Radiometric dating, analytical results and sample documentation

Fil: Panteleyev, A. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: Cravero, O. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Two elongate belts of rocks containing large hydrothermal alteration zones with indications of porphyry gold and copper-gold mineralization, as well as potential for epithermal gold-silver deposits, were examined near the border of Argentina with Chile in southern La Rioja and northern San Juan Provinces. On the west along the height of land a zone consists predominantly of Tertiary volcanic rocks and is referred to as the 'Faja de Potro'. This region is roughly midway between the wellmineralized porphyry gold- epithermal gold-silver Maricunga district in Chile to the north and the large, newly discovered high-sulphidation epithermal goldsilver Pascua-Veladero district that straddles the Argentinean-Chilean border to the south. To the east this belt of economic interest, the Cordón de la Brea, is made up of mainly Paleozoic felsic volcanic and sedimentary units and Permo-Triassic granitic and volcanic rocks. There the exploration interest has been both the base metal and gold potential. The Tertiary volcanic rocks in the study area consist of a basal unit of back-arc rocks of predominately andesitic composition that form eroded fie1ds of coalescing lava flow and pyroclastic units; a number of sma11, dark-coloured domes in this unit are made of basal t. Overlying volcanic units that comprise the bulk of the Cordillera consist of dacitic to andesitic are rocks, and less commonly quartz-phyric rocks ('rhyolite'), that give rise to pyroclastic accumulations with locally abundant flow domes. Ali Tertiary volcanic accumulations include locally derived volcanigenic sed iments. Previously ali the older volcanic units in this region were regarded to be equivalent to, and correlated with, the late Oligocene to early Miocene (26 - 21 Ma) Doña Ana Group . The term 'Group' is used in Chile whereas the equi valent rocks in Argentina are commonly referred to 'Formations'. The overlying successions of dacitic to andesititc rocks, with minor basalt units, are equivalent to the middle to late Miocene Cerro de Las Tortolas Group (17 to 1 O Ma). In this study we have recognized that the o1dest volcanics are late Eocene to 0Iigocene in age. They crop out as andesite and Iesser basaltic units in the Rio Peña Negra area and to the east of Ria Blanco at the Sapitos prospect. In this report we present resu1ts of new Ar-Ar dating results frorn these, and the other map units. These new data better constrain regional corre1ation of the Tertiary volcanic units. We also present new petrochemical data that characterize the vo1canics and allow a refined interpretation of their tectonic setting. This work can lead to the construction of a regional stratigraphic framework that is constrained by radiometric dating in which the regional metallogeny can be considered. The o1der rocks of the Cajón de la Brea belt, in addition to copper rnineralization, locally have significant gold enrichment. This appears to be associated in both granitic and rhyolitic hostrocks with quartz-feldspar porphyry dykes containing distinctive bipyrimidal, 'smoky' grey quartz phenocrysts. A single Ar-Ar date from K-feldspar from one of these dykes gives an Eocene age (52 Ma). This suggests that a Tertiary precious metal mineralizing episode occurred in this older Cordilleran terrane. Visits to a number of the alteration zones identified in the 1993 N orwest study, and a few other areas, have provided a large, well-documented sample collection füí those interested in details about the various alteration zones. This information is presented in Appendix C. In addition to whole rock petrochemistry sorne alteration minerals have been analyzed by infra-red spectrometry (PIMA), and there are a number of exploration geochemical sample analyses (assays)

Report on 1:100 000 Scale Geological and Metallogenic Maps Sheet 3163-19 Cosquín, Province of Córdoba

Fil: Stuart-Smith, Peter G. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.Cubrimiento parcial de la hoja.The Cosquin 1:100.000 Sheet area lies within the Córdoba Province, between 31o00’-31o20’S and 64o00’-64o30’W. The area is part of the Córdoba (3163-III)1:250 000 sheet area. The region includes the central northern part of the Sierra Chica, one of several north-trending mountain ranges which traverse the northern part of the Córdoba Province. The Sierra Chica is drained by the easterly flowing Ríos La Granja, Ascochinga, and Santa Sabina. Access to the region, from Córdoba city, is via El Manzano and Ruta Provincial 9 in the east. An unsealed road traverses the eastern flank of the Sierra Chica from El Manzano to La Cumbre (Jesús María sheet area)

Report on 1:100 000 Scale Geological and Metallogenic Maps Sheet 3166-27 Ulapes, Province of La Rioja

Fil: Pieters, P. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.The 1:100 000 scale Ulapes (3166-27) sheet covers the northern part of the Sierra de Las Minas and the surrounding plain which are located in the southern part of the La Rioja Province (Figures 1, 2). The map area is bounded by latitudes 31°20’ S and 31°40’ S, and by longitudes 66°00’ W and 66°30’ W. The area falls in the central eastern part of the 1:250 000 scale Chepes (3166-III) sheet. The area is easily accessible from Córdoba by Ruta Nacional 38, Ruta Provincial 32 and Ruta Nacional 79, from La Rioja by Ruta Nacional 38 and Rutas Provinciales 27, 28 and 29, and from San Juan by Ruta Nacional 141 and Rutas Provinciale 29. The nearest regularly serviced airport is located at La Rioja. The nearest major centre of population, logistics and commerce is Chepes on Ruta Nacional 141 located between the Sierra de Chepes and Sierra de Las Minas (outside the map area). Ulapes and La Jarilla are small population centres in the area

