Tuff Breccia Research Articles

Zircon U–Pb Dating of the Urahoro Group and Atsunai Formation in the Shiranuka Hills of Eastern Hokkaido, Northeast Japan: Implications for Tectonic Development

ABSTRACTZircon U–Pb dates for detrital grains in the Shakubetsu Formation of the uppermost Eocene Urahoro Group and the Upper Miocene Atsunai Formation distributed in the eastern part of Hokkaido have been determined for the first time. Both weighted mean 48.8 ± 1.4 Ma (n = 80) for < 70 Ma zircons and youngest grain 36.5 + 1.8, −2.5 Ma (Middle to Late Eocene) ages of the Urahoro Group are consistent with the sedimentary ages and Paleogene magmatic arc origin of the detritus clarified in the previous studies. Although the Zircon U–Pb ages (n = 24) of the Atsunai Formation range between 5 and ~1700 Ma, a weighted mean age of 7.05 ± 0.57 Ma (n = 10) for < 10 Ma zircons (youngest cluster) could constrain the maximum sedimentary age, which is consistent with the previous ages from diatom biostratigraphy and K‐Ar method. However, while the K‐Ar age was obtained from an Ol‐Cpx‐Opx basalt in tuff breccia, the dated zircons were probably derived from felsic tuff including many pumice grains. Therefore, the bimodal volcanism could have occurred at c. 7 Ma in the present forearc region, indicating that the volcanic front at this age migrated south significantly, correlated to the one which also occurred coevally in the seaward side of the present volcanic front in the NE Japan arc. Further, it has been found that the eastern boundary of the Shiranuka Hills is characterized by an ESE verging, large‐scale monocline based on the present field study and previous geological maps. Since the Atsunai Formation was involved in the formation of the large‐scale monocline, the structure started to form after the sedimentation at c. 7 Ma. The fact implies that the ongoing collision of the Kuril forearc sliver with the NE Japan arc has propagated to this area since the latest Late Miocene.

Mapping Subsurface and Surface Characteristics of the Recent Pesanggrahan Landslide, Central Java, Indonesia, for Landslide Hazard Management

Regions prone to deep landslides are characterized by thick materials exceeding 10 m and frequent natural disasters. This research aims to analyze the recent occurrence of Pesanggrahan landslide in Central Java, Indonesia, which is a region consisting of both settlements and rice fields. Surface mapping was conducted using aerial photos and direct field observations. Additionally, subsurface conditions to identify the unconsolidated material layers below the landslide surface have been analyzed using the seismic refraction method. The primary velocity (Vp) values are represented in 2D subsurface cross sections. Differences in Vp values corresponded to different geological layers. There were four distinct layers: Top Soil (TS), Clay (CL), Weathered Bedrock (WB), and Tuff Breccia (TB) within the 2D seismic refraction cross-section with Vp values ranging from 150 to 1,800 m/s. The ranges of Vp are: 150-600 m/s for Top Soil (TS), 600-1,200 m/s for Clay (CL), 1,200-1,800 m/s for Weathered Bedrock (WB), and values exceeding 1,800 m/s for Tuff Breccia (TB). The material layer is critical for sustainable land management strategies aimed to control landslides. Furthermore, the potential depth of the sliding plane was managed through effective environmental management practices, including proper disposal of household waste and minimizing the cutting of steep slopes.

Volcanic Zeolites from the Yagodninskoe Deposit (Kamchatka Krai)

This work is devoted to typification, study of the compositional features and properties of hydrothermal zeolites of the Yagodninskoe deposit (Kamchatka Krai), formed over volcanic rocks. To carry out the research, X-ray phase and X-ray fluorescence analyses, optical and scanning electron microscopy were used; the specific surface area, pore size distribution, and cation exchange capacity of zeolites were determined. As a result of the research, 4 main types of rocks found at the deposit were identified: original unaltered perlites, zeolites themselves, zeolitized tuffs, and weakly zeolitized tuff breccias. The content of zeolite group minerals reaches 70%, and are mainly represented by clinoptilolite and to a lesser extent mordenite, stilbite and heulandite. Zeolites are of the alkaline type, the cation exchange capacity of which is 205.9 mEq/100 g. It was established that the formation of zeolites occurred mainly in perlites and tuff breccias. It is noted that the zeolites of the Yagodninskoye deposit have high quality raw materials and are the promising object for further development.

