The distribution, petrology, and geochemistry of mid-late Tertiary magmatic rocks in the Main Andean Cordillera over the modern zone of shallow subduction ("flatslab"-28 to 33°S) correlate with the shallowing of the subducted plate and the thickening of the crust in central Chile and Argentina. The evolving characteristics of these "flat-slab" magmatic rocks suggest that crustal thickening occurred earlier in the central (near 30.5°) and northern (near 28°S) regions than in the southern region (near 33°S). Crustal thicknesses approximated by comparing the chemical characteristics (particularly the La/Yb ratios) of the "flat-slab" magmatic rocks with those of similar rocks in the modern Southern Volcanic Zone indicate that the crust thickened from ~35 to 40 km in the late Oligocene to =55 to 65 km in the late Miocene in the northern and central "flat-slab." As the region was under compression, ductile deformation in the lower crust accompanying magmatism was probably responsible for these relatively rapid crustal thickness increases. The mineralogy of crustal residues calculated from basaltic composition parents for the "flat-slab" volcanic rocks changes from a hydrous amphibolegarnet-plagioclase assemblage to an almost anhydrous plagioclase-poor garnet granulite assemblage as the crust thickens. Geochemically, these changes are reflected in the melts by increasing La/Yb ratios and Sr contents associated with decreasing Eu anomalies. A limit to crustal thickening may be the attainment of mantle density by lower crustal rocks as garnet and Al-rich pyroxene replace plagioclase.Early Miocene (»20 Ma) back-arc alkaline basalts at 31°S have relatively low 87 Sr/ 86 Sr ratios (-0.7036) and high eNd (+4.5) compared to "flat-slab" calc-alkaline magmatic rocks. This fact combined with evidence for increasing crustal thickness suggests that progressively higher 87 Sr/ 86 Sr ratios and lower eNd ( 87 Sr/ 86 Sr = 0.7046 to 0.7064; eNd = +1.2 to -3.5) in the "flat-slab" volcanic rocks correlate with an increase

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The aims of these recommendations were to develop clinical guidelines for evaluation and management of patients with differentiated thyroid cancer applicable to Latin American countries. The panel was composed by 13 members of the Latin American Thyroid Society (LATS) involved with research and management of thyroid cancer from different medical centers in Latin America. The recommendations were produced on the basis of the expert opinion of the panel with use of principles of Evidence-Based Medicine. Following a group meeting, a first draft based on evidences and the expert opinions of the panel was elaborated and, later, circulated among panel members, for further revision. After, this document was submitted to the LATS members, for commentaries and considerations, and, finally, revised and refined by the authors. The final recommendations presented in this paper represent the state of the art on management of differentiated thyroid cancer applied to all Latin American countries. Arq Bras Endocrinol Metab. 2009;53(7):884-97. KeywordśThyroid cancer; thyroid ultrasonography; radioiodine therapy; thyroglobulin; consensus RESUMO Estas recomendações tiveram por objetivo o desenvolvimento de diretrizes para avaliação e manejo de pacientes com câncer diferenciado da tiroide em países latino-americanos. Um painel composto por 13 membros da Sociedade Latino-Americana de Tireoide (SLAT) -que estavam envolvidos em pesquisas, e eram peritos no cuidado do paciente com câncer da tiroide e provenientes de diferentes centros médicos latino-americanos -utilizou os princípios da Medicina Baseada em Evidências para produzir esse consenso. Após uma primeira reunião, um texto inicial foi elaborado, baseado em evidências e opiniões dos especialistas do painel e, posteriormente, circulado entre os membros do painel, para revisão. Após a revisão, o documento foi enviado aos membros da SLAT para comentários e considerações e, finalmente, revisado e refinado pelos autores. As recomendações finais aqui apresentadas demonstram o estado da arte no manejo do câncer diferenciado da tireoide aplicadas aos países latino-americanos.Arq InTRODUCTIOn T he risk of malignancy in a thyroid nodule varies between 5% and 10% in iodine sufficient countries, and the amount of iodine supplemented in table salt influences on the morphology of the malignant tumor types (1).

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Measurable molybdenum isotope fractionation in molybdenites from different ore deposits through time provides insights into ore genesis and a new technique to identify open-system behavior of Re–Os in molybdenites. Molybdenite samples from six porphyry copper deposits, one epithermal polymetallic vein deposit, four skarns, and three Fe-oxide Cu–Au deposits were analyzed. The δ97Mo‰ (where δ97Mo = [(97Mo/95Mosample)/(97Mo/95MoICPMS standard)]-1 x 1000 ) for all samples varied from 1.34±0.09‰ to −0.26±0.04‰. This is the largest molybdenum isotopic variation in molybdenite from high-temperature ore deposits recorded to date. δ97Mo‰ of molybdenite varies as a function of the deposit type and the rhenium and osmium concentrations of the samples. Isotope values for Mo also vary within the individual deposits. In general, molybdenites from porphyry copper deposits have the lightest values averaging 0.07±0.23‰ (1σ). Molybdenites from the other deposit types average 0.49±0.26‰ (1σ). The variations could be related to the fractionation of Mo into different mineral phases during the ore-forming processes. A comparison of the Mo isotope ratios and the Re–Os ages obtained from the same aliquot may possess a geochronological evaluation tool. Samples that yielded robust ages have different Mo isotopic compositions in comparison to samples that yielded geologically unreasonable ages. Another observed relationship between the Re–Os andMo isotope data reveals a weak correspondence between Re concentration and Mo isotope composition. Molybdenites with higher concentrations of Re correspond to lighter Mo isotope values.This material is based upon work supported by the National Science Foundation under grant nos. CHE-0431328 and EAR 05-19144

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AbStRACt. Apatite fission track data for Miocene plutons of the western slope of the Principal Andean Cordillera in central Chile (33-35°S) define a distinct episode of enhanced crustal cooling through the temperature range of the apatite partial annealing zone (~125-60°C) from about 6 to 3 Ma. This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Chile. The timing coincides with the southward migration of the subducting Juan Fernández Ridge and the development of progressive subduction flattening northward of 33°S. It also corresponds to the time of active magmatic-hydrothermal processes and rapid unroofing of the world class Río Blanco-Los Bronces and El Teniente porphyry Cu-Mo deposits. Zircon fission track ages coincide with previous 40 Ar/ 39 Ar dates of the intrusions, and with some of the apatite fission track ages, being coherent with igneous-linked, rapid cooling following magmatic intrusion. The thermochronologic data are consistent with a maximum of about 8 km for Neogene exhumation of the plutons.