Digital Geologic Map Research Articles

An open-source, QGIS-based solution for digital geological mapping: GEOL-QMAPS

Digital geological mapping has experienced significant growth over the past three decades due to the advent of commercial geographical information systems, advances in global positioning systems, and the availability of portable hand-held devices, such as mobile personal computers (PCs), smartphones, and tablets. Numerous software packages have been developed to collect, combine, organise, visualise, publish, and share field data with enhanced spatial accuracy and minimal post-field processing. However, many of these tools are not open-source or are not made available to the geoscientific community, remaining specific to given mapping projects or organisations.In this contribution we introduce GEOL-QMAPS, an open-source, QGIS-based solution promoting digital geological mapping in a harmonised, comprehensive and flexible way. It can be used in the field with a tablet PC or via the QGIS-based QField app on iOS or Android mobile devices, enabling synchronisation with desktop QGIS and the creation of field databases. Designed as a general solution, the GEOL-QMAPS solution consists of a QGIS field data entry template and a custom QGIS plugin, both available on free-access online repositories. The plugin allows for the adaptation of dictionaries (i.e., lists of attributes describing geological features), initially set to international nomenclatures, to the guidelines of different mapping projects. The solution also facilitates the loading and consultation of relevant legacy geodatasets (e.g., preexisting field data, geochemical, geophysical maps or punctual datasets). A fact map, created from field data collected across the Archean Sula-Kangari greenstone belt in Sierra Leone, demonstrates the solution's advantages in terms of post-field processing and raw field data sharing.

Relative dating of fault activity using the principle of cross-cutting relationships: An automated approach

Fault dating plays an essential role in understanding deformation histories and modeling the tectonic evolution of orogenic belts. However, direct fault dating methods via different isotope geochronological techniques are expensive, and their use is often limited in many cases, making it essential to develop a fast and low-cost fault relative dating method. Therefore, on the basis of knowledge graphs and knowledge reasoning technology, this study proposes an automatic method to relatively date periods of fault activity using the principle of cross-cutting relationships between faults and strata. The method mainly involves (1) generating the knowledge graph based on a digital geological map; (2) using the knowledge reasoning algorithm to interpret the cross-cutting relationships amongst faults and generating the temporal sequence of fault activity; (3) relative dating the faults based on the cross-cutting relationships between faults and strata; and (4) according to the temporal sequence of fault activity, the relationship between faults can be revealed, and relative dating can be optimized. Results for cases in western Nevada and Qixia Hill of Nanjing illustrate the effectiveness of this method for interpreting the period of fault activity. The accuracy rates of the recognition results in the two cases were 90.24% and 80.77%, respectively, which means that the proposed method has the potential to relatively date fault activity across large areas. The algorithm is an effective supplement to the existing direct method of fault dating. The algorithm can efficiently infer the development sequence and the age of fault activity based on geological maps and geological cross-sections, which is of great significance for understanding regional tectonic history, evaluating earthquake disasters, and modeling tectonic evolution processes.

A dataset of the distribution and characteristics of debris flows along the National Highway 318 in the Sino-Nepalese transport corridor (2022)

Due to the unique geographical and geological conditions in the Sino-Nepal transportation corridor, there is a lack of reliable and comprehensive data on debris flow distribution data in the region. This dataset is compiled based on early identification of debris flows and field surveys, integrating Digital Elevation Models (DEM) and geological maps. It provides a catalog and detailed feature information of debris flows within the corridor along the National Highway 318 between China and Nepal from 1990 to 2022. Precipitation and temperature parameters are derived from 30 years (1980–2009) of interpolated data from national meteorological stations. Fault distribution information is sourced from the 1:50,000 digital geological maps published by the China Geological Survey. Terrain information is obtained from NASA's Shuttle Radar Topography Mission (SRTM) data, which provides a global DEM at a resolution of 12.5 m. Within the geographical coordinates of 28.0°–29.4°N and 85.1°–88.9°E, a total of 255 debris flow records have been extracted, covering an area of 1660.73 km². We primarily employed hydrological analysis methods in ArcGIS for the extraction of debris flow basins. Considering the limitations in DEM accuracy, we made necessary manual corrections with reference to Google Earth imagery. The dataset comprises three files: a vector file depicting the main distribution range of debris flows along the National Highway 318 in the Sino-Nepalese transport corridor; a vector file containing the catalog of debris flows; and a document detailing the parameters and characteristics of the debris flows.The dataset has undergone on-site field surveys and confirmation to ensure its reliability. Therefore, it can serve as a foundational dataset applicable to debris flow studies in the region.

