scholarly journals Cements, Waters, and Scales: An Integrated Study of the Szeged Geothermal Systems (SE Hungary) to Characterize Natural Environmental Conditions of the Thermal Aquifer

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Andrea Varga ◽  
Gábor Bozsó ◽  
István Garaguly ◽  
Béla Raucsik ◽  
Attila Bencsik ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Thermal Water ◽  
Pannonian Basin ◽  
Integrated Approach ◽  
High Heat ◽  
Geothermal Systems ◽  
Geothermal Waters ◽  
Deep Aquifer ◽  
Saturation State ◽  
Calcite Saturation

The study area, Pannonian Basin (Central Europe), is characterized by high heat flow and presence of low-enthalpy geothermal waters. In the Szeged Geothermal Systems (Hungary), having Miocene to Pliocene sandstone aquifers with dominantly Na–HCO3-type thermal water, unwanted carbonate scaling was observed. An integrated approach consisting of host rock and scale mineralogical and petrographic analyses as well as water chemistry led to a better understanding of the characteristic natural (geogenic) environmental conditions of the geothermal aquifers and to highlight their technical importance. Analyses of the reservoir sandstones showed that they are mineralogically immature mixed carbonate-siliciclastic rocks with significant macroporosity. Detrital carbonate grains such as dolomite and limestone fragments appear as important framework components (up to ~20–25%). During water–rock interactions, they could serve as a potential source of the calcium and bicarbonate ions, contributing to the elevated scaling potential. Therefore, this sandstone aquifer cannot be considered as a conventional siliciclastic reservoir. In mudrocks, a significant amount of organic matter also occurs, triggering CO2producing reactions. Correspondingly, framboidal pyrite and ferroan calcite are the main cement minerals in all of the studied sandstone samples which can suggest that calcite saturation state of the thermal fluid is close to equilibrium in oxygen-depleted pore water. Analysis of the dominant carbonate crystals in the scale can suggest that growth of the feather dendrites of low-Mg calcite was probably driven by rapid CO2degassing of CO2-rich thermal water under far-from-equilibrium conditions. Based on hydrogeochemical data and related indices for scaling and corrosion ability, the produced bicarbonate-rich (up to 3180 mg/l) thermal water has a significant potential for carbonate scaling which supports the aforementioned statement. Taking into consideration our present knowledge of geological setting of the studied geothermal systems, temporal changes in chemical composition and temperature of the thermal water during the heating period can indicate upwelling fluids from a deep aquifer. Regarding the pre-Neogene basement, hydrologic contact with a Triassic carbonate aquifer might be reflected in the observed chemical features such as decreased total dissolved solids and increased bicarbonate content with high scale-forming ability. The proposed upflow of basin-derived water could be channeled by Neogene to Quaternary fault zones, including compaction effects creating fault systems above the elevated basement high. The results may help to understand the cause of the high carbonate scale precipitation rates in geothermal systems tapping sandstone aquifers.

scholarly journals Hydrogeochemical Characterization as a Tool to Recognize “Masked Geothermal Waters” in Bahía Concepción, Mexico

Resources ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 23
Author(s):  
Pablo Hernández-Morales ◽  
Jobst Wurl ◽  
Carlos Green-Ruiz ◽  
Diego Morata
Keyword(s):  
Spatial Distribution ◽  
Thermal Water ◽  
Elevated Temperatures ◽  
Ph Value ◽  
Spring Water ◽  
Geothermal Resources ◽  
Geothermal Waters ◽  
New Approach ◽  
Deep Reservoir ◽  
Hydrogeochemical Characterization

