Geothermal Manifestations Research Articles

Eco-friendly synthesis of silver nanoparticles: Enhancing optimization reaction, characterization, and antimicrobial properties with Lantana camara from geothermal area

Green synthesis methods for producing silver nanoparticles (AgNPs) have garnered significant attention for their potential in medical applications. Despite the known potential of Lantana camara in AgNP synthesis, there is a lack of studies investigating its application when grown in extreme geothermal environments, which may influence the properties and efficacy of the synthesized nanoparticles. This research aimed to fabricate AgNPs utilizing aqueous extract from L. camara, a plant growing in an extreme geothermal manifestation area. Another aim of this study is to evaluate their antimicrobial activity. Qualitative and quantitative phytochemical analyses of the plant's leaves were also conducted. Reaction optimization was performed using response surface methodology (RSM), employing a central composite design (CCD) approach. The characterization of AgNPs involved UV–vis spectroscopy, FTIR, SEM-EDX, and PSA. The antimicrobial testing was conducted against Gram-positive bacterium (S. aureus), Gram-negative bacterium (E. coli), and the fungus (C. albicans). The phytochemicals analysis revealed that the L. camara leaf extract contains flavonoids, phenolics, saponins, tannins, and steroids, lacking alkaloids and terpenoids, with total phenolic and flavonoid contents of 11.94 mg (GAE/g) and 6.70 mg (QE/g), respectively. The AgNPs exhibited a spherical shape with a surface plasmon resonance (SPR) peak at a wavelength of 417 nm, and the smallest particle size measured was 44 nm. Based on FTIR analysis, AgNPs have functional groups such as OH, NH, CC, and CH that were identified as groups involved in the reduction of Ag+ to Ag0 during the green synthesis of AgNPs. The AgNPs demonstrated the lowest antifungal activity against C. albicans. In summary, the aqueous leaf extract of L. camara from geothermal manifestation areas can serve as a bioreductant for AgNPs, exhibiting higher antibacterial activity against Gram-positive bacteria compared to Gram-negative ones.

Integration of airborne geophysical data for the characterization of the geothermal system in Valle del Cura, high central Andes

The Valle del Cura region, located in the High Central Andes, over the Pampean flat-slab segment, exhibits several geothermal manifestations suggesting structural rather than magmatic controls. However, the structural and favorable conditions of this geothermal system have not been studied in detail yet. By integrating high-resolution airborne geophysical data with existing geological information using GIS tools, we can better characterize the structural controls of the thermal areas. The application of the upward continuation filter and tilt-angle derivative to the reduced to pole magnetic anomaly map allowed us to delineate structural lineaments that correlate well with known faults in the area. Euler deconvolution successfully identified local structures controlling the subsurface water upwelling and provided reliable depth estimations. Results indicate that the Despoblados area is characterized by NW-oriented deep structural controls reaching depths of up to 5 km. In contrast, the Bañitos-Gollete and the northern thermal areas are controlled by the intersection of N-S with E-W shallow structures at less than 3 km deep. Aeroradiometric data provided additional information for the characterization of several lithological units based on the dominance of radioelements (K, Th and U) in near-surface rocks by using individual and ternary maps. In addition, estimations of radiogenic heat production were crucial for assessing the potential energy of geothermal resources in the region. In particular, higher average values were obtained for igneous and metamorphic basement which may contribute to the geothermal gradient and temperature distribution at depth. Further studies, including new geophysical data acquisition and field verification, are still needed to fully describe the regional and local structures involved in these geothermal areas.

