puna, NW Argentina. 618 Uwe RILLER The Oriente Basin: an optimum tectonic-sedimentary environment for crude generation and accumulation. 621 Marco V. RIVADENEIRA M„ Patrice BABY The Bajo de Velis-San-Felipe-Yulto megafracture (San Luis, Argentina): An example of Andean reactivation of a recurrent 626 crustal discontinuity. Eduardo A. ROSSELLO, Mönica G. LOPEZ DE LUCHI, Armando C. MASSABIE & Claude A. LE CORRE Tectonic and sedimentary evolution of Cenozoic basins in the Eastern Cordillera, NW-Argentina (22°- 23°S). 630 Daniel RUBIOLO, Raul SEGGIARO, Roberto RODRIGUEZ, Alfredo DISALVO, David REPOL Apatite and zircon fission track analysis of the Ecuadorian sub-Andean (NAPO) zone: a record of the Oriente geodynamics 634 since early Jurassic. Geoffrey RUIZ, Richard SPIKINGS, Wilfried V1NK.LER, Diane SEWARD Seismic activity in Tungurahua volcano: Correlation between tremor and precipitation rates. 636 Mario RUIZ, Minard HALL, Pablo SAMANIEPO, Andres RUIZ, Darwin VILLAGÖMEZ Shear wave Splitting in the region of the Chile margin triple junction. 640 Raymond M. RUSSO and Ruth E. MURDIE

Geochemistry of Cayambe and Mojanda-Fuya Fiya volcanic complexes: evidences for slab melts-mantle wedge 644 interactions. P. SAMANIEGO, H. MARTIN, C. ROBIN, M. MONZIER, J-Ph. EISSEN, M.L. HALL Tectonic and gravitational strain fluctuations and earthquakes in northern Chile 648 K. SCHÄFER Recent crustal tilt between the Salar de Atacama and the volcano Lascar in northern Chile 652 K. SCHÄFER 3D density modelling, isostatic State and rigidity of the central Andes. 656 Sabine SCHMIDT, Hans-Jürgen GÖTZE, Andreas KIRCHNER and Michael KÖSTERS Assessment of the depth of intracrusta! melt generation and magma storage zones in the central-Andes - insights from 659 ignimbrite petrology and geochemistry. Axel K. SCHMITT, Robert B. TRUMBULL, Jan M. LINDSAY and Rolf EMMERMANN The crustal strueture and uplift history of the Guayana Shield, Venezuela. 663 Michael SCHMITZ, Daniel CHALBAUD, Jesus CASTILLO, Carlos IZARRA, Stefan LÖETH Electrical conductivity anomalies around the ANCORP-profile: An overview of new results. 668 K. SCHWALENBERG, P. LEZAETA, W. SOYER and H. BRASSE IX

The August 4"\ 1998, Bahia earthquake (Mw=7.1): rupture mechanism and comments on potential seismic activity. 673 SEGOVIA M., PACHECO J„ SHAPIRO N., YEPES H„ GUILLIER B„ RUIZ M., CALAHORRANO A., ANDRADE D, EGRED J. Early Miocene subvolcanic stocks in the central Chilean Andes: A case of slab melting? 678 Daniel SELLES MATHIEU Late Permian-early Mesozoic rifts in Peru and Bolivia, and their bearing on Andean-age tectonics. 680 Thierry SEMPERE, Gabriel CARLIER, Victor CARLOTTO, Javier JACAY, Nestor J1MENEZ, Silvia ROSAS, Pierre SOLER, Jose CÄRDENAS, Nicolas BOUDESSEUL Neogene silicic magmatism in the southern central Andes: New aspects of ignimbrite formation. 686 Wolfgang SIEBEL, Wolfgang SCHNURR, Knut HAHNE, Bernhard KRAEMER, Robert B. TRUMBULL Domains with uniform stress in the Wadati-Benioff Zone of Andean South America. 689 Alice SLANCOVÄ, Ales SPICÄK, Jiri VANEK and Vaclav HANUS New paleomagnetic data from Northern Chile: Further spatial-tempora! constraints on tectonic rotations in the region. 695 R. SOMOZA and A. TOMLINSON Salar de Antofalla: Transpressive regime in the Argentine Puna. 699 SOSAGÖMEZ, Jose Morphology of the Wadati-Benioff Zone and seismotectonic pattern of the Andean lithosphere in the Arica Elbow region. 701 Ales SPICÄK, Vaclav HANUS, Jiri VANEK and Alice SLANCOVÄ Low temperature (<300°C) thermal and tectonic history of the Eastern Cordillera, Ecuador. 707 Richard SPIKrNGS, Diane SEWARD and Wilfried WINKLER Neotectonics and landsliding in NW Argentina. 712 M R. STRECKER, R.N. ALONSO, R. HERMANNS, R.M. MARRETTand M. TRAUTH Bolivia: Proterozoico tardio-Paleozoico temprano. 716 RAMIRO SUAREZ-SORUCO Geodynamics of the Northern Andes: Intra-continental subduction and the Bucaramanga seismicity nest (Colombia). 719 A.TABOADA, L.A. RIVERA, A. FUENZALIDA, A. C1STERNAS, H. PHILIP, J.E. CASTRO, C. RIVERA Two-dimensional, thermal finite-element modelling of the Andes at 21°S from 60Ma to present; implications for thermal 725 evolution. David C. TANNER, Gerhard WÖRNER and Andreas HENK Magnetic properties of La Negra formation (Chilean coastal cordillera): comparative analysis between zones with and 729 without copper mineralization. A. TASSARA Mesozoic magmatism in Bolivia and its significance for the evolution of the Bolivian orocline. 733 TAWACKOLI, Reinhard RÖSSLING, Bernd LEHMANN, Frank SCHULTZ, Marcelo CLAURE ZAPATA & Boriz BALDERRAMA A new twist to the search for mineralization in northern Chile. 741 Graeme K TAYLOR and John GROCOTT Ordovician collision of the Argentine Precordillera with Gondwana, independent of the Laurentian Taconic orogeny. 745 William A. THOMAS and Ricardo A. ASTINI The association between islands arcs, tonalitic batholiths and oceanic plateaux in the Netherlands Antilles: implications for 749 Continental growth. Patricia M. E. THOMPSON, Rosalind V. WHITE, John TARNEY, Pamela D. KEMPTON, Andrew C. KERR and Andrew D. SAUNDERS Fission-track thermochronology of the Chilean Andes (42° to 48°S). 754 Stuart N. THOMSON, Francisco HERVE, Manfred R. BRIX and Bernhard STÖCKHERT Large-scale explosive eruption at Hyaynaputina Volcano, 1600AD, Southern Peru. 758 Jean-Claude THOURET and Jasmine DAVILA Chronology of the volcanic activity and regional thermal events: a contribution from the tephrochronology in the North of 761 the Central Cordillera Colombia. TORO, G., POUPEAU, G., HERMELIN, M„ SCHWABE, E. X