Geo-thermalism has been widely recognized on the Baja California Peninsula, especially during the last decade. The current research, carried out on Bahia Concepcion, evidences the existence of geothermal springs, which get recharged mainly by groundwater and seawater. The groundwater can be characterized as Na+-Cl− and Na+-HCO3− type, with a pH value close to neutrality. The slightly more acidic thermal sites presented temperatures between 32 °C and 59 °C at the surface. Based on the relationships of the Cl− and Br−, as well as the B/Cl−, and Br−/Cl− ratios, seawater was recognized as the main source of salinity. The spatial distribution is explained directly through marine intrusion, or via sprays and aerosols within the rainwater. Seawater ratios in thermal springs varied from 62% to 83%, corresponding mainly to shallow inflow, but seawater inputs into the deep thermal reservoir were also recognized. Temperatures in the geothermal deep reservoir were inferred from 114 to 209 °C, calculated through the SiO2 and Na+-K+ geothermometers. In addition to previously reported thermal sites at Bahía Concepción, and based on their elevated temperatures, two new sites were identified. Another five springs do not fulfill the commonly used definition, based on differential temperature, but show the typical hydrogeochemical signature of thermal water. A new approach to identify this low-temperature geothermal-influenced spring water by its hydrogeochemical composition is presented, for which the term “Masked Geothermal Waters” (MGW) is introduced. Our findings increase the area of the geothermal anomaly and, therefore, the potential of geothermal resources. The approach proposed in this research will also be useful to identify more MGW in other coastal areas.

Potentials of transboundary thermal water resources in the western part of the Pannonian basin

Geothermics ◽  
2015 ◽  
Vol 55 ◽  
pp. 88-98 ◽  
Author(s):  
Nina Rman ◽  
Nóra Gál ◽  
Daniel Marcin ◽  
Julia Weilbold ◽  
Gerhard Schubert ◽  
...  
Keyword(s):  
Water Resources ◽  
Thermal Water ◽  
Pannonian Basin

scholarly journals Biofilm Forming Bacteria during Thermal Water Reinjection

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Máté Osvald ◽  
Gergely Maróti ◽  
Bernadett Pap ◽  
János Szanyi
Keyword(s):  
Thermal Water ◽  
Oxygen Demand ◽  
Geothermal System ◽  
Biological Processes ◽  
Geothermal Systems ◽  
The Past ◽  
Surface System ◽  
Buffer Tank ◽  
Physical And Chemical ◽  
Phenol Index

Reinjection of heat-depleted thermal water has long been in the center of scientific interest in Hungary regarding around 1000 operating thermal wells. While the physical and chemical aspects of reinjection have partly been answered in the past years, the effects of biological processes are still less known. We carried out our investigations in the surface elements of the Hódmezővásárhely geothermal system which is one of the oldest operating geothermal systems in Hungary. About one-third of the used geothermal water has been reinjected since 1998 by two reinjection wells at the end of the thermal loops. During the operation, plugging of the surface system was experienced within a few-day-long period, due to biological processes. The goal of our research was to find the dominant species of the microbial flora and to make a proposal to avoid further bacterial problems. We found that the reinjected, therefore the produced, water’s chemical oxygen demand, phenol index, and BTEX composition basically determine the appearing flora on the surface. When the concentration of these compounds in the thermal water is significant and residence time is long enough in the buffer tank, certain bacteria can be much more dominant than others, thus able to form a biofilm which plugs the surface equipment much more than it is expected.

scholarly journals Processes determining the marine alkalinity and calcium carbonate saturation state distributions

2014 ◽  
Vol 11 (24) ◽  
pp. 7349-7362 ◽  
Author(s):  
B. R. Carter ◽  
J. R. Toggweiler ◽  
R. M. Key ◽  
J. L. Sarmiento
Keyword(s):  
Calcium Carbonate ◽  
The Arctic ◽  
Effect Of Temperature ◽  
Minor Role ◽  
Co2 Solubility ◽  
Saturation State ◽  
Marine System ◽  
Calcite Saturation ◽  
River Mouths ◽  
Arctic Surface