A comparison of PCA and ICA in geochemical pattern recognition of soil data: The case of Cyprus

Multivariate analysis of soil geochemistry is a powerful tool for differentiating lithological units and detecting geochemical dispersion halos related to mineralization or contamination. While univariate analysis can effectively identify lithological units with pronounced variations, it may fail to differentiate between subtler variations in lithologies. Traditional multivariate techniques such as principal component analysis (PCA) have limitations, including difficulties in understanding the individual contributions of each variable and an inability to work with non-Gaussian data. Independent component analysis (ICA) has emerged as a potential alternative, as it can effectively identify independent components of non-Gaussian data. In this study, we compared the effectiveness of PCA and ICA in relating multivariate soil geochemistry to parent lithology using the Soil Geochemical Atlas of Cyprus and associated digital geological maps. Both PCA and ICA were able to differentiate between the ultramafic units within the Troodos Ophiolite (TO) and the Circum-Troodos Sedimentary Succession (CTSS). However, ICA was more effective than PCA in identifying pillow lavas, providing a clear separation in the scores for IC4 and IC5. Furthermore, both PCA and ICA were able to separate the sheeted dykes from the cumulate mafic units within the TO. The gabbro unit is closely defined by IC2 scores. In contrast, PCA failed to provide factors that effectively delineated the Mamonia Terrane from other units, especially the TO, while ICA was able to provide a distinct separation in IC4 and IC5 scores. Separation between the CTSS and Quaternary units was weakly observed in IC2 scores. These findings demonstrate that there is a difference in the effectiveness of PCA and ICA in identifying different lithological units and emphasize the need for a careful selection of multivariate methods to differentiate between subtle differences in soil geochemistry relating to variations in parent lithology.

Digital Geological Map of the Upper Laja River Basin, Guanajuato, Mexico

A new geological map of the Upper Laja River Basin at 1:200,000 scale is presented, covering an area of ∼11,600 km2 in the northern part of Guanajuato. This map was edited based on local and regional geological studies available in the literature, photo interpretations, field verification of contacts and faults and structural data acquisition. The main objective of this map is to provide a regional geological framework for future local geological and hydrological studies in the region. It displays the geology of the basin, divided into seven chronostratigraphic groups, as well as the main faults that shape the basin. In contribution to the geological knowledge of the area, five new U-Pb ages are presented, obtained from samples collected at the eastern and western edges of the basin.

The British Geological Survey Rock Classification Scheme, its representation as linked data, and a comparison with some other lithology vocabularies

Controlled vocabularies are critical to constructing FAIR (findable, accessible, interoperable, re-useable) data. One of the most widely required, yet complex, vocabularies in earth science is for rock and sediment type, or ‘lithology’. Since 1999 the British Geological Survey has used its own Rock Classification Scheme in many of its workflows and products including the national digital geological map. This scheme pre-dates others that have been published, and is deeply embedded in BGS’ processes. By publishing this classification scheme now as a Simple Knowledge Organisation System (SKOS) machine-readable informal ontology, we make it available for ourselves and third parties to use in modern semantic applications, and we open the future possibility of using the tools SKOS provides to align our scheme with other published schemes. These include the IUGS-CGI Simple Lithology Scheme, the European Commission INSPIRE Lithology Code List, the Queensland Geological Survey Lithotype Scheme, the USGS Lithologic Classification of Geologic Map Units, and Mindat.org. The BGS lithology classification was initially based on four narrative reports that can be downloaded from the BGS website, although it has been added to subsequently. The classification is almost entirely mono-hierarchical in nature and includes 3454 currently valid concepts in a classification 11 levels deep. It includes igneous rocks and sediments, metamorphic rocks, sediments and sedimentary rocks, and superficial deposits including anthropogenic deposits. The SKOS informal ontology built on it is stored in a triplestore and the triples are updated nightly by extracting from a relational database where the ontology is maintained. Bulk downloads and version history are available on github. The RCS concepts themselves are used in other BGS linked data, namely the Lexicon of Named Rock Units and the linked data representation of the 1:625 000 scale geological map of the UK. Comparing the RCS with the other published lithology schemes, all are broadly similar but show characteristics that reveal the interests and requirements of the groups that developed them, in terms of their level of detail both overall and in constituent parts. It should be possible to align the RCS with the other classifications, and future work will focus on automated mechanisms to do this, and possibly on constructing a formal ontology for the RCS.

