1 Introduction Geological outcrops or sections are the basis of geological research.However,the traditional methods for presenting them are mainly photos which fall short of delivering a true visual sense (Deng et al....1 Introduction Geological outcrops or sections are the basis of geological research.However,the traditional methods for presenting them are mainly photos which fall short of delivering a true visual sense (Deng et al.,2009;Hou et al.,2014).With the continuous development of image acquisition technology using single-lens reflex camera (SLR camera),image synthesis,large file storage and acquisition,panoramic visualization and network technology.展开更多
We characterized the temperature conditions inside narrow rocky outcrops that served as habitats for semi-fossorial small mammals in a mountainous locality on the Japanese Islands. Usually, it is considered that the n...We characterized the temperature conditions inside narrow rocky outcrops that served as habitats for semi-fossorial small mammals in a mountainous locality on the Japanese Islands. Usually, it is considered that the narrow rocky outcrops have poorer resources than the soil ground of forest floors, which have rich vegetation and nutrition. On the basis of this tendency, it is considered that ecologically dominant species occupy the rich soil habitats and subordinate species are chased away to the narrow rocky outcrops by ecological species competitions, resulting in habitat segregation. However, the present temperature data revealed that the temperatures inside rocky terrains were more stable than the shaded ambient temperatures in the forest. The rocky habitats were apparently colder in summer and warmer in winter, in both daily maximum and minimum temperatures, than the ambient temperatures in the forest during the research period. In addition, the daily difference between maximum and minimum temperatures in the rocky habitats was apparently smaller than that of the ambient ones. These temperature conditions in the narrow rocky outcrops are advantageous to the small mammalian metabolic system. Namely, we estimate that the semi-fossorial small mammals are not chased out by the dominant species through ecological competitions and that the semi-fossorial small mammals may occupy the narrow rocky outcrops as a more advantageous habitat than the forest floor.展开更多
The coal fire is one of very serious disasters in natural, not only amount of coal resources was burned and some ecological environment problems such as ground subsidence, acid rain, pollution and vegetation died were...The coal fire is one of very serious disasters in natural, not only amount of coal resources was burned and some ecological environment problems such as ground subsidence, acid rain, pollution and vegetation died were caused serious. The No.4 coal seam outcrops fire in Haibaoqing was take as research object, based on the existing theory of mechanism and characteristics of coal outcrop fires, a new fire-fighting composite gel is applicated which fits in with extinguishment of outcrop coal fires well. The technology has many advantages in extinguishing coal fires including isolating the coal from oxygen and lowering the temperature of the high-temperature coal and rock. The structure and chemical composition as well as fires-fighting properties of the composite gel is analyzed profoundly, as a result, reduce and stop the environment destruction caused by the coal fire.展开更多
Network analysis is a powerful tool to identify key species for the stability of ecological communities.For endangered species like Fernseea itatiaiae,understanding its role within the network is vital for revealing h...Network analysis is a powerful tool to identify key species for the stability of ecological communities.For endangered species like Fernseea itatiaiae,understanding its role within the network is vital for revealing how interactions with pollinators influence its reproductive success and vulnerability.This insight is crucial for conservation strategies.Thus,the community context revealed by interaction networks can inform conservation strategies for threatened species.The ornithophilous bromeliad Fernseea itatiaiae(Wawra)Baker is restricted to the Itatiaia Plateau(southeast Brazil)and is assessed as endangered(EN).Fernseea itatiaiae and 14 other plant species have floral morphology related to hummingbird pollination(ornithophily),serving as floral resources for hummingbirds in the area.We used a field monitoring experiment to assess how the phenology and availability of conspecific and heterospecific ornithophilous floral resources at the community level affect the pollination of F.itatiaiae.We measured the fruit set,seed production(from controlled pollination experiments)and total amount of pollen deposited on stigmas as proxies of F.itatiaiae reproductive success and related it to the community context(monthly abundance of conspecific and ornithophilous flowers,floral display,presence of ornithophilous neighbors).The results showed overlapping flowering peaks of some ornithophilous plant species(Buddleja speciosissima and Gaultheria serrata)with F.itatiaiae.The species with the strongest interactions with shared hummingbirds were Fuchsia regia,F.itatiaiae,and Buddleja speciosissima,based on the relative frequency of hummingbird visitation per hour.Additionally,we found that,although the floral community context had no direct significant influence on the pollination success of F.itatiaiae,its reproductive success depended directly on the presence of hummingbirds.This dependence on pollinators suggests that the conservation of F.itatiaiae may rely not only on measures targeting the species itself,but also on broader effort to protect the ecological interactions that sustain the local pollination network.展开更多
To address the shortage of characterization scale of field outcrops,we used the characteristics of unmanned aerial vehicle(UAV)oblique photography with a wide field of view and a high degree of quantification for imag...To address the shortage of characterization scale of field outcrops,we used the characteristics of unmanned aerial vehicle(UAV)oblique photography with a wide field of view and a high degree of quantification for image acquisition,data processing,and geological interpretation of the outcrops of the Shaximiao Formation in the Sichuan Basin.We established a 3D digital outcrop model(DOM),which combines the advantages of visualization and digitization the 3D DOM to interpret the characteristics of typical channel sand bodies.Within the study area,we have identified three types of channel deposition:composite channel deposition,crevasse channel deposition,and abandoned channel deposition.Among these,the composite channel deposition was mainly sandstone,the bottom contains conglomerate,with large cross-bedding,and the maximum thickness of the single sand body was 1.96 m.The crevasse channel deposition was mainly fine sandstone and siltstone,with massive bedding and small cross-bedding,and the maximum thickness of the single sand body was 0.64 m.The abandoned channel deposition dominated by mudstone with thin sandstone,the sandstone was mainly lenticular in section,and the maximum thickness of the single sand body was 0.28 m.We identified the depositional model of the studied region,which is dominated by braided river deposition,based on the growth size and correspondence of the sand bodies.The research provides a comparative foundation for the detailed characterisation of the underground reservoir sands found in the Jurassic Shaximiao Formation in the Sichuan Basin.It also serves as a reference for the effective study of UAV oblique photography technology in the field.展开更多
