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3D gravity modelling of the Aguablanca Stock, tectonic control and emplacement of a Variscan gabbronorite bearing a Ni–Cu–PGE ore, SW Iberia

Romeo Briones, Ignacio and Tejero López, Rosa María and Capote del Villar, Ramón and Lunar, R. (2008) 3D gravity modelling of the Aguablanca Stock, tectonic control and emplacement of a Variscan gabbronorite bearing a Ni–Cu–PGE ore, SW Iberia. Geological magazine, 145 (3). pp. 345-359. ISSN 0016-7568

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Abstract

The Aguablanca stock is a Variscan mafic pluton located in the Ossa-Morena zone,
southern Iberian Massif, hosting an unusual Ni–Cu–PGE mineralization associated with magmatic
breccia pipes which intruded its northern part. The emplacement of the Aguablanca stock and the
mineralized breccia pipes are related to the activity of the Cherneca ductile shear zone, a Variscan
sinistral shear zone that favoured magma ascent through the upper crust. A detailed gravity study has
been carried out in order to investigate the 3D geometry of the Aguablanca intrusion and to get insights
about the emplacement mechanism and tectonic controls of the mineralization. The three-dimensional
gravity modelling shows that the stock has an inverted drop geometry with a feeder zone in contact
with the Cherneca ductile shear zone. The inferred orientation of the feeder zone suggests that the
emplacement probably took place along an open tensional crack formed within the strain field of the
adjacent Cherneca ductile shear zone. The modelling of the breccia pipes hosting the Ni–Cu–PGE ore
shows that they are included inside the feeder zone, thus their emplacement is probably controlled by
successive opening events of this tensional crack.


Item Type:Article
Uncontrolled Keywords:Three-dimensional models, Gravity, Plutons, Emplacement, Nickel ores, Variscan orogeny
Subjects:Sciences > Geology > Mineralogy
ID Code:12273
Deposited On:21 Feb 2011 13:27
Last Modified:21 Feb 2011 13:27

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