at intersecting grabens

Travertine geobodies have been identified as potential reservoir analogues to carbonate build-ups in pre-salt hydrocarbon systems. To investigate travertine geobody deformation, faults were mapped in 35 travertine quarries that excavate the Ballik travertine, i.e. a c. 12.5 km(2) large travertine geobody that precipitated at the intersection of the NE margin of the Denizli Basin and neighbouring Baklan Graben (SW Turkey). This travertine precipitated from cooling carbonate-saturated thermal spring waters that resurfaced along the margin fracture/fault network and through Neogene unconsolidated underlying sediments. From the Denizli basin floor to the uplifted graben shoulders, fault orientation is dominantly WNW-ESE oriented with major basin faults showing a left-stepping trend. Along the upper Denizli margin, travertine is only deformed by extensional normal faults. Along the lower margin, travertine starts with a subhorizontal facies but evolves to a travertine facies formed by a sloping topography with a domal architecture. Paleostress inversion of fault-slip data reveals that an Early Pleistocene NNE-SSW extensional-transtensional phase initiated the WNW-ESE oriented, graben-facing normal fault network. In the Middle Pleistocene, the Ballik fault network was left-lateral strike-slip reactivated because it acted as a transfer zone between the NW-SE extending neighbouring Baklan Basin and NW-SE extension along NE-SW oriented margin faults of the DGHS. In this stress configuration, travertine precipitated along the SW margin fault of the Baklan Graben. After strike-slip reactivation, a Late Pleistocene-to-current NNE-SSW extensional stress regime reinstalled during which margin faults widened and active travertine precipitation moved to more central parts of the DGHS. As different tectonic regimes affect graben intersections, reservoir analogues can have a complex deformation history driven by fault reactivation and recurrent stress permutations. This study concludes that large travertine geobodies can form at graben intersections because of their susceptibility to enhanced fluid flow through the complex fault-fracture network.C1 [Van Noten, Koen] Royal Observ Belgium, Seismol Gravimetry, Ringlaan 3, B-1180 Brussels, Belgium.[Van Noten, Koen] Royal Belgian Inst Nat Sci, Geol Survey Belgium, Jennerstr 13, B-1000 Brussels, Belgium.[Topal, Savas; Baykara, M. Oruc; Ozkul, Mehmet; Aratman, Cihan] Pamukkale Univ, Dept Geol Engn, Kinikli Campus, TR-20070 Denizli, Turkey.[Claes, Hannes; Aratman, Cihan; Swennen, Rudy] Katholieke Univ Leuven, Dept Earth & Environm Sci, Geodynam & Geofluids Res Grp, Celestijnenlaan 200E, B-3001 Leuven, Belgium.[Claes, Hannes] Rhein Westfal TH Aachen, Clay & Interface Mineral Energy & Mineral Resourc, Bunsenstr 8, D-52072 Aachen, Germany