The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across divers...The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across diverse geological settings.Large-scale models(LSMs),with vast parameter spaces and extensive training datasets,excel in solving complex visual problems.This study explores the potential of using one such LSM,Segment anything model(SAM),to identify facet-type discontinuities across several outcrops via interactive prompting.The findings demonstrate that SAM effectively segments two-dimensional(2D)discontinuities,with its generalization capability validated on a dataset of 2426 identified discontinuities across 170 outcrops.The model achieves 0.78 mean IoU and 0.86 average precision using 11-point prompts.To extend to three dimensions(3D),a framework integrating SAM with Structure-from-Motion(SfM)was proposed.By utilizing the inherent but often overlooked relationship between image pixels and point clouds in SfM,the identification process was simplified and generalized across photogrammetric devices.Benchmark studies showed that the framework achieved 0.91 average precision,identifying 87 discontinuities in Dataset-3D.The results confirm its high precision and efficiency,making it a valuable tool for data annotation.The proposed method offers a practical solution for geological investigations.展开更多
In Eastern South America,high altitude grasslands represent a mountain system that has a high number of endemic species.However,studies on the ecology of plant communities in these environments remain scarce.We aimed ...In Eastern South America,high altitude grasslands represent a mountain system that has a high number of endemic species.However,studies on the ecology of plant communities in these environments remain scarce.We aimed to evaluate the patterns of biodiversity and structure of plant communities from rocky outcrops in high altitude grasslands of three areas at the CaparaóNational Park,southeastern Brazil,by sampling 300 randomly distributed plots.Then,we compared the floristic composition,relative abundance,and biological and vegetation spectra among areas.We classified species as endemic and non-endemic and verified the occurrence of endangered species.Species richness was evaluated by rarefaction analysis on the sampling units.The importance value and species abundance distribution(SAD)models were assessed.We also performed an indicator species analysis.We sampled 58 species belonging to 49 genera and 32 families.The number of species decreased with increasing altitude,with significant differences being observed among areas regarding richness,abundance,and cover.Of the total number of species,10 are endemic to the CaparaóNational Park and 17 are listed on the Brazilian Red List of endangered species.The dominant families on all peaks were Asteraceae and Poaceae.The SAD models showed lognormal and geometric distributions,corroborating the fact that 10 species that were common to all three areas were also the most dominant ones in the communities and showed the highest importance values,which ranged between 35%and 60%.Indicator species analysis revealed that 28 species(48.27%)were indicators.Of these,42.85%had maximum specificity,meaning that they occurred only in one area.Thus,the number of species per life form ratio was similar among areas,yet vegetation spectra differed,especially for hemicryptophytes.The altimetric difference among the areas showed to be a very important driver in the community assembly,influencing the evaluated variables,however,other drivers as soil depth,slope and water could also influence the community structure on a smaller and local spatial scale.展开更多
The municipality of Boa Nova,in northeastern Brazil,is in an ecotone zone between the Caatinga and Atlantic Forest phytogeographic domains.The transition phytophysiognomy is seasonal forest and known locally as mata d...The municipality of Boa Nova,in northeastern Brazil,is in an ecotone zone between the Caatinga and Atlantic Forest phytogeographic domains.The transition phytophysiognomy is seasonal forest and known locally as mata de cipó.In these phytophysiognomies there are lajedos,which are rock outcrops colonized by vegetation welladapted to extreme microclimatic variation and vegetation diversity is affected by the vegetation types of the surrounding areas.Due to the singularity of these environments and the relevance of floristic studies for conservation,this work aimed to identify the species richness and compare the similarity of the flora on four rock outcrops in Boa Nova.The flora was surveyed during exploratory walks along lajedos between 2016 and 2019.In total,162 species were identified on the Boa Nova outcrops.The flora has a composition and structure similar to semiarid outcrops,as well as endemic species that also occur in surrounding phytophysiomies.Despite the proximity,a similarity index revealed there is floristic dissimilarity between the areas.Nine new occurrences were recorded for the region,five species are threatened with extinction(Aosa gilgiana,Ficus cyclophylla,Hippeastrum stigmovittatum,Pleroma caatingae and Trixis pruskii),and 43 species are common in anthropogenic areas.This reinforces the importance of actions to conserve these areas.展开更多
It is important to know the shape and distribution of sandstone bodies in the subsurface when formation and migration of a dune model are determined. The information plays a significant role in identification of the c...It is important to know the shape and distribution of sandstone bodies in the subsurface when formation and migration of a dune model are determined. The information plays a significant role in identification of the continental oil and gas accumulation. In this study,the combination of ground penetrating radar( GPR)and electrical resistivity tomography method( ERT) is used in mapping the distribution of sandstone bodies in Yanchang Formation. Six GPR profiles and seven ERT profiles are used to analysis. GPR data show clear reflections from the top interface of sandstones. ERT data show a continuous high resistivity anomaly corresponding to the sandstone body. Combined the reconstructed 3D images by GPR and ERT,the spatial distribution of sandstone bodies is described.展开更多
Through the regional geological survey,outcrop section measurement and other field geological work,a block of black shale is found at the outcrop of Mengjiawopu Section of Hongshuizhuang Formation in Jixian County,and...Through the regional geological survey,outcrop section measurement and other field geological work,a block of black shale is found at the outcrop of Mengjiawopu Section of Hongshuizhuang Formation in Jixian County,and organic geochemical source rock analysis and evaluation methods are used to study the source rocks in Hongshuizhuang Formation.The set of source rocks is mainly gray-black silty mudstone and gray-black shale,with a cumulative thickness of 78 m;the total organic matter(TOC)is generally high,with an average content of 1.35%,of which good and rich source rock samples account for 86%.A combined analysis of the stable carbon isotope of kerogen,the correlation between Pr/nC17 and Ph/nC18,and the ratio of saturated hydrocarbon to aromatic hydrocarbon identifies that the organic matter is mainly TypeⅡkerogen;the equivalent vitrinite reflectance R o of organic matter is from 1.68%to 1.94%.R c,the correlation of the methylphenanthrene index(MPI)against the vitrinite reflectance is from 1.63%to 1.81%,with an average of 1.71%,and the Odd/Even Predominance(OEP)value is between 0.87 and 1.11,both indicating that the source rocks of the Hongshuizhuang Formation are at the stage of high to over maturation.In summary,the set of source rocks in Hongshuizhuang Formation is characterized by high organic matter content,good kerogen types,and high to over maturation stage.展开更多
