Regional Geological Mapping Research Articles

Rmacrostrat : An R package for accessing and retrieving data from the Macrostrat geological database

The geological record is a vast archive of information that provides the only empirical data about the evolution of the Earth. In recent years, concentrated efforts have been made to compile macrostratigraphic data into the online centralized database Macrostrat. Macrostrat is a global stratigraphic database containing information regarding surface and subsurface rock units and their respective ages, lithologies, geographic extents, and various other associated metadata. However, these raw data are currently directly accessible only through the Macrostrat application programming interface, which is a barrier to potential users that are less familiar with such services. This data accessibility hurdle currently prevents full capitalization of the value offered by Macrostrat, particularly its potential to improve understanding of the geological and biological evolution of the Earth. Here, we introduce rmacrostrat, an R package that interfaces with the Macrostrat database to access and retrieve a variety of geological, paleontological, and economic data directly into the R programming environment. In this article, we provide details about how the package can be installed, its implementation, and potential use cases. For the latter, we showcase how rmacrostrat can be used to visualize regional stratigraphic columns, produce regional geologic outcrop maps, and investigate temporal trends in macrostratigraphic units. We hope that this package will make geological data more readily accessible and in turn will facilitate new research utilizing Earth system data.

A novel method for evaluating shale gas preservation conditions in an area on a regional scale

The Youjiang Basin is the main area of the Middle Devonian shale gas resources in southern China, with complex geological conditions, diverse stratigraphic structures, low level of exploration and limited hydrocarbon geological data. In this study, a method is proposed for evaluating the regional shale gas preservation conditions, by which it is easy to obtain information (using available data from regional geological maps) and to process data (processed by computer software). This method was applied to the evaluation of the preservation conditions of the Middle Devonian shale gas in the Youjiang Basin. Information extracted from geologic maps includes exposed stratum, magmatic rock distribution, stratigraphic occurrence and surface fracture distribution. Evaluation criteria for three indexes (stratigraphy index, dip angle index and fracture index) were established to classify the preservation conditions into five types from good to bad. Based on the calculated values of comprehensive index (CI), the comprehensive evaluation each area: 11621.23 km2 for CI of 0.7–1.0, 37162.67 km2 for CI of 0.5–0.7, 57784.43 km2 for CI of 0.3–0.5, 69303.77 km2 for CI of 0.1–0.3, and 69303.77 km2 for CI of 0.0–0.1, accounting for 3.19%, 10.19%, 15.84%, 18.99% and 51.80% of the whole area, respectively. These results are highly consistent with the actual exploration discoveries, showing that in the northern and central parts of the Guizhong Basin, the southern part of the Xidamingshan Uplift, and the northern part of the Qiannan Basin, there are large areas with good shale gas preservation conditions.

RSWFormer: A Multi-Scale Fusion Network from Local to Global with Multiple Stages for Regional Geological Mapping

RSWFormer: A Multi-Scale Fusion Network from Local to Global with Multiple Stages for Regional Geological Mapping

Spatial-temporal patterns of ecological-environmental attributes within different geological-topographical zones: a case from Hailun District, Heilongjiang Province, China

The climate change and extension of human activities are shedding more stresses on ecosystems. Ecological zoning could help manage the ecosystem and deal with environmental problems more effectively. Geology and topography could affect the ecology primarily and are vital perspectives on ecological zoning. It is worth preliminarily understanding the spatial-temporal patterns of ecological-environmental attributes within various geological-topographical ecological zones (GTEZs). The objective of this study was to delineate GTEZs and present a spatial-temporal analysis on soil and land surface parameters within GTEZs. Firstly, Landsat imageries, high resolution satellite imagery products, digital elevation model, regional geological map, black soil thickness, soil bulk density, meteorological data, and ground survey were collected and conducted. Secondly, GTEZs in Hailun District were delineated according to geological and topographical background. Thirdly, soil composition, and monthly land surface temperature (LST), enhanced vegetation index (EVI), net primary productivity (NPP) were derived from ground survey and Landsat imageries. Finally, spatial-temporal patterns of various ecological-environmental attributes within different GTEZs were preliminarily revealed and analyzed. Results show that sand alluvial plain zone and silt-clay undulating plain zone mainly possess thick soil with fine-medium granule and higher bulk density, and are mainly covered by crops and grass, vegetation flourish the most in August with the highest monthly EVI and NPP. While the sand-conglomerate hill zone, sandstone hill zone, and granite hill zone possess relatively thin soil with medium-coarse granule and lower bulk density, and are mainly covered by forest, vegetation flourish the most in June and July, and has the highest yearly total NPP. With thinner soil thickness and higher NPP, hill zones tend to have more vulnerability to disturbance and more contribution to carbon neutrality target.

