Geochemistry of fluid inclusions in travertines from Western and Northern Turkey: inferences on the role of active faults in fluids circulation

The understanding of the relationship between the geochemistry of fluids circulating during travertine deposition and the presence of active faults is crucial for evaluating the seismogenetic potential of an area. Here we investigate travertines from Pamukkale and Reşadiye (Turkey), sited in seismic regions and next to thermal springs. These travertines formed ~24,500–50,000 (Pamukkale) and ~240–14,600 years (Reşadiye) BP. We characterize fluid inclusions (FIs) and studied concentration of H2O, CO2, O2 + N2, and 3He, 4He, 20Ne, and 40Ar, and bulk composition (trace elements and δ13C‐δ18O). FIs from both localities are mainly primary with low salinity and homogenization temperature around 136–140 °C. H2O is the major component followed by CO2, with the highest gas content measured in Pamukkale travertines. Concentrations of Ne‐Ar together with O2 + N2 indicate that travertines from both areas precipitated from atmosphere‐derived fluids. The 3He/4He is 0.5–1.3 Ra in Pamukkale and 0.9–4.4 Ra in Reşadiye. Samples with R/Ra > 1 are modified by cosmogenic 3He addition during exposure to cosmic rays. Excluding these data, FIs of Reşadiye are mostly atmosphere‐derived. This implies a shallow formation where the circulation was dominated by meteoric waters, which is consistent with their young age. Instead, FIs of Pamukkale show mixing of mantle‐, crustal‐, and atmosphere‐derived He, indicating that these travertines formed in lithospheric fractures. Based on the δ13CCO2 and δ18O of bulk rocks, we infer that travertines formed involving crustal‐ (mechanochemical rather than organic) and mantle‐derived CO2. Trace elements of Pamukkale and Reşadiye show comparable rare earth element patterns. We conclude that travertines formed in response of seismogenetic activity.Published5473-54982T. Deformazione crostale attiva7T. Variazioni delle caratteristiche crostali e precursori sismici6A. Geochimica per l'ambiente e geologia medicaJCR Journa

20,000 years of societal vulnerability and adaptation to climate change in southwest Asia.

The Fertile Crescent, its hilly flanks and surrounding drylands has been a critical region for studying how climate has influenced societal change, and this review focuses on the region over the last 20,000 years. The complex social, economic, and environmental landscapes in the region today are not new phenomena and understanding their interactions requires a nuanced, multidisciplinary understanding of the past. This review builds on a history of collaboration between the social and natural palaeoscience disciplines. We provide a multidisciplinary, multiscalar perspective on the relevance of past climate, environmental, and archaeological research in assessing present day vulnerabilities and risks for the populations of southwest Asia. We discuss the complexity of palaeoclimatic data interpretation, particularly in relation to hydrology, and provide an overview of key time periods of palaeoclimatic interest. We discuss the critical role that vegetation plays in the human-climate-environment nexus and discuss the implications of the available palaeoclimate and archaeological data, and their interpretation, for palaeonarratives of the region, both climatically and socially. We also provide an overview of how modelling can improve our understanding of past climate impacts and associated change in risk to societies. We conclude by looking to future work, and identify themes of "scale" and "seasonality" as still requiring further focus. We suggest that by appreciating a given locale's place in the regional hydroscape, be it an archaeological site or palaeoenvironmental archive, more robust links to climate can be made where appropriate and interpretations drawn will demand the resolution of factors acting across multiple scales. This article is categorized under:Human Water > Water as Imagined and RepresentedScience of Water > Water and Environmental ChangeWater and Life > Nature of Freshwater Ecosystems

Age and Geochemical Constraints on Formation of Fault-related Late Quaternary Carbonate Veins from Southern Turkey

