Explore the vast range of titles available.

The Gonghe Basin Complex is a pull-apart basin located in the Northeastern Qinghai–Tibet plateau (Qinghai, China) displaying several geothermal features, such as high geothermal gradients and hot springs. The adjacent mountain ranges and the basement are comprised of granitoid rocks, which, at sufficient depth and temperature, are suitable for deep enhanced geothermal systems. Nonetheless, the origin of the heat source mechanisms is not conclusively determined so far. The presented study provides insights of the radiogenic heat productions of the Gonghe Basin Complex and its surroundings. In total, 30 newly sampled Triassic, Silurian, Ordovician, and Devonian intrusive rocks were extracted from outcrops in the surroundings and within the Gonghe Basin Complex, of which one sample was retrieved from exploration well DR2 at c. 1800 m. Samples were analyzed by thin section analysis and a petrographic description is provided. To geochemically characterize the samples, X-ray fluorescence measurements were performed, and radiogenic heat productions were subsequently calculated. Additionally, analysis of 341 intrusive, 105 extrusive, 155 sedimentary, and 76 metamorphic rocks of the Qinling–Qilianshan–Kunlunshan were taken from the literature and compared to the data sampled in the Gonghe Basin Complex. As evidenced in the presented research, the radiogenic heat production values measured in the Gonghe Basin Complex are within the highest calculated for the Qinling-Qilianshan-Kunlunshan. However, radiogenic heat production rates in the Gonghe Basin Complex range from < 1 µW m−3 in tonalites to > 5 µW m−3 in two-mica granites and syenogranites. Nonetheless, average heat productions analyzed do not evidence large intrusions of HHP (high heat producing) granitoids as a source of the geothermal features in the Gonghe Basin Complex.

This paper combines a review on the importance of dust composition with respect to numerous atmospheric impacts with field measurements performed in African and Central Asian dust. In the review part, the most important dust components and their relevance for certain processes are outlined. Typical compositions from bulk measurements for African and Asian dust are presented. Generally the local variation in composition can be higher than the differences between Asian and African dust and their according specific sources. While similar general results are available from individual particle analyses, these investigations add important information on mixing state and homogeneity of composition. Atmospheric aging of mineral dust is observed globally, depending on transport distances from the sources and transport environment. As an illustration, comparative field measurements of African and Asian dust deposition are presented.

Hydrothermal alteration is a common process in active geothermal systems and can significantly change the physiochemical properties of rocks. To improve reservoir assessment and modeling of high-temperature geothermal resources linked to active volcanic settings, a detailed understanding of the reservoir is needed. The Los Humeros Volcanic Complex, hosting the third largest exploited geothermal field in Mexico, represents a natural laboratory to investigate the impact of hydrothermal processes on the rock properties through andesitic reservoir cores and outcropping analogs. Complementary petrographic and chemical analyses were used to characterize the intensities and facies of hydrothermal alteration. The alteration varies from argillic and propylitic facies characterized by no significant changes of the REE budget indicating an inert behavior to silicic facies and skarn instead showing highly variable REE contents. Unaltered outcrop samples predominantly feature low matrix permeabilities (< 10–17 m2) as well as low to intermediate matrix porosities (< 5–15%), thermal conductivities (0.89–1.49 W m−1 K−1), thermal diffusivities (~ 0.83 10–6 m2 s−1), and sonic wave velocities (VP: ~ 2800–4100 m s−1, VS: ~ 1600–2400 m s−1). Average magnetic susceptibility and specific heat capacity range between 2.4–7.0 10–3 SI and 752–772 J kg−1 K−1, respectively. In contrast, the hydrothermally altered reservoir samples show enhanced porosities (~ 7–23%), permeabilities (10–17–10–14 m2), and thermal properties (> 1.67 W m−1 K−1; > 0.91 10–6 m2 s−1), but a significant loss of magnetic susceptibility (10–3–10–6 SI). In particular, this latter characteristic appears to be a suitable indicator during geophysical survey for the identification of hydrothermalized domains and possible pathways for fluids. The lack of clear trends between alteration facies, alteration intensity, and chemical indices in the studied samples is interpreted as the response to multiple and/or repeated hydrothermal events. Finally, the proposed integrated field-based approach shows the capability to unravel the complexity of geothermal reservoir rocks in active volcanic settings.