The Priority Areas for Groundwater Utilization in Fractured Rock Formation, Pangandaran Regency

Abstract Pangandaran Regency is one of the best tourist destinations in West Java; many tourist attractions and regional developments to facilitate visiting tourists increase the need for water. However, in some areas of Pangandaran Regency, it is included in the rare groundwater zone according to its aquifer productivity, especially in the fracture rock formation, so it is necessary to conduct research related to the presence of groundwater in the area. This study aims to determine priority areas for the development of groundwater utilization in fractured rock formations located in the Pangandaran Regency. The fracture rock formations in Pangandaran Regency are located from the northwest to the southeast; on the regional geological map, the formation’s name is the Jampang Formation. This study used the Groundwater Potential Index (GPI) method to determine groundwater potential and the Analytic Hierarchy Process (AHP) method to determine water utilization area levels. The parameters used are fracture (F), lithology (L), drainage (D), topography (T), rainfall (R), water usage, land use, and population distribution. This research shows that areas with rare groundwater zones still have groundwater potential that can be developed to meet water needs. There are five priority area classifications: very high is 19 km2, high is 17.92 km2, medium is 67.90 km2, low is 70.99 km2, and very low is 162.40 km2.

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.

Research on Evaluation of the Carbon Dioxide Sequestration Potential in Saline Aquifers in the Qiongdongnan–Yinggehai Basin

This paper evaluates the carbon dioxide sequestration potential in the saline aquifers of the South Qiongdongnan–Yinggehai Basin. By using a hierarchical evaluation method, the assessment is divided into five stages: the basin level, the zone level, the target level, the site level, and the injection level. The study primarily focuses on evaluating the sequestration potential of and identifying favorable zones of saline aquifers at the basin and zone levels. The optimized volumetric method is adopted, based on the integration of multi-source data such as regional geological maps, seismic data, core porosity, and permeability. The results show that the estimated potential of the Yinggehai Basin is 60.6 billion tons at the basin level and 54.6 billion tons at the zone level. Additionally, the estimated potential of the South Qiongdongnan Basin is 261.5 billion tons at the basin level and 234.8 billion tons at the zone level. The suitability evaluation indicates that the Yinggehai Basin is moderately suitable overall, the northern depression of the South Qiongdongnan Basin is suitable, the central uplift is moderately suitable, and the central depression is not suitable. This study provides a scientific foundation for carbon dioxide sequestration in marine basins and introduces novel ideas and methods for future similar research. This is highly significant for subsequent engineering applications and decision-making processes.

STUDI KOMPARASI KAPASITAS DUKUNG RENCANA DAN KAPASITAS DUKUNG AKTUAL FONDASI TIANG PANCANG PADA KONSTRUKSI SLAB ON PILE JALAN TOL SEMARANG – DEMAK SEKSI 2

