Salt Mobilization Research Articles

Geology of the eastern tip of the El Tordell Fault, Southern Pyrenees

ABSTRACT Along strike variations of frontal structures at fold and thrust belts allow us deciphering the evolution of contractional structures at early stages of deformation but also, how processes such as salt mobilisation, thrust emplacement, and folding develop. The external parts of the Pyrenees are suitable to investigate how these processes interacted during the Pyrenean Orogeny. The integration of fieldwork and subsurface data allowed us to obtain on the one hand the geological map of the eastern tip of the El Tordell Fault and the Súria Anticline and on the other hand, the 3D structural model of the study area. These two results allowed us to decipher the evolution of the area, which is characterised by the development, under compression, of a salt accumulation at early stages of deformation which was afterwards the locus of the El Tordell Thrust and finally, as deformation progressed, the development of the Súria Anticline.

Brine formation in cold desert, shallow groundwater systems: Antarctic Ca-Cl brine chemistry controlled by cation exchange, microclimate, and organic matter

Groundwater in the McMurdo Dry Valleys of Antarctica is commonly enriched in calcium and chloride, in contrast to surface and groundwater in temperate regions, where calcium chemistry is largely controlled by the dissolution of carbonates and sulfates. These Antarctic Ca-Cl brines have extremely low freezing points, which leads to moist soil conditions that persist unfrozen and resist evaporation, even in cold, arid conditions. Several hypotheses exist to explain these unusual excess-calcium solutions, including salt deliquescence and differential salt mobility and cation exchange. Although the cation exchange mechanism was shown to explain the chemistry of pore waters in permafrost cores from several meters depth, it has not been evaluated for near-surface groundwater and wetland features (water tracks) in which excess-calcium pore-water solutions are common. Here, we use soluble salt and exchangeable cation concentrations to determine whether excess calcium is present in water-track brines and if cation exchange could be responsible for calcium enrichment in these cold desert groundwaters. We show that calcium enrichment by cation exchange is not occurring universally across the McMurdo Dry Valleys. Instead, evidence of the present-day formation of Ca-Cl−rich brines by cation exchange is focused in a geographically specific location in Taylor Valley, with hydrological position, microclimate, soil depth, and organic matter influencing the spatial extent of cation exchange reactions. Up-valley sites may be too cold and dry for widespread exchange, and warm and wet coastal sites are interpreted to host sediments whose exchange reactions have already gone to completion. We argue that exchangeable cation ratios can be used as a signature of past freeze-concentration of brines and exchange reactions, and thus could be considered a geochemical proxy for past groundwater presence in planetary permafrost settings. Correlations between water-track organic matter, fine sediment concentration, and cation exchange capacity suggest that water tracks may be sites of enhanced biogeochemical cycling in cold desert soils and serve as a model for predicting how active layers in the Antarctic will participate in biogeochemical cycling during periods of future thaw.

Quantifying climate change impacts on future water resources and salinity transport in a high semi-arid watershed

High salinity mobilization and movement from salt-laden deposits in semi-arid landscapes impair soils and water resources worldwide. Semi-arid regions worldwide are expected to experience rising temperatures and lower precipitation, impacting water supply and spatio-temporal patterns of salinity loads and affecting downstream water quality. This study quantifies the impact of future climate on hydrologic fluxes and salt loads in the Gunnison River Watershed (GRW) (14,608 km2), Colorado, using the APEX-MODFLOW-Salt hydro-chemical watershed model and three different CMIP5 climate models projection downscaled by Multivariate Adaptive Constructed Analogs (MACA) for the period 2020–2099. The APEX-MODFLOW-Salt model accounts for the reactive transport of major salt ions (SO42−, Cl−, CO32−, HCO3−, Ca2+, Na+, Mg2+, and K+) to streams via surface runoff, rainfall erosional runoff, soil lateral flow, quick return flow and groundwater-stream exchange. Model results are analyzed for spatial and temporal trends in water yield and salt loading pathways. Although streamflow is primarily derived from surface runoff (65%), the predominant source of salt loads is the aquifer (73%) due to elevated concentrations of groundwater salt. Annual salt loading from the watershed is 582 Mkg, approximately 10% of the salt load in the Colorado River measured at Lee's Ferry, AZ. For future climate scenarios, annual salt loads from the watershed increased between 4.1% and 9.6% from the historical period due to increased salt loading from groundwater and quick return flow. From the results, applying the APEX-MODFLOW-Salt model with downscaled future climate forcings can be a helpful modeling framework for investigating hydrology and salt mobilization, transport, and export in historical and predictive settings for salt-affected watersheds.