Imaging and modelling the subsurface structure of the Rungwe Volcanic Province in SW Tanzania with aeromagnetic data: An improved structural map to support geothermal exploration

The Rungwe Volcanic Province (RVP) in the East African Rift System, SW Tanzania, provides a unique opportunity to investigate geothermal resources in the context of particularly complex continental rifting processes. To support geothermal resource targeting in the RVP, we present a revised neotectonic structural map based on an interpretation of aeromagnetic data constrained by 2D-forward modelling of magnetic anomalies integrated with the distribution of previously reported faults, seismic epicentre locations, 3D magnetotelluric resistivity models and surface geothermal manifestations. Magnetic anomalies in the RVP, including the nationally prominent Mbeya anomaly, are related to the high magnetic susceptibility or remanent magnetism of Precambrian rocks and Cretaceous carbonatite intrusions buried in the rift under a varying thickness of non-magnetic sediments and volcanic rocks. Magnetic lineaments are related to structures controlling the geometry of the Precambrian rocks and concealed dikes and the thickness of the sediments and volcanics. The recent Ngozi and Rungwe trachyte volcanics have relatively low magnetic susceptibility comparable to the low susceptibility of the sediments in the rift basins. The revised neotectonic structural map shows prominent NW, NE and NS-trending magnetic lineaments that correlate with previously reported faults and alignments of seismic epicentres in the study area and with the regional trend of the rift segments. The NE-trending magnetic lineaments are consistent with interpretations of the current stress field in the RVP. The main volcanoes in the RVP, Ngozi, Rungwe and Kiejo (also known as Kyejo and Kieyo), are aligned with the NW-trending linear magnetic feature joining the Lupa and Livingstone rift border faults. This lineament is intersected and frequently displaced by the NE and NS-trending lineaments, suggesting that the NE to NS-striking structures are younger. The Rungwe and Ngozi volcanoes as well as numerous ‘’monogenetic’’ eruption centres and the Mwakaleli caldera, which originated ca. 2 Ma ago (Ebinger et al., 1989) following a large explosive eruption emplacing widespread ignimbrite deposits, are located within a zone of low-intermediate magnitude magnetic features forming a basin-like structure surrounded by magnetic high anomalies of the Precambrian basement structures. We interpret the intersections between the NW-trending intra-rift faults and the NS and NE-trending faults as favourable locations for wells to target high permeability within the geothermal resource conceptual models previously constructed using 3D MT resistivity imaging integrated with supporting geoscientific data. The intersections provide a focus area for follow-up ground mapping of subtle features that may be associated with very recent fault movement.

Hidden magma reservoirs: Insights from helium and carbon isotopic compositions in shallow groundwater beneath the Wudalianchi volcanic field, Northeastern China

The lack of strong geothermal manifestations and limited fumarolic activity has sparked widespread debate about the presence of active magma reservoirs beneath the Wudalianchi volcanic field (WVF). Helium (He) in hydrological systems is sensitive and responsive to the mixture of mantle-derived He, making it an excellent tool for deciphering mantle-derived magmatic processes. Through investigating dissolved He and inorganic carbon (DIC) in shallow groundwater of the WVF, we found that He captures mantle characteristics with R/Ra ratios (R equals to 3He/4He ratios, Ra is atmospheric 3He/4He ratio of 1.39 × 10−6) ranging from 0.07 to 2.27 and the highest proportion of mantle-derived He is 30.38 %. In contrast, DIC shows minimal mantle influence, with low concentrations (1.91–7.39 mmol/L) and depleted δ13C-DIC values ranging from −17.9 ‰ to −13.6 ‰. The calculated mantle 4He fluxes in groundwater are 2–3 orders of magnitude higher than that in stable continents and show the signature of volcanic degassing. The high mantle He fluxes and high upward flow rates suggest the efficient release and transfer of mantle-derived He into shallow groundwater through magma degassing. Magma-aging model effectively constraints the period of magmatic activity to within the last 47 ka. These findings, consistent with seismic noise imaging results, support the presence of magma reservoirs in the upper–middle crust. The absence of magmatic carbon signature in groundwater suggests the decoupling of magmatic He and magmatic CO2. Magmatic CO2 may be removed during ascent, possibly being trapped through dissolution or precipitation processes within the low-resistivity bodies identified at ∼2.5 km depth by magnetotelluric imaging. These findings not only contribute to resolving the controversy surrounding the existence of magma reservoirs beneath the WVF but also have broader implications in guiding the exploration and validation of hidden magmatic systems.