In Argentina, the Araucaria araucana forest occupies a vast area in the Northwest of Patagonia, following a pronounced gradient of increasing xericity from west to east over a short distance. These forests have been t...In Argentina, the Araucaria araucana forest occupies a vast area in the Northwest of Patagonia, following a pronounced gradient of increasing xericity from west to east over a short distance. These forests have been the subject of detailed studies due to their uniqueness and ecological relevance. In this context, an exhaustive investigation was carried out to understand the diversity and structure of these ecosystems. The objective was to study the floristic and ecological differences in humid and xeric areas along a west-east transect where A. araucana is distributed. Floristic surveys, geomorphological analyses, and bioclimatic data were examined. In Argentina, A. araucana integrates two distinct forest types: mesic and xeric. The xeric A. araucana forest constitutes a forest with floristic, genetic, geomorphological, and bioclimatic identity. The results highlight the importance of understanding the local variability of these ecosystems for the design of effective conservation strategies. Furthermore, they highlight the need for further research into the ecology and dynamics of these forests, especially in the context of climate change and human activities.展开更多
Numerous hydrocarbon accumulations are found in ramp crest shoals worldwide and therefore this depositional setting has a high potential of being the hydrocarbon reservoir. In this paper, we combined digital outcrop g...Numerous hydrocarbon accumulations are found in ramp crest shoals worldwide and therefore this depositional setting has a high potential of being the hydrocarbon reservoir. In this paper, we combined digital outcrop geology and traditional geological mapping to build an outcrop-based geocellular model of the ramp-crest shoal complex of the Lower Triassic Feixianguan Formation in the Eastern Sichuan Basin. The outcrop model serves as an analogue for the subsurface reservoir of the Feixianguan Formation and illustrates the complexity of the lithofacies types, stratigraphic architecture, and reservoir heterogeneities at a scale below conventional subsurface data resolution. The studied ramp -crest shoal complex consists of thirteen types of lithofacies that can be grouped into three facies-groups corresponding to subtidal intraclastic shoal, sub- to inter-tidal oolitic shoal, and tidal flat depositional environments respectively. The stratigraphic architecture of the shoal complex shows mostly a strong progradation of the high energy facies associated with an overall decrease of accommodation space associated with relative sea level still stand. Two reservoir facies associations have been recognized. The first one consists of supratidai dolomudstone and upper intertidal partially dolomitized oolitic packstone with anhydrite or nodules. These facies were deposited above the high energy oolitic grainstones and occurs as thin-bedded and laterally continuous layers, characterized by high porosity and low permeability. The second reservoir facies association is composed of intertidal crystalline dolomite and subtidal intraclastic bindstone that occurs stratigraphically below the oolitic grainstones. These deposits consist of massive laterally discontinuously beds, and are characterized by high porosity and high permeability. Both types of reservoir facies tend to be stacked vertically and migrated laterally with the progradation of the shoal complex. The construction of the outcrop-based 3D geological model provide a description and quantification of the facies distribution within a robust stratigraphic framework and the style and amount of reservoir heterogeneities associated with a ramp-crest shoal complex reservoir such as the one found in Lower Triassic Feixianguan Formation and Cambrian Longwangmiao Formation in Sichuan Basin or other ramp-crest reservoir worldwide.展开更多
Due to inherent limits of data acquisition and geophysical data resolution, there are large uncertainties in the characterization of subsurface fractures. However, outcrop analogies can provide qualitative and quantit...Due to inherent limits of data acquisition and geophysical data resolution, there are large uncertainties in the characterization of subsurface fractures. However, outcrop analogies can provide qualitative and quantitative information on a large number of fractures, based on which the accuracy of subsurface fracture characterization can be improved. Here we take the tectonic fracture modeling of an ultra-low permeability sandstone reservoir based on an outcrop analogy, a case study of the Chang6t~ Formation of the Upper Triassic Yanchang Group of the Wangyao Oilfield in the Ordos Basin of China. An outcrop at the edge of the basin is a suitable analog for the reservoir, but the prerequisite is that they must have equivalent previous stress fields, similar final structural characteristics, relative timing and an identical depositional environment and diagenesis. The relationship among fracture density, rock type and bed thickness based on the outcrop is one of the most important fracture distribution models, and can be used to interpret fracture density in individual wells quantitatively. Fracture orientation, dip, geometry and scale, also should be described and measured in the outcrop, and can be used together with structure restoration and single well fracture density interpretation to guide fracture intensity prediction on bed surfaces and to constrain the construction of the 3D fracture geometry model of the subsurface reservoir. The application of the above principles shows the outcrop-based tectonic fracture models of the target ultra-low permeability sandstone reservoir are consistent with fractures inferred from microseismic interpretation and tracer tests. This illustrated that the fracture modeling based on the outcrop analogy is reliable and can reduce the uncertainty in stochastic fracture modeling.展开更多
