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Reliable dating is essential in order to put palaeoclimatological, palaeoenvironmental and archeological information from continental carbonates in the correct time frame. This study evaluates U/Th dating of travertines based on two case studies, i.e., in the Ballik (Denizli, SW Turkey) and Sutto (N Hungary) areas. Previous petrographic, mineralogical and elemental characterization of the travertines enabled sampling of, purely calcitic, micrite or spar dominant, zones that are non-, or solely weak, cathodoluminescent. Despite adapted sampling and detrital thorium corrections, U/Th ages of the Ballik and the Sato travertines are inconsistent with their stratigraphic position. Based on the observation of wavy extinction affecting micritic fabrics and ghost structures, the studied travertines behaved as an open system for uranium after deposition through recrystallisation. Their U/Th ages, consequently, can only be considered as minimum ages. The Ballik travertines precipitated earlier than 0.55-1.31 Ma ago, when late-stage cementation along fractures and in cavities took place, and form the oldest travertines deposited in the Denizli basin. The formation of the Sato travertine area started at the earliest around 2.5 Ma with precipitation of the Cukor travertine. With some short interruptions, active travertine formation in the area took place maximally until 120 ka. The decreasing ages of the Sutto travertines towards the Danube, prove the complex nature of travertines both during deposition as well as during diagenesis, which leads to anomalies with regard to the law of superposition. The diagenetic susceptibility of continental carbonate deposits poses problems in terms of accurate and precise dating. U/Th dating of the intrinsically heterogeneous fabrics of travertines and tufa, as presently applied, should be ceased. Travertines and tufa up to similar to 100 ka might be the exception due to the limited extent of recrystallisation. Sparite cements and veins can be dated more accurately but, even with multiple samples from the same study site and inclusion of coeval samples, give only minimum ages for the whole deposits. To better constrain the time frame of the whole bodies, results from independent dating methods and from the surrounding deposits are necessary. In addition, it is important to keep in mind that the open-system behavior of continental carbonates has implications for diagenetic, palaeoenvironmental and palaeoclimatological studies based on geochemical proxies. C1 [Claes, Hannes; Torok, Agnes; Soete, Jeroen; Mohammadi, Zahra; Vassilieva, Elvira; Hamaekers, Helen; Marques Erthal, Marcelle; Aratman, Cihan; Swennen, Rudy] Katholieke Univ Leuven, Dept Earth & Environm Sci, Geodynam & Geofluids Res Grp, BE-3001 Heverlee, Belgium. [Claes, Hannes] Rhein Westfal TH Aachen, Clay & Interface Mineral CIM, Bunsenstr 8, DE-52072 Aachen, Germany. [Torok, Agnes; Mindszenty, Andrea] Eotvos Lorand Univ, Inst Geog & Earth Sci, Dept Phys & Appl Geol, Pazmany P Setany 1-c, HU-1117 Budapest, Hungary. [Soete, Jeroen] Katholieke Univ Leuven, Dept Mat Engn, Nondestruct Testing Res Grp, BE-3001 Heverlee, Belgium. [Hamaekers, Helen] SCR Sibelco Nv, Dept Geol, De Zate 1, BE-2480 Dessel, Belgium. [Marques Erthal, Marcelle] Petrobras Res Ctr, Av Horacio de Macedo Cidade Univ 950, BR-21941915 Rio De Janeiro, RJ, Brazil. [Aratman, Cihan; Ozkul, Mehmet] Pamukkale Univ, Dept Geol Engn, Kinikli Campus, TR-20070 Denizli, Turkey. [Cheng, Hai; Edwards, R. Lawrence] Univ Minnesota, Dept Earth Sci, Minneapolis, MN 55455 USA. [Cheng, Hai] Xi An Jiao Tong Univ, Inst Global Environm Change, Xian 710049, Peoples R China. [Shen, Chuan-Chou] Natl Taiwan Univ, Dept Geosci, High Precis Mass Spectrometry & Environm Change L, Taipei 10617, Taiwan. [Shen, Chuan-Chou] Natl Taiwan Univ, Res Ctr Future Earth, Taipei 10617, Taiwan. [Shen, Chuan-Chou] Natl Taiwan Univ, Global Change Res Ctr, Taipei 10617, Taiwan. [Kele, Sandor] Hungarian Acad Sci, Inst Geol & Geochem Res, Res Ctr Astron & Earth Sci, Budaorsi Ut 45, HU-1112 Budapest, Hungary.

Elemental data from travertines are a treasure of depositional and diagenetic information. However, correct interpretation requires proper data acquisition and treatment. This study shows how results from elemental analyses complement sedimentological and other geochemical, i.e. isotopic, data and thereby contribute to our understanding of fossil travertines. Multivariate statistical element analyses, after multiple travertine digestion methods, demonstrate the link between elements, their mineralogical phases, and ultimately their origin. This study reveals that carbonate-phase related elements in travertines (Sr, S, Ba, Mg and Na) originate dominantly from the fluid source rocks. In combination with the δ18O and δ13C signatures, they are thus key geochemical variables for comparison of different travertine geobodies. Geochemical data analysis (elemental concentrations and isotope signatures), as illustrated here for the Turkish Ballık travertines, supports interpretation with regard to fluid source rock, distance from the vent and relative intensity of processes like evaporation and degassing. For fossil travertines, geochemical data can thus provide crucial insights for understanding the hydrologic system. In particular when information is restricted to borehole data, like in subsurface reservoirs, their application could be decisive. © 2019 Elsevier B.V.

