The Plutonic Complex of Táliga-Barcarrota crops out in the core of the Olivenza-Monesterio
anticline, where it intrudes the Upper Precambrian and Lower Cambrian
metasediments. As this Complex is made of a) the Circular Pluton of Barcarrota, where
the core is constituted by gabbros, diorites and pegmatoides and the outer rim shows
quartz monzonites, quartz syenites and hypersolvus granites, and b) the NW-SE elongated
Táliga Massif, almost entirely made of biotite orthogneisses, the sampling and the analyses
were done in accordance with this double character of the Complex. Taking into account
the K/Ar ages obtained on amphiboles, biotites and muscovites and the two Rb/Sr
"isochrones" (whole rocks), it is concluded that 1) the Táliga Massif has an intrusion age
of 525±2.5 M.A and a subsecuent pervasive recrystallization during the first hercynian
phase, 385 ± 11 M.A, and 2) the Barcorrota Complex has an intrusion age of 505±5 M.A,
as it is shown by the K/Ar and the Rb/Sr systematics. Also the Barcarrota Plutonic rocks
have lower initial Sr87/Sr86 (O,7031±5X1O-6 than the Táliga orthogneisses (0.70836±9Xl0-5)
pointing to a mantle versus. Crostal origin for both groups of magmas