Semarang - Demak Toll Road Section 2 with a length of 16.31 km crosses the North Coast of Java. The regional geological map shows that the North Coast of Java has alluvial soil layers with clay and silt characteristics. The results of soil investigations show that the depth of the soft layer reaches more than 60 m. This condition triggers construction engineering to support the Highway above it. One of the efforts to fulfill the elevation plan (finish grade) is the flyover concept with slab on pile construction. The planned traffic lane is laid on a concrete slab which is supported by piles with a diameter of 600 mm. With sufficiently deep soft soil layers, the bearing capacity of the foundation piles is borne by the frictional resistance provided by the soil along the piles. This comparative study compares the planned carrying capacity calculated by the empirical formula with the actual carrying capacity of the field as a result of the PDA Test. Calculations were made on 5 test poles for later comparisons were made with the PDA test record data. For the case of 14 days driving at the research location, the pile bearing capacity from the PDA test results is still below the design bearing capacity. The average actual carrying capacity obtained from the 5 test piles is 278 tons. This value is below the planned carrying capacity of the Shio & Fukui method of 381 tons, Meyerhoff's 355 tons, Biaud et al's 777 tons, and Luciano Decourt's 605 tons. At the age of the pile 14 days after the erection was completed, the results of the calculation of the bearing capacity of the Meyerhoff method are closest to the actual bearing capacity of the PDA test results with a ratio of 1.26. The next method is Shio & Fukui with a ratio of 1.36, Luciano Decourt (2.16), and Biaud et al (2.81). Some of the results of previous studies showed a positive correlation between the age after completion of the pile and the frictional carrying capacity. For this type of friction pile, this is of course very influential, so that it is possible that when it is realized that it is carried out with a longer service life, the actual bearing capacity obtained will increase. This requires further research to obtain a time relationship with an increase in pile bearing capacity, especially for locations that have deep soft soil layers such as in this study location.

Mapping a tropical regolith architecture: A comparative LANDSAT-8 and SENTINEL-2 analysis

Understanding of the lateritic regolith units is important for regional geological and pedological mapping and provides valuable insights into landscape evolution and mineral exploration, especially in tropical environments. To contribute to these issues, this study used Landsat-8 OLI and Sentinel-2 MSI imagery to map the different lateritic regolith units in an area of 133 thousand km2 in the Midwest of Brazil. The approach used the Directed Principal Component Analysis (DPCA) technique and SRTM data as predictor variables for the Random Forest (RF) classification model, with the aim of comparing the efficiency of both sensors following identical classification methods. The results showed a similar overall accuracy of 73% for Landsat-8 and 74% for Sentinel-2, however the Sentinel-2-based maps are the most accurate with a kappa of 0.63 and a tau of 0.68. The significant levels of accuracy highlight the efficiency and feasibility of the multispectral imagery and machine learning approach to lateritic regolith mapping. It also emphasizes the importance of considering the spectral and spatial characteristics of sensors when selecting the most appropriate one for geological, pedological and geomorphological studies in tropical regions.

Optimizing Surface Lithology Interpretation from Global Gravity Model and Landsat 8 Satellite Imagery in Semeru Mountain, Indonesia

Conventional geological mapping has high data accuracy but has ineffectiveness such as incomplete sample sweep coverage due to extreme topography, densely populated environmental conditions, and weather constraints in the field. Remote sensing is an effective alternative geological mapping solution through a combination of satellite gravity methods and satellite imagery interpretation. This study aims to apply remote sensing to obtain a more detailed distribution of Mount Semeru lithological types from regional geological maps. Integration of rock density results from satellite gravity and lithology distribution from satellite imagery results in a more detailed lithological types interpretation with more specific physical conditions of rock density. Relatively low rock density values (1.9 - 2.3 gr/cm3) distribution is at the top and foot of the mountain in the outermost areas of the study area indicating relatively thick pyroclastic material with relatively deep bedrock depth, and unconsolidated material. On the side of the body of the mountain slope, there is a relatively high rock density value (2.9 - 3.5 gr/cm3) with an indication of the formation of pyroclastic material which is relatively thinner with the presence of shallower bedrock and has consolidated material. Geological mapping optimization forms the basis for further research related to the planning and development of natural resources, as well as a more effective and efficient advanced geological mapping automation process.

Volcanic debris avalanche deposits and their significance in the architecture and evolution of the Miocene-Quaternary Călimani-Gurghiu-Harghita volcanic range (Eastern Transylvania, Romania)