Geological evolution and construction of a glacierized active intra-oceanic arc volcano: Visokoi Island (South Sandwich Islands)

Visokoi is a small volcanic island in the remote South Sandwich Islands and is unique in being dominated by the basaltic andesite products of highly explosive eruptions. Here, its geology is described in detail for the first time and can be used to characterize the construction of an active glacierized volcano in an intra-oceanic volcanic arc setting. More than 90% of the volcano is submarine and is composed of (1) a ~ 2.5 km-high mound formed of pillow lava and tuff breccia flanked by a low apron of mass flow deposits, together with (2) an overlying unit ~ 200 m thick composed of Surtseyan volcanic products representing a shoaling (and ultimately emergent) volcanic stage. The succeeding island commenced as a small volcanic shield composed of subaerial ‘a ‘ā lavas whose construction terminated in a caldera collapse that repressurized the magma chamber, presaging a major transition to highly explosive pyroclastic eruptions. They were mainly of sub-Plinian and Plinian type and their recognition on the island provides the first viable explanation for the presence of compositionally similar marine tephras sampled by drilling > 500 km from source, previously considered enigmatic. Eruptions probably took place under ice-poor conditions but evidence for quenching of juvenile clasts suggests that the magmas interacted with water high in the conduit sourced from melting of a small ice cap. The major period of high-discharge sub-Plinian and Plinian eruptions appears to have ended and any future events shall probably comprise small-volume eruptions forming Strombolian scoria cones or glaciovolcanic tuff cones.

Identification of Slip Surface Using Geoelectric Methods in post Cianjur Earthquake Landslide

Abstract The landslide occurrence after the 2022 earthquake was influenced by the geographical location of Cianjur Regency, located at the foot of Mount Gede, so the morphology of the highland relief is dominant. An earthquake measuring 5.6 on the Richter scale due to the movement of the Cugenang Fault triggered landslides at various points, one of which was in Cugenang District. This research aims to identify the slip surface of landslides in Cugenang District using the geoelectric method due to the 2022 Cianjur earthquake. This method is used to map subsurface resistivity values, producing 2D modeling. Surface slip inference is estimated at significant differences in subsurface resistivity values. The results of the interpretation of geoelectric measurements show the detection of slip surfaces at varying depths from the surface ranging from 5 to 15 meters, a distance of 20-90 meters from the first electrode with resistivity distribution values ranging from 0.01 Ωm to 155 Ωm. Consequently, the contact is considered to be the interface between the tuff breccia and the clay layer. This finding is confirmed by the shape of the layer which is thought to function as a sliding surface, which shows a concave/rotational shape following the slope in the geographically corrected 2D modeling.

Analysis of Pyrophyllite Quality as a Potential Industrial Raw Material in Argotirto Area, Sumbermanjing Wetan District, Malang Regency, East Java, Indonesia

The Argotirto area, Sumbermanjing Wetan District, Malang Regency, East Java is one of area which had industrial mineral, namely pyrophyllite. Pyrophyllite minerals in this area were generally found in rocks that have been altered by hydrothermal alteration. Pyrophyllite is an industrial mineral that can be used as a raw material in various industries. This research aims to determine the geological conditions, physical properties, mineralogical and geochemical properties of pyrophyllite in the research area and to determine the quality of pyrophyllite as a potential industrial raw material. The methods used in this research were megascopic analysis, petrographic analysis, X-Ray Diffraction (XRD) analysis, and X-Ray Fluorescene (XRF), and the quality assessment of pyrophyllite using the standard of PT Gunung Bale, SNI No. 15-1023-1989, and SNI No. 15-1325-1989. The lithology in the study area consists of basaltic lava, andesite breccia, dacitic tuff breccia, dacite intrusion, and limestone. Pyrophyllite in the study area has a quality ranging from low grade to high grade. The EIP sample is classified as high grade quality and can be used as raw materials for the refractory industry, class I refractory materials, and materials for making fine ceramics. The WSP sample is classified as medium grade quality, and can be used as class III refractory materials. The DSP sample is classified as low grade quality, and can be used as a class III refractory material.

The effects of dacitic (rhyolitic) tuff breccia and corn distillers' dried grains with solubles (DDGS) inclusion on pellet mill electrical efficiency, production rate, and subsequent pellet quality.