Combined U-series dating and high-resolution geochemical analyses of co-seismic carbonate veins offer an invaluable opportunity to document young (<1 Ma) earthquake activity and for tracing origins of associated fluids. In this study, we analysed a total of 23 samples of fault-related carbonate veins and slickenfibered calcites collected from two separate SW– S-trending fault zones developed near Anamur and Gazipaşa areas in Southern Turkey. Microtexturally the carbonate veins mainly comprise medium- to coarse-grained, columnar calcite crystals elongated along growth direction. U-series dating indicated episodic fault-related carbonate mineralization between 132 ± 2 and 5.6 ± 0.4 ka and between 530 ± 63 and 30.0 ± 2.1 ka in Anamur and Gazipaşa areas, respectively. Carbon and oxygen isotope compositions of carbonates from both Anamur (δ13C = -12 to -6‰, δ18O = -7 to -4‰; relative to V-PDB) and Gazipaşa (δ13C = -12 to -7‰, δ18O = -7 to -3‰) areas are almost identical, whereas Anamur samples (0.7074–0.7080) have slightly lower 87Sr/86Sr ratios compared to Gazipaşa samples (0.7081–0.7096). The 87Sr/86Sr values correlate well with that of modern and Cenozoic seawater (~0.709) and Permian limestone host rocks (~0.707). PAAS-normalized rare earth element-Yttrium patterns of most samples are characterized by negative Ce and positive Y anomalies, confirming a predominantly seawater source for calcite precipitating fluids. Our acquired age and geochemical data not only has revealed young (<500 ka) seismic activity for these previously undocumented fault systems, but it also has implications for upper crustal fluid flow and palaeoclimatological conditions in the region

Genetic investigation and comparison of Kartaldag and Madendag epithermal gold deposits in Canakkale, NW Turkey

Two epithermal gold deposits (Kartaldag and Madendag) located in NW Turkey have been characterized through the detailed examinations involving geologic, mineralogical, fluid inclusion, stable isotope, whole-rock geochemistry, and geochronology data.The Kartaldag deposit (0.01-17.65 ppm Au), hosted by Eocene dacite porphyry, is associated with four main alteration types with characteristic assemblage of: i) chlorite/smectite-illite +/- kaolinite, ii) quartz-kaolinite, iii) quartz-alunite-pyrophyllite, iv) quartz-pyrite, the last being characterized by three distinct quartz generations comprising massive/vuggy (early), fine-medium grained, vug-lining (early), and banded, colloform, comb (late) textures. Observed sulfide minerals are pyrite, covellite, and sphalerite. Oxygen and sulfur isotope analyses, performed on quartz (delta O-18((quartz)): 7.93 to 8.95 parts per thousand and calculated delta O-18((H2O)): -7.95 to 1.4 parts per thousand) and pyrite (delta S-34((pyrite)): -4.8 parts per thousand and calculated delta S-34((H2S)): -6.08 to -7.20 parts per thousand) separates, suggest a meteoric water source for water in the hydrothermal fluid, and an igneous source for the sulfur dissolved in ore-related fluids. Microthermometric analyses of primary fluid inclusion assemblages performed on quartz (late quartz generation) yield temperatures (Th) dominantly in the range of 245-285 degrees C and generally low salinity values at 0 to 1.7 wt.% NaCl eq. Based on the quartz textures and the associated base metal concentrations, along with fluid inclusion petrography, the early vug-lining quartz is considered to have been associated with the mineralization possibly through a boiling and a late mixing process at >285 degrees C.The Madendag deposit (027-20.60 ppm Au), hosted by Paleozoic mica schists, is associated with two main alteration types: sericite-illite-kaolinite, and quartz-pyrite dominated by two distinct quartz generations i) early colloform, comb and banded quartz and ii) late quartz, forming the cement in hydrothermal breccia. Whereas oxygen isotope analyses of quartz (delta O-18((quartz)): 9.55 to 18.19 parts per thousand and calculated delta O-18((H2O)): -2.97 to 5.54 parts per thousand) suggest varying proportions of meteoric and magmatic sources for the ore bearing fluid, sulfur isotope ratios (delta S-34((pyrite)): -2.2 parts per thousand and calculated delta S-34((H2S)): (-3.63) to (-3.75) parts per thousand) point to an essentially magmatic source for sulfur with or without contribution from sedimentary sources. Microthermometric analysis carried out on primary fluid inclusion populations of a brecciated sample (early quartz), give a temperature (Th) range of 235-255 degrees C and 0.0 to 0.7 wt% NaCl eq. salinity. Based on the textural relationship, base metal and high gold contents, the ore precipitation stage is associated with late stage quartz formation via a possible boiling process.The presence of alunite, pyrophyllite and kaolinite, vuggy quartz and covellite suggest a high-sulfidation type of epithermal deposit for Kartaldag. On the other hand, Madendag is identified as an adularia-sericite type owing to the presence of significant sericite, neutral pH clays (mostly illite, chlorite/smectite, and kaolinite), low temperature quartz textures (e.g., colloform, comb, and banded quartz), and limited sulfide minerals.Given the geographical proximity of Kartaldag and Madendag deposits, the similar temperature and salinity ranges obtained from their fluid inclusions, and the similar ages of igneous rocks in both deposits (Kartaldag: 40.80 +/- 036 to 42.19 +/- 0.45 Ma, Madendag: 43.34 +/- 0.85 Ma) the mineralizing systems in both deposits are considered to be genetically related. (C) 2013 Elsevier B.V. All rights reserved