The Călimani-Gurghiu-Harghita volcanic range (CGH) represents the surface manifestation of the post-collisional magmatism that followed the docking of its basement, the Dacia Mega Unit, onto the East European margin. Between ca. 11 and 0.3 Ma, detachment of subducted slab, magma generation, and volcanic activity in CGH propagated south-southeastward, sub-parallel with the collisional Eastern Carpathian Orogen, resulting in the construction of a series of mostly composite volcanoes dominated by calc-alkaline lavas and pyroclastic products. The generally well-preserved axial row of the CGH volcanic edifices is accompanied by voluminous volcaniclastic deposits of which sources and emplacement history persist as a matter of debate. In the standard view reflected in regional scale geologic maps, these deposits represent products of complete erosion of hypothetical earlier volcanoes. Other interpretation, however, suggest that they are at least partially constituted by voluminous volcanic debris avalanche deposits (VDADs).By combining evidence from field observation and GIS analysis with published and new data from petrography, bulk-rock geochemistry, and K/Ar geochronology, here we demonstrate that VDADs vastly dominate these volcanoclastic deposits. In addition to two previously identified VDADs (Western Călimani and Vârghiş), we show that further six VDADs (Eastern Călimani, Fâncel-Lăpuşna, Ostoroş, Ivo-Cocoizaş, Luci, and Pilişca) were generated due to the sector failure of a series of CGH volcanoes, most of which still preserve well-distinguishable collapse scars. Based on our estimates, debris avalanches with volumes between <1 km3 and > 100 km3 displaced 0.4–39% of the source edifices, transferring nearly a third of their cumulated volcanic output to the observed volcaniclastic deposits.K/Ar age constraints suggest VDAD formation closely followed in space and time the migrating volcanic activity between ca. 7.8 and 1.5 Ma. Relying on this age pattern, collapse scar orientations, and VDAD runout directions, we propose that regional scale deformation of the Dacia lithosphere imposed by progressive detachment of the underlying subducted slab, manifested on the surface as a transient subsidence–uplift couple traveling along CGH as well as opening of intramountain basins at the eastern flank of the range, was responsible for basement tilting and faulting that destabilised the CGH volcanic edifices. Seismic activity associated with slab detachment and shallow crustal fault system as well as explosive volcanic eruptions may have triggered the collapse of these edifices, leading to the generation of the VDADs.

Enrichment of Coal-Hosted Graphite Deposits Caused by Magmatic Heat Transfer and Tectonic Stress at Feng County, Western Qinling Orogen, China

China has ranked first worldwide in graphite imports in recent years, facing a graphite supply risk. Coal-hosted graphite is the focus of future graphite deposit exploration. The current research on the enrichment and mineralization mechanism of coal-hosted graphite is superficial, and the identification standard of coal-hosted graphite is incomprehensive, restricting the exploration of coal-hosted graphite mineral resources and the development of coal metamorphic evolution theory. In this study, the Caotangou–Meigoucoal-hosted graphite deposit in western Qinling Mountain was taken as a case study for dissection. Based on the data from 1/50,000 and 1/200,000 regional geological mapping and the data of graphite mines in the study area, the samples were systematically collected and analyzed to explore the mechanism of coal graphitization through a 1:5000 geological profile survey, 1/10,000 geological mapping in key areas, and the investigation and cataloguing of abandoned coal-hosted graphite adit. The result was that there were two main coal-hosted graphite ore bodies, striking from nearly east to west. The Rmax values of the samples were 7.23–8.15%, the average values of Vdaf were around 5.0%, the d002 value of the II ore body was 0.3433–0.3389 nm, the d002 value of the I ore body was mainly 0.3418–0.3429 nm, the graphitization degree G value of the II ore body was 8.14–59.30%, the graphitization degree G value of the II ore body was 12.79–25.58%. The II ore body was coal-hosted graphite, while some samples of the I ore body were coal-hosted graphite, and some samples were coal. The magmatic heat controls the thermal metamorphism of coal seams to form graphite. The closer the distance to the magma body, the larger the crystals, and the higher the euhedral degree, indicating the higher degree of coal seam metamorphism. The nearly north–south compressive structures mainly provided effective tectonic stress for the evolution of coal graphitization during the Yanshan period; the basic structural units (BSUs) rotated and rearranged, eventually forming a straight graphite structure, and tectonic stress catalyzed the graphitization process. The coal-hosted graphite deposits formed under the dual effects of magmatic heat transfer and tectonic stress.