Two experiments were conducted to evaluate the effect of Azomite (AZO) and 30% distillers' dried grains with solubles (DDGS) on pellet mill (PM) electrical consumption (kWh/MT), production rate, and pellet quality. Experiment 1 was conducted as a 2 × 2 × 2 factorial with main effects of diet formulation (0% or 30% DDGS), PM (1 or 2), and AZO (0% or 0.25%) with 4 replications per treatment. PMs were equipped with a 4.4 × 39.0-mm (L:D 8.9) or 4.4 × 35.8mm (L:D 8.2) die with PM production rates held constant at 31.8 metric ton (MT)/h and conditioning temperature was held constant at approximately 82 °C. Experiment 2 was designed as a 2 × 2 factorial of treatments with 4 replicates per treatment to evaluate the impact of AZO and DDGS on PM production rates and pellet quality. PM production rate was adjusted by the feeder screw to maintain 70% motor load, a 4.0 × 35.8-mm (L:D 8.75) PM die was used, and conditioning temperature held constant at approximately 82 °C. For experiment 1, a DDGS × PM interaction (P = 0.040) was observed. Diets containing 30% DDGS had a decreased kWh/MT compared to the control when using PM-1, whereas no differences were observed for kWh/MT between 0% and 30% when using PM-2. A DDGS × PM interaction (P = 0.019) was observed for kWh/MT standard deviation (STD). Diets containing DDGS increased STD compared to the control when pelleted with PM-2; however, there was no evidence of difference between the DDGS and control diets when pelleted with PM-1. There was an AZO × DDGS interaction (P < 0.05) for kWh/ton STD. No differences were observed in kWh/ton STD when pelleting corn-soy diets with or without AZO while AZO reduced kWh/ton STD in 30% DDGS diets. Diets containing AZO had reduced (P < 0.05) kWh/MT and pellet durability index (PDI) compared to diets pelleted without AZO. PDI was improved (P < 0.05) for diets containing DDGS. For experiment 2, diets containing AZO had increased (P < 0.05) PM production rate compared to those without AZO. The inclusion of 30% DDGS reduced (P < 0.05) PM production rate compared to the corn-soy diet. There was a tendency for an AZO × DDGS interaction (P = 0.083) for PDI. Azomite inclusion to corn-soy diets reduced PDI while there was no evidence of difference in diets containing DDGS. In conclusion, the addition of 0.25% AZO to the diet improved PM efficiency; however, this potentially leads to a reduced PDI depending on diet type and PM settings.

Characteristics of pyrophyllite and hydrothermal alteration at Argotirto area, Malang Regency, East Java, Indonesia

Abstract Argotirto area located in South Malang, East Java province, has abundant non-metallic mineral resources, e.g., pyrophyllite. The presence of pyrophyllite indicates that the area has undergone hydrothermal alteration processes. This research aims to determine characteristics of pyrophyllite and hydrothermal alteration at Argotirto and its surrounding area. The methods used in this research comprises geological and hydrothermal alteration mapping, thin section and X-ray diffraction (XRD) analyses from rock samples. There are five lithological units from the oldest to the youngest, namely altered basalt, altered andesite breccia, altered dacite intrusion, altered dacitic tuff breccia, and limestone units. In hand specimen, pyrophyllite has white to tan colour, massive and waxy/soapy textures. Furthermore, in thin section, pyrophyllite selectively replaces feldspar phenocrysts or it is disseminated in the matrix and intergrown with quartz. In the research area, there are four alteration zones, such as pyrophyllite-dickite-sericite-illite, pyrophyllite-vermiculite-alunite-tridymite, pyrophyllite-cristobalite-sericite-illite-smectite, and pyrophyllite-halloysite-sericite-illite zones. According to hydrothermal alteration mineral assemblages, it can be interpreted that those minerals are formed at low pH (approximately pH 4-5) and relatively low temperatures (100-&lt;250°C).