To move or not to move? Manganese oxide procurement during the Archaic period in the Atacama Desert

This paper investigates the possible sources of manganese (Mn) acquisition for the Chinchorro population of Arica, in northern Chile. To accomplish this, we analyse Mn distribution using digital geological map data and SEM/EDX and XRD analysis to chemically characterize twenty-five samples. Of these, eighteen were taken from geological sediments and seven from black pigments related to the Chinchorro mummification tradition (ca. 6950–2950 BP) from the archaeological sites of Maestranza 1, Morro 1, and Playa Miller 8. In contrast with previous highland Mn acquisition hypotheses, our results show that the lowland and coastal geological sediments near the Lluta river mouth have high Mn concentration, with a granular form that was easy to mine and process. The archaeological samples show that the Chinchorro used a high-grade Mn, without the need to use large mining tools (e.g. hafted hammers). This supports the proposition that there was a local (lowland and coastal) acquisition of good quality Mn, minimizing long-distance travel to the highlands for Mn procurement. The abundance of local finely-ground Mn sources can explain the cultural centrality of this pigment for several millennia during the Archaic period.

Morphometric Determination and Digital Geological Mapping by RS and GIS Techniques in Aseer–Jazan Contact, Southwest Saudi Arabia

The hydrological characteristics of the watershed in the southern Aseer and northern Jazan regions of Saudi Arabia (SA) were identified by integrated remote sensing (RS) and geographic information system (GIS) techniques using Shuttle Radar Topography Mission (SRTM) and Landsat data. For this purpose, the Wadi Ishran, Wadi Baysh, Wadi Itwad, Wadi Tabab, and Wadi Bayd drainage basins were extracted. Wadi Ishran is the largest, and Wadi Tabab is the smallest. Stream order and bifurcation ratio show that the Itwad and Bayd basins are permeable and of high aquifer potentiality. The multisupervised classification found seven rock units that were spread out in different ways across the basins. The areas with the highest vegetation were in the southeast, the centre, and the northwest. The bands’ ratios show more iron-rich sediments in the northeast and southwest. This paper’s outcomes serve as the basis for planning and managing groundwater resources. It finds potential groundwater zones, determines the risk of flooding, and chooses places where harvesting can be undertaken.

A new guideline for geological maps with QGIS

Abstract Being able to create digital geological maps has become a basic requirement for the skillset of today’s geologists. QGIS is a geographical information system that receives increasing popularity due to its user-friendliness and the fact that it is an open access software. This contribution provides an update and extension to a previously published software guideline that gives a stepwise explanation on how to create a geological map with QGIS. The article serves as a brief overview of the guideline through an illustrated example. The guideline itself is published as a supplement to this paper. Within six sections, the guideline explains how to create a geological map with QGIS: 1. Introduction, 2. Download and installation, 3. Basemaps, 4. Map drawing, 5. Plugins, 6. Layouts. The aim is to instruct geologists who are completely inexperienced with digital map creation as well as provide specific information for more advanced users. In general, providing software guidelines for the geological community is an important step towards increasing geologists’ digital proficiency and to keep up with today’s fast paced developments in digitalization.