Exploring Lime Mortar Microstructure: Investigating the Impact of Mixed-in Additives and their Role in Salt Efflorescence Inhibition

This study presents the analysis of the crystallization impact in four lime-based mortar mixtures in order to determine the extent of decay during salt crystallization, affected by the use of additives and change in microstructure. For this purpose, non-destructive micro-computed tomography was used to monitor salt crystallization in lime mortar cores. This technique allowed tracking of salt precipitation after accelerated weathering steps and further enabled the localization of damage due to salt crystallization in both time and space. Results indicate that the internal 3D microstructure of the lime mortars is greatly influenced by the type and the amount of additive used. Polyacrylic acid (PAA) acted as a superplasticizer and air entrainer in the mixture, resulting in the formation of larger air voids, which led to a decrease in compressive strength. Mobilization of salts within the mortar matrix was observed, causing accumulation and cracking of the mortar wall towards the end of the weathering experiment.

Translation, collision and vertical‐axis rotation in the Organyà and Montsec minibasins (South‐Central Pyrenees, Spain)

AbstractThis paper presents a sequentially restored cross‐section of the Organyà and Montsec minibasins based on geological mapping, new field observations and available borehole data. The main objective was to describe the geometry and evolution of both basins in terms of salt tectonics and minibasin mobility. To this end, a comprehensive palaeomagnetic database has been used to constrain vertical‐axis rotations potentially related to minibasin translation and pivoting. The Organyà minibasin constitutes an asymmetric depocentre formed during the Upper Jurassic‐Lower Cretaceous by translation above a southerly inclined salt layer. Salt evacuation and minibasin touchdown induced salt accumulation on the northern side of the basin that culminated in the development of the major Santa Fe unconformity during the late Albian—early Cenomanian. Indicative of salt quiescence is the following isopachous Cenomanian to lower Santonian sequence Salt tectonics resumed during the late Santonian—Palaeocene, with the Montsec minibasin downbuilding coinciding with the onset of Pyrenean convergence. Changes of the base‐salt topography reflects regional‐scale geodynamic processes. The acceleration of crustal thinning in the North Pyrenean zone during the late Albian‐early Cenomanian favoured uplift in the Axial Zone, increasing slope and triggering salt mobilization in the Southern Pyrenees. Likewise, the onset of contraction renewed the downslope gliding of the Organyà and Montsec minbasins, and supports the idea that the early stages of basin inversion were governed by gravity tectonics. The kinematic reconstruction suggests that the more that 30° counterclockwise vertical axis rotation records pivoting during the suprasalt translation of the Organyà minibasin rather than solely the Iberian microplate rotation.

Contrasting Styles of Salt‐Tectonic Processes in the Ionian Zone (Greece and Albania): Integrating Surface Geology, Subsurface Data, and Experimental Models

AbstractThe Ionian Zone (IZ) is one of the key elements of the fold and thrust belt (FTB) of the Albanian and Hellenides orogen and contains large outcrops of Triassic evaporites. The IZ consists of various thrust sheets with a general westward vergence, stacking over the Apulian and Pre‐Apulian zones, and repeating a thick carbonate sequence of Upper Triassic to Eocene age. Thrusting becomes younger toward the west with a piggyback sequence, starting during the latest Oligocene Epoch in the Internal Ionian and ending in the Pliocene in the External Ionian. We have studied the IZ in southern Albania and northwestern Greece using field observations and borehole data and by fully interpreting a recently acquired 2D seismic data set. Our objectives are to establish the geometry and nature of the contacts associated with the major Triassic outcrops, to unravel precursor salt diapirs, and to assess their role during the Alpine contraction. Salt structures include gentle salt pillows, isolated salt plugs and diapirs, thrust welds, and salt walls. Combining these observations with experimental modeling results, we show how these structures control the geometry and kinematics of the Alpine thrusts or the location and kinematics of recent strike‐slip faults. Salt minibasins have also been identified, demonstrating salt mobility conditioned Mesozoic sedimentation in the Ionian Basin. The use of salt‐tectonics principles to evaluate the structural style and evolution of the IZ FTB also opens new directions for interpreting the subsurface structure and evolution of the region.