Preliminary Conceptual Model of Hydrogeological System in The Pandanduri Dam and its Surrounding Area on the Lombok Island

Abstract the availability of water resources is increasingly limited and even tends to be increasingly scarce; an in-depth study of geological-hydrogeological analysis of springs and groundwater is needed to support various community activities. This research was conducted to determine the hydrogeological system in the Pandanduri Dam area and its surroundings. Geological conditions and geomorphology determine the hydrogeological system and groundwater flow direction patterns. Geological conditions were obtained by conducting field investigations, and groundwater level data was obtained by measuring dug wells from 36 points and measuring 13 points of spring locations. Volcanic sedimentary rocks and volcanic breccia dominate the study area. Three (3) rock units can be distinguished, namely (1) the Andesite tuff breccia – pumice unit is located in the southern part of the study area, precisely in the reservoir area, and (2) the Andesite tuff breccia unit dominates located in the southern part of the study area. The study area’s eastern, western, and northern parts and (3) alluvial deposit units located in the study area covered the andesite volcanic breccia. The aquifer consists of volcanic sedimentary rock and volcanic breccia with a sandy bottom. The 2D interpretation of the dam area shows that the sandy volcanic breccia unit has a resistivity value between 5 ohms - 25 ohms in the form of lapilli tuff sand interspersed with fine tuff, located at a depth of 8 meters below the surface. The pattern of the direction of groundwater flow indicates that the movement of groundwater follows the shape of the topography that flows from the hilly area west-northwest of Santong Village to the southeastern river valley of Pandanduri Village; geological and geomorphological conditions affect this groundwater flow pattern.

Analysis Of The Potential Of Volcanic Aquifers In Supporting The Development Of Groundwater Resources In Bogor District, West Java

This research is crucial for understanding the aquifer potential of volcanic deposits as a sustainable groundwater source, especially in regions experiencing rapid urbanization and agricultural expansion. It aims to analyze the aquifer potential of volcanic deposits in Bogor Regency, focusing on the Bogor Groundwater Basin, the upper Cisadane watershed, the eastern slopes of Mount Salak, and the western slopes of Mount Pangrango. The methods used include secondary data collection from regional geological maps and primary data collection through field surveys, geological mapping, and hydrogeological mapping. The results show that the volcanic rock units in this area, consisting of stony tuff, tuff breccia, lava, and andesite lava, have unique characteristics with significant potential as aquifers. Detailed geomorphological and hydrogeological mapping revealed different types of springs and physical properties of water that support the sustainability of groundwater resources. These findings contribute significantly to the development of better groundwater management policies, effective water infrastructure development, and environmental conservation strategies in Bogor District, ensuring clean water availability for the future.

Zircon U-Pb Dating, Geochemistry, Lu-Hf Isotope Characteristics, and Geological Significance of Volcanic Rocks in Zhenghe Fozi Mountain National Geopark, Fujian, China

Fozi Mountain National Geopark is located in Zhenghe County in the northern region of Fujian Province, where the volcanic rocks of the Zhaixia Formation of the Shimaoshan Group are exposed. Zircon U-Pb dating and geochemical analysis were carried out to constrain its age and tectonic environment. The results show that three zircon U-Pb dating samples have attained ages of 99.2 ± 1.0 Ma, 99.6 ± 0.8 Ma, and 99.7 ± 2.0 Ma. Volcanic rocks in the core scenic area of Fozi Mountain were formed during the Late Cretaceous period. Elemental analysis showed that these volcanic rocks were dominated by the shoshonite series. They include gray dacite porphyry, grayish-white breccia tuff, volcanic agglomerate, and gray tuffaceous sandstone. These rocks were characterized by high silicon, high alkali content, and rich potassium levels. Lu-Hf isotope analysis of zircons revealed that their εHf(t) values varied from −8.7 to −6.8. The corresponding TDM2 values were primarily distributed in the range of 1.71 Ga to 1.59 Ga. These findings indicated that the magma primarily originated from the partial melting of the Mesoproterozoic crystalline basement, accompanied by a small number of mantle-derived materials. Tectonic environment analysis indicated that these rocks were formed in the post-orogenic intraplate extensional environment, which was associated with the back-arc extension or lithospheric thinning caused by the subduction of the paleo-Pacific plate beneath the Eurasian plate. The formation of these volcanic rocks was attributed to post-orogenic magmatism.

