What can we learn from melt inclusions in migmatites and granulites?

With less than two decades of activity, research on melt inclusions (MI) in crystals from rocks that have undergone crustal anatexis \u2013 migmatites and granulites \u2013 is a recent addition to crustal petrology and geochemistry. Studies on this subject started with glassy inclusions in anatectic crustal enclaves in lavas, and then progressed to regionally metamorphosed and partially melted crustal rocks, where melt inclusions are normally crystallized into a cryptocrystalline aggregate (nanogranitoid). Since the first paper on melt inclusions in the granulites of the Kerala Khondalite Belt in 2009, reported and studied occurrences are already a few tens. Melt inclusions in migmatites and granulites show many analogieswith theirmore common and long studied counterparts in igneous rocks, but also display very important differences and peculiarities,which are the subject of this review. Microstructurally, melt inclusions in anatectic rocks are small, commonly 10 \u3bcm in diameter, and their main mineral host is peritectic garnet, although several other hosts have been observed. Inclusion contents vary from glass in enclaves that were cooled very rapidly from supersolidus temperatures, to completely crystallized material in slowly cooled regional migmatites. The chemical composition of the inclusions can be analyzed combining several techniques (SEM, EMP, NanoSIMS, LA\u2013ICP\u2013MS), but in the case of crystallized inclusions the experimental remelting under confining pressure in a piston cylinder is a prerequisite. The melt is generally granitic and peraluminous, although granodioritic to trondhjemitic compositions have also been found. Being mostly primary in origin, inclusions attest for the growth of their peritectic host in the presence of melt. As a consequence, the inclusions have the unique ability of preserving information on the composition of primary anatectic crustal melts, before they undergo any of the common following changes in their way to produce crustal magmas. For these peculiar features, melt inclusions in migmatites and granulites, largely overlooked so far, have the potential to become a fundamental tool for the study of crustal melting, crustal differentiation, and even the generation of the continental crust

Micropetrology: Are Inclusions Grains of Truth?

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Mesoarchean melt and fluid inclusions in garnet from the Kangerlussuaq basement, Southeast Greenland

The present work reports the first anatectic melt inclusions found so far in the Mesoarchean basement in East Greenland. Using optical microscope observations and MicroRaman spectroscopy, we show that garnets in metasedimentary migmatite contain primary polycrystalline aggregates which can be confidently interpreted as former droplets of anatectic melt, i.e. nanogranitoids. In some cases, they coexist with coeval fluid inclusions under conditions of primary fluid-melt immiscibility. The re-evaluation of the metamorphic pressure and temperature conditions with up-to-date phase equilibria modelling, combined with the identification of nanogranitoids and fluid inclusions, suggests metamorphic peak equilibration and partial melting in presence of a COH-fluid at T ~1000°C and P > 7 kbar. To date, this is the oldest verified occurrence of nanogranitoids and fluid-melt immiscibility during garnet growth in a partially molten environment

granitoid magmas preserved as melt inclusions in high grade metamorphic rock

This review presents a compositional database of primary anatectic granitoid magmas, entirely based on melt inclusions (MI) in high-grade metamorphic rocks. Although MI are well known to igneous petrologists and have been extensively studied in intrusive and extrusive rocks, MI in crustal rocks that have undergone anatexis (migmatites and granulites) are a novel subject of research. They are generally trapped along the heating path by peritectic phases produced by incongruent melting reactions. Primary MI in high-grade metamorphic rocks are small, commonly 5–10 μm in diameter, and their most common mineral host is peritectic garnet. In most cases inclusions have crystallized into a cryptocrystalline aggregate and contain a granitoid phase assemblage (nanogranitoid inclusions) with quartz, K-feldspar, plagioclase, and one or two mica depending on the particular circumstances. After their experimental remelting under high-confining pressure, nanogranitoid MI can be analyzed combining several techniques (EMP, LA-ICP-MS, NanoSIMS, Raman). The trapped melt is granitic and metaluminous to peraluminous, and sometimes granodioritic, tonalitic, and trondhjemitic in composition, in agreement with the different ![Formula][1] conditions of melting and protolith composition, and overlap the composition of experimental glasses produced at similar conditions. Being trapped along the up-temperature trajectory—as opposed to classic MI in igneous rocks formed during down-temperature magma crystallization—fundamental information provided by nanogranitoid MI is the pristine composition of the natural primary anatectic melt for the specific rock under investigation. So far ~600 nanogranitoid MI, coming from several occurrences from different geologic and geodynamic settings and ages, have been characterized. Although the compiled MI database should be expanded to other potential sources of crustal magmas, MI data collected so far can be already used as natural "starting-point" compositions to track the processes involved in formation and evolution of granitoid magmas. [1]: /embed/mml-math-1.gi