Advances in photogrammetry have eased the acquisition of high-resolution digital information from outcrops, enabling faster, non-destructive data capturing and improved reservoir modeling. Geocellular models for flow ...Advances in photogrammetry have eased the acquisition of high-resolution digital information from outcrops, enabling faster, non-destructive data capturing and improved reservoir modeling. Geocellular models for flow dynamics with in the virtual outcrop in siliciclastic deposits at different sets of sandstone facies architecture remain, however, a challenge. Digital maps of bedding, lithological contrast, spatial-temporal variations of bedding and permeability characteristics make it more easy to understand flow tortuosity in a particular architecture. An ability to precisely model these properties can improve reservoir characterization and flow modeling at different scales. Here we demonstrate the construction of realistic 2 D sandstone facies based models for a pragmatic simulation of flow dynamics using a combination of digital point clouds dataset acquired from LiDAR and field investigation of the Sandakan Formation, Sabah, Borneo.Additionally, we present methods for enhancing the accuracy of outcrop digital datasets for producing high resolution flow simulation. A well-exposed outcrop from the Sandakan Formation, Sabah, northwest Borneo having a lateral extent of 750 m was chosen in order to implement our research approach. Sandstone facies and its connectivity are well constrained by outcrop observations, data from air-permeability measurements, bilinear interpolation of permeability, grid construction and water vector analysis for flow dynamics.These proportions were then enumerated in terms of static digital outcrop model(DOM) and facies model based on sandstone facies bedding characteristics. Flow simulation of water vector analysis through each of the four sandstone facies types show persistent spatial correlation of permeability that align with either cross-bedded orientation or straight with more dispersion high quality sandstone(porosity 21.25%-41.2%and permeability 1265.20-5986.25 mD) and moderate quality sandstone(porosity 10.44%-28.75% and permeability 21.44-1023.33 mD). Whereas, in more heterolithic sandstone(wavy-to flaser-bedded and bioturbated sandstone), lateral variations in permeability show spatially non-correlated patterns over centimeters to tens of meters with mostly of low quality sandstone(porosity 3.4%-12.31% and permeability < 1 mD to 3.21 mD). These variations reflect the lateral juxtaposition in flow dynamics. It has also been resulted that the vertical connectivity and heterogeneities in terms of flow are mostly pragmatic due to the interconnected sandstone rather than the quality of sandstone.展开更多
Relationships between topography,soil properties and the distribution of plant communities on two different rocky hillsides are examined in two subtropical karst forests in the Maolan National Natural Reserve,southwes...Relationships between topography,soil properties and the distribution of plant communities on two different rocky hillsides are examined in two subtropical karst forests in the Maolan National Natural Reserve,southwestern China.Surveys of two 1-ha permanent plots at each forest,and measurements of four topographic and thirteen edaphic factors on the slopes were performed.Twoway Indicator Species Analysis(TWINSPAN) and Detrended Canonical Correspondence Analysis(DCCA) were used for the classification of plant communities and for vegetation ordination with environmental variables.One hundred 10m×10m quadrats in each plot were classified into four plant community types.A clear altitudinal gradient suggested that elevation was important in community differentiation.The topography and soil explained 51.06% and 54.69% of the variability of the distribution of plant species in the two forest plots,respectively,indicating both topographic factors(eg.elevation,slope and rock-bareness rate) and edaphic factors(e.g.total P,K and exchangeable Ca) were the important drivers of the distribution of woody plant species in subtropical karst forest.However,our results suggested that topographical factors were more important than edaphic ones in affecting local plant distribution on steep slopes with extensive rock outcrops,while edaphic factors were more influential on gentle slope and relatively thick soil over rock in subtropical karst forest.Understanding relationships between vegetation and environmental factors in karst forest ecosystems would enable us to apply these findings in vegetation management strategies and restoration of forest communities.展开更多
Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This st...Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This study presents a systematic outcrop research of fracture pattern variations in a complicated rock slope,and the qualitative and quantitative study of the complex phenomena impact on threedimensional(3D)discrete fracture network(DFN)modeling.As the studies of the outcrop fracture pattern have been so far focused on local variations,thus,we put forward a statistical analysis of global variations.The entire outcrop is partitioned into several subzones,and the subzone-scale variability of fracture geometric properties is analyzed(including the orientation,the density,and the trace length).The results reveal significant variations in fracture characteristics(such as the concentrative degree,the average orientation,the density,and the trace length)among different subzones.Moreover,the density of fracture sets,which is approximately parallel to the slope surface,exhibits a notably higher value compared to other fracture sets across all subzones.To improve the accuracy of the DFN modeling,the effects of three common phenomena resulting from vegetation and rockfalls are qualitatively analyzed and the corresponding quantitative data processing solutions are proposed.Subsequently,the 3D fracture geometric parameters are determined for different areas of the high-steep rock slope in terms of the subzone dimensions.The results show significant variations in the same set of 3D fracture parameters across different regions with density differing by up to tenfold and mean trace length exhibiting differences of 3e4 times.The study results present precise geological structural information,improve modeling accuracy,and provide practical solutions for addressing complex outcrop issues.展开更多
For the purpose of reservoir characterization of oilfields discovered in Albertine Graben, it is necessary to study the regional stratigraphy and sedimentary characteristics. The Semliki outcrops display a complete st...For the purpose of reservoir characterization of oilfields discovered in Albertine Graben, it is necessary to study the regional stratigraphy and sedimentary characteristics. The Semliki outcrops display a complete stratigraphy of Miocene, and the sediments are likely to provide valuable analogues for the reservoirs at Albertine Graben oilfields. The outcrops were observed and described in detail, mainly including lithology, colour, thickness, grain size and sedimentary structure. The sedimentology, depositional environment, climate, reservoir geometries and dimensions were analyzed. The Miocene stratigraphic section of Semliki basin was finally established, with lithology, sedimentary structure, sedimentary cycle, interpretation and climate information on it. It provides an analogy for the reservoir characterization, especially provides a basis for appropriate prediction of reservoir geometries in the field.展开更多
