This work focuses on two fault-controlled deposits, the Atella and Rapolla travertines, which are associated with high-angle extensional faults of the Bradano Trough, southern Apennines (Italy). The Atella travertine is along a NW-SE striking, deep-seated extensional fault, already described in literature, which crosscuts both Apulian carbonates and the overlying foredeep basin in fill. The Rapolla travertine is on top of a NE-SW striking, shallow-seated fault, here described for the first time, which is interpreted as a tear fault associated with a shallow thrust displacing only the foredeep basin infill. The results of structural, sedimentological, mineralogical, and C and O isotope analyses are here reported and discussed to assess the provenance of mineralizing fluids, and to evaluate the control exerted by the aforementioned extensional faults on deep, mantle-derived and shallow, meteoric fluids. Sedimentological analysis is consistent with five lithofacies in the studied travertines, which likely formed in a typical lacustrine depositional environment. Mineralogical analysis show that travertines mainly consist of calcite, and minor quartz, feldspar and clay minerals, indicative of a terrigenous supply during travertine precipitation. The isotope signature of the two studied travertines shows different provenance for the mineralizing fluids. At the Atella site, the δ13C PDB values range between +5.2 and +5.7 ‰ and the δ18O PDB values between −9.0 and − 7.3 ‰ , which are consistent with a mantle-derived CO2component in the fluid. In contrast, at the Rapolla site the δ13C PDB values vary from −2.7 to +1.5 ‰ and the δ18O PDB values from −6.8 to − 5.4 ‰ , suggesting a mixed CO2 source with both biogenic-derived and mantle-derived fluids. The results of structural analyses conducted along the footwall damage zone of the fault exposed at the Rapolla site, show that the whole damage zone, in which fractures and joints likely channeled the mixed fluids, acted as a distributed conduit for both fault-parallel and cross-fault fluid migration

Contrasting fault fluids along high-angle faults: a case study from Southern Apennines (Italy)

SINISI, ROSA;AGOSTA, FABRIZIO;PATERNOSTER, Michele;
2016

Abstract

This work focuses on two fault-controlled deposits, the Atella and Rapolla travertines, which are associated with high-angle extensional faults of the Bradano Trough, southern Apennines (Italy). The Atella travertine is along a NW-SE striking, deep-seated extensional fault, already described in literature, which crosscuts both Apulian carbonates and the overlying foredeep basin in fill. The Rapolla travertine is on top of a NE-SW striking, shallow-seated fault, here described for the first time, which is interpreted as a tear fault associated with a shallow thrust displacing only the foredeep basin infill. The results of structural, sedimentological, mineralogical, and C and O isotope analyses are here reported and discussed to assess the provenance of mineralizing fluids, and to evaluate the control exerted by the aforementioned extensional faults on deep, mantle-derived and shallow, meteoric fluids. Sedimentological analysis is consistent with five lithofacies in the studied travertines, which likely formed in a typical lacustrine depositional environment. Mineralogical analysis show that travertines mainly consist of calcite, and minor quartz, feldspar and clay minerals, indicative of a terrigenous supply during travertine precipitation. The isotope signature of the two studied travertines shows different provenance for the mineralizing fluids. At the Atella site, the δ13C PDB values range between +5.2 and +5.7 ‰ and the δ18O PDB values between −9.0 and − 7.3 ‰ , which are consistent with a mantle-derived CO2component in the fluid. In contrast, at the Rapolla site the δ13C PDB values vary from −2.7 to +1.5 ‰ and the δ18O PDB values from −6.8 to − 5.4 ‰ , suggesting a mixed CO2 source with both biogenic-derived and mantle-derived fluids. The results of structural analyses conducted along the footwall damage zone of the fault exposed at the Rapolla site, show that the whole damage zone, in which fractures and joints likely channeled the mixed fluids, acted as a distributed conduit for both fault-parallel and cross-fault fluid migration
File in questo prodotto:
File Dimensione Formato  
2016 Sinisi et al. TECTO.pdf

solo utenti autorizzati

Tipologia: Pdf editoriale
Licenza: DRM non definito
Dimensione 3.53 MB
Formato Adobe PDF
3.53 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11563/123800
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 18
  • ???jsp.display-item.citation.isi??? 15
social impact