A borehole heat exchanger array was installed in an Alpine karst aquifer for the first time in Europe. It is composed of nine 400 m deep boreholes in the dolomitic marble of the Hochstegen Formation. New approaches were developed for this unprecedented application and potential risks were checked throughout the sinking of the initial exploratory wellbore. As Finkenberg is located in a tourist area, drilling operations had to be executed within only a few weeks. Several springs downstream from the drilling site are sources of drinking water and tap water supply. Given that the degree and distribution of the Hochstegen Formation karstification was unknown, a spring monitoring program was mandatory in order to obtain drilling permission from public authorities. A practicable and affordable spring monitoring program including several physical and chemical parameters was developed and implemented to document the potential impact of the drilling activities on the spring water. A temporary and locally limited impact of the drilling works on groundwater quality was detected by turbidity measurements. This paper reports the implementation of geothermal drilling in a karst aquifer with a focus on karstification as well as planning, implementation and the results of the spring monitoring program. Such a program can be recommended for comparable projects or questions, adapting the characteristic parameters to be collected and the measurement intervals in consultation with the relevant authorities. It might also increase the chances of gaining approval for geothermal projects in karst and could enhance public acceptance.Key words: Pneumatic down hole hammer drilling, Borehole heat exchanger, Groundwater monitoring, Turbidity, Hochstegen Formation.Geotermalno vrtanje v alpskem kraškem vodonosniku in njegov vpliv na dolvodne izvire - študija primera Finkenberg, Tirolska, AvstrijaV alpskem kraškem vodonosniku je bilo prvič v Evropi vzpostavljeno polje geosond. Vključuje devet 400 m globokih vrtin, izvrtanih v dolomitnem marmorju Hochstegenove formacije. Razvili smo nove pristope za to aplikacijo brez primere in potrdili morebitna tveganja v času potopitve prvotne raziskovalne vrtine. Ker je študijsko območje Finkenberg na turističnem območju, je bilo treba opraviti vrtanje v samo nekaj tednih. Več izvirov od mesta vrtanja so viri oskrbe s pitno vodo. Glede na to, da stopnja in porazdelitev zakraselosti Hochstegenove formacije nista bili znani, je bilo treba za pridobitev dovoljenja za vrtanje nujno opazovati izvire. Da bi dokumentirali vpliv vrtanja na izvirsko vodo, je bilo pri spremljanju izvirov treba upoštevati več fizikalnih in kemijskih parametrov. Zaznali smo občasen in lokalno omejen vpliv vrtanja na kakovost podzemne vode. V prispevku smo predstavili izvajanje geotermalnega vrtanja v kraškem vodonosniku s poudarkom na identifikaciji zakraselosti ter načrtovanju ter na izvedbi in spremljanju kakovosti voda na izviru. Tak program se lahko uporabi pri primerljivih projektih ali iskanju odgovorov na podobna vprašanja s prilagojenim programom opazovanih parametrov in intervalov merjenja. Prav tako bi lahko povečal možnosti za pridobitev soglasja za geotermalne projekte na krasu in povečal ozaveščenost javnosti.Ključne besede: vrtanje s pnevmatskim kladivom, geosonda, spremljanje podzemne vode, motnost, Hochstegenova formacija. A borehole heat exchanger array was installed in an Alpinekarst aquifer for the first time in Europe. It is composed of nine400 m deep boreholes in the dolomitic marble of the HochstegenFormation. New approaches were developed for thisunprecedented application and potential risks were checkedthroughout the sinking of the initial exploratory wellbore. AsFinkenberg is located in a tourist area, drilling operations hadto be executed within only a few weeks. Several springs downstreamfrom the drilling site are sources of drinking water andtap water supply. Given that the degree and distribution of theHochstegen Formation karstification was unknown, a springmonitoring program was mandatory in order to obtain drillingpermission from public authorities. A practicable and affordablespring monitoring program including several physical andchemical parameters was developed and implemented to documentthe potential impact of the drilling activities on the springwater. A temporary and locally limited impact of the drillingworks on groundwater quality was detected by turbidity measurements.This paper reports the implementation of geothermaldrilling in a karst aquifer with a focus on karstification aswell as planning, implementation and the results of the springmonitoring program. Such a program can be recommended forcomparable projects or questions, adapting the characteristic

Zusammenfassung Wie in anderen Alpenregionen auch, erfolgt die Trinkwasserversorgung in den Zillertaler Alpen vorwiegend privat oder in Genossenschaften aus nahe gelegenen Quellen, typischerweise mit kleinen Einzugsgebieten. Durch eine Veränderung der österreichischen Trinkwasserverordnung wurde der Arsengrenzwert von 50 µg/l auf 10 µg/l herabgesetzt, wodurch Quellwässer vielerorts nicht mehr den Anforderungen genügen. Es sind Maßnahmen zur Einhaltung des Grenzwertes herbeizuführen. In dieser Studie werden Ergebnisse der Stichtagsbeprobung des Zemmbacheinzugsgebietes auf einer Gesamtfläche von 225 km 2 vorgestellt. Binnen elf Tagen wurden 135 Quellen und Oberflächengewässer beprobt. Die Untersuchungen dienten der Auswahl alternativer Quellen anhand trinkwasserrechtlich relevanter Kennwerte mit Fokus auf Arsen und Uran. In einigen Teilen des Untersuchungsgebietes variiert die Grundwasserbeschaffenheit aufgrund diverser Wechsel petrographischer Einheiten kleinräumig. Das angewendete Konzept einer Stichtagsbeprobung ist gut dazu geeignet, einen weiträumigen Überblick der Grundwasserbeschaffenheit zu erhalten und Quellen zur Ergänzung oder Ersetzung der lokalen Wasserversorgung zu identifizieren. Diese Quellen sind intensiver zu beobachten, um letztlich mittels Zeitreihen Entscheidungen zu treffen.