Mineralogic and geochemical characteristics of late quaternary veins from Anamur-Gazipaşa fault zones (S Turkey)

Widespread vein-type carbonate (e.g., travertine) occurrences developed along active fault systems during the late Quaternary period in Turkey, a region of known active tectonism. This study presents preliminary high precision U-series and geochemical data on hypogenic fluids migrated and precipitated as carbonate veins along fractures developed in NNW-SSE trending active fault zones in S Anatolia (Ören-Anamur and Gazipaşa). U-series dates of fault-related carbonate (mainly as calcite) vein and fault plane calcite slickened fibers collected from the study areas range between >500 ka and 5.6 ka. Anamur vein samples formed between 132±2 ka and 5.6±0.4 ka, whereas ages of Gazipaşa samples vary between 530±63 ka and 30.0±2.1. Petrographic and XRD analyses revealed that the samples contain medium- to coarse-grained, equigranular, and elongated columnar calcite crystals. In some samples, calcite growth zones are identified with micrite and small groups of inclusion trails aligned perpendicular to the growth axes. According to the stable isotope analyses, the δ13C values of the fault calcite from Anamur region range between -12 and -6‰ (VPDB), and Gazipaşa samples have similar δ13C values between -12 and -7‰ (VPDB). Carbonate δ18O isotope values of Anamur and Gazipaşa regions are almost identical (Anamur: -7 – -4‰, Gazipaşa: -7 – -3‰; VPDB). Mean 87Sr/86Sr ratios of Gazipaşa samples are higher than those of both Anamur vein samples (mean=~0.708) and Permian limestone wall rock (mean=~0.707). This mean value correlates well with the mean 87Sr/86Sr ratios of modern and Cenozoic seawater (~0.709). In addition, 87Sr/86Sr values of Permian limestone wall rock samples are similar to that of Permian seawater (~0.707). A primary seawater source for calcite vein deposits is also evident in PAAS-normalized rare earth element-Yttrium diagrams, where vein samples display negative Ce and positive Y anomalies. The comparison of the project`s results with other travertine and calcite vein deposits in Turkey and the Eastern Meditarranean and the interpretation in terms of regional tectonic and climatological dynamics are still continue

Linking CO2 degassing in active fault zones to long-term changes in water balance and surface water circulation, an example from SW Turkey

