http://hdl.handle.net/10366/4128 2026-06-09T23:38:08Z http://hdl.handle.net/10366/171744 [EN]Soils are an important storage of water and an efficient filter that enables a certain percentage of precipitation to reach groundwater, contributing to hydrological resources. In this paper, soil water content (SWC) was monitored during 2 years to characterize the hydrological dynamics and quantify water resources. The studied soil is developed over a carbonate bedrock in the Mediterranean region of Croatia. The site has a classical red Mediterranean soil with high clay content and pedogenic carbonates. The hydrological monitoring along the soil profile was conducted using sensors based on frequency domain reflectometry (FDR) technology. However, soil characteristics resulted in factors other than SWC affecting the recorded signal. The measured SWC signals record short-term variability in response to precipitation events, although their absolute values and their long-term variability are unreliable. To better understand local hydrological dynamics, a 1D hydrological model was implemented. Basic corrections were applied to raw SWC signals to use measured data to calibrate the model. In average, the simulation explains 72% of the corrected SWC variability and properly reproduces the short-term variability measured by sensors, improving the original and corrected SWC signals. This research shows that even if FDR sensors provide unreliable data in problematic soils, the measured signals can still be used to calibrate hydrological models and to produce realistic simulated data. The methodology followed in this research can inspire similar observation-simulation studies and be used as a guide to improve the understanding of hydrological dynamics in any type of soil with technical difficulties to acquire quality observational SWC data. 2026-01-01T00:00:00Z http://hdl.handle.net/10366/171743 [EN]Chemical weathering of carbonate minerals (CWC) plays an important role in global carbon cycle, as it bridges the atmospheric, lithospheric and hydrospheric carbon pools. However, data limitations have hindered an accurate estimation of the carbon sink flux induced by global CWC (CSFCWC), as well as its response to environmental change. Conventional hydrochemical methods, which infer CSFCWC indirectly from riverine hydrochemistry, provide only catchment-integrated signals, yet cannot resolve the specific contribution of CWC across different climate, pedological, and ecological settings within a catchment. Here, we synthesize 2444 globally-distributed in-situ CWC rates measured by rock tablet tests, and investigate the magnitude, spatiotemporal variation and controlling factors of CSFCWC using a machine learning model. We find that soil physicochemical properties (e.g. pH and moisture) play a more important role in determining global CWC spatial variation than climate, hydrology and vegetation factors. The machine-learning model developed in this study explains 68% of the variance in globally observed CSFCWC values. Global application of our model indicates that CWC generates a carbon sink of 0.27 Pg C yr−1 worldwide, which is comparable to previous catchment-integrated estimates derived using different approaches, accounting for approximately 8% of the total terrestrial carbon sink. Over the past two decades, global greening has significantly accelerated global total carbon sink induced by CWC, with this acceleration particularly pronounced in Asia. Overall, this study provides a benchmark estimate of global CSFCWC and advances the mechanistic understanding of carbonate weathering. Our findings contribute to improving existing weathering models and reducing uncertainties in future projections of the terrestrial carbon sink. 2026-01-01T00:00:00Z http://hdl.handle.net/10366/171385 [EN]This study investigates two burial‐related remagnetizations in the Jaca–Pamplona foreland basin (Southern Pyrenees): one with dual polarity and a positive reversals test, and another with only reverse polarity. These components, labeled C3 and C4 based on their mean unblocking temperatures, were identified from a paleomagnetic analysis of 142 sites in Eocene turbidites of the Hecho Group. Component C3 shows unblocking temperatures of 250°C–350°C, systematic reverse polarity, and a predominantly post‐folding timing. Component C4 exhibits unblocking temperatures of 250°C–550°C, dual polarity and a mainly syn‐to postfolding acquisition. The spatial distribution of C4 polarity defines WNW–ESE bands parallel to structures and younging southward. The acquisition of C4 is interpreted as a chemical remagnetization triggered by progressive burial driven by combined sedimentary and tectonic loading that increased temperatures (up to ∼250°C in the deeper northern sectors, according to previous paleotemperature studies). This thermal evolution promoted authigenic, stable single‐domain magnetite growth, beginning during the Lutetian (chron C20) and probably ending in the Rupelian (chrons C11‐C10) as uplift and exhumation progressed. In contrast, the reverse polarity and post‐folding behavior of component C3 suggest a mixed origin involving both chemical remagnetization and a thermoviscous overprint during the long chron C12r (Rupelian), contemporaneous with the youngest reverse C4 band and preceding the final exhumation of the basin. These findings highlight the complex interplay among tectonics, sedimentation, and chemical remagnetization processes in the South Pyrenean foreland, providing new insight into the timing and kinetics of remagnetization in fold‐and‐thrust belts. 