The highest volcano in Mexico,at the same time the third largest mountain in North America(Citlaltépetl,5610 m a.s.l.),is home to the largest glacier in the country.Because of the extinction of the Popocatép...The highest volcano in Mexico,at the same time the third largest mountain in North America(Citlaltépetl,5610 m a.s.l.),is home to the largest glacier in the country.Because of the extinction of the Popocatépetl glacier(5500 m a.s.l.)caused by eruptive activity,and the almost disappearance of the Iztaccíhuatl glaciers(5220 m a.s.l.)due to the lower elevation of the mountain,the Glaciar Norte of Citlatépetl has been the only glacier that has shown a certain degree of stability as a response to the altitude in which it is located.However,as occurs in almost all glaciers on the planet,the retreat of its glacier terminus has been continuous.Furthermore,during the last years the thickness of its upper part began to decrease rapidly until its bedrock was exposed for the first time in 2019.Due to its ecosystem importance and because it is the main glacier in Mexico,as well as the only one in the world located at latitude 19°N,in this work its current dimensions are updated,as well as the local climatology that governs the current state of the glacier is pointed out.The study was based on the analysis of high-resolution Sentinel-2 optical images,as well as through Sentinel-1 SAR images,with the support of climatological information from the study area.Therefore,the outcropping of the bedrock in the accumulation zone and the consequent horizontal retreat of the upper part of the glacier are documented;at the same time,the decrease in the thickness of the ice along it is noted.The rocky outcrop in the accumulation zone suggests that the flow dynamics of the ice towards the ablation zone will be considerably less,accelerating the retreat of the glacier terminus.Finally,the ascent of the glacial front to 5102 m a.s.l.and the modelled altitude of the equilibrium line to 5276 m a.s.l.are reported as a warning signal in terms of snow catchment and mass balance;likewise,the decrease of 23%of its surface is also indicated regarding the surface reduction monitoring that has been done until 2017.These findings may indicate that the future of this glacier is related to its possible extinction sooner than previously thought,with severe environmental consequences,especially in terms of the provision of drinking water for thousands of inhabitants of the slopes of the volcano.This research is expected to help reflect on the impacts of current climate variability and at the same time serve as a reference for the tropical glaciers on the planet.展开更多
基金granted by National Natural Science Foundation of China (Grant No.41725007)Chinese Academy of Sciences (Grant Nos.XDB10010100 and XXH13506)State Key Laboratory of Palaeobiology and Stratigraphy,NIGPAS (Grant No.20183127).
文摘1 Introduction Geological outcrops or sections are the basis of geological research.However,the traditional methods for presenting them are mainly photos which fall short of delivering a true visual sense (Deng et al.,2009;Hou et al.,2014).With the continuous development of image acquisition technology using single-lens reflex camera (SLR camera),image synthesis,large file storage and acquisition,panoramic visualization and network technology.
文摘We characterized the temperature conditions inside narrow rocky outcrops that served as habitats for semi-fossorial small mammals in a mountainous locality on the Japanese Islands. Usually, it is considered that the narrow rocky outcrops have poorer resources than the soil ground of forest floors, which have rich vegetation and nutrition. On the basis of this tendency, it is considered that ecologically dominant species occupy the rich soil habitats and subordinate species are chased away to the narrow rocky outcrops by ecological species competitions, resulting in habitat segregation. However, the present temperature data revealed that the temperatures inside rocky terrains were more stable than the shaded ambient temperatures in the forest. The rocky habitats were apparently colder in summer and warmer in winter, in both daily maximum and minimum temperatures, than the ambient temperatures in the forest during the research period. In addition, the daily difference between maximum and minimum temperatures in the rocky habitats was apparently smaller than that of the ambient ones. These temperature conditions in the narrow rocky outcrops are advantageous to the small mammalian metabolic system. Namely, we estimate that the semi-fossorial small mammals are not chased out by the dominant species through ecological competitions and that the semi-fossorial small mammals may occupy the narrow rocky outcrops as a more advantageous habitat than the forest floor.
文摘The coal fire is one of very serious disasters in natural, not only amount of coal resources was burned and some ecological environment problems such as ground subsidence, acid rain, pollution and vegetation died were caused serious. The No.4 coal seam outcrops fire in Haibaoqing was take as research object, based on the existing theory of mechanism and characteristics of coal outcrop fires, a new fire-fighting composite gel is applicated which fits in with extinguishment of outcrop coal fires well. The technology has many advantages in extinguishing coal fires including isolating the coal from oxygen and lowering the temperature of the high-temperature coal and rock. The structure and chemical composition as well as fires-fighting properties of the composite gel is analyzed profoundly, as a result, reduce and stop the environment destruction caused by the coal fire.
基金the Minas Gerais State Research Support Foundation(FAPEMIG)for the master's scholarship.MW thanks CNPq(Process 436335/2018-2)PJB thanks FAPERJ(Process E-26/201.867/2020).
文摘Network analysis is a powerful tool to identify key species for the stability of ecological communities.For endangered species like Fernseea itatiaiae,understanding its role within the network is vital for revealing how interactions with pollinators influence its reproductive success and vulnerability.This insight is crucial for conservation strategies.Thus,the community context revealed by interaction networks can inform conservation strategies for threatened species.The ornithophilous bromeliad Fernseea itatiaiae(Wawra)Baker is restricted to the Itatiaia Plateau(southeast Brazil)and is assessed as endangered(EN).Fernseea itatiaiae and 14 other plant species have floral morphology related to hummingbird pollination(ornithophily),serving as floral resources for hummingbirds in the area.We used a field monitoring experiment to assess how the phenology and availability of conspecific and heterospecific ornithophilous floral resources at the community level affect the pollination of F.itatiaiae.We measured the fruit set,seed production(from controlled pollination experiments)and total amount of pollen deposited on stigmas as proxies of F.itatiaiae reproductive success and related it to the community context(monthly abundance of conspecific and ornithophilous flowers,floral display,presence of ornithophilous neighbors).The results showed overlapping flowering peaks of some ornithophilous plant species(Buddleja speciosissima and Gaultheria serrata)with F.itatiaiae.The species with the strongest interactions with shared hummingbirds were Fuchsia regia,F.itatiaiae,and Buddleja speciosissima,based on the relative frequency of hummingbird visitation per hour.Additionally,we found that,although the floral community context had no direct significant influence on the pollination success of F.itatiaiae,its reproductive success depended directly on the presence of hummingbirds.This dependence on pollinators suggests that the conservation of F.itatiaiae may rely not only on measures targeting the species itself,but also on broader effort to protect the ecological interactions that sustain the local pollination network.