Mapping of gold mineralization using an integrated interpretation of geological and geophysical data—a case study from West Baranes, South Eastern Desert, Egypt

The current study is mainly devoted to the integration, analysis, and interpretation of the available geologic, remote sensing, and potential field data (mainly magnetic) to delineate the subsurface geologic structural elements controlling the western part of Baranes, South Eastern Desert, Egypt, and its relation to the southwestern desert structural regime. Additionally, to detect potential mineralization zones for future mining plans in the study area. The Western part of Baranes has not had enough geomorphological mapping, consequently, potential discoveries of mineralization zones are very low. So, in this paper, an attempt is initiated to better understand the evolution of the geomorphology and structural regime of the region and construct a digital geological map and structural patterns showing the possible locations of mineralization zones based on the previous knowledge from similar potential sites and focus on the future economic importance of the region. To achieve this purpose, processed Landsat-8 images successfully revealed the lithological contacts and fault zones helping in distinguishing between the different rock units; moreover, the aeromagnetic data available in the area is used and several filters are applied including reduction to the pole, Euler homogeneity equation, analytic Signal (AS), and advanced grid filtering are sequentially used aiming to detect the possible subsurface distribution of mineralization zones from the integrated interpretation of magnetic susceptibilities and available geologic and remote sensing data.

Digital geologic map, petrography and U-Pb geochronology of the Río Santiago Shear Zone, southernmost Sierra Madre Occidental, western Mexico

The boundary between the Sierra Madre Occidental (SMO) and the Trans-Mexican Volcanic Belt (TMVB) is well exposed along the Santiago River, on the border of the states of Nayarit and Jalisco. This region includes a polydeformed belt produced by the relative motion between the Jalisco Block and the SMO, here defined as the “Rio Santiago Shear Zone” (RSSZ). In this work, we present detailed geological cartography, petrographic descriptions, and new zircon U-Pb ages that allow us to establish the stratigraphy of the region surrounding the RSSZ, providing temporal constraints to its tectonic evolution. In the mapped area, the base of the SMO stratigraphic column consists of a succession of massive andesitic lava flows intruded by felsic dikes and a felsic subvolcanic body of 27.5 and 27.2 Ma, and it is covered by a series of ignimbrites of 26.8 and 25.3 Ma. A red beds succession separates a second package of ignimbrites of ∼20-19 Ma, in turn capped by rhyolitic lava domes of 19.7 and 18.6 Ma and a rhyodacitic lava flows of 15.6 Ma, this Miocene succession is also intruded by a felsic body of 18.3 Ma west of the La Yesca dam. The SMO succession is covered by rocks belonging to the bimodal volcanism of the TMVB, emplaced between the end of the Miocene and the Pleistocene. The RSSZ developed through several deformation phases that occurred since the end of the Oligocene. The Oligocene succession of the SMO is affected by NE-SW and WNW-ESE trending lateral faults, NW-SE open folds and WNW-ESE and E-W trending reverse oblique faults. Some of the reverse oblique faults were later reactivated as normal faults. WNW-ESE trending normal faults associated with the Tepic-Zacoalco Rift affected the area south of the Santiago River during the Pliocene and Pleistocene. Normal faulting produced an accumulated vertical offset up to 700 m between the northern and southern regions of the Santiago River.

ЦИФРОВЕ ГЕОЛОГІЧНЕ КАРТУВАННЯ ТА АНАЛІЗ ПОЛЬОВИХ ГЕОДАНИХ ІНСТРУМЕНТАМИ ТА ПЛАГІНАМИ QGIS

Purpose. The article aims is to demonstrate the possibilities, methods and advantages of using Quantum GIS (QGIS) plugins and mobile applications for digital geological mapping, input and primary analysis of field geodata in Earth Sciences – Structural Geology, Engineering Geology, Hydrogeology, Ecology, Geophysics, etc. Methodology. The most important tools and plugins of QGIS, an open source GIS program, that works on the most widespread platforms – Windows, MacOS X, Linux and applications on Android, iOS for digital mapping, structural geodata analysis, and visualization are used. Results. The most important tools and plugins of QGIS (Georeferencer GDAL, GarminCustomMap, Profile Tool, VoGIS-ProfilTool, qProf, qgSurf, Stereonet, qgis2web, and QField mobile application) are analyzed. Their using for digital geological mapping, input and analysis of structural and other geodata, construction of 2D topographic profiles, visualization of geodata in web browsers are briefly described. Scientific novelty. Tools and plugins of QGIS, which are necessary for certain purposes for working with various types of data on geological maps, their analysis, and construction of geological and geophysical profiles are defined. QGIS software applications allow to add new plugins, create your own notations for digital mapping that can be used to solve specific geological tasks and analyze geospatial and geological data, or add ready-made specialized geological notations according to geological standards. Practical significance. Complex using of basic, additional external plugins of QGIS and specialized geological markings contributes to effective field digital mapping, modern visualization of various types of geological maps with spatial reference, creation of new digital electronic and complex demonstration maps for printing and visualization in web browsers, construction topographic and geological 2D profiles, GIS analysis of structural geodata, slope analysis, etc. Data obtained in QGIS can be imported into such specialized programs as Petrel Exploration & Production Software Platform (Shlumberger), MOVE Software (Midland Valley), etc. Keywords: Quantum GIS or QGIS, QGIS tools and plugins, digital geological mapping, QField, GIS analysis of structural geodata, slope analysis.