2026-01-01T00:00:00Z http://hdl.handle.net/10366/171384 [EN]The anisotropy of the magnetic susceptibility (AMS) in mudrocks has been widely used to study orogenic belts due to their sensitivity to strain, while paleomagnetism remains the most effective method to quantify vertical axis rotations (VARs) resulting from the accommodation of along-strike variations in shortening. However, AMS can be also eventually used as a passive marker to detect VARs and the integration of both techniques offers a powerful approach to understand the tectonic evolution of fold-and-thrusts-belts. In this work, a combined AMS and paleomagnetic study along a stratigraphic section of continental rocks from the Campodarbe Formation in the Jaca-Pamplona Basin, southern Pyrenees, was carried out. This stratigraphic section (Martes section) records the tectonic evolution of this part of the basin from Priabonian to Rupelian times. The magnetic fabrics show the imprint of early stages of deformation, characterized by dominantly oblate ellipsoids and WNW-ESE horizontal magnetic lineations (axes of maximum magnetic susceptibility kmax), parallel to bedding and the main regional structures. In the lower part of the section, kmax axes trend around 290º, gradually rotating to 270º towards the top. The AMS is interpreted as locked under the imprint of the layer parallel shortening (LPS) associated to the activity of the basement thrusts in the northern Jaca-Pamplona Basin. On the other hand, paleomagnetic data indicate clockwise VARs of 6º to 12º in the lower part of the section, and a counterclockwise rotation of 7º to 14º in the upper part. These differential rotations could result from lateral changes in the Biniés basement thrust or the Jaca thrust system that were active during Oligocene times. Both techniques record a net rotation of ca. 25º between the lower and upper part of the section, which support the interpretation that early-locked AMS behaves as a passive marker and validates its use for detecting and quantifying VARs. 2026-01-01T00:00:00Z http://hdl.handle.net/10366/171232 [EN]Rock weathering is a key component of the rock cycle that transforms rocks in sediments, soils and/or dissolves minerals to ions, and plays an important role in landforms development and landscape evolution. The quantification of weathering is often challenging due to the impact of measuring techniques on the rock itself and/or the assumptions required to perform the calculations. Among different methods used to quantify rock weathering, rock tablet method is one of the most widely used. The rock tablet method consists of cutting rock samples in a shape that allows precise calculation of their volume and surface. These rock pieces, often named tablets when they are flat, are dried, precisely weighed and exposed to the natural environment for certain amount of time. After retrieval, the same laboratory procedure is repeated, and from the weight loss, the weathering rate is calculated. When the density of the rock is known and it is reasonable to assume that the lost material is removed from the ground surface, the weight loss can be used to calculate denudation rates. This is the case in karst regions, where rock tablets are one of the most commonly used methods to calculate denudation. This simple and versatile method requires only a limited amount of laboratory equipment to be implemented which makes it very popular. However, experimental design, preparation of samples and calculations are not homogeneous among researchers, sometimes making the results of this method challenging to be evaluated and compared. In this paper we describe the rock tablet method, include its historical overview, review the most significant studies that have used this technique, highlight its limitations, introduce correction factors to minimize some of those limitations, and provide good practice recommendations to help other researchers to obtain comparable results around the world. 2021-01-01T00:00:00Z http://hdl.handle.net/10366/171231 [EN]The isotope signature of cave waters provides an excellent opportunity to better understand the recharge in karst regions and the complexity of drainage systems in the vadose zone. We have developed a cave isotope hydrological model (ISODRIP) that requires entering basic hydrometeorological information and a precipitation δ18O record to simulate the discharge and δ18O signals of different drip sites. The model includes four different modules to simulate various flow route regimes: continuous and discontinuous drips under diffuse or preferential flows. We use precipitation and cave water δ18O records that were obtained in Eagle Cave (central Spain) during a 5-year period to test our model and to better understand the dynamics of karst aquifers. Eagle Cave waters do not record evaporation. The δ18O signals do not have seasonality, although they record intra-annual and inter-annual variability. Additionally, cave water δ18O signal falls within the range of the annual average weighted isotope composition of precipitation. Well-mixed cave waters, that characterize diffuse flows, record 1‰ δ18O variability, whereas partially-mixed waters, that flow along preferential drainage routes, have up to 3‰ δ18O variability. The results suggest that precipitation takes on average 15 months to reach the cave through the diffuse flow network, whereas under preferential flow the transit time is highly variable depending on the previous condition of the system. ISODRIP includes a soil layer above the vadose zone that controls large recharge events, together with direct recharge components that bypass the soil layer enabling at least some recharge all year round. Thus, the simulations reproduce the observed lack of seasonal bias in the cave water δ18O composition in relation to the average weighted isotope composition of precipitation. This research highlights the importance of understanding recharge dynamics and the configuration of particular drips sites to properly interpret speleothem δ18O records. 