The antenna DSA 3 and its potential use for Radio Astronomy

The European Space Agency (ESA) will inaugurate its third Deep Space Antenna (DSA 3) by the end of 2012. DSA 3 will be located in Argentina near the city of Malarg"ue in the Mendoza province. While the instrument will be primarily dedicated to communications with interplanetary missions, the characteristics of its antenna and receivers will also enable standalone leading scientific contributions, with a high scientific-technological return. We outline here scientific proposals for a radio astronomical use of DSA 3.Comment: 4 pages, submitted as Proceedings for the BAA

LP/HT metamorphism as a temporal marker of change of deformation style within the Late Palaeozoic accretionary wedge of central Chile

A Late Palaeozoic accretionary prism, formed at the southwestern margin of Gondwana from Early Carboniferous to Late Triassic, comprises the Coastal Accretionary Complex of central Chile (34–41°S). This fossil accretionary system is made up of two parallel contemporaneous metamorphic belts: a high‐pressure/low temperature belt (HP/LT – Western Series) and a low pressure/high temperature belt (LP/HT – Eastern Series). However, the timing of deformation events associated with the growth of the accretionary prism (successive frontal accretion and basal underplating) and the development of the LP/HT metamorphism in the shallower levels of the wedge are not continuously observed along this paired metamorphic belt, suggesting the former existence of local perturbations in the subduction regime. In the Pichilemu region, a well‐preserved segment of the paired metamorphic belt allows a first order correlation between the metamorphic and deformational evolution of the deep accreted slices of oceanic crust (blueschists and HP greenschists from the Western Series) and deformation at the shallower levels of the wedge (the Eastern Series). LP/HT mineral assemblages grew in response to arc‐related granitic intrusions, and porphyroblasts constitute time markers recording the evolution of deformation within shallow wedge material. Integrated P–T–t–d analysis reveals that the LP/HT belt is formed between the stages of frontal accretion (D1) and basal underplating of basic rocks (D2) forming blueschists at c. 300 Ma. A timeline evolution relating the formation of blueschists and the formation and deformation of LP/HT mineral assemblages at shallower levels, combined with published geochronological/thermobarometric/geochemistry data suggests a cause–effect relation between the basal accretion of basic rocks and the deformation of the shallower LP/HT belt. The S2 foliation that formed during basal accretion initiated near the base of the accretionary wedge at ~30 km depth at c. 308 Ma. Later, the S2 foliation developed at c. 300 Ma and ~15 km depth shortly after the emplacement of the granitoids and formation of the (LP/HT) peak metamorphic mineral assemblages. This shallow deformation may reflect a perturbation in the long‐term subduction dynamics (e.g. entrance of a seamount), which would in turn have contributed to the coeval exhumation of the nearby blueschists at c. 300 Ma. Finally, 40Ar–39Ar cooling ages reveal that foliated LP/HT rocks were already at ~350 °C at c. 292 Ma, indicating a rapid cooling for this metamorphic system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115992/1/jmg12166-sup-0001-FigS1-S5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115992/2/jmg12166_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115992/3/jmg12166.pd

A first report of variscite tairona artifacts (a.d. 1100-1600) from the Sierra Nevada de Santa Marta, Colombia, and its implications for precolumbian exchange networks in the region

Archaeoznetric analyses (Raman Spectroscopy Analysis, X-Ray Diffraction, and Electron Microprobe Analysis) of greenstone beads of the precolumbian Tairona culture (A.D. 1100-1600) of the Sierra Nevada de Santa Marta, Colombia, have revealed that they are made of variscite-group minerals. These beads were curated at the Museo del Oro, Bogota, and the Archaeology Laboratory of the Universidad del Norte, Barranquilla. Variscite minerals of the variscite-strengite series are rare in nature, and therefore provenance data of source material are useful for the development of intercultural influence models. The abundance of this rare material in prehistoric Colombian collections strongly indicates not only that this material had important symbolic and prestige value for ancient Tairona societies (Nahuange and Tairona periods) but also that these societies participated in ancient trade routes, including, at least, the Andes of present-day Colombia and Venezuela, and the southern Caribbean coast

