scholarly journals Fluid pathways identified beneath Narlı Lake (Central Anatolia) show the geothermal potential of former volcanoes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maren Brehme ◽  
Ronny Giese ◽  
Uğur Erdem Dokuz ◽  
Fatih Bulut

AbstractWe investigated the volcanic Narlı Lake in Central Anatolia combining high-resolution bathymetry and geochemical measurements. In this study, we present it as proof of a new concept to verify fluid pathways beneath lakes integrating the structure of the geothermal reservoir into the surrounding tectonic frame. We recognized dextral faults fracturing inherited volcanic formations and thus generating highly permeable zones beneath the lake. At intersection points of faults, reservoir fluids discharge from deep holes as imaged by the high-resolution bathymetry at the bottom of the Narlı Lake. Onshore, the tectonic setting also generates both extensional and compressional structures. Extensional structures result in extensive fluid discharge through hot springs while compressional structures do not discharge any fluid. The water of the lake as well as in the hot springs is highly saline and has relatively high concentrations of Cl, HCO3, SO4, Na, Ca, Mg, and Si. In several hot springs, we observed mixtures of high-saline fluids having a deep origin and low-saline shallow groundwater. We observed discharge into the lake by gas bubbles, which contain probably CO2 or H2S. Mineral precipitation indicates a carbonatic source at the lake bottom and along the shoreline. Extensive travertine precipitation also occurs near hot springs along the nearby extensional zone of Ihlara Valley. In summary, the composition of fluids and minerals is controlled by water–rock interaction through the volcanic and carbonatic rocks beneath this volcanic lake.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maren Brehme ◽  
Ronny Giese ◽  
Lily Suherlina ◽  
Yustin Kamah

Abstract We investigate fluid pathways beneath volcanic lakes using bathymetry and geochemical measurements to locate best-possible drilling sites. Highly permeable structures, such as faults, provide fluid channels that are the most suitable access points to the geothermal resource. Accurate mapping of these structures therefore guides the successful targeting of wells. Lakes, rivers or ocean, can hide surface footprints of these permeable structures, such as in our case beneath Lake Linau. High-resolution bathymetry identifies linear and conical discontinuities, which are linked to offshore tectonic structures as confirmed by surrounding outcrops and hot springs. Geochemical measurements document inflow of hot saline acidic water into the lake verifying bathymetry-located highly permeable structures. Integrating onshore well data, our bathymetry and chemical results locates an ideal drilling site into the geothermal reservoir beneath the western shore line of Lake Linau.


2021 ◽  
Vol 26 (1(38)) ◽  
pp. 149-168
Author(s):  
D. V. Melkonyan ◽  
E. A. Cherkez ◽  
V. G. Tyuremina

Problem Statement and purpose. The study area encompassing the territory of about 150 km2, in August 2000, was declared as a zone of environmental emergency due to increasing pollution rates in shallow groundwater, in surface water and to health deterioration of the inhabitants of some settlements. Groundwater is widely used by the local population in numerous boreholes for domestic and agricultural purposes. In the zone of environmental emergency there are about 35 anthropogenic objects, such as: industrial and domestic landfills, pesticide and fertilizer storage, various livestock farm complexes, settling tanks, wastewater and solid waste discharges, etc. The insecurity of shallow groundwater, also its location close to the surface and in the lowest parts of the terrain leads to intensive pollution of groundwater. Besides, groundwater in relation to the fractured waters of the Precambrian crystalline rocks, which lie below and are used for drinking water supply, perform the functions of both a protective screen and a source of pollution. In this case, a multifaceted study of shallow groundwater chemical composition and their formation conditions is a priority task of this study for the environmental emergency zone and for the district as a whole. The purpose of this paper to study the chemical composition and to establish the processes and factors controlling the shallow groundwater chemistry in modern and Pleistocene sediments of the Southern Bug and Syniukha interfluve. Data and Methods. A total of 102 water samples were collected from groundwater wells and boreholes and were hydrochemically analyzed for their macrocomponent composition. Groundwater quality geochemical assessment was carried out using statistical methods in combination with conventional graphical methods by examining groundwater in the Boleslavchik village, where they are most polluted. Results. The dominant hydrochemical types of shallow groundwater are SO4- Na, HCO3-Na and mixed SO4-Mg-Na, SO4-Ca-Na types, sometimes NO3-HCO3 and NO3-Cl-Na types. These groundwater types are formed under the influence of natural and anthropogenic factors, such as water-rock interaction, evaporation-crystallization, precipitation and anthropogenic impact. In this case, water-rock interaction processes, such as silicate weathering, carbonate and sulfate dissolution, ion exchange, evaporation-crystallization and anthropogenic impact play major roles. The weathering of feldspars, chlorites and dissolution of calcites, dolomites are the primary sources for Na+, K+, Mg2+, Ca2+ ions, and dissolution of gypsum, sulfide mineralization for SO4 2– ions. High concentrations of Na+, Cl–, SO4 2–, NO3 – in shallow groundwater reflect agricultural activity as the main source of these ions.