2021-01-01T00:00:00Z http://hdl.handle.net/10366/171224 [EN]Although temperature is a nonconservative tracer, it often provides useful information to understand hydrological processes. This study explores the potential of temperature to characterize the hydrological dynamics of a submarine spring and its coastal karst aquifer in Krka Estuary (Croatia). The estuary is well stratified and its water column has a clear thermocline. A network of loggers was designed to monitor the temperature along vertical profiles in the estuary and the coastal aquifer, taking advantage of an anchialine cave that enabled access to the subterranean estuary. The location of the thermocline in the groundwater, which defines the upper boundary of the saline intrusion, depends on (1) the recharge of the aquifer via infiltration of precipitation, (2) the evolution of the thermocline in the estuary, and (3) the tidal oscillations. The sources of water flowing though the anchialine cave were identified: brackish water from the estuary above the thermocline, saline water from the estuary below the thermocline, and freshwater from infiltrated precipitation. A conceptual model is described that characterizes the hydrological dynamics of this coastal aquifer and its interactions with the estuary. Thus, at least for some hydrological settings, temperature is a valid tracer to characterize the main hydrological processes. The measurement of temperature is inexpensive compared to other (conservative) tracers. Therefore, for those hydrological settings that have water masses with distinct temperatures, the use of temperature as a tracer to establish conceptual models of the hydrological dynamics is encouraged. 2018-01-01T00:00:00Z http://hdl.handle.net/10366/171223 [EN]Quantification of soil plasticity is usually based on Atterberg limits or indices, which are then used for engineering and agricultural purposes on clay soils. Because these limits/indices are seldom analyzed during routine soil surveys, they are sometimes estimated from available soil properties using pedotransfer functions (PTFs). Main aim of this study was to test if two robust PTFs, previously created by other authors for other soils/areas, may be used for predicting plasticity of typical clay soils on fluvial deposits in Croatia. We analyzed mineralogy, plasticity, and related physicochemical properties of four representative soil profiles along Sava and Drava, two longest Croatian rivers. Particle size distribution patterns pointed to more uniform sedimentation along Sava, compared to Drava. Also, more clay was found within Sava profiles. Soil texture was finer farther away from the sources of both rivers. Soil cation exchange capacity (CEC) was almost fully positively correlated to clay content. On the other hand, Corg content showed no correlation to CEC. This is attributed to the significant presence of smectite across all studied soils. Clay was recognized as the main factor influencing soil plasticity. When compared to the measured values, the predicted values of plasticity index and liquid limit were heavily underestimated. Hence, region-specific PTFs should be developed for more accurate prediction of plasticity in these soils. According to the WRB-2015, the soils were classified as Eutric Reductigleyic Stagnic Gleysols (Clayic, Humic, Protovertic). Because soils were not dry during field description, shrink-swell cracks were not prominent, and therefore soils were not classified as Vertisols. We suggest that field criteria for classification of Vertisols should not depend on actual soil moisture. Instead, plastic limits/ indices could be used. 2020-01-01T00:00:00Z http://hdl.handle.net/10366/171220 [EN]The development of a karst landscape results from complex interactions between lithology, climate, hydrology, soil, vegetation and tectonics. Weathering and erosion of carbonate rocks leads to denudation of karst landscapes. As dissolution of carbonate rocks is often considered to be the main process governing carbonate weathering, other processes are often overlooked. Here we present research done in the North Dalmatian Plain, a carbonate erosive surface located in the Dinaric karst region. Although the study site is composed of two different carbonate lithologies having different weathering style, there is no evident lithological impact on the topography of the erosive surface. Analyses of 36Cl concentration were performed in ten proximal bedrock samples from both lithologies and resulted in long-term denudation rates ranging from 14.7 to 22.8 m/Ma. Since no statistical significance was found between samples from different lithologies (all samples belong to a single normal population) and they have the same geomorphological context and climate features, variable denudation rates are attributed to local (sample specific) differences. In the study site there are no large outstanding rock residuals or patches with deep soil profiles. Thus, to maintain the levelled erosive surface, local differential denudation rates have to vary with time. We hypothesize that lichens and pedogenic carbonates have a significant role in modulating local differences in denudation rates. Our study shows that even at outcrop scale those differences can be significant, and the study of sample populations is preferred to single or limited number of analyses. Thus, the longterm denudation rate of the North Dalmatian Plain, including its local variability is 18.91±0.81 m/Ma. Despite classical studies on karst terrains assume that dissolution is the main process responsible for development of these landscapes, our research highlights the importance of physical weathering in combination with dissolution of carbonates as main controls on the denudation of karst landscapes. 