Subsurface Interpretation of the Panjang Fault Area, Lampung, Based on Geomagnetic Method

Research on the area along the Panjang Fault - Lampung, the area from the Teluk Betung to Tanjung Karang Barat area using the 19-T GSM PPM tool with base rover acquisition on 2 tracks 2 kilometers apart obtained 40 acquisition points with a spacing of 0.3 kilometers. This study aims to determine the type of lithology and subsurface rock structure by utilizing the susceptibility value of rocks from magnetic anomalies. In the process of processing magnetic anomaly data, upward continuation is carried out as high as 350 m which is intended to reduce the total anomaly with the upward anomaly results so that a residual anomaly is obtained. Next, make a 2D subsurface model on the incision A - B in the residual anomaly map. Based on the results of qualitative interpretation, the total magnetic anomaly of the research area illustrates positive to negative anomaly values with a tighter contour pattern that indicates the presence of a fault structure. While based on quantitative interpretation, the 2D modeling in incision A - B shows a susceptibility value of 0.100 cgs which can be identified as breccia tuff rock, a susceptibility value of 0.0391 cgs is thought to be rhyolitic tuff rock, pumice tuff rock, and sandstone tuff, and a susceptibility value of 0.150 cgs is a rock from the intrusion of Mount Betung in the form of andesite-basalt lava. In addition, rocks with a susceptibility value of 0.0024 cgs are metamorphic rocks. The correlation between 2D modeling and regional geology is seen in the research area, which is in the Tarahan Formation (Tpot), which is suspected to be a fault structure in the Bumi Waras area with a strike direction of NW - SE which is the course of geothermal manifestations or minerals.

Fluoride leaching from tuff breccia and its removal by natural and commercial adsorbents

In Japan, the concentration of fluoride (F−) leached from rocks, such as tuff breccia, excavated in tunnel construction projects often exceeds the Japanese environmental standard of 0.8 mg/L. Because of this, proper disposal methods are necessary for managing F−-bearing excavated rocks. One effective solution based on circular economy is the use of an adsorption layer system. This system can simultaneously prevent the migration of F− released from excavated rocks and allow the recycling of this construction waste material. To determine the most suitable material for the disposal of excavated F−-bearing tuff breccia from a tunnel construction in Hokkaido, Japan, four types of natural geological materials (S-1, S-2, S-3, and S-4) obtained near the tunnel construction site, as well as three types of commercial adsorbents (calcium (Ca), magnesium (Mg), and CaMg adsorbents) were selected for evaluation. The batch adsorption test results showed that S-1 and S-4 had high adsorption capacities for F−, and the adsorption process followed the Langmuir isotherm. The adsorption of F− to the natural adsorbents was strongly influenced by the pH and the presence of bicarbonate ions (HCO3−), but unaffected by chloride (Cl−) and sulfate (SO42−). There was also a strong positive correlation between the abundance of amorphous aluminum (Al) and iron (Fe) extracted and the adsorption of F−, indicating the importance of ion exchange reactions associated with surface OH− in immobilizing F−. Meanwhile, the Mg-bearing adsorbent exhibited the highest adsorption affinity for F− among the commercial adsorbents. This was attributed to adsorption through electrostatic interactions and coprecipitation with magnesium hydroxide (Mg(OH)2) formed during the hydration of magnesium oxide (MgO). To effectively incorporate these adsorbents into the adsorption layer system, parameters such as permeability and residence time need to be determined in order to maximize the retention of F− through adsorption, ion exchange and coprecipitation reactions.

INTERFACE SHEAR STRENGTH DEGRADATION IN PROGRESSIVE LANDSLIDE OF WEATHERED CLAY SHALE OVERBURDEN ON UNDISTURBED CLAY SHALE

In accomplishing Sustainable Development Goals (SDGs), the construction of roads played a substantial role in achieving economic equity. However, landslides due to problematic soil would hinder its construction process. Thus, it is essential to understand the mechanism of slope movement to reduce landslide problems. A landslide that happened during the construction of the Semarang-Bawen toll road was analyzed in this research. The landslide was known to fail between the interface of the tuff breccia overburden and the problematic clay shale soil. This research proposed the direct shear test to determine the interface shearing behavior. Before the test, the overburden was differentiated as various sand and weathered clay shale ratios. After the overburden soils were compacted, a multistage interface direct shear test was conducted with three different loadings. Water was added to the overburden layer to model the infiltration at the interface by increasing the water content. From the test, results such as the interface cohesion, friction angle, and average stress ratio were obtained. Overall, the interface shear strength decreased as the water content increased. The decreasing value was due to the wetting at the interface. Thus, it would moisten the interface and disrupt the structure of both the top and bottom layers of the sample. In conclusion, the interface direct shear test was able to describe the shear behavior at the clay shale interface. It also indicated that water had a considerable role in triggering interface landslides for two different soil layers.