Geometry and kinematics of the Middle to Late Miocene salt tectonics, central Egyptian Red Sea margin

The Red Sea basin includes a thick Middle to Late Miocene evaporitic succession that underwent halokinesis and caused intensive reshaping of the seafloor and the development of salt-tectonic structures. However, the geometry and kinematics of these structures are still poorly understood. This study uses 2D and 3D seismic surveys and well data of the northern Egyptian Red Sea to systematically describe the distribution and morphology of salt structures, discuss their initiation, and construct a kinematic model for their origin. Our results indicate that the massive salt layer developed into five major NW-SE to NNE-SSW trending salt walls, characterized by relatively irregular crests and moderately dipping flanks. In addition, several symmetrical and asymmetrical folds and two categories of normal faults (subsalt and suprasalt) have been recognized. Based on our observations, salt mobilization in the study area started in the Late Miocene, during the precipitation of layered evaporites, and continued until the present day. In the northern Egyptian Red Sea, seismic interpretation indicates that halokinesis was triggered by a combination of thin- and thick-skinned systems, where the latter played a major role. The salt layer was welded during the Quaternary as several sags and grabens developed above the salt diapirs. Thick-skinned physical models are compatible with our observations, supporting the impact of basement faulting on Red Sea diapirism.

Lithology and Lithofacies Characteristics of Deeply Buried Clastic Reservoirs in Alternating Wet-arid Climate and its Hydrocarbon Significance

There have been series of HPHT (high temperature and high pressure) reservoirs with good quality and high productivity discovered in the Triassic Skagerrak Formation in the Central Graben of the UK North Sea. The bottlenecks for further E&P activity are the complicated depositional facies and high reservoir heterogeneity. The main reservoir space is a mixed porosity network composed of primary pores, micro-pores, secondary pores, secondary micro-pores and micro-fractures. Reservoirs of the Skagerrak Formation have greatly varied lateral connectivity as well as poor vertical connectivity. In the case of sufficiently high pressure differentials, hydrocarbon can be fed from high-potential area to low-potential area. There is no simple linear relationship between depth and reservoir quality. The primary depositional texture (grain size/sorting/clay content, etc.) linked to facies has a fundamental control on reservoir quality. Clean and well sorted cross laminated sandstone has the best reservoir quality, while the reservoir quality of planar laminated sandstone decreased due to increased degree of compaction caused by mica drapes. The reservoir quality of the fine-grained ripple cross laminated sandstone is even poorer than that of the planar laminated sandstone, due to abundant mica and clay drapes. Mottled bioturbated sandstone is fine grained with high clay content, which is more muddy because of containing burrows and insect larva. Pedoturbated sandstone has the poorest reservoir quality due to severe dolomite cementation. The dominant detrital material of the Skagerrak Formation is feldspar that provides abundant secondary porosity by alteration and dissolution. Chlorite coats are commonly developed and stained with residual oil or bitumen, which clearly inhibits quartz cementation and feldspar overgrowth. The presence of these clay coats contributes to the preservation of anomalously high porosity at depth in the cleaner and coarser grained fluvial channel facies. The Skagerrak formation facies is a dryland fluvial-lacustrine depositional system which is controlled by fluctuations of depositional base level due to salt mobilisation. The Skagerrak formation consists of several cycles that are vertically separated by lacustrine mudstone. The reservoir permeability system is composed of active fluvial channel sandstones, terminal splay sandstones, abandoned fluvial channel sandstones, minor channel sandstones connecting fluvial channel and terminal splay, as well as low-permeability faults, while the active fluvial channel sandstone is the “sweet spot”. The analysis of controls on deeply buried reservoir quality is significant to precisely predict “sweet spot” in the Skagerrak Formation.

Hot corrosion mechanism and thermal cycling performance of air-plasma-sprayed LaYbZr2O7 thermal barrier coatings in the vanadate-containing molten salts

LaYbZr2O7 has been regarded as a promising thermal barrier coatings (TBC) material due to its excellent mechanical and thermal properties. In this study, the LaYbZr2O7 coating was prepared by atmospheric plasma spraying (APS), and its hot corrosion mechanism and thermal cycling performance in vanadate-containing molten salts (V2O5 and Na2SO4 + V2O5) were investigated. Results indicated the hot corrosion reaction of LaYbZr2O7 coatings in molten V2O5 was temperature dependent, attributed to the thermal decomposition of ZrV2O7 above 800 °C. A continuous dense corrosion layer could form on the top surface of LaYbZr2O7 coatings after hot corrosion in molten V2O5 salt, effectively preventing the further penetration of molten salt. However, the dense corrosion layer could not form when exposed to Na2SO4 + V2O5 molten salts at 1000 °C, since the formation of NaVO3 could improve the mobility of molten salts and slow the precipitation reaction rate of corrosion products. Furthermore, thermal cycling tests indicated that the Na2SO4 + V2O5 mixture could be more detrimental to LaYbZr2O7 coatings than single V2O5 salt, and the dense corrosion layer could act as a sacrifice layer to protect the inner coating from corrosion degradation. The hot corrosion mechanism of LaYbZr2O7 was discussed in detail based on the Lewis acid-base and dissolution-precipitation rule.

Development of Numerical Analysis Model for New Magnesium Electrolysis Process Using COMSOL

Magnesium (Mg) has good physical properties including light weight, excellent specific strength and high stiffness, and Mg is used in many fields. But current production methods of Mg have disadvantages, such as the generation of sulfur oxide and chlorine gas. In this situation, The Korea Institute of Geoscience and Mineral Resources (KIGAM) developed a Molten Salt Electrolysis Using Liquid Metal Cathode (MSELMC) method to produce high-purity magnesium. The MSE-LMC method can obtain 99.998-99.999% highpurity magnesium by the electrolysis of MgO dissolved in (MgF2)-LiF molten salt at 1053-1083 K, and by vacuum distilling an alloy generated by reacting with a metallic liquid cathode at 1200-1300 K. This study developed a numerical analysis model using COMSOL Multiphysics electrodeposition module to optimize the design of the electrolysis process. The model temperature was 1053K and molten salt was 54MgF2-46LiF with a 0.6wt% MgO system. 10A constant current was applied at the anode. This model uses the Butler-Volmer equation and the Nernst equation for the electric reaction. The Stokes-Einstein equation and Nernst-Einstein relation were used to calculate the diffusivity and electric mobility of salts. Unlike the experiment, in this model chlorine gas was generated. However, this model satisfied Faraday’s law. Therefore we define a new parameter using electric flux and voltage to conduct a quantitative evaluation according to the electrode shape, and compared that parameter by the changing angle of the anode.

Reconstructing the Iberian Salt‐Bearing Rifted Margin of the Southern Pyrenees: Insights From the Organyà Basin

AbstractReinterpretation of the Organyà Basin, based on new detailed field observations and subsurface data, emphasizes the key contribution of Upper Triassic evaporites in the tectono‐sedimentary evolution of the South‐Central Pyrenees. Results are integrated in a 65‐km long restored cross‐section through the Serres Marginals, Montsec and eastern Organyà salt‐related depocenters. The reconstructed part of the Jurassic–Cretaceous northern Iberian salt‐rich rifted margin shows a template characterized by inherited Permo‐Triassic basement normal faults and an initial salt thickness of 0.7 km to the south and 1.5 km to the north. The Organyà Basin is part of the South Pyrenean Diapiric Province, a large system of salt related depocenters and minibasins, that is limited to the north by the more than 120‐km long Senterada salt wall complex separating the supra‐salt and sub‐salt domains in the Southern Pyrenees. Three main stages of diapiric activity are recognized along the northern Iberian margin from Asturias to the Eastern Pyrenees: a Jurassic early salt mobilization; a latest Jurassic–middle Albian main diapiric evolution associated with rifting; and a Campanian–Miocene diapiric reactivation during basin inversion that produced salt welds and thrust welds and translated the salt province some 60 km to the south.

On the nature, composition and gas content of epigenetic mineralization in the salt column of the Verkhnekamskoe deposit (on the example of the Usolsky mine)

Research subject. The paper considers the tectonic position of the zone of epigenetic mineralization in the salt strata of one of the mines of the Verkhnekamskoye deposit, the gross and microelement chemical composition, gas content and component composition of gases. Materials and methods. To assess the composition of the original and epigenetic formations, structural and geological observations were carried out in mine workings, sampling, determination of the gross chemical composition (XRF, Bruker S8 Tiger spectrometer), trace elements (Aurora M90 inductively coupled plasma mass spectrometer), gas content and component composition of associated gases (gas chromatograph 450-GC company “Varian, Inc”). Results. It has been established that vein mineralization fills delamination cracks in the cores of the synclinal fold and is accompanied by zones of halite leaching and sylvite recrystallization. Further down the section, possible sources of K-oversaturated brines are recorded, which are generated in numerous small structures such as pop-ups or kink bands. The enrichment in light hydrocarbon gases, as well as easily soluble salts and mobile elements (KCl, CaCl 2 , MgCl 2 , Br, Rb, Li, Sr, Zn, Cu, Co, Te, Se, Sn, Pb), reflects their formation from sediment-brines mobilized during folding from sylvinite rocks. Conclusions. One of the mechanisms for the mobilization of fluids, salts, and trace elements in the salt column is characterized, which is associated with the folded appearance of small scattered chambers in the lower silyvinite bed KrIII and subsequent pulsating migration up the section along the synclinal bends of larger folds in the bed KrII. It is shown that in the process of formation of the zone of epigenetic mineralization, differentiation of small elements and gases occurs, which is associated with different sorption properties of halite, sylvin, and clay material.

The effects of salt flow on the cross-section restoration of salt-bearing fold-and-thrust belts: An example from the Kuqa depression

Thrust sequence analysis using cross-section restoration is critical for understanding the evolution involved in folds and thrusts as well as kinematics, the distribution of strain, and hydrocarbon accumulation. However, the application of cross-section restoration is challenging in salt-bearing fold-and-thrust belts. Salt flow causes uncertainty and difficulty in quantifying the geometry because of salt mobility and poorly constrained deformation kinematics. In this paper, we first analyze the role of salt flow in the cross-section restoration of salt-bearing fold-and-thrust belts using a synthetic model. Then an applicable method has been systematically described to quantify the effect of salt flow on the cross-section restoration. The method is efficient in determining the sub-salt thrust sequence, whereas accurate fault throw can be restored when the history of salt flow is known. Two well-constrained seismic profiles in the western Kuqa salt-bearing fold-and-thrust belts are restored sequentially to analyze the evolutionary process of sub-salt faults. The results show that the sub-salt thrust system propagates forward in sequence in the Bozi segment and out of sequence in the Dabei segment. The differential evolution of the sub-salt thrust between the Bozi and Dabei segments forms an oblique transfer zone. This study shows that understanding salt flow is the key point for cross-section restoration in salt-bearing fold-and-thrust belts, and relationships between supra-salt deformations and sub-salt thrust can be built by clarifying the contribution of salt flow.

Реконструкция развития соляных структур Верхнекамского месторождения солей

The article highlights some issues of geology and genesis of structural forms of the Verkhnekamskoye Salt Deposit (Perm krai). On the example of the Popovskiy salt dome location, the results of detailed studies and analysis of data on the geological structure of sedimentary strata and their morphology are presented. The reconstruction of the evolution of salt structures, the uplifts and depressions was carried out. The main factors and mechanisms, which controlled the development of a modern tectonic structure of this territory, were determined. Significant role in formation of the modern tectonic features of the upper part of the sedimentary cover played the accumulation in the Kungurian age of the Permian the ductile salt rocks, which, at the Late Paleozoic - Early Mesozoic subsequent stages of the territory evolution, determined the increased tectonic mobility of salt and supra-salt deposits, and the formation of high-amplitude uplifts and basins. Differences in tectonogenesis of the upper part of the sedimentary cover, comprising the ductile salt-bearing strata and the underlying rigid rocks, led to the division of the sedimentary cover of the Solikamskaya depression of the Cis-Ural trough into two tectonic stages. The lower level includes uplifts representing the draping structures of the Fransian-Tournaisian reef massifs and brachianticline folds of longitudinal compression, and the upper level comptises the structures formed as a result of the halokinesis of plastic rocks.

Restoration strategies for water and salt transport in saline soils: A 20‐year bibliometric analysis

AbstractWorld Soil Day 2021 encouraged the prevention of soil salinization and improved land productivity. As research underpins this effort, we analysed trends in research on water and salt mobilization in saline soils and groundwater over the past 20 years. We found that the average studies have increased by 30%, from 110 in 2003–2015 to 143 in 2016–2022, with agriculture, water resources and environmental science being the main research fields. The most common research interests were anthropogenic impact (28.6%) and climate change (27.8%), followed by agricultural irrigation management (20%). A keyword clustering analysis revealed that the studies could be classified into four categories: “Agricultural production,” “Freshwater and groundwater salinization,” “Seawater intrusion,” and “Solute dynamic migration.” The most frequently used keyword was “transport” while the use of “freshwater,” “groundwater,” and “seawater intrusion” has increased sharply, suggesting that seawater intrusion and freshwater salinization are an area of increasing interest related to climate change. We identified comprehensive simulating systems for seawater intrusion as an important area for future research. We recommend that promoting a comprehensive and quantitative understanding of water and salt transport in saline soil is needed to ensure stakeholders are provided with science‐based information required for policymaking aimed towards sustainable development.

Regularities of the structure of the Mozyr salt cryptodiapir (Gomel region of Republic Belarus)

According to drilling data, the internal structure of the Mozyr salt cryptodiapir has been reconstructed, the main elements of which are strongly compressed folds with radially arranged layers on the wings, complicating domes and inter-dome depressions, flexures. A high degree of interrelation between the modern relief and the cryptodiapir roof buried at a depth of several hundred meters has been established. It is explained by the continued mobility of salts at the present stage. This feature allows us to supplement the structural and geological data with the results of morphostructural analysis of the relief and to identify certain elements of order in the structure of the Mozyr dome.

Quantifying the impact of climate extremes on salt mobilization and loading in non-developed, high-desert landscapes using SWAT

Excess salt loading from watershed landscapes into river systems acts as a chemical stressor in water bodies and can have significant impacts on downstream water quality. High salinity threatens sustainable crop production globally and is especially prevalent in semi-arid and arid regions. However, relatively little research has been conducted to evaluate salt movement and loadings in natural, high-desert catchments in the face of climate change and extreme climate events. In this study, we use the watershed model SWAT and a newly developed salinity module to simulate the mass transport of 8 major salt ions, SO42−, Cl−, CO32−, HCO3−, Ca2+, Na+, Mg2+, and K+, in the soil-aquifer-stream system of the Purgatoire River Watershed (PRW) (Colorado, USA, 8935 km2) via major hydrologic pathways (surface runoff, percolation, recharge, soil lateral flow, groundwater upflux, groundwater discharge) and quantify changes in predicted salt loads with possible future increasing storm intensity. The PRW is susceptible to high salt transport due to high topographic slopes, dry climatic conditions, and sparse vegetation, and loads to the Arkansas River, a major source of irrigation water in the Arkansas River Basin. From study results we conclude that 99% of salt in the Purgatoire River originates from subsurface water pathways (soil lateral flow, groundwater flow), composed primarily of SO42−, Ca2+, and HCO3−. If intensity of large storms increases by 5% and 35%, the total salt mass exported from the watershed increases by 12% and 73%, respectively, indicating large influxes of legacy salt from the soil-aquifer system. For baseline and storm intensity scenarios, the PRW contributes significant salt loads to agricultural regions via the Arkansas River, highlighting the need for basin-wide salt management strategies to include upland desert regions. We expect these results, and associated consequences for salt management, to be similar for other upland desert catchments worldwide.

Freshwater Salinization Syndrome Alters Retention and Release of 'Chemical Cocktails' along Flowpaths: from Stormwater Management to Urban Streams.

We investigate impacts of Freshwater Salinization Syndrome (FSS) on mobilization of salts, nutrients, and metals in urban streams and stormwater BMPs by analyzing original data on concentrations and fluxes of salts, nutrients, and metals from 7 urban watersheds in the Mid-Atlantic U.S. and synthesizing literature data. We also explore future critical research needs through a survey of practitioners and scientists. Our original data show: (1) sharp pulses in concentrations of salt ions and metals in urban streams directly following both road salt events and stream restoration construction (e.g., similar to the way concentrations increase during other soil disturbance activities); (2) sharp declines in pH (acidification) in response to road salt applications due to mobilization of H+ from soil exchange sites by Na+; (3) sharp increases in organic matter from microbial and algal sources (based on fluorescence spectroscopy) in response to road salt applications likely due to lysing cells and/or changes in solubility; (4) significant retention (~30-40%) of Na+ in stormwater BMP sediments and floodplains in response to salinization; (5) increased ion exchange and mobilization of diverse salt ions (Na+, Ca2+, K+, Mg2+), nutrients (N, P), and trace metals (Cu, Sr) from stormwater BMPs and restored streams in response to FSS; (6) downstream increasing loads of Cl-, SO4 2-, Br-, F-, and I- along flowpaths through urban streams, and P release from urban stormwater BMPs in response to salinization, and (7) a significant annual reduction (> 50%) in Na+ concentrations in an urban stream when road salt applications were dramatically reduced, which suggests potential for ecosystem recovery. We compared our original results to published metrics of contaminant retention and release across a broad range of stormwater management BMPs from North America and Europe. Overall, urban streams and stormwater management BMPs consistently retain Na+ and Cl- but mobilize multiple contaminants based on salt types and salinity levels. Finally, we present our top 10 research questions regarding FSS impacts on urban streams and stormwater management BMPs. Reducing diverse 'chemical cocktails' of contaminants mobilized by freshwater salinization is now a priority for effectively and holistically restoring urban waters.

Structural analysis of layered evaporites using internal deformation patterns: Examples from Santos and Campos basins, Brazil

The Santos and Campos basins, offshore southeastern Brazil, contain layered evaporite sequences (LES) deposited during the Late Aptian, marking the end of lacustrine and beginning of restricted marine conditions. Density and velocity differences between evaporite minerals such as halite, anhydrite, carnalite, tachyhydrite and other bittern salts result in strong seismic impedance contrasts and therefore enable excellent stratal imaging of internal salt deformation. Different acoustic responses allow a detailed analysis of the internal deformation of evaporites, with the corresponding mechanical properties providing constraints on regional salt flow in the Santos and Campos basins. Detailed mapping and analysis of deformed LES support conclusions from cross-section restorations and provide insight on local salt flow and deformation mechanisms. This study utilizes kinematically restored regional sections to characterize overall basin-wide salt flow, while leveraging salt facies and their control on internal salt fold styles to demonstrate localized salt deformation. The important results from this study are the following. a) Santos and Campos basins are linked extension-contraction systems, however pre-existing basin-wide changes in paleo-topography represents a fundamental control in the overall salt flow, accounting for much of the downdip contraction in the middle of the basins rather than the toe of the system. b) Salt mobilization due to gravity initiated early and there is evidence that it was contemporaneous with evaporite deposition in many parts of the basins. Intrasalt unconformities and stratigraphic features are presented to support this conclusion. c) Mechanical stratigraphy within the LES play an important role in controlling intra-salt structural styles, and their fold interference patterns can be used to understand salt deformation in great detail. These results can be applied to better investigate a spectrum of salt tectonic problems in the basins and elsewhere, such as regional and localized salt flow, sub-regional prediction of weld kinematics and local prediction of weak salt units for drilling hazard analysis.

Umbrella evaporator for continuous solar vapor generation and salt harvesting from seawater

Solar vapor generation, which uses photothermal materials to desalinate seawater by evaporation, is a promising technology to mitigate the water scarcity problem, but its performance is hindered by large heat leak and salt accumulation problems. Here we report an umbrella evaporator that achieves efficient vapor generation and salt harvesting concurrently via double-sided evaporation and reveal the salt nucleation, growth, and falling mechanism. The evaporator reaches an evaporation rate of 1.25 kg m −2 ·h −1 under ambient conditions, and its continuous operation for vapor and salt production from seawater is demonstrated. The salt mobility on the evaporation surface determines whether the salt could accumulate at the edge, which is influenced by water supply, solar intensity, salinity, and Mg 2+ and Ca 2+ contents.A simple salt creeping test on a glass slide is developed to determine whether and to what extent seawater needs to be pre-treated for continuous operation. • Umbrella evaporator achieves a high efficiency via double-sided evaporation • Central water supply results in salt accumulation at edges • Salt grows from the front by wicking water through its porous structures • Salt creeping behaviors indicate if Ca 2+ and Mg 2+ content is below the lower limit Solar evaporation could mitigate water stress problems, but challenges remain in structural improvement of devices, salt accumulation, and salt harvesting mechanisms. Ma et al. show an umbrella evaporator that achieves efficient vapor generation and salt harvesting concurrently via double-sided evaporation and reveal the salt nucleation, growth, and falling mechanism of salt harvesting.