2022-01-01T00:00:00Z http://hdl.handle.net/10366/171181 [EN]The formation of karst landscapes is the result of a series of processes, whereby rock weathering and denudation play important roles. Soluble carbonate rocks are chemically weathered (dissolved) on the surface or under soil cover resulting in the formation of different karst morphologies and controlling surface denudation. The Dinaric karst area is the type-site for numerous karst features and phenomena, but studies on carbonate weathering in this region are still scarce, especially in the mountainous regions. To better understand the formation of Dinaric karst mountainous landscapes, we studied denudation rates at the northern part of Velebit Mountain using the rock tablet method. Denudation was measured using rock tablets consisting of local lithologies and “standard rock tablets” exposed to the natural environment at the surface, but also buried in the soil. Furthermore, rock tablets were placed in three different settings (open slope, small clearing, bottom of a doline) to evaluate the local factors impacting the denudation rate. The results of this study showed that the denudation rate is highly dependent on local factors and lithology, and that local rock tablets from different lithologies should be used to determine the actual denudation rate. 2024-01-01T00:00:00Z http://hdl.handle.net/10366/170964 [EN]During each Heinrich stadial (HS), temperatures in southern Europe typically dropped several degrees during several hundred to few thousand years. We have developed a one-dimensional thermal conduction model that transfers the typical surface temperature anomaly of a HS to a series of hypothetical underlying caves. The results show that with increasing depth, the thermal anomaly is attenuated, the lag time increases, and the signal structure experiences larger modifications. The model suggests that in most cases, it is not acceptable to assume a synchronous thermal variability and similar average temperature values between the surface atmosphere and the cave interior at millennial timescales. We also simulated the thermal impact of the modeled HS on speleothem δ18O records. The outputs of most model scenarios suggest that temperature changes associated with the HS produce δ18O anomalies capable of contributing significantly or even decisively to the speleothem isotope variability. Therefore, despite controls other than temperature often being considered more important when interpreting Pleistocene speleothem δ18O records in temperate climates, this research suggests that temperature is expected to be one of the major controls of δ18O values in most cave sites outside the tropics and should be included as a significant parameter affecting Pleistocene speleothem δ18O records. 2020-01-01T00:00:00Z http://hdl.handle.net/10366/170963 [EN]Models provide quantitative solutions that enable better understanding of karst soils hydrology. A location in central Spain was selected to implement a 1-D hydrological model that uses a reservoir cascade scheme (RCS) approach to simulate soil water content (SWC) at daily resolution. The model simulates SWC for six soil layers and includes additional modules to reproduce preferential flow regime. The soil profile in the model is 0.5 m deep, developed in silt loam soil on top of dolomite marbles. Three different configurations of the model were considered. Configuration 1 considers a basic RCS module, whereas other configurations include preferential flows. Thus, Configuration 2 considers RCS module together with a continuous preferential flow module, where 1 to 5% of available SWC from each layer is drained every day along preferential pathways. Configuration 3 contains a discontinuous preferential flow module in addition to previous modules. The discontinuous preferential flow is only activated during rainfall events occurring after long dry periods. Simulated SWC values are compared with measured SWC values, so model parameters are iteratively adjusted to optimize the model results. The model produces the best simulations implementing the Configuration 3, when matrix flow and two preferential flow regimes are considered. The model shows that preferential flows significantly contribute to recharge and should not be neglected in soil hydrological models and recharge estimations in karst areas. 