Investigation on radon levels in soil and water associated with Mount Tampomas geothermal activity in Indonesia

ObjectiveTo investigate radon emanation in geothermal manifestations around Mount Tampomas, West Java, Indonesia, and assess radon concentrations in soil and water samples. MethodsRadon measurements were conducted using the Durridge Rad7 instrument, supplemented with a soil gas probe for in-situ soil radon measurements at a depth of 80 ​cm. In-situ water radon measurements were performed using the Rad Aqua instrument, while radon measurements for hot water samples were conducted separately. Radon measurements for hot water samples were corrected for decay using a radon decay correction factor. ResultsThe analysis of radon measurements revealed a wide range of concentrations in soil and water samples. Soil radon concentrations ranged from 15 Bq/m³ to 4,660 Bq/m³, with localized hotspots exhibiting exceptionally high concentrations. Water radon measurements showed elevated levels, ranging from 0.2 Bq/L to 13.4 Bq/L in-situ, particularly in hot springs. In collected water samples, radon concentrations ranged from 1 Bq/L to 6 Bq/L. These combined results highlight significant variability in radon levels across different water sources influenced by geothermal activity. ConclusionsThese findings indicate active emanation processes influenced by geological factors and underscore the role of subsurface geology and aquifer characteristics in radon transport mechanisms. The presence of localized radon hotspots suggests the need for comprehensive monitoring and proactive management strategies to mitigate environmental and public health risks associated with radon exposure.

Identifikasi Struktur Bawah Permukaan Menggunakan Geomagnet Wilayah Hot Spring Lau Sigembura Deli Serdang

This research was conducted at the Lau Sigembura hot spring tour, STM Hilir sub-district, Deli Serdang district using the magnetic method. This study aims to determine. Subsurface structures and the distribution of magnetic anomalies which are geothermal manifestations. The number of measurement points is 50 with an area of ​​1000 square meters. Data acquisition was carried out using the PPM Model GEM System type GSM 19T.While data processing uses daily corrections and IGRF corrections as well as upward continuations. Modeling is done using Mag2DC software. The total magnetic field ranges from -900 nT to 500 nT based on the contour of the local magnetic anomaly, the variation in the value of the anomaly is around -1050 nT to 350 nT. While the quantitative interpretation indicates the presence sandstone rock with susceptibility value 0,1075 cgs, Andesit with susceptibility values 0,0183 cgs, limestone with a susceptibility value of 0.0001 cgs – 0.0021 cgs. And shales with susceptibility value 0,021 cgs.

Satellite land surface temperature for mapping the structurally controlled geothermal anomalies in the Cretaceous rift, South Egypt

ABSTRACT Exploration of new geothermal systems often requires regional-scale investigation. Satellite Land Surface Temperature (LST) products are essential in geothermal anomaly identification and mapping. In this study, seven thermal anomalies covering Egypt were observed using the Sentinel-3 LST images acquired in 2019 and confirmed using the 2020 LST images. In addition, the LST analysis reveals three new anomalies covering the southern part of Egypt (Kalabsha, Natash, and Wadi Allaqi), which are structurally controlled. Nuqra-Kharit-Natash is a good site for geothermal energy owing to the following reasons: 1) the high geothermal gradient beneath the Wadi Natash region (heat flow ~100 mW/m2); 2) the presence of many geothermal anomalies retrieved from the analyses of the Landsat-8 acquired in August 2018; 3) existence of surface geothermal manifestation at the western boundary of the basin includes warm springs and the tufa deposits. Intricate structural patterns, including NW-oriented normal faults, ENE-to-WNW-oriented right-lateral faults, and NNE-oriented sinistral strike-slip faults, characterise Wadi Natash. Wadi Natash LST anomaly shows a solid relation to fault trends. High values of LST are arranged along NW and NNE faults and recorded the peak at the intersection of two fault trends. Recent seismic activity along the NNE fault system enhances the permeability along this trend and its intersection with the NW-oriented fault.