Estimating the Geological Strength Index (GSI) in Regional Seismic‐Landslide Zonation Using the Empirical Regression Model

The assessment of the strength parameters of geological formations in regional scale which encounters thousands of slopes is a complicated approach and time consuming and needs huge field work. This issue is an important research topic concerning the regional seismic‐landslide susceptibility analysis or hazard zonation. An empirical regression model was presented to estimate the Geological Strength Index (GSI) with an implication on geological quadrangle of Gorgan region at Alborz mountains range (north of Iran). Two main sets of data were applied in this study: (1) geomorphological data including the slope height, aspect, and distance from faults and distance from thrusts and (2) the physical and mechanical properties of rocks including the unit weight, uniaxial compressive strength (σci), and the petrographic constant (mί) of intact rock. The first group was extracted from a 1 : 100,000 digital geologic map and 10 m digital elevation model (DEM) and the second group was obtained from the Hoek–Brown failure criterion recommended tables. Linear regression equations were generated applying data collected from 294 studied stations using SPSS software. The regression equation predicted GSI in terms of (1) the distance from faults, (2) the distance from thrusts, and (3) the uniaxial compressive strength (σci). The equation had an R2 value of 0.739 and thus fit well to the data. The new method in its present state was recommended for the estimation of the GSI values in regional scale conditions for the assessment of landslide susceptibility and hazard mapping or post events landslide occurrence prediction in the case of probable big earthquakes in Alborz area that is required for emergency responses. The results indicated that the estimation error was about ±30 while the average error was within +5 and −5 and average error percentage was about 3%.

From Crystals to Crustal‐Scale Seismic Anisotropy: Bridging the Gap Between Rocks and Seismic Studies With Digital Geologic Map Data in Colorado

AbstractDeep continental crustal structures are enigmatic due to lack of direct exposures and limited tools to investigate them remotely. Seismic waves can sample these rocks, but most seismic methods focus on coarse crustal structures while laboratory measurements concentrate on crystal‐scale rock properties, and little work has been conducted to bridge this interpretation gap. In some places, geologic maps of crystalline basement provide samples of the intermediate‐scale fabrics and structures that may represent in situ deep crust. However, previous research has not considered natural geometric variations from map data, nor is this heterogeneity typically included in map‐scale seismic property calculations. Here, we test how map‐scale fabrics influence crustal seismic anisotropy in Colorado by analyzing structural data from geologic maps, combining those data with bulk rock elastic tensors to calculate map‐scale seismic properties, and evaluating the resulting comparisons with observed receiver function A1 (360° periodic) arrivals. Crystalline fabrics, predicted seismic properties, and tectonic structures positively correlate with shallow and deep crustal A1 arrivals. Additionally, widespread correlations occur between mapped fault traces and regional foliations, implying that preexisting mechanical heterogeneity may have strongly influenced subsequent reactivation. We interpret that various mapped geologic contact types (e.g., lithologic and structural) generate A1 arrivals and that multiple parallel features (e.g., faults, foliations, and intrusions) contribute to a seismically visible tectonic grain. Therefore, Colorado's exhumed basement, as expressed in outcrops and maps, offers insight into modern deep crustal geological and geophysical structure.

