Petrology of the Miocene igneous rocks of Lavrion area (SE Attica, Greece)

摘要: A detachment fault juxtaposes blueschist facies rocks (Upper Unit) above lower Mesozoic mylnitized marbles and schists (Basal Unit) at Lavrion area. The original contact between the two units was a thrust plane. The Miocene igneous rocks of the area form part of the granitoid province of the central Aegean. Undeformed, subvertical dykes of porphyritic and poikilitic rocks, ranging from quartz-syenites through quartz-monzonites to granodiorites, and a variably altered granodiorite intrude only the “Basal Unit”. The dykes strike WNW-ESE to WSW-ENE. A 9.4±0.3 Ma K-Ar age on feldspar for a porphyritic dyke rock provides a minimum age for the igneous activity in Lavrion. Intrusion of the granodiorite was accompanied by contact metamorphism of metaclastic rocks of the Basal Unit, followed by skarn formation. East-west orientation of the porphyritic dykes and the quartz veins cutting the hydrothermally altered portion …