Petrographical and petrophysical properties of the Turkish Ballik-Belevi travertine shrubs demonstrate the necessity of reservoir oriented classifications for shrub-related lithotypes and associated pore types. The presented shrub-related lithotype classification incorporates morphology, size and fabric, which are linked to specific pore-types and sizes. The travertines show highly complex pore networks, as observed from Computed Tomography reconstructions, making them of interest for the development and optimization of pore characterization methodologies and techniques, following an upscaling approach. Porosity (3-15%) and permeability (0-505 mD) strongly vary for the Ballik-Belevi travertines. The highest porosities and permeabilities are measured for horizontal samples dominated by slightly dissolution enlarged intershrub and interdigit growth framework porosity, mostly found for dendritic shrubs. The presented shrub and pore-type classification can be applied to shrubs worldwide. Studying outcrop analogues of continental carbonates helps to better understand heterogeneities, lateral variability and properties of Pre-Salt Cretaceous continental carbonate reservoirs, offshore Brazil and Angola. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.

Carbonate spring deposits gained renewed interest as potential contributors to subsurface reservoirs and as continental archives of environmental changes. In contrast to their fabrics, petrophysical characteristics – and especially the importance of microporosity (< 1µm) – are less understood. This study presents the combination of advanced petrophysical and imaging techniques to investigate the pore network characteristics of three, common and widespread spring carbonate facies, as exposed in the Pleistocene Cakmak quarry (Denizli, Turkey): the extended Pond, the dipping crystalline Proximal Slope Facies and the draping Apron and Channel Facies deposits formed by encrustation of biological substrate. Integrating mercury injection capillary pressure, bulk and diffusion Nuclear Magnetic Resonance (NMR), NMR profiling and Brunauer–Emmett–Teller (BET) measurements with microscopy and micro-computer tomography (µ-CT), shows that NMR T 2 distributions systematically display a single group of micro-sized pore bodies, making up between 6 and 33% of the pore space (average NMR T 2 cut-off value: 62 ms). Micropore bodies are systematically located within cloudy crystal cores of granular and dendritic crystal textures in all facies. The investigated properties therefore do not reveal differences in micropore size or shape with respect to more or less biology-associated facies. The pore network of the travertine facies is distinctive in terms of (i) the percentage of microporosity, (ii) the connectivity of micropores with meso- to macropores, and (ii) the degree of heterogeneity at micro- and macroscale. Results show that an approach involving different NMR experiments provided the most complete view on the 3-D pore network especially when microporosity and connectivity are of interest. © 2016. American Geophysical Union. All Rights Reserved.

Sonic velocities of Pleistocene travertines were measured under variable confining pressures. Combined with petrographical characteristics and petrophysical data, i.e. porosity, permeability and density, it was determined that travertine porosity, pore types and cementation control compressional-wave (V-p) and shear-wave velocity (V-s). At 40 MPa confining pressures, V-p ranges between 3695 and 6097 m/s and V-s between 2037 and 3140 m/s. Velocity variations in travertines are, as with all carbonates, primarily linked to sample heterogeneity, i.e. differences in fabric, texture and porosity. They thus not necessarily emanate from changes in mineralogy or composition. Body wave velocities have a positive correlation with sample density and an inverse correlation with porosity. The travertines, sampled in extensional settings with normal faulting activity, define a specific compressional-wave velocity (y-axis) versus porosity (x-axis) equation, i.e. (log(y) = -0.0048x + 3.7844) that differs from the V-p-porosity paths defined by marine carbonates. Acoustic wave velocities are higher for travertines than for marine carbonates. Travertine precipitates form rigid rock frames, often called framestone, with large primary pores. Marine carbonates on the other hand often consist of (cemented) transported sediments, resulting in a rock frame that permits slower wave propagation when compared to the continental limestones. Acoustic velocity variations are linked to variations in pore types. Mouldic pores (macropores) show faster wave propagation than expected from their total porosities. Microporosity, interlaminar and interpeloidal porosity result in slower acoustic velocities. Framework pores and micro-moulds are associated with lowered acoustic velocities, while vug porosity is found above, on and below the general velocity-porosity trend. Not only the pore type, but also pore shapes exert control on body wave velocities. Cuboid-and rod-like pore shapes increase the velocity, while plate-and blade-like pore shapes have a negative effect on the velocity. The study demonstrates how seismic sections in travertine systems can contain seismic reflections that are not caused by non-carbonate intercalations, but relate to geobody boundaries, in which the seismic expression is function of porosity, pore types and shapes. This study provides and relates petrophysical data, i.e. porosity, permeability and acoustic velocities of travertines and is of importance for the interpretation of seismic reflection data in subsurface continental carbonate reservoirs. (C) 2014 Elsevier Ltd. All rights reserved.

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 Ballk 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 Ballk travertine architecture that potentially can be used as an analogue for subsurface travertine reservoirs worldwide and illustrates the importance of the combined use of C-13 and Sr-87/Sr-86 signatures in the delineation of the CO2-origin of travertine precipitating waters.

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. © 2015 The Authors. Sedimentology and 2015 International Association of Sedimentologists.

The Denizli Basin is a fault-bounded Neogene-Quaternary depression located in the Western Anatolian Extensional Province, Western Turkey. The basin is a unique geological site with abundant active and fossil (Quaternary) travertine and tufa deposits. Fluid inclusion microthermometry and isotopic analysis were applied to study the genesis of the Ballk fossil travertine deposits, located in the south-eastern part of the basin. Microthermometry on fluid inclusions indicates that the main travertine precipitating and cementing fluids are characterized by low salinity (