Programa Nacional de Cartas Geológicas de la República Argentina 1:100.000

Fil: Cardó, R. SEGEMAR - San Juan; Argentina.Fil: Díaz, I. SEGEMAR - San Juan; Argentina.Fil: Bordonaro, O. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, CONICET, Mendoza; Argentina.Fil: Cardinali, A. Departamento de Minería de la Provincia de San Juan; Argentina.Fil: Fauqué, L. SEGEMAR - Buenos Aires; Argentina.La Hoja Geológica 3169-34, Los Berros, está situada al sur de la provincia de San Juan y lleva el nombre de una importante localidad calera. Comprende parte de dos provincias geológicas: las Sierras Pampeanas Occidentales y la Precordillera (Oriental y Central).Las Sierras Pampeanas están representadas, en el cerro Valdivia, por un basamento de edad proterozoica media, el Complejo Pie de Palo, compuesto por rocas máficas y ultramáficas, anfibolitas y esquistos anfibólicos, micáceos y cuarzo-feldespáticos, afectados por metamorfismo regional y dinámico.La Precordillera comprende secuencias carbonáticas de plataforma del Cámbrico-Ordovícico con abundante fauna fósil (forma-ciones La Laja, Zonda, La Flecha, La Silla y San Juan) y depósitos siliciclásticos del Silúrico, Devónico, Carbonífero y Terciario. Los depósitos silúricos (Formación Rinconada) corresponden a una melange sedimentaria de bloques alóctonos clásticos y carbonáticos ubicados en el sector oriental de la Hoja, en el ámbito de la Precordillera Oriental.Las sedimentitas silúrico-devónicas (Formación Corralitos) que afloran en la Precordillera Central están constituidas por lutitas, areniscas, brechas carbonáticas y olistolitos de calizas en el sector noroeste de la Hoja.El Devónico (Formación Punta Negra) consiste en una potente secuencia clástica de abanicos detríticos submarinos generados por corrientes de turbidez provenientes del este.Los depósitos carboníferos comprenden secuencias de conglomerados, areniscas, limolitas y lutitas carbonosas, que indican ambientes fluviales y lacustres con episodios periglaciales, bien representados en el sector austral de la Hoja por las formaciones Jejenes, La Deheza y Andapaico.En el período extensivo del Pérmico-Triásico se emplazó una unidad volcánica, Traquita La Flecha, compuesta por traquitas que podría representar manifestaciones del Grupo Choiyoi o posteriores.Durante el Neógeno se depositaron areniscas, limolitas y piroclastitas, en discordancia sobre unidades carboníferas y más antiguas, representadas por las formaciones Albarracín, El Corral y Lomas de Las Tapias.El Cuaternario está integrado por depósitos aluviales, de piedemonte, eólicos y de barreales.La Precordillera Oriental está formada por corrimientos norte-sur que ocasionaron la imbricación y repetición de secuencias del Paleozoico mediante fallas inversas. Estos corrimientos están limitados por fallas normales o de desplazamiento de rumbo. La estruc-tura es de tipo “piel gruesa” con vergencia al oeste, donde se involucran depósitos del Paleozoico inferior, Carbonífero y Terciario.La Precordillera Central está controlada por corrimientos frontales de un sistema de imbricación del tipo “piel delgada”, con una vergencia al este.La interacción de vergencias opuestas en la Precordillera genera una zona triangular denominada Corredor Acequión-Maradona-Zonda, con la presencia de complicaciones estructurales, magmatismo y fallamiento neotectónico.En esta Hoja se destaca la importancia de la actividad minera, ya que la mayoría de la producción de cales de la provincia se extrae de yacimientos situados en ella.Entre los sitios de interés geológico se destacan los relacionados con la presencia de bloques alóctonos en La Rinconada y en la quebrada del Telégrafo, la secuencia cámbrica completa de la quebrada de La Flecha, los yacimientos mineros del cerro Pedernal de Los Berros y los depósitos sinorogénicos terciarios del cordón del Infiernill

Report on 1:100 000 Scale Geological and Metallogenic Maps Sheet 3166-15 Santa Rita de Catuna, Province of La Rioja

Fil: Pieters, P. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.The 1:100 000 scale Santa Rita de Catuna (3166-15) sheet covers the northeastern part of the Sierra de Chepes, the southeastern part of the Sierra de Los Llanos, and the adjacent plain; this area is located in the southern part of the La Rioja Province (Figures 1, 2). The map area is bounded by latitudes 30°40’ S and 31°00’ S, and by longitudes 66°00’ W and 66°30’ W. The area falls in the southeastern part of the 1:250 000 scale Chamical (3166-I) sheet. The area is easily accessible from Córdoba and La Rioja by Ruta Nacional 38 and Ruta Provincial 32, and from San Juan by Ruta Nacional 141 and Ruta Provincial 32. The nearest regularly serviced airport is located at La Rioja. The nearest major centre of population, logistics and commerce is Chepes on Ruta Nacional 141 located between the Sierra de Chepes and Sierra de Las Minas (outside the map area). Santa Rita de Catuna, Solca, Olpas and Los Aguirres are small population centres in the map area

