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Paper No. 4
Presentation Time: 8:45 AM


GUMIEL, Pablo1, ARIAS, Mónica2, MARTÍN-IZARD, Agustín3, PALERO, Fernando4, BELLIDO, Félix5, SÁNCHEZ, Teresa6, ORDOÑEZ, Berta3 and LOCUTURA, Juan5, (1)Recursos Minerales, Instituto Geológico y Minero de España (IGME), Departamento de Geología, Universidad de Alcalá, Rios Rosas, 23, Madrid, 28003, Spain, (2)Departamento de Geología, Universidad de Alcalá, Facultad de Ciencias, Alcalá de Henares, 28871, Spain, (3)Departamento de Geología, Universidad de Oviedo, C/ Arias de Velasco s/n, Oviedo, 33005, Spain, (4)Departamento de Geología e Ingeniería de Minas, Universidad de Castilla- La Mancha, Almadén, 13400, Spain, (5)Recursos Minerales, Instituto Geológico y Minero de España (IGME), Rios Rosas, 23, Madrid, 28003, Spain, (6)Geología, Instituto Geológico y Minero de España (IGME), Rios Rosas, 23, Madrid, 28003, Spain,

This contribution shows the importance of the mineral deposits at the southern border of the Ossa Morena Zone. The mineralizing process is complex as is characteristic of transpressive belts, and this metallogenic complexity is responsible for the overlap in time of different mineralizing stages leading to a varied type of mineral deposits:
  • Stratiform and stratabound-type magnetite beds (IOCG) and VHMS hosted in Upper Precambrian-Lower Cambrian rocks strongly deformed by the Variscan Orogeny.
  • Sin-orogenic shear-zone related Cu disseminations in Upper Precambrian-Lower Cambrian volcaniclastic rocks.
  • Banded magnetite skarns and stratabound-type hydrothermal iron beds hosted in Lower Cambrian limestones with Alpine reactivations of karstic origin.
  • Medium-low temperature (Pb-Zn-Ag-Cu-Ba) hydrothermal veins filling extensional Variscan and late-Variscan faults.
  • Low temperature fluorite-barite mineralizations related to Alpine reactivations of post-Variscan extensional faults.

The geological characteristics of these mineral deposits and their mineralogical associations (paragenesis) have been established. Geological and geophysical data (gravity, magnetic and radiometric surveys) and spatial statistics (autocorrelation Fry method, nearest neigbhor distances to fractures and host-lithologies) have all been analyzed in a GIS.

The data obtained strongly support the geological and structural controls of the mineralizations. The distribution of fracture networks reveals trends due to processes that operated at district and prospect scales (dilation zones, off-sets, releasing-bends and pull-aparts between certain groups of NW-SE and ENE-WSW fractures) along with high fracture density zones promote fluid flow, connectivity and mineral concentration in localized areas.

The distribution of 800 mineral deposits and prospects shows a considerable degree of clustering, and has been simulated using fractal and multifractal models of the ore concentration constrained by known geological controls. The final target is to elaborate robust geological models at different scales in order to establish exploration guides in this segment of the Ossa Morena Zone.

Project CGL2008-03046/BTE funded by the Science and Innovation Ministry of Spain (MICINN)

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