Identification of geothermal pathways by fault fracture density (ffd) and gravity methods in Karangan sub-district, East Kutai district, East Kalimantan province

Abstract The Presence of geothermal manifestations in the form of hot springs is very close to the presence of geological structures that become permeable zones in a Mangkalihat High geothermal system. There are two hot springs in this area, which are crossed by regional structures. So, it is important to identify the geothermal manifestation with the geological structure in this area to know the path of the geothermal flow. In this research, the fault fracture density method is used to determine the existence of structures on surface and the gravity method to determine the existence of structures below surface, which then from the results of the analysis will be correlated with the existence of geothermal manifestations in the area. The analysis results are found with the FFD method. The density of the study area has a value of 0 - 2,355 km/km2. Meanwhile, the results of the gravity method show that there are six normal faults and four thrust faults identified in the study area. Geothermal manifestations in the study area are related to the existence of high-density values in the study area, and geological structures identified through gravity are structures that are the pathway for the movement of hot springs.

Detecting Geothermal Phenomena at Sikidang Crater Area Based on Ground Penetrating Radar Method

Abstract Sikidang Crater (2000 masl) is one of the leading tourist sites in the Dieng area. However, not many people realise that Sikidang Crater is located in the Dieng Volcanic Complex where most of the volcanoes belong to the type A category. Sikidang Crater is one of the main geothermal manifestations occupied by mud pools, solfatara, fumaroles, and altered rocks. These manifestations have potential geological hazards such as toxic gases, base surge, and mud explosions. On the other hand, it has a high level of human activity that increases the risk of disasters. As an effort to prevent and mitigate disasters, it is necessary to know the subsurface geological conditions of the crater. This study aims to determine the subsurface geological conditions of the crater. This research uses the methods of detailed geological mapping, manifestation observation, and Ground Penetrating Radar (GPR) geophysical survey. The tool used is Akula Geoscanner 9000C running at 64.75 Hz frequency, capable of penetrating 50 meters deep, and has a vertical resolution of > 0.85 meters. Sikidang Crater is located at the southeastern foot of Mount Pangonan and it forms semicircular like a horseshoe. According to Van Zuidam, the crater is classified as a solfatara and fumarole field geomorphology unit. The lithology of this area is dominated by the eruption products of Mount Pangonan. In general, radargrams resulting from GPR surveys show various amplitudes of reflected electromagnetic waves. This is consistent when correlated with the variation in rock density of the research area. At some points, there is a decrease in electromagnetic wave velocity due to contrast in dielectric constant values, which is interpreted as geothermal fluid flow towards the surface. The potential level of geothermal fluid flow is classified into high, medium, low, and none based on the density of potential points seen in the radargram.

Interpretation of Subsurface Structure Based on Magnetic Anomaly Analysis as Geothermal Manifestation in Lake Linting Deli Serdang

Interpretation of Subsurface Structure Based on Magnetic Anomaly Analysis as Geothermal Manifestation in Lake Linting Deli Serdang

Design and Application of Low-Temperature Geothermal Thermoelectric Power Generation (Lotemg–TPG) in Sari Ater Hot Spring, Ciater, Subang, West Java, Indonesia

The use of surface geothermal manifestations in Indonesia is still very limited as a tourist attraction. Solid-state thermoelectric generator technology is an alternative to converting electrical energy directly from a heat source in the form of low-temperature geothermal manifestation. Low-temperature geothermal thermoelectric power generation (Lotemg–TPG) was designed, manufactured, and tested to take advantage of this opportunity. It was also applied to the Sari Ater Hot Spring, Ciater. The Lotemg–TPG unit comprises seven M8T modules in two frame blocks equipped with hot- and cold-water circulation channels. The M8T module is the main part of the Lotemg–TPG, which consists of eight TEG elements of type TEG1-241-1.4-1.2, flanked by a hot-side radiator and a cold-side radiator. The measurement results showed that at the temperature difference between the hot-side Th and the cold-side Tc of ∆T 17.38 °C, one module can produce 1.30 W of power, so the total power of the Lotemg–TPG unit is around 9.10 W. This result is quite good considering that the heat source is obtained for free, and the device can operate to produce stable electrical power.