Mineralogy and geochemistry of Fe-Ti oxide ores from the Don Dieguito massif type anorthosite suite, Sierra Nevada de Santa Marta, Colombia

Fe-Ti oxide ores are commonly associated with Proterozoic massif-type anorthosite bodies emplaced during the Grenville orogeny (~1.2-1.0 Ga). Some of these anorthositic bodies occur in the northernmost part of the Santa Marta Massif, Colombia. They locally contain crosscutting Fe-Ti(-V) ore bodies between the El Hierro creek and the Don Dieguito river. We have distinguished two types of Fe-Ti(-V) ores: i) oxide-apatite norite (fine grained ilmenite and magnetite disseminated in an assemblage of apatite, amphibole, chlorite, rutile and sericitized plagioclase) and ii) banded nelsonite (coarser grained ilmenite, magnetite and apatite distributed in bands, with minor baddeleyite, srilankite and högbomite)

Petrographic and Geochemical Characteristics of the Djabatoure Massif Metamagmatites from Pan-African Orogen in Togo, West Africa

The Dahomeyide orogen in Togo and adjoining parts of SE-Ghana and Benin records the suture of West Africa Craton (WAC) into NW Gondwana. The suture zone corresponds to a narrow and lithologically diverse area with HP granulites complexes. In Togo, the Djabatoure massif, located in the central part of Togo, belongs to the suture zone. The aim of this paper is to present the petrographic and geochemical characteristics of the Djabatoure massif in order to understand its implication in the geodynamic evolution of the Dahomeyide belt in Togo. The methodology implemented is based on a synthesis of previous works, a petrographic study of twenty thin sections and a geochemical study through discrimination diagrams of fifteen samples. The result shows that the Djabatoure massif is composed of granulites, pyroxenites, amphibolites, talcschists and gneisses. These rocks were equilibrated under granulite facies conditions and subsequently partially retrogressed to amphibolite facies. They display tholeiitic affinity, enriched LREE and negative anomalies in Nb, Zr and Ti indicating subduction zone magma. These features are consistent with protoliths of tholeiites, N-MORB and volcanic arc basalts affinities. The Djabatoure massif rocks were set up in oceanic environment and are thought to have been derivated from a metasomatized mantle

Petrographic and Geochemical Characteristics of the Djabatoure Massif Metamagmatites from Pan-African Orogen in Togo, West Africa

The Dahomeyide orogen in Togo and adjoining parts of SE-Ghana and Benin records the suture of West Africa Craton (WAC) into NW Gondwana. The suture zone corresponds to a narrow and lithologically diverse area with HP granulites complexes. In Togo, the Djabatoure massif, located in the central part of Togo, belongs to the suture zone. The aim of this paper is to present the petrographic and geochemical characteristics of the Djabatoure massif in order to understand its implication in the geodynamic evolution of the Dahomeyide belt in Togo. The methodology implemented is based on a synthesis of previous works, a petrographic study of twenty thin sections and a geochemical study through discrimination diagrams of fifteen samples. The result shows that the Djabatoure massif is composed of granulites, pyroxenites, amphibolites, talcschists and gneisses. These rocks were equilibrated under granulite facies conditions and subsequently partially retrogressed to amphibolite facies. They display tholeiitic affinity, enriched LREE and negative anomalies in Nb, Zr and Ti indicating subduction zone magma. These features are consistent with protoliths of tholeiites, N-MORB and volcanic arc basalts affinities. The Djabatoure massif rocks were set up in oceanic environment and are thought to have been derivated from a metasomatized mantle

Diversidad genética de las razas porcinas ibérica y alentejana mediante el genotipado de variantes genéticas en genes mayores y genes candidatos