Abstract. We introduce a composite tracer for the marine system, Alk*, that has a global distribution primarily determined by CaCO3 precipitation and dissolution. Alk* is also affected by riverine alkalinity from dissolved terrestrial carbonate minerals. We estimate that the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk* in the Arctic surface and particularly near river mouths. Strong net carbonate precipitation results in low Alk* in subtropical gyres, especially in the Indian and Atlantic oceans. Upwelling of dissolved CaCO3-rich deep water elevates North Pacific and Southern Ocean Alk*. We use the Alk* distribution to estimate the variability of the calcite saturation state resulting from CaCO3 cycling and other processes. We show that regional differences in surface calcite saturation state are due primarily to the effect of temperature differences on CO2 solubility and, to a lesser extent, differences in freshwater content and air–sea disequilibria. The variations in net calcium carbonate cycling revealed by Alk* play a comparatively minor role in determining the calcium carbonate saturation state.

scholarly journals Morphology of <i>Emiliania huxleyi</i> coccoliths on the North West European shelf – is there an influence of carbonate chemistry?

2014 ◽  
Vol 11 (3) ◽  
pp. 4531-4561 ◽  
Author(s):  
J. R. Young ◽  
A. J. Poulton ◽  
T. Tyrrell
Keyword(s):  
Environmental Samples ◽  
Significant Variation ◽  
Emiliania Huxleyi ◽  
Morphometric Study ◽  
Saturation State ◽  
North West ◽  
The North ◽  
Microscope Images ◽  
Calcite Saturation ◽  
The Uk

Abstract. Within the context of the UK Ocean Acidification project, Emiliania huxleyi (type A) coccolith morphology was examined from samples collected during cruise D366. In particular, a morphometric study of coccolith size and degree of calcification was made on scanning electron microscope images of samples from shipboard CO2 perturbation experiments and from a set of environmental samples with significant variation in calcite saturation state (Ωcalcite). One bioassay in particular (E4 from the southern North Sea) yielded unambiguous results – in this bioassay exponential growth from a low level occurred with no artificial stimulation and coccosphere numbers increased ten-fold during the experiment. The samples with elevated CO2 saw significantly reduced coccolithophore growth. However, coccolithophore morphology was not significantly affected by the changing CO2 conditions even under the highest levels of perturbation (1000 μatm). Environmental samples similarly showed no correlation of coccolithophore morphology with calcite saturation state. Some variation in coccolith size and degree of calcification does occur but this seems to be predominantly due to genotypic differentiation between populations on the shelf and in the open ocean.

HyTheC - Multidisciplinary approach to conceptual modelling of hydrothermal systems in Croatia

2021 ◽  
Author(s):  
Mirja Pavić ◽  
Staša Borović ◽  
Maja Briški ◽  
Tihomir Frangen ◽  
Kosta Urumović
Keyword(s):  
Thermal Water ◽  
Pannonian Basin ◽  
Structural Characteristics ◽  
Hydrothermal Systems ◽  
Data Availability ◽  
System Level ◽  
Thermal Waters ◽  
Geophysical Research ◽  
Research Project ◽  
Systems Research