Identifying the structure as a hot water outflow path using gravity in Jatimulyo, South Lampung

Abstract Geothermal manifestations have been utilized as a tourist attraction (geo-tourism) worldwide. Geothermal manifestation systems could be found in many forms such as hot springs. The path of the hot water flow is controlled by the existence of geologic structures such as faults as the medium. Geophysical methods in general have been used to image and characterize subsurface layers. The gravity method using the natural source has been employed to determine the geological structure, such as faults. This study aims to identify the structure related to the outflow path which is part of the geothermal system using gravity method in Jatimulyo Village, Jati Agung, South Lampung. The result shows the contrast anomaly indicating the existence of a fault that could be a hot water path. An outflow zone which is characterized by low temperatures because it is far from heat sources. The complete Bouguer Anomaly is used to create 2D forward modelling where the model is divided in 2 layers. The first layer is indicated as Lampung Formation (QTl) with density of 1.8 g/cc, and second layer recognized as bedrock with denser rock of 2.78 g/cc representing Tertiary Paleozoic (Pzg) Gunung Kasih Complex Formation.

Strontium isotopes and rare earth elements in terrestrial hot-spring deposits: Characterization and geothermal implications

Identifying geothermal reservoir rock types is fundamental in geothermal exploration, but the absence of active surface geothermal manifestations (especially hot springs) in blind geothermal systems makes this identification difficult. Nevertheless, blind geothermal systems may develop early-formed hot-spring deposits. As (bio-)chemical precipitate, these deposits may retain geochemical signatures of spring waters and thus provide insights into reservoir rock types. To assess their geothermal implications, the 87Sr/86Sr and rare earth elements + yttrium (REE + Y) characteristics of hot-spring deposits in two geothermal systems were investigated and compared with those of their reservoir rocks. Results showed relatively uniform 87Sr/86Sr values in hot-spring deposits within each system, but occasional 87Sr/86Sr contamination induced by exogenous detritus input was also observed. The amount of detritus input relates to the potential for interaction with surrounding soils/rocks and is thus environmentally controlled. Hot-spring deposits with high Sr concentrations showed greater 87Sr/86Sr contamination resistance than those with low Sr concentrations, revealing the influence of Sr concentration in hot-spring deposits on detrital 87Sr/86Sr contamination. The detritus input also influenced the REE + Y signatures of the hot-spring deposits, underscoring the necessity of contamination assessment before geochemical interpretation. Excluding samples with significant 87Sr/86Sr and/or REE + Y contamination, the remaining samples closely mirrored their respective reservoir rocks in terms of 87Sr/86Sr, with partial overlap in REE + Y signatures. This suggests that the 87Sr/86Sr and REE + Y characteristics of hot-spring deposits provide valuable insights into reservoir rock types. However, variations in 87Sr/86Sr or REE + Y compositions between some hot-spring deposits and corresponding reservoir rocks indicate additional influencing factors beyond reservoir rock types. Therefore, a comprehensive understanding of reservoir rock types requires integrated geochemical characterization, probably including 87Sr/86Sr, REE + Y, and other parameters. These findings underscore the potential of geochemical characterization of hot-spring deposits for identifying geothermal reservoir rock types, and this geochemical approach can complement geological and geophysical data to improve exploration efficiency, especially in blind geothermal systems.

Geothermal potential area analysis using Landsat 8 OLI/TIRS and digital elevation model images (case study: Lawu Mount, Central Java)

Mount Lawu is one of the volcanoes in Central Java Province with hidden geothermal potential. This research aims to identify geothermal potential areas, especially hydrothermal alteration areas, using Landsat 8 imagery in Mount Lawu, Central Java. Hydrothermal alteration serves as a crucial indicator in the exploration of geothermal potential in an area. Multispectral image processing methods of Landsat 8 are employed to map the distribution patterns of hydrothermal alterations in the study area, together with the anomaly of temperature and heatflux in the surface. This approach involves principal component analysis and spectral alteration indications that combine information from various image channels. Lithology and lineament density analysis strengthen the delineation and analysis of the geothermal potential area. The western-northwestern part of Mount Lawu is the most potential region for geothermal resources based on the distribution of hydrothermal alteration areas and the high density of faulted regions, which are also supported by geothermal manifestations such as hotspring sites in the area.