Las razas porcinas ibérica y alentejana se encuentran biogeográficamente localizadas en el suroeste de la península Ibérica. Estas razas comparten un conjunto de características comunes. Ambas son fenotípicamente muy similares; muestran un bajo índice de crecimiento y una elevada deposición grasa y tienen un sistema común de producción al aire libre en el que se explotan los recursos de la Dehesa. El objetivo del presente trabajo, dentro del marco del proyecto TREASURE, consistió en caracterizar la diversidad genética de ambas razas usando los datos de genotipado de 39 polimorfismos localizados en 34 genes previamente asociados a distintos caracteres de interés económico. Estos polimorfismos fueron genotipados en 950 cerdos pertenecientes a las razas ibérica y alentejana y a 18 razas europeas autóctonas adicionales. Los bajos valores para heterozigosidad observada y esperada indican una baja diversidad genética en ibéricos y alentejanos. Las distancias genéticas estimadas usando DS y FST fueron cercanas a 0 (0.007 y 0.039, respectivamente), sugieren que estas razas son genéticamente muy similares. Asimismo, las técnicas de análisis multivariante utilizadas como análisis de componentes principales y asignación a grupos mostraron que los individuos de estas razas están muy próximos formando clusters diferenciados del resto de razas. Estos resultados concuerdan con los de otros autores que ya mostraron distancias genéticas cortas entre ambas razas usando secuencias de ADN mitocondrial

Petrographic and Geochemical Characteristics of the Djabatoure Massif Metamagmatites from the Pan-African Orogen in Central Togo, West Africa

The Dahomeyide orogen, in Togo and adjoining parts of southeast Ghana and Benin, represents the suture of West Africa Craton (WAC) into northwest Gondwana. The suture zone corresponds to a narrow and lithologically diverse area with high pressure granulite complexes. The Djabatoure massif, located in the central part of Togo, belongs to the suture zone. The aim of this paper is to present the petrographic and geochemical characteristics of the Djabatoure massif in order to better understand the geodynamic evolution of the Dahomeyide belt in Togo. The methodology implemented is based on a synthesis of previous works, a petrographic study of 20 thin sections, and a geochemical study through discrimination diagrams of 15 rock samples. Results show that the Djabatoure massif is composed of granulites, pyroxenites, amphibolites, talcschists and gneisses. These rocks were equilibrated under granulite facies conditions and subsequently partially retrogressed to the amphibolite facies. The Djabatoure massif rocks also display tholeiitic affinity, enriched LREE, and negative anomalies in Nb, Zr and Ti; all these characteristics indicate subduction zone magmtism. These features are consistent with protoliths of tholeiites, N-MORB, and volcanic arc basalts affinities. The Djabatoure massif rocks were emplaced in an oceanic environment and likely originated  from a metasomatized mantle

HP-LT rocks exhumed during intra-oceanic subduction: the example of the Escambray massif (Cuba).

High-Presssure metabasites embedded in a serpentinite or metasedimentary matrix from the Sancti Spiritus dome (Escambray massif, Central Cuba) have been studied in order to better understand the origine and the evolution of the Northern Carribean boundary plate during the Cretaceous, in a global subduction context. Geochemical analyses (major, trace elements and isotopes) of the high pressure rocks show that they could be partially derived from the Cretaceous calc-alkaline arc described in Central Cuba, these were probably incorporated in the subduction zone by tectonic erosion. The High-Pressure rocks record a prograde path from the epidote bearing amphibolite facies to the barroisite bearing eclogite facies (P = 19 ± 2 Kbar, T = 590 ± 90 °C). These metabasites show evidence of retrogression starting from the glaucophane bearing eclogite facies to the lawsonite bearing blueschist facies. Therefore, these HP/LT rocks are characterized by a counter-clockwise cooling P/T path, which can be explained by the exhumation of HP rocks while the subduction was still active. Concordant geochronological data (Rb/Sr and Ar/Ar) suggest that the main exhumation of HP/LT rocks from the Sancti Spiritus dome occurred 70 Ma ago by top to SW thrusting. The retrogressed trajectory of these rocks, means that the northeast subduction of the Farallon plate continued after 70Ma. The final exhumation can be correlated with the beginning of the collision between the Bahamas platform and the Cretaceous island arc that induced a change of the subduction kinematic