Geological Characterization, Lithogeochemistry and the Metallogenic Potential for Chromium of the Riacho do Mocambo Mafic-Ultramafic Body, Northeast of the São Francisco Craton, BA, Brazil

In the geotectonic context of the Salvador-Curaçá Orogen, north portion of the São Francisco Craton, an association of mafic-ultramafic (M-UM) rocks was identified and described in this paper as the Riacho do Mocambo Mafic- Ultramafic Body (RMMUB). Despite being located approximately 60 km from the Vale do Jacurici Complex (VJC), the host of Brazil’s largest reserves of Cr, the RMMUB has never been associated with this Complex in regional geologic mapping projects. When it is mentioned in the bibliography, the M- UM rocks of the RMMUB are genetically related to the São José do Jacuípe Suite (SJJS). While the VJC is described as differentiated sills, associated with a synorogenic to a tardi-orogenic event, the SJJS is interpreted as fragments of an Archean-Paleoproterozoic oceanic crust or as a Gabbro- Anorthosite Stratiform Complex. Such contrasting genesis raised doubts about the RMMUB’s origin and field work along with geochemical analyses were carried out in order to better understand the possible source of the RMMUB. In the field, the RMMUB exhibits an elongated shape of small thickness (7 km of extension by less than 100 m of apparent thickness), displayed concordantly with the Tanque Novo-Ipirá Complex metasediments. In the mapped outcrops it is possible to observe the rhythmic and gradual alternation amid the lithotypes of the RMMUB, varying from serpentinite to metagabbro, suggesting that it is a layered igneous body. The geochemical results support the primitive aspect of the ultramafic rocks of this body (MgO up to 38 wt.%; Ni up to 2972 ppm; Cr up to 7799 ppm) and suggest that the RMMUB shows distinctive characteristics from the SJJS, but similar ones with magma of the VJC such as geochemical signatures, source, depth, and tectonic environment. The discovery of this new M-UM body in an area of great metallogenic fertility opens a potential for the identification of new Cr mineralization and magmatic sulfides of Ni, Cu, and EGP, in the Salvador- Curaçá Orogen, São Francisco Craton, the northeast region of the state of Bahia.

Evidence for a Paleogene boninitic arc following oceanic plateau-continent collision in the Western Cordillera of Colombia

The Caicedo Tuffs is a recently mapped Paleogene volcanic arc unit in the northern Andes, which provides insight into the magmatism of northwestern South America following its collision with the Caribbean-Colombian Oceanic Plateau (CCOP) in the latest Cretaceous. New regional geological mapping, igneous petrography, whole-rock and pyroxene geochemistry, and zircon U-Pb dating are provided for the northern sector of the eastern flank of the Western Cordillera of Colombia (Antioquia). These data reveal that the Caicedo Tuffs unit is predominantly composed of primary volcaniclastic deposits (tuff to breccia) that record mafic subaqueous volcanism and limited orogenic building shortly after collision of the CCOP. The geochemistry of these deposits includes major element characteristics and immobile trace element patterns that are typical of boninites. Zircons from these igneous rocks constrain a crystallization age of ca. 57 Ma, with meso-Proterozoic to Jurassic inherited zircons most likely reflecting continental recycling by turbidites in the subduction zone. The boninitic affinity of the Caicedo Tuffs and existing regional igneous and tectonic constraints can be explained by resuming of subduction and/or sinking of an older oceanic slab along northern South America following collision of the CCOP with South America. The boninitic, primary volcaniclastic deposits of the Caicedo Tuffs are crosscut by basaltic-gabbroic sills and dykes with oceanic plateau-like geochemical affinities, which lack evidence for hydrous melting and are compositionally similar to igneous rocks of the CCOP. These intrusions are interpreted to reflect decompression melting of plume-related mantle inherited during the collision of the CCOP with South America or slab detachment. The occurrence of oceanic plateau-like intrusions in a Paleocene volcanic arc casts doubt on the origin of other oceanic plateau sequences of the Western Cordillera, which are generally attributed to the Cretaceous CCOP. The Caicedo Tuffs is a unique boninite unit of which the detailed spatiotemporal extent and petrogenesis remain to be constrained, but that can provide valuable insight into tectono-magmatic processes during oceanic plateau-continent collision.