Report on 1:100 000 Scale Geological and Metallogenic Maps Sheet 3166-14 Malanzán, Province of La Rioja

Fil: Pieters, P. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.Cubrimiento parcial de la hoja.The 1:100 000 scale Malanzán (3166-14) sheet covers the northwestern part of the Sierra de Chepes, the southwestern part of the Sierra de Los Llanos, and the adjacent plain; this area is located in the southern part of the La Rioja Province (Figures 1, 2). The map area is bounded by latitudes 30°40’ S and 31°00’ S, and by longitudes 67°00’ W and 66°30’ W. The area falls in the central south part of the 1:250 000 scale Chamical (3166-I) sheet. The area is easily accessible from Córdoba and La Rioja by Ruta Nacional 38 and Ruta Provincial 32, and from San Juan by Ruta Nacional 141 and Ruta Provincial 32. The nearest regularly serviced airport is located at La Rioja. The nearest major centre of population, logistics and commerce is Chepes on Ruta Nacional 141 located between the Sierra de Chepes and Sierra de Las Minas (outside the map area). Malanzán and El Portezuelo are small population centres in the map area

Evaluation of the Concept that Pumahuasi Veins Indicate a Potential for the Existence of Underlying Undiscovered Sedex Deposits, Northern Argentina

Fil: Sangster, Alan L. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: Sangster, Donald F. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.We have been asked by SEGEMAR to comment on the possibility that the Pumahuasi veins (Figure 1) may be mobilized Sedex mineralization and that their presence indicates an exploration potential for Sedex base metal deposits, similar to the Aguilar deposit, in the Pumahuasi area

Strengthening Disaster Risk Reduction Across the Americas Summit - Simulated Exercise

Fil: Luis Bermudez. Open Geospatial ConsortiumFil: Asato, Carlos Gabriel. Open Geospatial Consortium y SEGEMAR; Argentina. ORCID: 0000-0002-1968-7741Fil: Taylor, Trevor. Open Geospatial ConsortiumDisasters are responsible for major socioeconomic damages. Global initiatives call for the improvement of information technology infrastructure to better share data and advance multinational collaboration. The "Strengthening Disaster Risk Reduction Across the Americas: A Regional Summit on the Contributions of Earth Observations" held on September 3-8 in 2017 in Buenos Aires, Argentina strengthened the collective ability to share the many challenges of disaster risk reduction in Latin America and the Caribbean (LAC) while promoting the awareness and better use of earth observations (EO). A simulation exercise took place during the summit. The exercise brought together government, emergency managers, earth observation data providers, academics, nongovernmental organizations, and commercial companies. The participants assessed the capabilities and needs of policymakers, regional and on-the-ground decision makers, and learned what information products can be produced, and when and how such products are available. This ER describes the description and results of the simulated scenario including the postexercise activity that captured the lessons learned from the participants

Geoscientific Mapping of the Sierras Pampeanas, Argentine-Australian Cooperative Project

Proyecto de Cooperación Argentino-Australiano.Versión Preliminar (en inglés)Fil: Sims, John P. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.The 3366-16 map area forms an east-west transect within San Luis Province; ~46km by ~40km between latitude 32°40’-33°00’ S and longitude 65°30’-66°00’ W. The area includes part of two 1:250 000 scale map sheets: San Francisco del Monte de Oro (3366-I), and Sierras de San Luis y Comechingones. The area is contained within the Sierras de San Luis and covers the minor population centre of Paso Grande, and is traversed by provincial routes 2, 2A, 10, 22, 24, 38, 40 and 41. The main drainage is via Río Conlara, Río de la Cañada Honda, and Río Rosario

Report on 1:100 000 Scale Geological and Metallogenic Maps Sheet 3166-20 Ñoquebe, Province of La Rioja

Fil: Pieters, P. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.Cubrimiento parcial de la hoja.The 1:100 000 scale Ñoquebe (3166-20) sheet covers the southwestern part of the Sierra de Chepes and the adjacent plain; this area is located in the southern part of the La Rioja Province (Figures 1, 2). The map area is bounded by latitudes 31°00’ S and 31°20’ S, and by longitudes 67°00’ W and 66°30’ W. The area falls in the central north part of the 1:250 000 scale Chepes (3166-III) sheet. The area is easily accessible from Córdoba and La Rioja by Ruta Nacional 38 and Ruta Provincial 32, and from San Juan by Ruta Nacional 141 and Ruta Provincial 32. The nearest regularly serviced airport is located at La Rioja. The nearest major centre of population, logistics and commerce is Chepes on Ruta Nacional 141 located between the Sierra de Chepes and Sierra de Las Minas (outside the map area). Ñoquebe, San Antonio, Chepes Vieja, Villa Casana, Puerto La Aguada and La Calera are small population centres in the map area