Calcite veins are commonly found at shallow depth (a few metres below the surface) in damage zones of active normal fault systems in southwest Turkey. Although earlier studies demonstrated the link between the vein formation and seismicity, the association of near-surface carbonate precipitation with climate-driven hydrological conditions (water table, amount of precipitation and evaporation, and water discharge) is poorly understood. In this study, using the U/Th dating method we investigate the timing of vein formation and the interrelationship between tectonic and climatic-related hydrological processes. Carbonate precipitation is interpreted to occur as a result of sudden pressure drops and CO release after earthquake-induced fracturing. Vein formation mostly occurred during glacial periods, which coincide with slow growth rates and higher oxygen isotope values of speleothems from the Eastern Mediterranean region. We relate these episodes to reduced winter rainfall due to the decrease in westerly flow in SW Turkey. These somewhat drier conditions influenced the chemical composition of circulating water, creating conditions conducive to carbonate precipitation and sealing of damage zones. These conditions also facilitated CO accumulation and overpressure build-up in the rupture zones. Failure of the faults resulted in the release of large volumes of CO -rich fluids and the generation of shallow carbonate veins. It is proposed that during phases of increased winter rainfall CO is advected to the surface and discharged as passive degassing when meteoric water circulation is enhanced. While regional tectonics is the ultimate driver of fault activity and fracture formation, climate-driven near-surface hydrological changes may have played an important role in modulating CO -rich fluid circulation and surface discharge

Memmo Lorenzo

PubMedWoSScopu

Are U‐Th dates correlated with historical records of earthquakes? Constraints from co‐seismic carbonate veins within the North Anatolian Fault Zone

U-Th dating of carbonate veins in connection with active tectonics has recently been used as an attractive tool for constraining the absolute timing of late Quaternary crustal deformations. In this study, for the first time we correlate U-Th ages of travertine deposits in coseismic fissures along the North Anatolian Fault Zone with records of paleoseismological studies supported by historical earthquake catalogued data. U-Th ages are assessed in relation to the recurrence interval and the size and epicenter distance of major Holocene earthquakes. Our statistical evaluations on age correlations indicate that the carbonate vein precipitation is concentrated in eight different periods along the North Anatolian Fault Zone. The periods are well correlated with historical earthquake records and with previous dating results of the nearby trench studies. At least six of the periods correspond to the earthquakes reported in the historical catalogues. The age correlations of carbonate precipitation intervals for the last millennium show a recurrence along the eastern North Anatolian Fault Zone with a mode at 130–330 years that is consistent with a previously proposed paleoseismic recurrence interval of the fault. Recorded events in carbonate veins indicate a close-epicenter (d VI) paleoearthquakes. Our results suggest that coseismic carbonate veins could be used to determine paleoseismic records as a supplementary tool to augment paleoseismological techniques. This tool has advantages over traditional paleoseismological methods for the understanding of long-term earthquake behavior, particularly for prehistoric late Pleistocene events which cannot be dated easily by traditional paleoseismological methods

20,000 years of societal vulnerability and adaptation to climate change in southwest Asia.

The Fertile Crescent, its hilly flanks and surrounding drylands has been a critical region for studying how climate has influenced societal change, and this review focuses on the region over the last 20,000 years. The complex social, economic, and environmental landscapes in the region today are not new phenomena and understanding their interactions requires a nuanced, multidisciplinary understanding of the past. This review builds on a history of collaboration between the social and natural palaeoscience disciplines. We provide a multidisciplinary, multiscalar perspective on the relevance of past climate, environmental, and archaeological research in assessing present day vulnerabilities and risks for the populations of southwest Asia. We discuss the complexity of palaeoclimatic data interpretation, particularly in relation to hydrology, and provide an overview of key time periods of palaeoclimatic interest. We discuss the critical role that vegetation plays in the human-climate-environment nexus and discuss the implications of the available palaeoclimate and archaeological data, and their interpretation, for palaeonarratives of the region, both climatically and socially. We also provide an overview of how modelling can improve our understanding of past climate impacts and associated change in risk to societies. We conclude by looking to future work, and identify themes of "scale" and "seasonality" as still requiring further focus. We suggest that by appreciating a given locale's place in the regional hydroscape, be it an archaeological site or palaeoenvironmental archive, more robust links to climate can be made where appropriate and interpretations drawn will demand the resolution of factors acting across multiple scales. This article is categorized under:Human Water &gt; Water as Imagined and RepresentedScience of Water &gt; Water and Environmental ChangeWater and Life &gt; Nature of Freshwater Ecosystems