Rb/Sr geochronology and geochemical characters of the Sithonia plutonic complex (Greece)
Christofides, Georgios; D'amico, Claudiο; Del Moro, Aldo; Eleftheriadis, Geοrgiοs; Kyriakopoulos, Cοstantinοs
published: Mar 8, 1990
manuscript accepted: Oct 18, 1989
manuscript received: Apr 24, 1989
ArtNo. ESP147050201006, Price: 29.00 €
Abstract The Sithonia plutonic complex occupies the greater part of the Sithonia Peninsula (Chalkidiki, Northern Greece). It comprises moderately peraluminous to metaluminous rocks ranging in composition from two-mica granites and leucogranites through biotite and hornblende bearing-granodiorites to granodioritic tonalites. Enclaves of quartz diorite composition are common. Aplitic and pegmatitic dykes are present, cutting both the pluton and the country rocks. The general geochemical characteristics suggest fractional crystallization during the genesis of the Sithonia pluton, which is complicated by some crustal contamination. The Sr isotopic data seem to point to a possible contamination with material rich in radiogenic Sr, thus increasing the initial Sr isotopic composition from 0.7055 to 0.7072 during differentiation. The studied rocks have features consistent with a subduction related origin. A seven-point, Rb/Sr whole-rock isochron yields an intrusion age of 50.4 ± 0.7 Ma and an initial 87Sr/86Sr ratio of 0.7072 ± 1. Muscovite ages range from 54.6 ± 1.8 to 44.6 ± 1.4 Ma, whereas biotites yield 47.7 ± 1.4 to 28.8 ± 0.9 Ma. The younger age values (the lowest are found in the leucogranites) are thought to be related to late-stage deformation.