El plutón de Linares (Jaén)cartografía, petrología y geoquímica

Resumen

Magma emplacement within the Linares granite, a part of the Los Pedroches Batholith, took place in the sequence: biotite granodiorite with microgranular enclaves, biotite monzogranites, and dike swarm complex. Dikes are: WNW-ESE rhyolite to rhyodacite, aplopegmatite and abundant NE-SW ore-bearing quartz. The Linares intrusion and psamo-pelitic Carboniferous host metasediments (Los Pedroches Culm) are, in part, discordantly covered by Mesozoic (Trias) and Tertiary to Quaternary terrigenous deposits. Bulk rock chemistry of granodiorite shows minor variations in SiO2 (64.75 - 67 wt %) and REE contents (ΣREE = 158 -160 ppm), and nearly constant A/CNK (ISA) ratio (1.1 - 1.15). Monzogranites have higher SiO2 (66.87 - 68.4 wt %), alkali and REE contents (ΣREE = 168 - 193 ppm), with A/CNK (ISA) ratio of 1.06 - 1.09. Both granodiorite and monzogranites are peraluminous rocks that may correspond to an aluminous association or to evolved terms of an aluminocafemic association (Debon & Lefort, 1983). Variation diagrams for major and trace elements, including REE, of granodiorite and monzogranites are compatible with magmatic differentiation processes by fractional crystallization starting from a primary granodioritic magma.