基金supported by the Natural Science Foundation of China(No.42130813)CNPC Innovation Fund(No.2024DQ02-0502)。
文摘To address the shortage of characterization scale of field outcrops,we used the characteristics of unmanned aerial vehicle(UAV)oblique photography with a wide field of view and a high degree of quantification for image acquisition,data processing,and geological interpretation of the outcrops of the Shaximiao Formation in the Sichuan Basin.We established a 3D digital outcrop model(DOM),which combines the advantages of visualization and digitization the 3D DOM to interpret the characteristics of typical channel sand bodies.Within the study area,we have identified three types of channel deposition:composite channel deposition,crevasse channel deposition,and abandoned channel deposition.Among these,the composite channel deposition was mainly sandstone,the bottom contains conglomerate,with large cross-bedding,and the maximum thickness of the single sand body was 1.96 m.The crevasse channel deposition was mainly fine sandstone and siltstone,with massive bedding and small cross-bedding,and the maximum thickness of the single sand body was 0.64 m.The abandoned channel deposition dominated by mudstone with thin sandstone,the sandstone was mainly lenticular in section,and the maximum thickness of the single sand body was 0.28 m.We identified the depositional model of the studied region,which is dominated by braided river deposition,based on the growth size and correspondence of the sand bodies.The research provides a comparative foundation for the detailed characterisation of the underground reservoir sands found in the Jurassic Shaximiao Formation in the Sichuan Basin.It also serves as a reference for the effective study of UAV oblique photography technology in the field.
基金support in dataset preparation.This study was funded by National Natural Science Foundation of China(Nos.42422704 and 52379109)Opening the fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(No.SKLGP2024K028)Science and Technology Research and Design Projects of China State Construction Engineering Corporation Ltd.(No.CSCEC-2024-Q-68).
文摘The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across diverse geological settings.Large-scale models(LSMs),with vast parameter spaces and extensive training datasets,excel in solving complex visual problems.This study explores the potential of using one such LSM,Segment anything model(SAM),to identify facet-type discontinuities across several outcrops via interactive prompting.The findings demonstrate that SAM effectively segments two-dimensional(2D)discontinuities,with its generalization capability validated on a dataset of 2426 identified discontinuities across 170 outcrops.The model achieves 0.78 mean IoU and 0.86 average precision using 11-point prompts.To extend to three dimensions(3D),a framework integrating SAM with Structure-from-Motion(SfM)was proposed.By utilizing the inherent but often overlooked relationship between image pixels and point clouds in SfM,the identification process was simplified and generalized across photogrammetric devices.Benchmark studies showed that the framework achieved 0.91 average precision,identifying 87 discontinuities in Dataset-3D.The results confirm its high precision and efficiency,making it a valuable tool for data annotation.The proposed method offers a practical solution for geological investigations.
文摘In Eastern South America,high altitude grasslands represent a mountain system that has a high number of endemic species.However,studies on the ecology of plant communities in these environments remain scarce.We aimed to evaluate the patterns of biodiversity and structure of plant communities from rocky outcrops in high altitude grasslands of three areas at the CaparaóNational Park,southeastern Brazil,by sampling 300 randomly distributed plots.Then,we compared the floristic composition,relative abundance,and biological and vegetation spectra among areas.We classified species as endemic and non-endemic and verified the occurrence of endangered species.Species richness was evaluated by rarefaction analysis on the sampling units.The importance value and species abundance distribution(SAD)models were assessed.We also performed an indicator species analysis.We sampled 58 species belonging to 49 genera and 32 families.The number of species decreased with increasing altitude,with significant differences being observed among areas regarding richness,abundance,and cover.Of the total number of species,10 are endemic to the CaparaóNational Park and 17 are listed on the Brazilian Red List of endangered species.The dominant families on all peaks were Asteraceae and Poaceae.The SAD models showed lognormal and geometric distributions,corroborating the fact that 10 species that were common to all three areas were also the most dominant ones in the communities and showed the highest importance values,which ranged between 35%and 60%.Indicator species analysis revealed that 28 species(48.27%)were indicators.Of these,42.85%had maximum specificity,meaning that they occurred only in one area.Thus,the number of species per life form ratio was similar among areas,yet vegetation spectra differed,especially for hemicryptophytes.The altimetric difference among the areas showed to be a very important driver in the community assembly,influencing the evaluated variables,however,other drivers as soil depth,slope and water could also influence the community structure on a smaller and local spatial scale.
基金the Coordena??o de Aperfei?oamento de Pessoal de Nível Superior(CAPES)(process number 88882.451229/2019-01)for the scholarship granted to the first authorto Programa de ApoioàPós-Gradua??o(PROAP)for the financial support provided for data collection。
文摘The municipality of Boa Nova,in northeastern Brazil,is in an ecotone zone between the Caatinga and Atlantic Forest phytogeographic domains.The transition phytophysiognomy is seasonal forest and known locally as mata de cipó.In these phytophysiognomies there are lajedos,which are rock outcrops colonized by vegetation welladapted to extreme microclimatic variation and vegetation diversity is affected by the vegetation types of the surrounding areas.Due to the singularity of these environments and the relevance of floristic studies for conservation,this work aimed to identify the species richness and compare the similarity of the flora on four rock outcrops in Boa Nova.The flora was surveyed during exploratory walks along lajedos between 2016 and 2019.In total,162 species were identified on the Boa Nova outcrops.The flora has a composition and structure similar to semiarid outcrops,as well as endemic species that also occur in surrounding phytophysiomies.Despite the proximity,a similarity index revealed there is floristic dissimilarity between the areas.Nine new occurrences were recorded for the region,five species are threatened with extinction(Aosa gilgiana,Ficus cyclophylla,Hippeastrum stigmovittatum,Pleroma caatingae and Trixis pruskii),and 43 species are common in anthropogenic areas.This reinforces the importance of actions to conserve these areas.