2022-01-01T00:00:00Z http://hdl.handle.net/10366/170962 [EN]Pedogenic carbonates are secondary carbonate deposits and are a constitutional part of many soils. We analysed a 95 cm deep Calcocambisol soil profile at a location in the Dinaric part of Croatia. Here, pedogenic carbonates are more abundant in the deeper part of the profile (>23 cm), and their amount and size increase with depth corresponding to soil properties along the profile. These pedogenic carbonates are spherical to irregular in shape and can be classified as nodules. Microscopical analysis of these nodules shows that dissolution and re-precipitation of carbonate take place in situ, without considerable movement through the soil profile. The growth of the nodules starts from multiple centres of nucleation, and their internal structure is a result of spatial and temporal environmental conditions in the soil matrix during carbonate precipitation. The inclusion of noncarbonate particles and preservation of the original soil structure confirm the replacive nature of nodule growth. Furthermore, the internal structure of nodules reveals multiple stages of calcite precipitation, indicating seasonal or event-based precipitation of carbonate. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/170961 [EN]Studies of denudation rates in carbonate areas are an important step to understand rates of karst landscape development. Weathering of carbonate rocks is an essential process in soil formation and has a significant role in the global CO2 budget. We studied short-term weathering and denudation rates at a location in the Dinaric karst using the rock tablet method while monitoring surficial and soil environmental parameters. We exposed “standard” rock tablets and those from local lithologies to the natural environment at the surface and buried them at two depths (20 and 50 cm) in the soil profile. Our results show that the average actual denudation rate measured at this site is 2.28 μm/a (for rock tablets exposed at the surface and buried in the soil). Furthermore, this rate is higher at the surface (2.95 μm/a) than those recorded in the soil (1.46 μm/a and 1.99 μm/a at 20 and 50 cm depth, respectively) and is dominated by physical weathering processes driven by diurnal temperature cycles. On the other hand, weathering of rock tablets buried in the soil profile is dominated by chemical weathering processes strongly dependent on the availability of CO2 in the soil, resulting in higher denudation rates deeper in the soil profile. Furthermore, the denudation rate strongly depends on lithology; thus, local lithologies should be used to obtain actual denudation rates. 2026-01-01T00:00:00Z http://hdl.handle.net/10366/170941 [EN]Tufa sediments are freshwater carbonates that precipitate in karst regions after degassing of carbon dioxide from groundwater in contact with the atmosphere. When laminated, these carbonates can provide high-resolution records for the study of climate, hydrological and environmental conditions at the time of their precipitation. The formation of these carbonates directly depends on the hydrological regime, and in karst regions discontinuous discharges are often recorded. This study investigates the record of recent laminated tufa sediments precipitated downstream overflow springs in Trabaque Canyon (central Spain). The hydrological dynamics of the karst system were monitored for over three years and a stable isotope record was obtained from laminated tufa carbonates precipitated from an overflow spring. Additionally, a hydrological model of overflow springs was generated and a tufa δ18O record under constrained parameters was simulated. Temperature is the dominant control of the variation in tufa δ13C and δ18O values within each lamina, although when comparing different laminae, δ13CDIC and δ18O of river water are also major controls. The positive correlation between tufa δ13C values and water temperature is caused by the fractionation occurred by carbon dioxide degassing due to the thermal dependence of carbon dioxide solubility. Additionally, the system recorded a temperature-independent degassing process caused by the large gradient between groundwater and atmospheric carbon dioxide that is limited to the proximity of the spring. This study cautions on the risk of assuming continuous deposition when studying laminated tufa sediments and highlights the potential of their stable isotope records to provide hydrological information of their aquifers during the past. 2017-01-01T00:00:00Z http://hdl.handle.net/10366/170940 [EN]Calcocambisol is the most dominant soil type developed on Dinaric karst. It is formed by pedogenic processes acting on carbonate rocks, which include weathering, accumulation of insoluble residue, organic matter, and allogenic material and braunification. Further development of Calcocambisol includes leaching of clay from upper soil horizons and secondary accumulation in lower horizons. Calcocambisols are exclusively developed on carbonate rocks characterised by diverse relief forms resulting in variable soil depth over short distances and consequently different phases of soil development. Thus, the goal of this study was to analyse morphological, physical, and chemical properties of Calcocambisols in different stages of development from a location within the Krka National Park. Results of soil analysis showed similarities in morphological properties, soil field and air capacity, density and SOC content. On the other hand, differences in properties included different carbonate content and pH values of topsoil and difference in particle size distribution. These differences can be attributed to irregular rocky surface which plays important role in allogenic particles distribution and water percolation. Increased leaching of clay particles to deeper horizons results in diversification of Bt (argic) horizon, indicating more advanced stage of soil development towards Luvisol formation. 2021-01-01T00:00:00Z