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The Denizli Basin in the West Anatolian Extensional Province in western Turkey is well-known for its numerous travertine occurrences. A combined sedimentological, diagenetic and geochemical investigation is executed on the Ece and Faber travertines of the Ballık area, the largest travertine site in the Denizli Basin. The first aim of this study is the reconstruction of a three-dimensional geo-model in combination with a detailed sedimentological description from fabric to lithotype, lithofacies and geobody scale, with a focus on integrating pore-typing. The second aim involves the delineation of the CO2-origin of ancient travertine precipitating waters. Peloidal, phyto and dendritic lithotypes dominate the studied travertines and honeycomb and bacteriform shapes and encrusted bacterial or fungal filaments related to their fabrics suggest a microbial influence. The environment of travertine precipitation evolved from dominantly sub-aqueous, as represented by the sub-horizontal and biostromal reed travertine facies, to dominantly sub-aerial in a thin water film, resulting in the cascade, waterfall and biohermal reed travertine facies. A general progradation of the travertine mound is indicated by the occurrence of stacked waterfall travertines. This results in sigmoidal clinoforms inside a general mound boundary configuration. Strontium and oxygen-carbon isotope signatures of the travertines point to a mixing mechanism of palaeofluids with deeply originated, heavy carbon CO2 with lighter carbon CO2 of shallow origin. These deposits can thus be considered as endogenic travertines. Carbonates of the Lycian Nappes acted as main parent carbon source rocks. The relative contribution of the lighter carbon isotopes is most likely to have originated from organic matter or soil CO2. This study provides a unique three-dimensional insight into the Ballık travertine architecture that potentially can be used as an analogue for subsurface travertine reservoirs worldwide and illustrates the importance of the combined use of δ13C and 87Sr/86Sr signatures in the delineation of the CO2-origin of travertine precipitating waters. [ABSTRACT FROM AUTHOR]

Subsurface Pre-salt Lower Cretaceous reservoir systems encountered offshore Brazil and Angola that consist of porous continental carbonates are difficult to access because of the limited core material that is under concession. Therefore, it is important to study comparable continental carbonate analogues, such as travertines and lacustrine carbonates, that potentially possess similar porosity and permeability characteristics. The Budakalász Pleistocene travertines (Buda Hills, Hungary) have been studied from a sedimentological, geochemical and reservoir properties point of view in order to understand their formation, petrophysical properties and 3D reservoir architecture. The three-dimensional geobody architecture of the Budakalász travertines illustrates the potential complexity of kilometre scale continental carbonate systems. Heterogeneous low angle sloping travertine lobes consisting of terrace slope, smooth slope and reed facies, are covered by a lime mudstone dominated, gastropod- and charophyte-rich marsh-pool facies. The observed facies represent a change from a subaerial travertine to a palustrine to lacustrine system, reflecting the ceasing of the system due to tectonic uplift. The dominant paleo-flow direction of the sloping lobes was towards the Danube depression, with several subordinate flow systems identified. The Sr C O isotope geochemical signatures reflect travertine precipitation at ambient to superambient temperatures from meteoric derived fluids with a mixed CO 2 origin of the marine carbonate substrate rocks, a potential atmospheric and a soil-derived component. Although the uniform signatures of the stable oxygen and carbon isotopes, in addition to petrographic observations suggest partial diagenetic isotopic resetting, the primary isotope trends seem to have been preserved. A reservoir-oriented facies evaluation in the three-dimensional geobody frame of the Budakalász carbonates based on porosity and permeability core plug analyses reveals their heterogeneous nature. Terrace, smooth slope and marsh-pool facies have considerable porosities of 5–15%, while the porosity of the reed facies may reach up to 27%. Permeability of all facies is strongly anisotropic, mainly controlled by a better connectivity along layer-parallel primary pores. The reconstruction of the 3D geobody architecture of the Budakalász lobe complex coupled to its geochemical and petrophysical properties provides a unique dataset that contributes in understanding fossil travertine systems. [ABSTRACT FROM AUTHOR]