文摘It is important to know the shape and distribution of sandstone bodies in the subsurface when formation and migration of a dune model are determined. The information plays a significant role in identification of the continental oil and gas accumulation. In this study,the combination of ground penetrating radar( GPR)and electrical resistivity tomography method( ERT) is used in mapping the distribution of sandstone bodies in Yanchang Formation. Six GPR profiles and seven ERT profiles are used to analysis. GPR data show clear reflections from the top interface of sandstones. ERT data show a continuous high resistivity anomaly corresponding to the sandstone body. Combined the reconstructed 3D images by GPR and ERT,the spatial distribution of sandstone bodies is described.
基金China Geological Survey Project(DD20160167)PetroChina Innovation Foundation(2017D-5007-0105)+1 种基金Open Fund of Key Laboratory of Exploration Technologies for Oil and Gas Resources(Yangtze University)Ministry of Education(K2018-20).
文摘Through the regional geological survey,outcrop section measurement and other field geological work,a block of black shale is found at the outcrop of Mengjiawopu Section of Hongshuizhuang Formation in Jixian County,and organic geochemical source rock analysis and evaluation methods are used to study the source rocks in Hongshuizhuang Formation.The set of source rocks is mainly gray-black silty mudstone and gray-black shale,with a cumulative thickness of 78 m;the total organic matter(TOC)is generally high,with an average content of 1.35%,of which good and rich source rock samples account for 86%.A combined analysis of the stable carbon isotope of kerogen,the correlation between Pr/nC17 and Ph/nC18,and the ratio of saturated hydrocarbon to aromatic hydrocarbon identifies that the organic matter is mainly TypeⅡkerogen;the equivalent vitrinite reflectance R o of organic matter is from 1.68%to 1.94%.R c,the correlation of the methylphenanthrene index(MPI)against the vitrinite reflectance is from 1.63%to 1.81%,with an average of 1.71%,and the Odd/Even Predominance(OEP)value is between 0.87 and 1.11,both indicating that the source rocks of the Hongshuizhuang Formation are at the stage of high to over maturation.In summary,the set of source rocks in Hongshuizhuang Formation is characterized by high organic matter content,good kerogen types,and high to over maturation stage.
文摘In Argentina, the Araucaria araucana forest occupies a vast area in the Northwest of Patagonia, following a pronounced gradient of increasing xericity from west to east over a short distance. These forests have been the subject of detailed studies due to their uniqueness and ecological relevance. In this context, an exhaustive investigation was carried out to understand the diversity and structure of these ecosystems. The objective was to study the floristic and ecological differences in humid and xeric areas along a west-east transect where A. araucana is distributed. Floristic surveys, geomorphological analyses, and bioclimatic data were examined. In Argentina, A. araucana integrates two distinct forest types: mesic and xeric. The xeric A. araucana forest constitutes a forest with floristic, genetic, geomorphological, and bioclimatic identity. The results highlight the importance of understanding the local variability of these ecosystems for the design of effective conservation strategies. Furthermore, they highlight the need for further research into the ecology and dynamics of these forests, especially in the context of climate change and human activities.
基金supported by grants from the National Key Oil and Gas Program of China(No.2016ZX05004002)from Special Program of PetroChina(No.2014E-32-02)
文摘Numerous hydrocarbon accumulations are found in ramp crest shoals worldwide and therefore this depositional setting has a high potential of being the hydrocarbon reservoir. In this paper, we combined digital outcrop geology and traditional geological mapping to build an outcrop-based geocellular model of the ramp-crest shoal complex of the Lower Triassic Feixianguan Formation in the Eastern Sichuan Basin. The outcrop model serves as an analogue for the subsurface reservoir of the Feixianguan Formation and illustrates the complexity of the lithofacies types, stratigraphic architecture, and reservoir heterogeneities at a scale below conventional subsurface data resolution. The studied ramp -crest shoal complex consists of thirteen types of lithofacies that can be grouped into three facies-groups corresponding to subtidal intraclastic shoal, sub- to inter-tidal oolitic shoal, and tidal flat depositional environments respectively. The stratigraphic architecture of the shoal complex shows mostly a strong progradation of the high energy facies associated with an overall decrease of accommodation space associated with relative sea level still stand. Two reservoir facies associations have been recognized. The first one consists of supratidai dolomudstone and upper intertidal partially dolomitized oolitic packstone with anhydrite or nodules. These facies were deposited above the high energy oolitic grainstones and occurs as thin-bedded and laterally continuous layers, characterized by high porosity and low permeability. The second reservoir facies association is composed of intertidal crystalline dolomite and subtidal intraclastic bindstone that occurs stratigraphically below the oolitic grainstones. These deposits consist of massive laterally discontinuously beds, and are characterized by high porosity and high permeability. Both types of reservoir facies tend to be stacked vertically and migrated laterally with the progradation of the shoal complex. The construction of the outcrop-based 3D geological model provide a description and quantification of the facies distribution within a robust stratigraphic framework and the style and amount of reservoir heterogeneities associated with a ramp-crest shoal complex reservoir such as the one found in Lower Triassic Feixianguan Formation and Cambrian Longwangmiao Formation in Sichuan Basin or other ramp-crest reservoir worldwide.