&lt;p&gt;The increase in thermal water utilisation is foreseen by many European and Croatian strategic documents regulating energetics, tourism, environmental protection and sustainable development. Croatian Geological Survey wishes to establish a multidisciplinary group for hydrothermal systems research which will contribute to responsible geothermal development in our country through a 5-year research project HyTheC which started in 2020.&lt;/p&gt;&lt;p&gt;Pannonian part of Croatia has favourable geothermal characteristics and natural thermal water springs emerge at two dozen localities, with temperatures up to 65 &amp;#176;C. These waters have been used for millennia, and in the past fifty years they are a basis for the development of tourism and health care centres which use the thermal water resource for heating, therapy and recreation (Borovi&amp;#263; &amp; Markovi&amp;#263;, 2015). As their water demand increased, higher quantities were abstracted and additional intake structures and wells were constructed.&lt;/p&gt;&lt;p&gt;Thermal springs are part of hydrothermal systems which include: recharge areas in the mountainous hinterlands of the springs; geothermal aquifers - in Croatia mostly fractured and karstified Mesozoic carbonate rocks (Borovi&amp;#263; et al., 2016) - in which water resides and gets heated due to heat flow from the Earth; and discharge areas in places with favourable structural characteristics of higher permeability. The continuous functioning of such systems depends on a delicate balance between groundwater flow velocities, precipitation/dissolution processes and structural framework.&lt;/p&gt;&lt;p&gt;In order to maintain that balance and use thermal water resources in a sustainable manner, a system-level understanding is required. Multidisciplinary methodology (structural geology, hydrogeology, geothermal, hydrogeochemical and geophysical research and remote sensing) will be used to construct conceptual models of systems, perform 3D geological modelling, hydrogeological and thermal parametrisation of the geological units involved in the thermal fluid flow, and conduct numerical simulations of system functioning in undisturbed conditions and with different extraction scenarios.&lt;/p&gt;&lt;p&gt;This methodology will be tested in three pilot areas in Croatia where thermal water is being utilized (Daruvar, Hrvatsko zagorje and Topusko). These three areas have significantly different levels of initial data availability and it shall therefore be determined which methodology and order of application of different methods should be applied while researching the systems with considerable existing data, medium amount of data and very scarce data, respectively.&lt;/p&gt;&lt;p&gt;Keywords&amp;#160;: hydrothermal system, natural thermal spring, multidisciplinary research, Croatia&lt;/p&gt;&lt;p&gt;References&lt;/p&gt;&lt;p&gt;Borovi&amp;#263;, S. &amp; Markovi&amp;#263;, T. 2015 : Utilization and tourism valorisation of geothermal waters in Croatia. Renewable and Sustainable Energy Reviews, 44, pp. 52-63.&lt;/p&gt;&lt;p&gt;Borovi&amp;#263;, S., Markovi&amp;#263;, T., Larva, O., Brki&amp;#263;, &amp;#381;. &amp; Mraz, V. 2016 : Mineral and Thermal Waters in the Croatian Part of the Pannonian Basin. U: Papi&amp;#263;, P., ur., Mineral and Thermal Waters of Southeastern Europe. Cham: Springer, pp. 31-45.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;ACKNOWLEDGMENT&lt;/p&gt;&lt;p&gt;The Installation Research project HyTheC (UIP-2019-04-1218) is funded by the Croatian Science Foundation.&lt;/p&gt;

Crustal and upper mantle velocity structure of the Pannonian Region using Rayleigh wave ambient noise tomography

2021 ◽  
Author(s):  
Máté Timkó ◽  
Lars Wiesenberg ◽  
Amr El-Sharkawy ◽  
Zoltán Wéber ◽  
Thomas Meier ◽  
...  
Keyword(s):  
Rayleigh Wave ◽  
Ambient Noise ◽  
Velocity Structure ◽  
Pannonian Basin ◽  
Vertical Component ◽  
High Heat ◽  
Moho Depth ◽  
Ambient Noise Tomography ◽  
Period Range ◽  
Waveform Data

&lt;p&gt;The Pannonian Basin is located in Central-Europe surrounded by the Alpine, Carpathian, and Dinarides mountain ranges. This is a back-arc basin characterized by shallow Moho depth, updoming mantle and high heat flow. In this study, we present the results of the Rayleigh wave based ambient noise tomography to investigate the velocity structure of the Carpathian-Pannonian region.&amp;#160;&lt;/p&gt;&lt;p&gt;For the ambient noise measurements, we collected the continuous waveform data from more than 1280 seismological stations from the broader Central-Eastern European region. This dataset embraces all the permanent and the temporary (AlpArray, PASSEQ, CBP, SCP) stations from the 9-degree radius of the Pannonian Basin which were operating between the time period between 2005 and 2018. All the possible vertical component noise cross-correlation functions were calculated and all phase velocity curves were determined in the 5-80 s period range using an automated measuring algorithm.&amp;#160;&lt;/p&gt;&lt;p&gt;The collected dispersion measurements were then used to create tomographic images that are characterized by similar velocity anomalies in amplitude, pattern and location that are consistent with the well-known tectonic and geologic structure of the research area and are comparable to previous tomographic models published in the literature.&lt;/p&gt;

scholarly journals Integrated high-resolution stratigraphy of a Middle to Late Miocene sedimentary sequence in the central part of the Vienna Basin