Geological mapping and chronology of lunar landing sites: Apollo 14

The lunar cratering chronology function is based on the careful and systematic correlation of crater size-frequency distributions (CSFDs) with radioisotopic ages of samples from the Apollo, Luna, and Chang'e landing sites. The link between the samples and the CSFDs requires a detailed understanding of the landing site geology. Therefore, in this study, we have created a new detailed regional geological map of the Apollo 14 landing site using LRO, M3, and SELENE/Kaguya data. The geologic map allows us to define homogeneous areas for new CSFD measurements, from which updated N(1) values (i.e., cumulative number of craters with diameter ≥ 1 km) can be determined for the sampled geologic units. In particular, at the Apollo 14 landing site we measured the N(1) of the Imbrian Fra Mauro Formation (Ifm), which is interpreted to be ejecta from the Imbrium basin, and can be correlated with the Apollo 14 Imbrium ejecta samples. This new calibration point can be compared with the lunar chronology of Neukum (1983). We find that the new calibration point is consistent with the lunar cratering chronology of Neukum (1983). Together with our previous studies, this result supports the validity of this chronology.

Application of Seismicity and Gravity Observation-Based Filtering Model for Mapping a Fault Structure in Weh Island, Indonesia

Aceh Province is one of the Indonesian regions prone to earthquakes beneath the Great Sumatran Fault, which has been focused mapped on the land. At the same time, the continuity of the Great Sumatran Fault to the marine and islands is rarely investigated. We apply the Gravity Model Plus which has a resolution of 200 m/px, to map a detailed structure of the the Great Sumatran Fault in Weh Island. The Bouguer anomaly varied between 32 – 78 mGal, which reveals the response of the rocks comprising Weh Island, such as those on the east side with a high-value reaction corresponding to highly dense basalts 2.84 g/cm3 and on the west side with a low-value response representing the density of andesites 2.56 g/cm3. The residual anomaly indicated several local faults, e.g., Sabang and Seuke faults located on the east side, Lhok Jeumpa on the central side, and Pria Laot on the west side. Meanwhile, the derivative data from the Bouguer anomaly could explain the fault structures corresponding to regional geological maps, such as the Sabang fault in Balohan in the northwest-southeast direction and several others controlling the Jaboi volcano, i.e., Ceunohot and Leumomate. The focal mechanism from seismicity analysis figured the fault orientation from the Seulimeum segment in the direction of NW-SE, which is essential to assess an active fault. Based on data processing, we concluded the the Gravity Model Plus data is effective for first mapping the fault structure in developing countries, such as Indonesia.

Biostratigraphic Interpretation of Lutut Beds, Kerek Formation, Based on Foraminifera Fossils

Lutut Beds are the sandstone beds exposed in the northwest margin of Kendeng Basin, which contain abundant metamorphic-quartz grains, frequent recycled sedimentary quartz, and reworked bioclasts. Lutut Beds are not shown on the regional geological map and are often neglected in determining the geological history of Kendeng Basin. However, they have significant roles because it was deposited on the basin edge, which may carry important keys. This study aims to discover the larger and smaller foraminifera fossils contained in the Lutut Beds. Outcrop samples were collected in Kali Lutut and its surrounding area, including Lutut Beds and its overlying layers. Larger foraminifera was identified within 3 of 11 thin sections, mostly of Order Rotaliida, which occur as reworked bioclasts. The smaller foraminifera was barely found in most samples except for the samples from the overlying layers of Lutut Beds. The study reveals that Lutut Beds were deposited during Early to Middle Miocene, marked by the occurrence of Miogypsina sp. and Miogypsinoides sp. and also contains reworked Eocene – Early Oligocene larger foraminifera such as Nummulites sp., Discocyclina sp., and Dictyoconus sp. Besides, the overlying layer of Lutut Beds is identified to be deposited in the Middle Miocene to Pliocene based on the occurence of smaller planktonic foraminifera, Sphaeroidinella subdehiscens. The bathymetric interpretation based on smaller benthic foraminifera showed that Lutut Beds were deposited in the upper-middle bathyal zone. We also believe that the larger benthic foraminifera fossils in Lutut Beds were transported along the slope from its original life position. Accordingly, it is considered as allochthonous fossils.

