In the Balagne area, two main corse-grained deposits characterized by the presence of mafic rocks are recognized. The first one is represented by the Toccone breccia (Late Cenomanian) belonging to the succession of the Balagne ophiolitic nappe, whereas the second one, referred as Volparone breccia (post-Jurassic) occurs as slice at the base of the same nappe without relationships with others lithologies. Both breccias can be regarded as deposits located close to their source area, as suggested by their sedimentological/stratigraphical features. Even if not coeval, these breccias were probably belonging to the same basin, supplied by a source area consisting of a metamorphic basement intruded by granitoids and covered by carbonate deposits. The recognized lithologies suggest that its source area was represented by a domain belonging to the Corsica continental margin. Both the Toccone and Volparone breccias are both characterized by mafic rocks that can be classified as tholeiitic within-plate basalts. Moreover, it is noteworthy that the clasts of opholites are lacking at all. The mafic rocks preserved as clasts in the Toccone and Volparone breccias can be regarded as the witness of a magmatism, connected with the crustal thinning processes developed in the Triassic-Jurassic time span before the Ligure-Piemontese oceanic basin opening. This magmatism was originally located in an area of the Corsica continental margin, probably in the oceanward side, that represented the source area of the studied breccias.
Mafic rocks from the sedimentary breccias associated to the Balagne ophiolitic Nappe (northern Corsica):Geochemical features and geological implications
SACCANI, Emilio
2001
Abstract
In the Balagne area, two main corse-grained deposits characterized by the presence of mafic rocks are recognized. The first one is represented by the Toccone breccia (Late Cenomanian) belonging to the succession of the Balagne ophiolitic nappe, whereas the second one, referred as Volparone breccia (post-Jurassic) occurs as slice at the base of the same nappe without relationships with others lithologies. Both breccias can be regarded as deposits located close to their source area, as suggested by their sedimentological/stratigraphical features. Even if not coeval, these breccias were probably belonging to the same basin, supplied by a source area consisting of a metamorphic basement intruded by granitoids and covered by carbonate deposits. The recognized lithologies suggest that its source area was represented by a domain belonging to the Corsica continental margin. Both the Toccone and Volparone breccias are both characterized by mafic rocks that can be classified as tholeiitic within-plate basalts. Moreover, it is noteworthy that the clasts of opholites are lacking at all. The mafic rocks preserved as clasts in the Toccone and Volparone breccias can be regarded as the witness of a magmatism, connected with the crustal thinning processes developed in the Triassic-Jurassic time span before the Ligure-Piemontese oceanic basin opening. This magmatism was originally located in an area of the Corsica continental margin, probably in the oceanward side, that represented the source area of the studied breccias.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