Digital geological map and geochronological database of the Cenozoic cover of the southern Mesa Central province, Mexico

The digital geological map of the southern sector of the Mesa Central province is presented, covering an area of ~41 000 km2 in central Mexico. This first interactive map is a compilation of the geological maps available in the literature and the unpublished maps done by our work team. The map focuses on the Cenozoic stratigraphy, supported by a geochronological database of 261 isotopic ages derived from K-Ar, U-Pb, Ar-Ar, and fission tracks methods. The interactive map displays the lithostratigraphic and chronostratigraphic units and the major and second-order Cenozoic faults. Map construction considered lithostratigraphy and geochronological correlation criteria and the main unconformities. Integrating these data in a single digital map allows a regional vision of the southern Mesa Central, making the map a valuable work tool to better understand the Cenozoic geologic evolution of central Mexico.

Geological framework for assessing variability in subsurface piping parameters underneath dikes in the Rhine-Meuse delta, the Netherlands

Dike failure due to piping – concentrated flow of seepage water underneath the dike during periods of high flood water levels – has been recognized as a major component of flood risk. Simulation models to predict piping in risk assessments require detailed information on subsurface characteristics such as sediment grain size and thickness of overburden layers. Quantitative local determination of these characteristics poses a major challenge in natural environments with a heterogeneous substrate. Geological knowledge on the natural genesis and resulting structure of the subsurface may provide useful information on the spatial variability of substrate characteristics. When correctly implemented, available subsurface geological information can provide for a-priori identification of dike sections of which the subsurface is susceptible to piping (strategic to new data collection), and a-posteriori screening of new collected field data (identifying unexpected values). In these two ways it has potential to reduce the uncertainty in parameter estimates for calculations that determine the potential occurrence of piping at a specific site. Here we describe a framework for using geological subsurface information for these assessments. Based on existing digital geological mapping products and knowledge of the geological development of the Rhine-Meuse delta, we first compiled a map that distinguishes primary hydrologically relevant units: upper main aquifer sands (pre-deltaic subunits), topped by the deltaic wedge aquitard that is dissected by channel belt sand bodies (deltaic subunits). We then used these spatial divisions in an analysis of digital borehole data (>130.000 locations, UU-LLG dataset), to provide quantitative information on grain sizes of the very top of sand bodies and non-sand overburden thicknesses, split per subunit and summarized for sub regions (lower delta, central delta, upper delta, delta rim sectors). This framework enables us to demonstrate to what extent the median grain size of the top of sand deposits varies within the delta. We quantitatively determined (1) a delta-scale longitudinal downstream fining trend due to drops in specific stream power through changes in gradient and substrate erodibility, (2) pulsed variations associated with local uptake and reworking of pre-deltaic sediments within channel belts. Although tailored for the Rhine-Meuse delta, utilizing geological knowledge as a substantiation for grouping of subsurface data underneath local dike sections can be transposed for such applications in delta regions elsewhere. This regionalization of the delta plain can greatly help streamline data acquisition, anticipating growing availability of medium to high density subsurface datasets in increasingly urbanized deltas with managed rivers around the world.

Automated geological map deconstruction for 3D model construction using <i>map2loop</i> 1.0 and <i>map2model</i> 1.0

Abstract. At a regional scale, the best predictor for the 3D geology of the near-subsurface is often the information contained in a geological map. One challenge we face is the difficulty in reproducibly preparing input data for 3D geological models. We present two libraries (map2loop and map2model) that automatically combine the information available in digital geological maps with conceptual information, including assumptions regarding the subsurface extent of faults and plutons to provide sufficient constraints to build a prototype 3D geological model. The information stored in a map falls into three categories of geometric data: positional data, such as the position of faults, intrusive, and stratigraphic contacts; gradient data, such as the dips of contacts or faults; and topological data, such as the age relationships of faults and stratigraphic units or their spatial adjacency relationships. This automation provides significant advantages: it reduces the time to first prototype models; it clearly separates the data, concepts, and interpretations; and provides a homogenous pathway to sensitivity analysis, uncertainty quantification, and value of information studies that require stochastic simulations, and thus the automation of the 3D modelling workflow from data extraction through to model construction. We use the example of the folded and faulted Hamersley Basin in Western Australia to demonstrate a complete workflow from data extraction to 3D modelling using two different open-source 3D modelling engines: GemPy and LoopStructural.