LAND SUBSIDENCE AND GEOTECHNICAL IMPACT OF JAKARTA KOTA AREA

Land subsidence has long occurred around the Special Capital Region of Jakarta. It is important to know and deal with Land subsidence events which also cause various negative impacts. Aim: When large amounts of groundwater are withdrawn from certain types of rocks, such as fine-grained sediments, land subsidence occurs. The rock compacts because the water helps to keep the ground in place. When the water is removed, the rocks collapse in on themselves.The immediate impact is the building collapse around the Kota Tua of DKI Jakarta. Methodology and Results: The research method used is a quantitative descriptive survey method by observing the amount of land subsidence that occurs in the Kota Tua area and its surroundings. The results showed that there has been a vertical land subsidence that varies between 20-60 cm. Based on the results of the resistivity values and coordinates plotted on the Regional Geological Map (Jakarta and Kep Seribu), the research location is classified into Lithology: Clay, Sand Silt, Gravel, and Pebbles (Quartenary deposits). The phenomenon, land subsidence, is caused by a combination of various parameters, including natural consolidation of alluvial soils, excessive groundwater extraction, and also building loads from infrastructure development and tectonic factors. Conclusion, significance, and impact study: Knowing the value of land subsidence and its location is expected to support urban planning, basic infrastructure planning and development, housing, settlement planning, and local financial improvement in efforts to mitigate land subsidence disasters.

Geologi dan Pola Sebaran Serta Kemenerusan Lapisan Batubara Menggunakan Metode Kontur Struktur di Desa Suo-Suo dan Sekitarnya Kecamatan Sumay Kabupaten Tebo Provinsi Jambi

Coal is a non-renewable natural resource. Coal has an important role in domestic and foreign energy resources. Coal is generally used in steam power plants (PLTU). In supporting the sustainability of coal energy, further exploration in coal development is needed. The research uses the required structural contour method with the aim of determining the distribution limits and direction of the continuity of the coal seam and only refers to the position of the coal seam and is applied to topographic maps. The observation location (LP) found in the research area contained 7 coal seams. Based on the criteria of the Indonesian National Standard (SNI), the number of outcrops that have a coal seam thickness above 1 meter are 2 outcrops with a thickness of 2.15 meters and 1.24 meters, respectively. The results of drawing the distribution pattern using the structural contour method based on the bottom of the coal seam, it is found that the direction of the distribution pattern is northwest-southeast. The continuity follows the direction of the hills and valleys based on a distribution pattern that is trending northwest-southeast with a developed control structure in the form of a pure rising fault. This is in accordance with the regional geological map of the study area with the direction of the continuity of the coal seam trending northwest-southeast. From the results of the distribution pattern and continuity, there are 2 coal outcrops that can be exploited with economic value.

Territory Suitability Assessment for Conducting Detailed Geological and Mineralogical Mapping Based on Statistical Methods of Remote Sensing Data Processing Landsat-8: A Case Study in the Southeastern Transbaikalia, Russia

The work considers the suitability of using multispectral satellite remote sensing data Landsat-8 for conducting regional geological and mineralogical mapping of the territory of south-eastern Transbaikalia (Russia) in conditions of medium- low-mountain relief and continental climate. The territory was chosen as the object of study due to its diverse metallogenic specialization (Au, U, Mo, Pb-Zn, Sn, W, Ta, Nb, Li, fluorite). Diversity in composition and age of ore-bearing massifs of intrusive, volcanogenic and sedimentary rocks are also of interest. Statistical processing algorithms to increase spectral information content of satellite data Landsat-8 were used; they include: principal component analysis (PCA); minimum noise fraction (MNF) and independent component analysis (ICA). Eigenvector matrices analysed on the basis of statistical processing results and two-dimensional correlation graphs were built to compare thematic layers with geological material classes: oxide/hydroxide group minerals containing transition iron ions (Fe3+ and Fe3+/Fe2+); a group of clay minerals containing A1–OH and Fe, Mg–OH; minerals containing Fe2+ and vegetation cover. Pseudo-coloured RGB composites representing the distribution and multiplication of geological materials classes was generated and interpreted. Integration of informative thematic layers with using fuzzy logic model was carried out to construct a prospectivity map. Received map was compared with geological information, and positive conclusions about territory suitability for further remote mapping research of hydrothermally altered zones and hypergenesis products in order to localize areas promising for identifying hydrothermal-metasomatic mineralization were made.