Preliminary study of waste storage ponds delineation area in the Ungaran Geothermal Mining working area, Semarang, Indonesia

The Gedongsongo and Nglimut areas have the potential for Indonesian geothermal exploration projects. One of the problems of the PLTP sector is producing geothermal waste in the form of brine, and geothermal mud can endanger human health and ecosystems. This study aimed to determine the best zone for waste storage ponds in this prospect area. The method integrates DEM and Landsat data analysis, producing Maps of Slopes and Lineaments to delineate the best area for making ponds. There are several parameters for determining the pond-making zone: area with a slope of less than 15%, distance from the fault is more than 200 m, and distance from areas of geothermal manifestations such as hot springs and fumaroles is more significant than 200 m. This analysis results in four delineation zones suitable for creating waste storage ponds. In the Nglimut area, there are N1 and N2; in the Gedongsongo area, there are G1 and G2 as potential zones. The best zones were N2 and G1. Locations N1 and G2 are fair zones because the eastern area of G2 is 200 m from the fault, and the northern region of N1 is close to the hot spring.

Perbandingan Stabilitas Atmosfer di Permukaan Manifestasi Panas Bumi dengan Tanpa Manifestasi Panas Bumi menggunakan Bilangan Richardson

The stability of the atmosphere can affect the weather conditions in an area. This study aims to compare atmospheric stability carried out in Lake Linow which has two surfaces, namely the surface of geothermal manifestation and the surface without geothermal manifestation. In determining the stability of the atmosphere, researchers use the Richardson number method. To determine atmospheric stability using the Richardson number, data on wind speed and temperature at each altitude are needed. The measured height is 2 meters and 4 meters from the surface. The results of this study show that on the surface geothermal manifestations have unstable atmospheric stability with Richardson numbers -1.4729 to -0.1420, while on the surface without geothermal manifestations have 3 states of atmospheric stability, namely: stable, neutral, and unstable, with Richardson numbers -1.1316 to 0.9808. Therefore, it can be concluded that the state of the atmosphere on the surface of geothermal manifestations is more unstable, compared to surfaces without geothermal manifestations.

Karakteristik Kimia Fisik Fluida Mata Air Panas dan Estimasi Temperatur Reservoir di Sekitar Rano Raindang Desa Leilem, Kecamatan Sonder, Kabupaten Minahasa

To meet future energy needs, the Indonesian government has developed alternative energy sources: geothermal energy. Rano Raindang is one of the areas with a geothermal field due to several geothermal manifestations, such as hot springs. This study aims to examine the fluid type, the reservoir temperature estimation, and the functional group of hot springs. The method used is a geoindicator of Na, K, Mg, Cl, SO4, and HCO3, combining spectrophotometry and FTIR spectroscopy. Research results show that the type of hot spring fluid around Rano Raindang with geoindicators Na, K, Mg is immature waters, this is because the type of hot spring fluid around Rano Raindang has undergone a mixing process, while the geoindicators Cl, SO4, HCO3 are bicarbonate (HCO3) types. This corresponds to the results of measurements using FTIR spectroscopy. The estimated reservoir temperature in the area is 193.66 °C and is included in the medium-temperature geothermal system, as the temperature around Rano Raindang is between 125–225 °C. The functional group of hot spring molecules around Rano Raindang has functional groups C=O and O-H.

Characterization of Geochemical and Isotopic Profiles in the Southern Zone Geothermal Systems of Mount Seulawah Agam, Aceh Province, Indonesia