Rapid groundwater potential mapping in humanitarian contexts: improving borehole implementation in basement environments

Emergency responses in humanitarian contexts require rapid set-up of water supply. Boreholes are often drilled where the needs are highest and not where hydrogeological conditions are most favourable. The Rapid Groundwater Potential Mapping (RGWPM) methodology was therefore developed as a practical tool to support borehole siting when time is critical, allowing strategic planning of geophysical campaigns. RGWPM is based on the combined analysis of satellite images, digital elevation models and geological maps, obtained through spatial overlay of the two main hydrogeological variables controlling groundwater potential: water availability (WA) and reservoir capacity (RC). The WA associates hydrogeomorphological features to groundwater dynamic processes, while the RC reflects estimates of the hydraulic conductivity. RGWPM maps are produced through an overlay of WA and RC with the overall groundwater potential (GWP) characterized as ‘very low’, ‘low’, ‘medium’, and ‘high’, with each zone associated to a specific water supply option. The first RGWPM map was elaborated during a drilling campaign in Northern Uganda. The average yield for the eight boreholes sited ‘with’ RGWPM was 35 m3/h versus 3 m3/h for the 92 preexisting boreholes that were sited ‘without’ RGWPM. Statistical comparison of the classified yields of all hundred boreholes with the RGWPM predicted-yield ranges revealed a good correlation for the ‘low’ GWP unit, highlighting areas where well siting for motorised systems should be avoided. A rather poor correlation of 33% was found for the ‘medium’ GWP unit, believed to be artificially induced by the numerous hand pumps (low yields) located in potentially higher yielding areas.

Digital Geological Mapping to Facilitate Field Data Collection, Integration, and Map Production in Zhoukoudian, China

The development of innovative information technologies has improved the geological mapping process through the use of smart and portable equipment to collect field data, build a geological database and produce geological maps. This revolution has also brought great influence and challenges to practical training in field geology. In this paper, we present our workflow and application of the Digital Geological Survey System (DGSS) during field geology training for undergraduates in Zhoukoudian. The DGSS employs a Point-Routing-Boundary (PRB) model to reform the methods of geological section survey and geological mapping in terms of data collection and map-making and provides a pipelined solution from field data collection to map-making. The experiences of data collection, geological mapping, cross-section survey, and production of stratigraphic histograms and cross-section maps prove that DGSS can save time and reduce labor intensity for undergraduates during learning field geology. Based on the field practice of undergraduates in Zhoukoudian, the influence of the DGSS in promoting field geological teaching and the students’ feedbacks to DGSS are discussed. Overall, the DGM system is more popular than the conventional notebook and toolbox. The experience in Zhoukoudian proves that digital devices are efficient and useful for geological practical training of field geology for undergraduates.

한반도 남부의 지질 유형별 지형 기복과 삭박 저항력

This study tried to reveal relative surface denudation resistance and ranking by geologic types in the Southern Korean Peninsula using an 1:250,000 digital geologic map and ASTER GDEM. Among rock types such as igneous, sedimentary and metamorphic rocks, metamorphic rock showed the greatest resistance to surface denudation. The most resistant rock to surface denudation by geologic periods (e.g., the Precambrian, Paleozoic, Mesozoic and Cenozoic) was found from the Precambrian. Among the major tectonic settings in the Southern Korean Peninsula such as the Gyeonggi massif, Okcheon belt, Yeongnam massif, Gyeongsang basin and Pohang basin, the Okcheon belt indicated the greatest resistance. The most and least resistant rocks from the representative nine rocks in the Southern Korean Peninsula were Paleozoic limestone, and Cretaceous sedimentary rock and Cenozoic sedimentary rock, respectively. This study suggests that Paleozoic limestone, Cretaceous volcanic rock, Paleozoic sedimentary rock and Precambrian gneiss can be regarded as hard rocks with high elevation, steep slope and complicated relief, while soft rocks with low elevation, gentle slope and simple relief are Jurassic granite, Cretaceous sedimentary rock and Cenozoic sedimentary rock.