ASZTENOSZFÉRA-EREDETŰ FLUIDUMOK SPINELL LHERZOLITOKBAN: ESETTANULMÁNYOK ÉSZAKKELET- AUSZTRÁLIÁBÓL ÉS KAMERUNBÓL

A szubkontinentális litoszféraköpenyben az általában nagy H2O aktivitással jellemezhető, szubdukciós eredetű fluidumok (jelen munkában az illó-gazdag komponensekre fókuszálva) litoszferikus köpenyre kifejett metaszomatikus hatásáról széles irodalmi ismeret áll rendelkezésre (pl: Manning, 2004 és hivatkozásai). Ezzel szemben jelentősen kevesebb adat ismert annak a fluidumnak a jellemvonásáról, amelyik riftesedés során az asztenoszféra litoszferizációjával migrálnak a litoszféraköpenybe. E munkában két lelőhelyről (Kamerun Vulkáni Vonal és Mt. Quincan, ÉK-Ausztrália) származó, spinell lherzolitokban csapdázódott fluidumzárványok részletes vizsgálati eredményét mutatjuk be. A vizsgált fluidumzárványok a peridotitos kőzetekkel kölcsönható asztenoszferikus fluidumok mintáinak tekinthetőek. Vizsgálatukkal pontosabb kép alkotható a riftesedés során a litoszferikus köpeny metaszomatózisát eredményező fluidumokról

Demonstration of a partially integrated silicon photonics ONU in a self-coherent reflective FDMA PON

We report about the final results of the FABULOUS European project, demonstrating the feasibility of real-time Ethernet transmission on a self-coherent reflective passive optical network, using an optical network unit (ONU) whose main optical functions are performed by a silicon-photonics device; 500 Mbps per user with a power budget of 24 dB in offline processing and 21 dB in real time is shown. We also report details about the packaging process and the special technique developed for the flip-chipping of a CMOS electrical driver, used for driving the ONU with low voltage, onto a silicon Mach-Zehnder modulator

Historia reciente. Reflexiones epistemológicas y metodológicas para una historia crítica de la psicología en Argentina

Este taller busca abrir un espacio de reflexión sobre una modalidad de historiografía crítica denominada en nuestro idioma como historia reciente, historia actual o historia del tiempo presente; en inglés contemporary history y Zeitgeschichte en alemán. Esta se caracteriza por sus múltiples facetas y aristas que determinan problemas epistemológicos diversos y complejos. Nuestra presentación intenta discutir algunas de ellas y explicitar las posibles soluciones ofrecidas. Se propone discutir: 1) la permanencia de visiones unificadas del pasado como la presencia de pronunciados silencios, propios de una memoria que no termina de sanar; 2) el lugar del historiador de la disciplina en tanto sujeto situado en una encrucijada determinada por un quehacer profesional ajustado a reglas académicas, pero también atravesado por una historia colectiva y su propia subjetividad; 3) el concepto de extrema traumatización como efecto del terrorismo de estado en Argentina, y las dificultades que implica la transposición de un término desde una disciplina a otra, en este caso un término de la psicología trasladado a la disciplina histórica y al debate jurídico. Como ejercicio práctico, y a fin de lograr una revisión epistemológica y metodológica de cuestiones referidas a la subjetividad, la memoria y el testimonio, nos proponemos analizar estudios realizados sobre las mujeres entre 1960 y 1983. Esto adquiere particular significación dado que gran parte de las profesionales, docentes y alumnas de Psicología eran mujeres que se vieron impactadas por los cambios acontecidos en los años sesenta y setenta: nuevos posicionamientos en relación a la familia, la sexualidad, las tareas domésticas, la profesionalización, los procesos de politización e incorporación a diversas organizaciones, y luego del golpe militar, las situaciones de censura, encarcelamiento, tortura, desaparición forzada, exilio.Fil: Scherman, Patricia. Universidad Nacional de Córdoba. Facultad de Psicología. Cátedra "B", Escuelas, Corrientes y Sistemas de la Psicología Contemporánea; Argentina.Fil: Ferrero, Leandro. Universidad Nacional de Córdoba. Facultad de Psicología. Cátedra "B", Escuelas, Corrientes y Sistemas de la Psicología Contemporánea; Argentina.Fil: Fantini, Nilda. Universidad Nacional de Córdoba. Facultad de Psicología; Argentina.Fil: Guzmán, María Celeste. Universidad Nacional de Córdoba. Facultad de Psicología; Argentina.Fil: Ingui, Patricia. Universidad Nacional de Córdoba; Argentina.Fil: Ingui, Patricia. Universidad Nacional del Litoral; Argentina.Fil: Quiroga, Elena. Universidad Nacional de Córdoba. Facultad de Psicología. Cátedra "B", Escuelas, Corrientes y Sistemas de la Psicología Contemporánea; Argentina.Fil: Roggio, Patricia. Universidad Nacional de Córdoba. Facultad de Psicología; Argentina.Fil: Saal, Aarón. Universidad Nacional de Córdoba. Facultad de Psicología. Cátedra “A” Problemas Epistemológicos de la Psicología; Argentina.Fil: Vissani, Laura. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades; Argentina.Fil: Zúñiga, Silvio. Universidad Nacional de Córdoba. Facultad de Psicología. Cátedra "B", Escuelas, Corrientes y Sistemas de la Psicología Contemporánea; Argentina