The Seulawah Agam geothermal area exhibits significant potential as a source of energy for power generation, with an estimated capacity of 130 MW. Geological and geochemical investigations indicate that the Seulawah Agam geothermal system is part of the extensive Sumatra Fault. Analysis of the geochemical composition of geothermal water at the South Zone manifestation location of Mount Seulawah Agam, Aceh Province-Indonesia, involves examining cation (K+, Na+, Ca2+, and Mg2+), anion (Cl-, HCO3-, and SO42-), and isotope (δD and δ18O) contents. This data aids in estimating reservoir temperatures using geothermometer equations. Surface characteristics of the South Zone manifestation reveal neutral to alkaline pH values (6.02 to 8.68), relative temperatures (29.97 to 42.57 ºC), conductivity (49.8 to 100.7 mV), and TDS (Total Dissolved Solids) ranging from 352.6 to 497.0 mg/L. The dominant water composition is sodium–calcium–bicarbonate (Ca–Na–HCO3), indicating a bicarbonate water type. Average temperature depths in the South Zone manifestation of Mount Seulawah Agam are estimated as follows: Alue Ie Seu’um around 288.84 ± 2.19 ºC, Alue Ie Masam around 304.17 ± 20.9 ºC, Alue PU around 290.02 ± 6.85ºC, and Alue Teungku around 265±11.39 ºC. Isotope data (δD and δ18O) suggest meteoric water as the source for this manifestation. Fluid geochemical analysis indicates the potential for utilizing the geothermal manifestations of the South Zone of Mount Seulawah Agam for geothermal development or the construction of a geothermal power plant, given its high enthalpy system with an average temperature exceeding 225 ºC. Further research, including data drilling, is essential to gather precise subsurface data. Additionally, the Aceh Provincial Government should formulate policies to identify strategic areas for geothermal development, leveraging the existing exploitable potential.

ANALYSIS OF THE EXISTENCE OF GEOTHERMAL MANIFESTATIONS USING FAULT FRACTURE DENSITY (FFD) IN TEMPURAN DISTRICT, MAGELANG REGENCY

Being in an active fire lane means that Indonesia has geothermal potential. The geothermal research location is in the Tempuran area, Magelang Regency. The method used is by using alignment in the National Digital Elevation Model (DEMNas) data and calculating it using the Fault Fracture Density (FFD) method, the result of which is a contour map. This research aims to identify the existence of geothermal manifestations with FFD values. The research results show that the FFD value in the Tempuran geothermal manifestation area varies between 0.09 - 1.80 km/km2. The FFD value shows that the Tempuran geothermal manifestation is in a low density zone. There is no direct correlation between the presence of geothermal manifestations and the FFD value. The Tempuran geothermal manifestation is thought to be related to geological formations composed of volcanic rock and related to an aquifer system, as well as faults that trend northwest-southeast.

Metagenomics of two aquifers with thermal anomalies in Mallorca Island, and proposal of new uncultivated taxa named following the rules of SeqCode

Groundwater offers an intriguing blend of distinctive physical and chemical conditions, constituting a challenge for microbial life. In Mallorca, the largest island of Balearic archipelago, harbours a variety of thermal anomalies (i.e., geothermal manifestation where surface aquifers exhibiting temperatures exceeding the regional average). The metagenomes of two aquifers in the centre and southern of the island showed Pseudomonadota to be the most represented phylum when using extracted 16S rRNA gene sequences. However, the microbial structures within and between aquifers were remarkably diverse but similar in their metabolic profiles as revealed by the metagenome-assembled genomes (MAGs) pointing to a prevalence of aerobic chemolithoautotrophic and heterotrophic metabolisms, especially in the Llucmajor aquifer. Also, some evidences of anaerobic lifestyles were detected, which would indicate that these environments either could suffer episodes of oxygen depletion or the anaerobes had been transported from deeper waters. We believe that the local environmental factors (temperature, external inputs or chemistry) seem to be more relevant than the connection and, eventually, transport of microbial cells within the aquifer in determining the highly divergent structures. Notably, most of the reconstructed genomes belonged to undescribed bacterial lineages and from them two high-quality MAGs could be classified as novel taxa named following the rules of the Code for Nomenclature of Prokaryotes Described from Sequence Data (SeqCode). Accordingly, we propose the new species and genus Costitxia debesea gen. nov., sp. nov., affiliated with the novel family Costitxiaceae fam. nov., order Costitxiales ord. nov. and class Costitxiia class. nov.; and the new new species and genus Lloretia debesea gen. nov. sp. nov. affiliated with the novel family Lloretiaceae fam. nov.