2021 ◽  
Vol 13 (1) ◽  
pp. 820-834
Author(s):  
Jun Ma ◽  
Zhifang Zhou

Abstract The exploration of the origin of hot spring is the basis of its development and utilization. There are many low-medium temperature hot springs in Nanjing and its surrounding karst landform areas, such as the Tangshan, Tangquan, Lunshan, and Xiangquan hot springs. This article discusses the origin characters of the Lunshan hot spring with geological condition analysis, hydrogeochemical data, and isotope data. The results show that the hot water is SO4–Ca type in Lunshan area, and the cation content of SO4 is high, which are related to the deep hydrogeological conditions of the circulation in the limestone. Carbonate and anhydrite dissolutions occur in the groundwater circulation process, and they also dominate the water–rock interaction processes in the geothermal reservoir of Lunshan. The hot water rising channels are deeply affected by the NW and SN faults. Schematic diagrams of the conceptual model of the geothermal water circulation in Lunshan are plotted. The origin of Tangshan, Tangquan, and Xiangquan hot springs are similar to the Lunshan hot spring. In general, the geothermal water in karst landforms around Nanjing mainly runs through the carbonate rock area and is exposed near the core of the anticlinal structure of karst strata, forming SO4–Ca/SO4–Ca–Mg type hot spring with the water temperature less than 60°C. The characters of the hot springs around Nanjing are similar, which are helpful for the further research, development, and management of the geothermal water resources in this region.


2021 ◽  
pp. 1-10
Author(s):  
Adam Weintrit ◽  
Jacek Pietraszkiewicz ◽  
Wiesław Piotrzkowski ◽  
Wojciech Tycholiz

Abstract In recent years the transition of marine navigation to the digital era has been gaining momentum. Implementation of e-Navigation solutions varies from country to country in terms of their priorities, goals, levels and effects. Maritime authorities in Poland have been setting the pace in this transition process, not only in Poland but also in general as a global solution. The most recent example is the planned deployment of a variety of e-Navigation tools in the Vistula Lagoon: from GNSS-RTK Ground-Based Augmentation System, to virtual and synthetic aids to navigation, high-resolution bathymetry and advanced navigational software for piloting. The major objectives of this paper are, first, to summarise recent dynamics in the e-Navigation field, and second, to present a practical implementation of the e-Navigation concept in the Vistula Lagoon area.


2020 ◽  
Author(s):  
Ben Orsburn

AbstractThe production of hemp and products derived from these plants that contain zero to trace amounts of the psychoactive cannabinoid tetrahydrocannabidiol (THC) is a rapidly growing new market in the United States. The most common products today contain relatively high concentrations of the compound cannabidiol (CBD). Recent studies have investigated commercial CBD products using targeted assays and have found varying degrees of misrepresentation and contamination of these products. To expand on previous studies, we demonstrate the application of non-targeted screening by high resolution accurate mass spectrometry to more comprehensively identify potential adulterants and contaminants. We find evidence to support previous conclusions that CBD products are commonly misrepresented in terms of cannabinoid concentrations present. Specifically, we observe a wide variation in relative THC concentrations across the product tested, with some products containing 10-fold more relative signal than others. In addition, we find that several products appear to be purposely adulterated with over the counter drugs such as caffeine and melatonin. We also observe multiple small molecule contaminants that are typically linked to improper production or packaging methods in food or pharmaceutical production. Finally, we present high resolution accurate mass spectrometry data and tandem MS/MS fragments supporting the presence of trace amounts of fluorofentanyl in a single mail order CBD product. We conclude that the CBD industry would benefit from more robust testing regulations and that the cannabis testing industry, in general, would benefit from the use of non-targeted screening technologies.


1986 ◽  
Vol 23 (9) ◽  
pp. 1442-1449 ◽  
Author(s):  
Daniel J. Conley ◽  
Claire L. Schelske ◽  
Brian G. Dempsey ◽  
Charles D. Campbell ◽  
Teresa L. Newberry

The spatial distribution of biogenic silica (BSi) in the surficial sediments of Lake Michigan is described from Shipek grab samples collected in 1975 and gravity cores obtained in 1983. Significantly smaller surficial BSi concentrations in the 1975 samples were attributed primarily to the inability of a Shipek grab to collect intact surficial sediment samples. Lower concentrations o.f BSi were found in nondepositional and transitional areas of sediment accumulation than in depositional basins. Therefore, BSi accumulation is restricted primarily to the 40% of the lake bottom where sediments are presently accumulating. High concentrations found in Green Bay surficial sediments are related to high productivity in the bay coupled with inputs of new silica from the Fox River. In the open lake, BSi concentrations of surficial sediments in depositional basins appeared to vary inversely with sedimentation rate in that lower BSi concentrations were found in areas with higher sedimentation rates.


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