Galena lead isotope characterization from ore deposits of the Aysen region, southern Chile: Metallogenic implications. 764 TOWNLEY, Brian K. Tertiary gold mineralization in San Luis, Argentina. 768 Nilda E. URBINA and Lidia MALVICINI Mezozoic - Cenozoic evolution of the northern Subandean zone, Ecuador. 772 Cristian VALLEJO Late Cenozoic geomorphologic evolution of the Antofagasta southern area. 776 Gabriel VARGAS, Luc ORTLIEB & Nury GUZMÄN Identification of volcanic materia! prone to mass removal events associated with slope instabilities in the Pre-Andean sector 781 adjacent to the central Valley between latitudes 33°S and 34°S, Chile. Nicole VATIN-PERIGNON, Sara ELGUETA, Sofia REBOLLEDO and Guy KIEFFER 40Ar/'9Ar Ages, very low-grade metamorphism and geochemistry of the volcanic rocks from „Cerro El Abanico", Santiago 785 Andean Cordillera (33°30'S - 70°30'-70°25'W). Mario VERGARA, Diego MORATA, Renato VILLARROEL, Jan NYSTRÖM and Luis AGUIRRE Uplift and surface morphology of the westem Altiplano: An effect of basal accretion and tectonic shortening? 789 Pia VICTOR & Onno ONCKEN Seismic activity at Guagua Pichincha Volcano, Ecuador. 793 Darwin VILLAGÖMEZ, Mario RUIZ, Hugo YEPES, Minard HALL, Bertrand GUILLIER, Alex ALVARADO, Mönica SEGOVIA and Alcinoe CALAHORRANO Diversity in the convergent margin strueture offshore south America. 797 VON HUENE and RANERO, C.R. A lower crustal and upper mantle model for southern Colombia, based on xenolith evidence. 801 WEBER Marion, Ray KENT and John TARNEY The Impact of Tectonics and Topography on the Extent of the last glaciation of the southern Patagonian icefield (Chile, 806 Argentina) Gerd WENZENS Uplift and gravitational collapse of the westem Andean escarpment at 18°S 810 WÖRNER G„ SEYFRIED H., KOHLER I„ UHLIG D. The role of the Juan Fernandez ridge in the long lived Andean segmentation at 33.5°S 815 Gonzalo YANEZ and Cesar RANERO Guagua Pichincha: Managing the crisis 820 Hugo A. YEPES Characterization of the Altiplano-Puna magma body central Andes, South America. 824 George ZANDT, Josef CHMIELOWSKI, Christian HABERLAND, Xiaohui YUAN, Rainer KIND Lower Ordovician graptolites propose a new stratigraphic subdivision for the southern Puna (NW Argentina): First finds of 828 Arneograptus murrayi and Clonograptus sp. in the Puna U. ZIMMERMANN, M.C. MOYA & H. BAHLBURG The evolution of the Ordovician southern Puna retro-arc basin (NW Argentina): provenance analysis and paleotectonic 830 setting. U. ZIMMERMANN & H. BAHLBURG Petrology and geochemistry of Mg-rich basalts from Western Ecuador : remnants of the Late Cretaceous Caribbean 832 plateau ? M. MAMBERTI, D. BOSCH, H. LAPIERRE, J. HERNANDEZ, E. JAILLARD, M. POLVE This abstract has beert mistakenly omitted in due Cime and, accordingly, is not at it 's correct place.

RESUMES EN FRANCAIS 836 INDEX DES AUTEURS / AUTHOR INDEX / INDICE DE LOS AUTORES 880