Saturated hydraulic conductivity and water retention curve of variably weathered tuff breccia bedrock in a headwater catchment

Although recent studies have emphasized the importance of water flow through bedrock to hydrological processes in headwater catchments, information on the hydraulic properties of bedrock, required for physically characterizing water flow processes, is lacking. In this study, the saturated hydraulic conductivity, Ks, and water retention curve of tuff breccia bedrock core were determined in samples collected from boreholes in a headwater catchment in northern Japan. These core-scale properties, together with core shape and in situ Ks values, were used to define two groups of bedrock: CM- and CL-class (weakly to moderately weathered) and D-class (highly weathered). Little change in the volumetric water content θ of CM- and CL-class bedrock was observed in the dry range at a pressure head ψ < –200 cm, but slight changes occurred in the wet range (ψ > –200 cm), resulting in low core-scale Ks values of 10–8–10–7 cm s−1. Core shape and in situ Ks values much larger than the core-scale values suggested that in situ water flow is restricted to fractures, with little contribution of the matrix to total flow. In D-class bedrock, on the other hand, the change in θ with ψ was somewhat larger than in CM- and CL-class bedrock, especially in the wet range, resulting in moderate core-scale Ks values of 10–5 cm s−1. These results indicated that flow in D-class bedrock is better represented by matrix flow than by preferential flow through fractures. The hydraulic properties presented herein provide a basis for analyzing subsurface water flow, including through bedrock layers. Those analyses will provide a better understanding of water flow processes in headwater catchments.

Reconstruction of the deformation history of an active fault: implications from the Atera Fault, Central Japan

Atera Fault clay gouges were collected for age dating near Kawaue, Nakatsugawa City, Central Japan, and the results integrated within its complex geological history. The results form an internally consistent data set constrained by extensive geochronological data (AFTA, ZFTA, CHIME) and support the application of gouge dating in constraining timing of brittle deformation in Central Japan. The Atera illite age data complete recently obtained limited illite fault gouge age data from underground exposure in the Toki Granite; the new illite age data are identical within error. The age of the heterogenous welded tuff breccia zone (Atera 1) ranges from 40.6 ± 1.0 Ma to 60.0 ± 1.4 Ma, whereas ages of the fault core gouge sample (Atera 2) range from 41.8 ± 1.0 Ma to 52.7 ± 1.2 Ma. The finest < 0.1 µm fraction of the fault breccia and fault core gouge yield ages around 41 Ma, identical within error. The new illite age data indicate brittle faulting and a following geothermal event occurring in the Paleogene–Eocene, similar to the nearby Toki Granite area and confirm they were both synchronous with a post-intrusive pluton exhumation. The Atera Fault illite age data provide additional insights into an integrated, regional-scale record of the tectonic displacement of Central Japan and might be influenced by large-scale tectonic processes such as the Emperor sea mount kink around 55 to 46 Ma with fault initiation around 50 Ma and brittle fault cessation or reactivation around 40 Ma in the Eocene.Graphical

Identifikasi Jenis Batuan Panas Bumi Di Desa Angseri Dan Sekitarnya Dengan Metode Gravitasi

The research has been done on 2D model of the subsurface structure of the hot springs in Angseri Village and its surroundings using the gravity method. The purposes of the research is to determine the distribution of gravity anomaly values, density values and subsurface rock structures. The results showed that the value of Bouguer anomaly was between 10-137 mGal, the regional anomaly was between 42-105 mGal, and the residual anomaly was between (-32)-(35) mGal. The modeling results showed that the subsurface structure of the study area was composed of lava rock (1.1-1.73 gr/cm3), tuff (1.61-2.52 gr/cm3), tuff breccia (2.51-2,79 gr/cm3), lava (2.8-2.89 gr/cm3) and volcanic breccia (2.9-3.2 gr/cm3), where volcanic breccia rocks as permeable rocks and tuff breccia rocks as cover rocks.