2011 ◽  
Vol 62 (2) ◽  
pp. 155-169 ◽  
Author(s):  
Wieske Paulissen ◽  
Stefan Luthi ◽  
Patrick Grunert ◽  
Stjepan Ćorić ◽  
Mathias Harzhauser
Keyword(s):  
High Resolution ◽  
Late Miocene ◽  
Pannonian Basin ◽  
Foreland Basin ◽  
Integrated Approach ◽  
Tectonic Activity ◽  
Sedimentary Sequence ◽  
Vienna Basin ◽  
Lake Pannon ◽  
North Alpine Foreland Basin

Integrated high-resolution stratigraphy of a Middle to Late Miocene sedimentary sequence in the central part of the Vienna BasinIn order to determine the relative contributions of tectonics and eustasy to the sedimentary infill of the Vienna Basin a high-resolution stratigraphic record of a Middle to Late Miocene sedimentary sequence was established for a well (Spannberg-21) in the central part of the Vienna Basin. The well is located on an intrabasinal high, the Spannberg Ridge, a location that is relatively protected from local depocentre shifts. Downhole magnetostratigraphic measurements and biostratigraphical analysis form the basis for the chronostratigraphic framework. Temporal gaps in the sedimentary sequence were quantified from seismic data, well correlations and high-resolution electrical borehole images. Stratigraphic control with this integrated approach was good in the Sarmatian and Pannonian, but difficult in the Badenian. The resulting sedimentation rates show an increase towards the Upper Sarmatian from 0.43 m/kyr to > 1.2 m/kyr, followed by a decrease to relatively constant values around 0.3 m/kyr in the Pannonian. The sequence reflects the creation of accommodation space during the pull-apart phase of the basin and the subsequent slowing of the tectonic activity. The retreat of the Paratethys from the North Alpine Foreland Basin during the Early Sarmatian temporarily increased the influx of coarsergrained sediment, but eventually the basin acted mostly as a by-pass zone of sediment towards the Pannonian Basin. At a finer scale, the sequence exhibits correlations with global eustasy indicators, notably during the Sarmatian, the time of greatest basin subsidence and full connectivity with the Paratethyan system. In the Pannonian the eustatic signals become weaker due to an increased isolation of the Vienna Basin from Lake Pannon.

Geochemical features of the geothermal and mineral waters from Apuseni Mountains, Romania

2020 ◽  
Author(s):  
Alin-Marius Nicula ◽  
Artur Ionescu ◽  
Cristian-Ioan Pop ◽  
Carmen Roba ◽  
Walter D’Alessandro ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Pannonian Basin ◽  
Water Sources ◽  
Mineral Waters ◽  
Thermal Waters ◽  
Geothermal Waters ◽  
Study Region ◽  
Apuseni Mountains ◽  
The North ◽  
North Western

&lt;p&gt;&lt;strong&gt;Geochemical features of the geothermal and mineral waters from Apuseni Mountains, Romania&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Alin-Marius Nicula&lt;sup&gt;1&lt;/sup&gt;, Artur Ionescu&lt;sup&gt;1,2&lt;/sup&gt;, Cristian-Ioan Pop&lt;sup&gt;1&lt;/sup&gt;, Carmen Roba&lt;sup&gt;1&lt;/sup&gt;, Walter D&amp;#8217;Alessandro&lt;sup&gt;3&lt;/sup&gt;, Ferenc Lazar Forray&lt;sup&gt;4&lt;/sup&gt;, Iancu Oraseanu&lt;sup&gt;5&lt;/sup&gt;, Calin Baciu&lt;sup&gt;1&lt;/sup&gt;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;&amp;#160;&lt;/sup&gt;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;Babes-Bolyai University, Faculty of Environmental Science and Engineering, Str. Fantanele nr. 30, 400294, Cluj-Napoca, Romania ([email protected])&lt;/p&gt;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;University of Perugia, Department of Physics and Geology, Via A. Pascoli 06123, Perugia, Italy&lt;/p&gt;&lt;p&gt;&lt;sup&gt;3&lt;/sup&gt;Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Via Ugo la Malfa, 153,&lt;/p&gt;&lt;p&gt;90146 Palermo, Italy&lt;/p&gt;&lt;p&gt;&lt;sup&gt;4&lt;/sup&gt;Department of Geology, Babes-Bolyai University, Kogalniceanu 1, 400084 Cluj-Napoca, Romania&lt;/p&gt;&lt;p&gt;&lt;sup&gt;5&lt;/sup&gt;Romanian Association of Hydrogeologists, Bucuresti, Romania&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The Apuseni Mountains are located in the western part of Romania and separate the Pannonian Basin from the Transylvanian Basin. These mountains are famous and intensely studied for their important non-ferrous metal resources. Few data were published about the geothermal potential of this area. More works have been dedicated to mineral waters, while the geothermal waters are only briefly described, without sufficient emphasis on them. The current research is focusing on the two categories, cold mineral and geothermal water in the Apuseni Mountains, compared to the surrounding areas, in order to better understand their genesis and the general context of the geothermalism in the study region. A preliminary survey of these waters was done in 2019 taking water and gas samples from 41 sources.&lt;/p&gt;&lt;p&gt;The pH varies between 6.00 and 9.02 and, the lowest values have been measured in the CO&lt;sub&gt;2&lt;/sub&gt;-rich waters of the Southern Apuseni Mountains. Water temperatures vary between 11.1 &lt;sup&gt;&amp;#226;&amp;#151;&amp;#139;&lt;/sup&gt;C and 81 &lt;sup&gt;&amp;#226;&amp;#151;&amp;#139;&lt;/sup&gt;C. In the southern part of the Apuseni Mountains, the geothermal waters are of the calcium bicarbonate type (Ca-HCO&lt;sub&gt;3&lt;/sub&gt;), while in the north-western part, the sodium bicarbonate type (Na-HCO&lt;sub&gt;3&lt;/sub&gt;) is more common. The water sources from the north-western part are close to the Pannonian Basin and show features comparable to the thermal waters of this basin. Conductivity values show significant variations between 142 and 2040 &amp;#181;S/cm, but regional homogeneities were observed. The highest concentration of bicarbonate was measured in one of the localities of the northern study area (Beiu&amp;#197;&amp;#159; Depression - 3318.4 mg/L). The dissolved heavy metal concentrations (Zn, Pb, Cd, Cr, Ni, Cu, Fe) in the water samples were also measured. For all the investigated waters, the heavy metal content was low. The highest concentrations were recorded for Fe 342.90 &amp;#181;g/L and Zn 86.14 &amp;#181;g/L. The isotopic data (&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H) demonstrate the meteoric origin of the thermal waters.&lt;/p&gt;&lt;p&gt;Some springs and wells release free gases. The gas chromatographic analyses show the prevalence of N&lt;sub&gt;2&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt;, with minor amounts of CH&lt;sub&gt;4 &lt;/sub&gt;in the water sources close to the Pannonian Basin. The isotope composition of Helium shows values between 0.9 and 2.18 R/Ra indicating a prevailing crustal source with a significant mantle component. In the case of &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C-CO&lt;sub&gt;2&lt;/sub&gt; the values range between -12.7 and -6.1 &amp;#8240; vs.V-PDB, indicating that the CO&lt;sub&gt;2&lt;/sub&gt; originates possibly from a limestone source.&lt;/p&gt;

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