Erratum zu: Grundwasser – Zeitschrift der Fachsektion Hydrogeologie 2019 https://doi.org/10.1007/s00767-019-00436-9 Im Beitrag, S. 2 im Abschnitt Untersuchungsgebiet, 1. Absatz wurde mg/l anstatt µg/l angegeben. Korrekt muss es heißen: … (maximal 23,6 µg/l As und 22,7 µg/l U, siehe Abb. 3) …

A nonconformity refers to a hiatal surface located between metamorphic or igneous rocks and overlying sedimentary or volcanic rocks. These surfaces are key features with respect to understanding the relations among climate, lithosphere and tectonic movements during ancient times. In this study, the petrological, mineralogical and geochemical characteristics of Variscan basement rock as well as its overlying Permian volcano-sedimentary succession from a drill core in the Sprendlinger Horst, Germany, are analyzed by means of polarization microscopy, and environmental scanning electron microscope, X-Ray diffraction, X-ray fluorescence and inductively coupled plasma mass spectrometry analyses. In the gabbroic diorite of the basement, the intensity of micro- and macro-fractures increases towards the top, indicating an intense physical weathering. The overlying Permian volcanic rock is a basaltic andesite that shows less intense physical weathering compared with the gabbroic diorite. In both segments, secondary minerals are dominated by illite and a mixed-layer phase of illite and smectite (I–S). The corrected chemical index of alteration (CIA) and the plagioclase index of alteration (PIA) indicate an intermediate to unweathered degree in the gabbroic diorite and an extreme to unweathered degree in the basaltic andesite. The τ values for both basaltic andesite and gabbroic diorite indicate an abnormal enrichment of K, Rb and Cs that cannot be observed in the overlying Permian sedimentary rocks. Accompanying minerals such as adularia suggest subsequent overprint by (K-rich) fluids during burial diagenesis which promoted the conversion from smectite to illite. The overall order of element depletion in both basaltic andesite and gabbroic diorite during the weathering process is as follows: large-ion lithophile elements (LILEs) > rare earth elements (REEs) > high-field-strength elements (HFSEs). Concerning the REEs, heavy rare earth elements (HREEs) are less depleted than light rare earth elements (LREEs). Our study shows that features of supergene physical and chemical paleo-weathering are well conserved at the post-Variscan nonconformity despite hypogene alteration. Both can be distinguished by characteristic minerals and geochemical indices. Based on these results, a new workflow to eliminate distractions for paleoclimate evaluation and evolution is developed.

Emplacement of granitoid magmas and simultaneous exhumation of deeply buried rocks has been investigated along the western part of the Central Bohemian shear zone (CBSZ, Bohemian Massif). Combined structural, petrological and geochronological data of the steeply dipping shear zone suggest complex uplift and exhumation of deeply buried, high-temperature Moldanubian rocks, resulting in the juxtaposition against the supracrustal Teplá-Barrandian unit. Uplift of Moldanubian rocks from depths of probably more than 30 km was initiated after crustal stacking in Upper Devonian times. Syntectonic Lower Carboniferous emplacement of the Klatovy pluton into the pre-existing shear zone led to melt-controlled strain softening and localization. However, the major part of the total displacement of the CBSZ was accommodated within a late- to post-intrusive high-temperature shear zone in the uprising Moldanubian unit and a post-intrusive unexposed fault zone in the Klatovy pluton, respectively. During uplift of the Moldanubian rocks, strain was strongly partitioned into melt-bearing zones (Klatovy pluton, migmatites of the Moldanubian unit) resulting in a repeated shift of deformation in space and time.

Despite enormous enhancements in air quality, many cities still have serious problems to comply with the legal limits of air pollution. Concentrations of nitrogen oxides and fine particulate matter remain high, originating in relevant proportions from urban traffic. The impact of traffic-induced immissions on our built heritage is the focus of this study. The proportion of historic buildings exposed to elevated traffic emissions was estimated in five German cities of different sizes and different traffic loads. Less than 100 up to more than 1000 historic buildings per city are exposed to increased traffic emissions. For five buildings at heavy-trafficked roads, the near-field air flow and the deposition rate of air pollutants were modelled. Passive samplers were exposed at these buildings to determine the composition and amount of particulate matter, the concentrations of NO2 and HNO3 in the air, as well as the soiling and the recession rate of stone samples. The results clearly demonstrate the deposition of large amounts of particulate matter and the corresponding soiling of stone samples as consequences of road traffic. Despite high concentrations of NO2, the deposition of nitrates on stone surfaces seems to play a limited role. In addition, the deposition of sulphate and at some exposure sites chloride deposition was observed.