Nature and Origin of a Massive Sulfide Occurrence in the Karrat Group: Evidence for Paleoproterozoic VMS Mineralization in Central West Greenland

Abstract Mafic volcanic rocks of the Kangilleq Formation of the Paleoproterozoic Karrat Group host volcanogenic massive sulfide (VMS) mineralization in the area of central Kangiusap Kuua, central West Greenland. The mafic volcanic rocks display evidence of subaqueous, effusive eruption and redeposition by mass debris flows generated along fault scarps on the sea floor. A zone of semiconformable quartz alteration and disconformable chlorite alteration within hydrothermal breccias and mafic tuff breccias near the top of the volcanic sequence is interpreted to reflect a synvolcanic hydrothermal system. Conformable, massive to semimassive, and discordant, stringer-style sulfide mineralization is hosted within the quartz- and chlorite-altered volcanic rocks. The massive to semimassive sulfide mineralization is ~10 m thick and crops out along strike for ~2,000 m. The stringer zone is ≤10 m thick with individual sulfide stringers ranging in width from 5 to 90 cm. All sulfide zones are dominated by coarse pyrrhotite and pyrite, with trace amounts of sphalerite and chalcopyrite. The pillow lavas are subalkaline with geochemical characteristics typical of modern transitional to tholeiitic mid-ocean ridge or back-arc basin basalt. Trace element and Nd isotope data suggest that these lavas erupted in an epicratonic, back-arc basin. Characteristics of the host rocks indicate a period of localized rifting, volcanism, and VMS formation during genesis of the Karrat Group, which is dominated by siliciclastic rocks.

Photosynthetically active radiation is required for seedling growth promotion by volcanic dacitic tuff breccia (Azomite).

A plant's growth and development are shaped by its genome and the capacity to negotiate its environment for access to light, water, and nutrients. There is a vital need to understand the interactions between the plant, its physical environment, and the fertilizers used in agriculture. In this study, a commercially available volcanic ash fertilizer, Azomite®, characterized as dacitic (rhyolitic) tuff breccia, was tested for its effect on promoting early seedling vigor. Early growth and photomorphogenesis processes are well studied in Arabidopsis. Seedling assays under different light conditions were used to dissect the underlying mechanisms involved. These assays are well established and can be translated to agriculturally important crop plants. The volcanic ash fertilizer was tested at different concentrations on seedlings grown on basic media lacking sucrose either in continuous darkness (Dc), continuous Red (Rc), Far-Red (FRc), or White Light (WLc). Micronutrients in the volcanic ash significantly increased seedling growth under Rc and WLc, but not under Dc and FRc, indicating that photosynthetically active radiation was required for the observed growth increase. Furthermore, red-light photoreceptor mutant, phyB-9, lacked the growth response, and higher amount of fertilizer reduced growth in all conditions tested. These data suggest that light triggers the ability of the seedling to utilize micronutrients in volcanic ash in a dose-dependent manner. The methods described here can be used to establish mechanisms of activity of various nutrient inputs and, coupled with whole-genome expression profiling, can lead to better insights into optimizing nutrient field applications to improve crop production.

Identification of Geothermal System in Cisolok, West Java based on the Correlation of Gravity Method, ADMT (Active Directory Magnetotelluric), and Drill Log Data

Indonesia has 40% geothermal potential of the world’s geothermal potential. One proof of its potential is in Cisolok, West Java. The method used in this study is the gravity method from 2013 GGMPlus satellite with First Horizontal Derivative (FHD) analysis which is correlated with ADMT and drill log data. Based on overlaid between Land Surface Temperature (LST) map and residual anomaly map, Cisolok has a temperature of around 23.8 – 26.5 °C. These correlations describe the normal fault structure in the south that controls the Cisolok geothermal system. The results of the 3D inversion modeling show alternating layers of tuff, tuff breccia and silt as a cap rock with a density contrast of 0 – 0.2 gr/cc at a depth of 0 – 325 m, thick limestone layers with a density contrast of -0.1 – (-0.05) gr/cc at a depth of 325 – 700 m, and a layer of granodiorite rock as an intrusion body with a density contrast of -0.2 – (-0.15) gr/cc at a depth of 700 – 900 m. Based on the results obtained, it can be proven that the gravity method and the ADMT method have a fairly good correlation in geothermal exploration activities.