Evaluación de escombreras de mármoles para su aprovechamiento como agregado en una estructura de pavimento, Córdoba, Argentina

In this contribution, 10,000 tonnes of marble waste dumps have been characterized in order to define the physico-mechanical and mineralogical parameters and determine their feasibility to be applied as main components in road bases and sub-bases. he Los Angeles abrasion values obtained (41-53%) exceeded those permitted for the standard technical specifications. However, particle-size distribution, plasticity and California Bearing Ratio (C.B.R.)(76, 83, 100% at 97, 98 and 100% of maximum density, respectively) satisfied, marginally, those specifications. Therefore, with a simple screening, these waste dumps would be applied as granular materials in roads. This is an alternative: a) environmentally sustainable, since future crushed stone exploitations would be reduced and removed a potential environmental passive; b) technically feasible, because the carrying capacity of the granular layers would not be affected; and c) economically profitable, because adds value to a currently non useful material and reduces the extraction and transportation costs.En este trabajo se caracterizaron 10.000 toneladas de escombreras de mármoles a fin de definir sus parámetros físico-mecánicos y mineralógicos y determinar su aptitud como componente principal en capas granulares de una estructura de pavimento. Aunque los coeficientes Los Ángeles (41-53%) exceden lo permitido en la especificación de referencia, la granulometría, plasticidad y California Bearing Ratio (C.B.R.) (76, 83, 100% al 97, 98 y 100% de la densidad máxima, respectivamente) satisfacen lo especificado, con condicionamientos. Por consiguiente, con un simple cribado, este material de escombrera podría ser utilizado en terraplenes, sub-bases y bases granulares de carreteras, constituyendo una alternativa: a) Ambientalmente sostenible: porque evita nuevas explotaciones y elimina un potencial pasivo ambiental; b) Técnicamente viable: ya que la capacidad portante de las capas granulares no se vería afectada; c) Económicamente conveniente: porque aporta un valor agregado a un sub-producto hoy desechado y reduce costos de explotación y transporte

Tourmaline orbicules in peraluminous monzogranites of Argentina: A study case of fluid-rock interaction between leucogranite and country-rock metasediments

Tourmaline orbicules hosted in peraluminous granites are documented worldwide. Seven occurrences were identified in Argentina. Petrography, mineral chemistry, whole-rock geochemistry mass balance and microthermometric studies were performed in orbicules formed at the cupola of a peraluminous A-type leucogranite (Los Riojanos pluton), as well as complementary investigation was achieved in other orbicules of similar geological setting. Mass balance computations in zoned orbicules consistently confirmed immobility of Si both in core and halo, immobility of K and little loss of Al during halo reactions. Elements gained and lost in the schorl-rich core are Fe, Al, Mg, Ti, Ba, Sr, Y and Zr, and Na, K, Rb and Nb, respectively; in the halo, K, Ba, Sr, Y, Zr and locally CaO, were gained, and Fe, Mg, Na, Al, Rb and Nb were lost. The schorl-rich core is enriched in LREE relative to the leucogranite host. A temperature-salinity plot from fluid inclusion data delineates a magmatic-meteoric mixing trend of diluting salinity with descending temperature. Computed δDH20 values from Los Riojanos orbicule schorl suggest magmatic and magmatic-meteoric mixed origins. In Los Riojanos, mass balance constraints suggest that Fe, Mg, Ba, Sr and metallic traces like Zn and V (±Pb) were most likely derived from country-rock schists and gneisses through fluid-rock exchange reactions. A late magmatic-, volatile-rich- fluid exsolution scenario for the formation of orbicules is envisaged. Schorl crystallization was likely delayed to the latest stages of leucogranite consolidation, not only favored by the high diffusivity of B2O3 preferentially partitioned into the exsolved aqueous-rich fluid, but also likely limited to the low availability of Fe and Mg from the scarce granitic biotite, and to the high F− content of the melt. The spatial confination of orbicules to the contact zone granite-metasediments suggests that orbicules were not formed until exsolved fluids reached the boundary with the biotite-rich country-rock.Fil: Lira, Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Museo de Geología y Miner."dr.a.stelzner"; ArgentinaFil: Poklepovic, María Fernanda de Los Ángeles. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Museo de Geología y Miner."dr.a.stelzner"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin