Hydrodynamic conceptual model of groundwater in the headwater of the Rio de Oro, Santander (Colombia) by geochemical and isotope tools

Abstract Metamorphic, igneous and sedimentary rocks, with low to no primary porosity, outcrop in the La Moza micro-basin stream (headwater of the Rio de Oro). In this high mountain system, water isotopic composition of rainwater, water isotopes and geochemistry of groundwater (springs) and surface water were determined. Groundwater flows are associated to phreatic aquifers in relationship with secondary porosity generated by fracturing, which is increased by dissolution processes in case of carbonate formation producing karstic systems and by the weathering phenomenon mainly affecting granodioritic rocks. Water geochemistry shows low to medium electrical conductivity (EC) depending on the geological formation, but a unique calcium bicarbonate facies. Spring water EC shows limited temporal variations. The isotopic composition of spring indicates a meteoric origin, local infiltration and groundwater flows with low residence time. A conceptual model of the recharge zone is proposed that crosses the surface watershed and covers part of the adjacent Rio Jordán basin, where the Berlin Paramo is located.

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Hydrothermal alteration of aragonitic biocarbonates: assessment of micro- and nanostructural dissolution–reprecipitation and constraints of diagenetic overprint from quantitative statistical grain-area analysis

Biogeosciences ◽

10.5194/bg-15-7451-2018 ◽

2018 ◽

Vol 15 (24) ◽

pp. 7451-7484 ◽

Cited By ~ 4

Author(s):

Laura A. Casella ◽

Sixin He ◽

Erika Griesshaber ◽

Lourdes Fernández-Díaz ◽

Martina Greiner ◽

...

Keyword(s):

Hydrothermal Alteration ◽

Structural Changes ◽

Geochemical Data ◽

Present Contribution ◽

Secondary Porosity ◽

Biogenic Carbonate ◽

Carbonate Formation ◽

Hard Tissues ◽

Primary Porosity ◽

Carbonate Materials

Abstract. The assessment of diagenetic overprint on microstructural and geochemical data gained from fossil archives is of fundamental importance for understanding palaeoenvironments. The correct reconstruction of past environmental dynamics is only possible when pristine skeletons are unequivocally distinguished from altered skeletal elements. Our previous studies show (i) that replacement of biogenic carbonate by inorganic calcite occurs via an interface-coupled dissolution–reprecipitation mechanism. (ii) A comprehensive understanding of alteration of the biogenic skeleton is only given when structural changes are assessed on both, the micrometre as well as on the nanometre scale.In the present contribution we investigate experimental hydrothermal alteration of six different modern biogenic carbonate materials to (i) assess their potential for withstanding diagenetic overprint and to (ii) find characteristics for the preservation of their microstructure in the fossil record. Experiments were performed at 175 °C with a 100 mM NaCl + 10 mM MgCl2 alteration solution and lasted for up to 35 days. For each type of microstructure we (i) examine the evolution of biogenic carbonate replacement by inorganic calcite, (ii) highlight different stages of inorganic carbonate formation, (iii) explore microstructural changes at different degrees of alteration, and (iv) perform a statistical evaluation of microstructural data to highlight changes in crystallite size between the pristine and the altered skeletons.We find that alteration from biogenic aragonite to inorganic calcite proceeds along pathways where the fluid enters the material. It is fastest in hard tissues with an existing primary porosity and a biopolymer fabric within the skeleton that consists of a network of fibrils. The slowest alteration kinetics occurs when biogenic nacreous aragonite is replaced by inorganic calcite, irrespective of the mode of assembly of nacre tablets. For all investigated biogenic carbonates we distinguish the following intermediate stages of alteration: (i) decomposition of biopolymers and the associated formation of secondary porosity, (ii) homoepitactic overgrowth with preservation of the original phase leading to amalgamation of neighbouring mineral units (i.e. recrystallization by grain growth eliminating grain boundaries), (iii) deletion of the original microstructure, however, at first, under retention of the original mineralogical phase, and (iv) replacement of both, the pristine microstructure and original phase with the newly formed abiogenic product.At the alteration front we find between newly formed calcite and reworked biogenic aragonite the formation of metastable Mg-rich carbonates with a calcite-type structure and compositions ranging from dolomitic to about 80 mol % magnesite. This high-Mg calcite seam shifts with the alteration front when the latter is displaced within the unaltered biogenic aragonite. For all investigated biocarbonate hard tissues we observe the destruction of the microstructure first, and, in a second step, the replacement of the original with the newly formed phase.

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Hydrogeochemical temporal variations related to changes of seismic activity at Tenerife, Canary Islands

10.5194/egusphere-egu21-15098 ◽

2021 ◽

Author(s):

Cecilia Amonte ◽

María Asensio-Ramos ◽

Gladys V. Melián ◽

Nemesio M. Pérez ◽

Eleazar Padrón ◽

...

Keyword(s):

Isotopic Composition ◽

Seismic Activity ◽

Temporal Variations ◽

Total Alkalinity ◽

Molar Ratio ◽

Sampling Point ◽

Volcanic System ◽

Mean Values ◽

Isotopic Analyses ◽

San Fernando

The oceanic active volcanic island of Tenerife (2034 km2) is the largest of the Canarian archipelago. There are more than 1,000 galleries (horizontal drillings) in the island, which are used for groundwater exploitation and allow reaching the aquifer at different depths and elevations. During a two-year period (July 2016 to July 2018), a hydrogeochemical study was carried out in two galleries on Tenerife (Fuente del Valle and San Fernando) for volcanic monitoring purposes with weekly sampling. Physicochemical parameter of water, such us temperature (&#186;C), pH and electrical conductivity (E.C., &#181;S&#183;cm-1), were measured in-situ at each sampling point and chemical/isotopic composition of the water determined later in the laboratory.Temperature values showed mean values of 28.1 &#186;C and 19.0 &#186;C for Fuente del Valle and San Fernando galleries, respectively. According to the average pH values, which were 6.30 for Fuente del Valle and 7.13 for San Fernando, and based on the chemical composition, both galleries are sodium-bicarbonate (Na-HCO3) type. E.C. values in both galleries presented high ranges, with mean values of 975 and 1648 &#181;S&#183;cm-1 for Fuente del Valle and San Fernando, respectively. The total alkalinity mean value of groundwater from Fuente del Valle gallery was 11.3 mEq&#183;L-1 HCO3-, while that from San Fernando was 17.3 mEq&#183;L-1 HCO3-. The SO42-/Cl molar ratio was 0.59 and 3.4 for the samples from Fuente del Valle and San Fernando galleries, respectively.The &#948;18O and &#948;D isotopic analyses showed a meteoric origin of groundwaters, with mean values of -6.2&#8240; and -26&#8240; vs. VSMOW for Fuente del Valle and -6.2&#8240; and -21 &#8240; vs. VSMOW for San Fernando. The isotopic data showed a strong interaction with endogenous gases such as CO2, H2S, H2, etc. Regarding the isotopic composition of total dissolved carbon species, expressed as &#948;13CTDIC, average values of -0.17&#8240; and 0.26&#8240; were obtained for Fuente del Valle and San Fernando galleries, respectively. These results show an endogenous origin CO2 signature, heavier for Fuente del Valle gallery groundwater compared to that of San Fernando.Groundwater physicochemical parameters exhibited stable values throughout the study period, while significant temporal variations were observed in the total alkalinity, SO42-/Cl- molar ratio, &#948;18O and &#948;D. Changes in isotopic ratios coincided with variations observed in the alkalinity and the SO42-/Cl- molar ratio. On October 2, 2016, a seismic swarm of long-period events was recorded on Tenerife followed by a general increase of the seismic activity in and around the island. A correlation was observed between some hydrogeochemical parameters in the groundwaters of the galleries, related to observed changes of the seismic activity. This study demonstrates the suitability of monitoring the chemical and isotopic composition of groundwater from Fuente del Valle and San Fernando galleries, as they are sensitive to changes in volcanic activity on Tenerife island. The study of groundwaters associated to a volcanic system can provide information about the magmatic gas input in the aquifer, modelling how the groundwaters flow through the edifice, and offer important geochemical information that could herald a future eruption.

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Petrophysical Properties and Digenetic Evolution of Shuaiba Formation in Nasiriyah Oil Field, Southern Iraq

Iraqi Journal of Science ◽

10.24996/ijs.2021.62.12.19 ◽

2021 ◽

pp. 4810-4818

Author(s):

Marwah H. Khudhair

Keyword(s):

Gamma Ray ◽

Water Saturation ◽

Middle Part ◽

Effective Porosity ◽

Oil Field ◽

Neutron Density ◽

Petrophysical Properties ◽

Secondary Porosity ◽

Primary Porosity ◽

Gamma Ray Log

Shuaiba Formation is a carbonate succession deposited within Aptian Sequences. This research deals with the petrophysical and reservoir characterizations characteristics of the interval of interest in five wells of the Nasiriyah oil field. The petrophysical properties were determined by using different types of well logs, such as electric logs (LLS, LLD, MFSL), porosity logs (neutron, density, sonic), as well as gamma ray log. The studied sequence was mostly affected by dolomitization, which changed the lithology of the formation to dolostone and enhanced the secondary porosity that replaced the primary porosity. Depending on gamma ray log response and the shale volume, the formation is classified into three zones. These zones are A, B, and C, each can be split into three rock intervals in respect to the bulk porosity measurements. The resulted porosity intervals are: (I) High to medium effective porosity, (II) High to medium inactive porosity, and (III) Low or non-porosity intervals. In relevance to porosity, resistivity, and water saturation points of view, there are two main reservoir horizon intervals within Shuaiba Formation. Both horizons appear in the middle part of the formation, being located within the wells Ns-1, 2, and 3. These intervals are attributed to high to medium effective porosity, low shale content, and high values of the deep resistivity logs. The second horizon appears clearly in Ns-2 well only.

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Desiccation-crack-induced salinization in deep clay sediment

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-13155-2012 ◽

2012 ◽

Vol 9 (11) ◽

pp. 13155-13189

Author(s):

S. Baram ◽

Z. Ronen ◽

D. Kurtzman ◽

C. Küells ◽

O. Dahan

Keyword(s):

Isotopic Composition ◽

Conceptual Model ◽

Pore Water ◽

Vadose Zone ◽

Land Surface ◽

Water Infiltration ◽

Arid Environments ◽

Desiccation Cracks ◽

The Impact ◽

Desiccation Crack

Abstract. A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water-content and on the chemical and isotopic composition of the sediment and pore-water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ∼3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl-) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a Desiccation-Crack-Induced Salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

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Temporal variations of methane concentration and isotopic composition in groundwater of the St. Lawrence Lowlands, eastern Canada

Hydrogeology Journal ◽

10.1007/s10040-017-1677-y ◽

2017 ◽

Vol 26 (2) ◽

pp. 533-551 ◽

Cited By ~ 4

Author(s):

Christine Rivard ◽

Geneviève Bordeleau ◽

Denis Lavoie ◽

René Lefebvre ◽

Xavier Malet

Keyword(s):

Isotopic Composition ◽

Methane Concentration ◽

Temporal Variations ◽

Eastern Canada

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Desiccation-crack-induced salinization in deep clay sediment

Hydrology and Earth System Sciences ◽

10.5194/hess-17-1533-2013 ◽

2013 ◽

Vol 17 (4) ◽

pp. 1533-1545 ◽

Cited By ~ 23

Author(s):

S. Baram ◽

Z. Ronen ◽

D. Kurtzman ◽

C. Külls ◽

O. Dahan

Keyword(s):

Isotopic Composition ◽

Conceptual Model ◽

Pore Water ◽

Vadose Zone ◽

Land Surface ◽

Water Infiltration ◽

Arid Environments ◽

Desiccation Cracks ◽

The Impact ◽

Desiccation Crack

Abstract. A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water content and on the chemical and isotopic composition of the sediment and pore water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ~ 3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl−) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a desiccation-crack-induced salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

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Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

Biogeosciences ◽

10.5194/bg-7-1469-2010 ◽

2010 ◽

Vol 7 (5) ◽

pp. 1469-1479 ◽

Cited By ~ 14

Author(s):

M. Bartrons ◽

L. Camarero ◽

J. Catalan

Keyword(s):

Isotopic Composition ◽

Nitrogen Deposition ◽

Pore Water ◽

Soil Type ◽

Inorganic Nitrogen ◽

Mountain Lakes ◽

High Mountain ◽

Dissolved Inorganic Nitrogen ◽

High Mountain Lakes ◽

Type Flow

Abstract. Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN) between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover) vary considerably with elevation. The isotopic composition of nitrogen (δ15N) is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio. We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW) and sediment pore water (SPW) from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰), with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes. In the water column, the range of δ15N values was larger for ammonium (−9.4‰ to 7.4‰) than for nitrate (−11.4‰ to −3.4‰), as a result of higher variation both between and within lakes (epilimnetic vs. DCM water). For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion). Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil interaction; and another highly influenced by soil conditions. The snow-type flow path contributes low DIN concentrations depleted in 15N, whereas the soil-type flow path contributes high nitrate concentrations with higher δ15N. The proportion of these two types of source correlates with average catchment features when there is extensive snow cover during spring and early summer and probably becomes more dependent on local characteristics around the lake as summer advances. Lake depth and pore water ammonium concentrations, among other features, introduce secondary variation. In the context of nitrogen deposition studies, lakes with higher snow-type influence will probably register changes in N deposition and pollution sources better, whereas lakes with higher soil-type influence may reflect long-term effects of vegetation and soil dynamics.

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Temporal Variations of Isotopic Composition of Glacier-River Water During Summer: Observations at Austre Okstindbreen, Okstindan, Norway

Journal of Glaciology ◽

10.1017/s0022143000007073 ◽

1988 ◽

Vol 34 (118) ◽

pp. 309-317 ◽

Cited By ~ 22

Author(s):

Wilfred H. Theakstone

Keyword(s):

Isotopic Composition ◽

River Water ◽

Temporal Variations ◽

Surface Melting ◽

Base Flow ◽

Strongly Correlated ◽

Drainage Systems ◽

Fine Weather ◽

Air Temperatures ◽

Glacier Ice

AbstractThe isotopic composition of river water discharging from the Norwegian glacier, Austre Okstindbreen, in summer varies on both daily and longer-term scales. Most δ18o values of samples from the principal river are within the range −12.5 to −14.0‰). Because new snow tends to be relatively depleted of 8180, water leaving the glacier early in the summer has low δ18O values. Subsequently, values rise as contributions of old snow, glacier ice, and their melt waters, which are isotopically heavier (median δ18O values generally above −12.0‰) dilute the δ18O depleted base-flow component of discharge, a mixture of waters with different histories of formation, storage, and transit. Accumulation-area melting contributes significantly to river discharge. Towards the end of the summer, as surface melting declines, δ18O values tend to fall. Between-year differences of within-summer trends reflect differences of development of the glacier’s drainage systems. The drainage systems are affected by outbursts from a glacier-dammed lake. During fine weather, δ18ovariations follow the diurnal cycle of surface melting: they are strongly correlated with, but lag behind, air temperatures. Perturbations during rainfall cannot be explained simply in terms of the isotopic composition of the precipitation, since low values may be associated with isotopically heavy rainfall. Displacement of water previously stored within or below the glacier may account for the anomaly. Contrasts of composition characterize different rivers leaving the glacier, because the relative contributions of various water sources differ.

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