基金supported by Open Fund (PLC201203) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology)Major Project of Education Department in Sichuan Province (13ZA0177)
文摘Due to inherent limits of data acquisition and geophysical data resolution, there are large uncertainties in the characterization of subsurface fractures. However, outcrop analogies can provide qualitative and quantitative information on a large number of fractures, based on which the accuracy of subsurface fracture characterization can be improved. Here we take the tectonic fracture modeling of an ultra-low permeability sandstone reservoir based on an outcrop analogy, a case study of the Chang6t~ Formation of the Upper Triassic Yanchang Group of the Wangyao Oilfield in the Ordos Basin of China. An outcrop at the edge of the basin is a suitable analog for the reservoir, but the prerequisite is that they must have equivalent previous stress fields, similar final structural characteristics, relative timing and an identical depositional environment and diagenesis. The relationship among fracture density, rock type and bed thickness based on the outcrop is one of the most important fracture distribution models, and can be used to interpret fracture density in individual wells quantitatively. Fracture orientation, dip, geometry and scale, also should be described and measured in the outcrop, and can be used together with structure restoration and single well fracture density interpretation to guide fracture intensity prediction on bed surfaces and to constrain the construction of the 3D fracture geometry model of the subsurface reservoir. The application of the above principles shows the outcrop-based tectonic fracture models of the target ultra-low permeability sandstone reservoir are consistent with fractures inferred from microseismic interpretation and tracer tests. This illustrated that the fracture modeling based on the outcrop analogy is reliable and can reduce the uncertainty in stochastic fracture modeling.
基金Institute of Hydrocarbon Recovery, Universiti Teknology PETRONAS and Petroliam Nasional Berhad, Malaysia Oil and Gas Company for funding this research project (YUTP cost # 0153AA-E79)
文摘Advances in photogrammetry have eased the acquisition of high-resolution digital information from outcrops, enabling faster, non-destructive data capturing and improved reservoir modeling. Geocellular models for flow dynamics with in the virtual outcrop in siliciclastic deposits at different sets of sandstone facies architecture remain, however, a challenge. Digital maps of bedding, lithological contrast, spatial-temporal variations of bedding and permeability characteristics make it more easy to understand flow tortuosity in a particular architecture. An ability to precisely model these properties can improve reservoir characterization and flow modeling at different scales. Here we demonstrate the construction of realistic 2 D sandstone facies based models for a pragmatic simulation of flow dynamics using a combination of digital point clouds dataset acquired from LiDAR and field investigation of the Sandakan Formation, Sabah, Borneo.Additionally, we present methods for enhancing the accuracy of outcrop digital datasets for producing high resolution flow simulation. A well-exposed outcrop from the Sandakan Formation, Sabah, northwest Borneo having a lateral extent of 750 m was chosen in order to implement our research approach. Sandstone facies and its connectivity are well constrained by outcrop observations, data from air-permeability measurements, bilinear interpolation of permeability, grid construction and water vector analysis for flow dynamics.These proportions were then enumerated in terms of static digital outcrop model(DOM) and facies model based on sandstone facies bedding characteristics. Flow simulation of water vector analysis through each of the four sandstone facies types show persistent spatial correlation of permeability that align with either cross-bedded orientation or straight with more dispersion high quality sandstone(porosity 21.25%-41.2%and permeability 1265.20-5986.25 mD) and moderate quality sandstone(porosity 10.44%-28.75% and permeability 21.44-1023.33 mD). Whereas, in more heterolithic sandstone(wavy-to flaser-bedded and bioturbated sandstone), lateral variations in permeability show spatially non-correlated patterns over centimeters to tens of meters with mostly of low quality sandstone(porosity 3.4%-12.31% and permeability < 1 mD to 3.21 mD). These variations reflect the lateral juxtaposition in flow dynamics. It has also been resulted that the vertical connectivity and heterogeneities in terms of flow are mostly pragmatic due to the interconnected sandstone rather than the quality of sandstone.
基金supported by the "Hundred Talents Program" of the Chinese Academy of Sciences (to Jian Ni)the National Basic Research Program (No. 973) of the Ministry of Science and Technology of China(Grant No. 2013CB956704)the Scientific Research Foundation of the Education Department of Guangxi Zhuang Autonomous Region (Grant No.201106LX296)
文摘Relationships between topography,soil properties and the distribution of plant communities on two different rocky hillsides are examined in two subtropical karst forests in the Maolan National Natural Reserve,southwestern China.Surveys of two 1-ha permanent plots at each forest,and measurements of four topographic and thirteen edaphic factors on the slopes were performed.Twoway Indicator Species Analysis(TWINSPAN) and Detrended Canonical Correspondence Analysis(DCCA) were used for the classification of plant communities and for vegetation ordination with environmental variables.One hundred 10m×10m quadrats in each plot were classified into four plant community types.A clear altitudinal gradient suggested that elevation was important in community differentiation.The topography and soil explained 51.06% and 54.69% of the variability of the distribution of plant species in the two forest plots,respectively,indicating both topographic factors(eg.elevation,slope and rock-bareness rate) and edaphic factors(e.g.total P,K and exchangeable Ca) were the important drivers of the distribution of woody plant species in subtropical karst forest.However,our results suggested that topographical factors were more important than edaphic ones in affecting local plant distribution on steep slopes with extensive rock outcrops,while edaphic factors were more influential on gentle slope and relatively thick soil over rock in subtropical karst forest.Understanding relationships between vegetation and environmental factors in karst forest ecosystems would enable us to apply these findings in vegetation management strategies and restoration of forest communities.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3080200)the National Natural Science Foundation of China(Grant No.42022053)the China Postdoctoral Science Foundation(Grant No.2023M731264).
文摘Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This study presents a systematic outcrop research of fracture pattern variations in a complicated rock slope,and the qualitative and quantitative study of the complex phenomena impact on threedimensional(3D)discrete fracture network(DFN)modeling.As the studies of the outcrop fracture pattern have been so far focused on local variations,thus,we put forward a statistical analysis of global variations.The entire outcrop is partitioned into several subzones,and the subzone-scale variability of fracture geometric properties is analyzed(including the orientation,the density,and the trace length).The results reveal significant variations in fracture characteristics(such as the concentrative degree,the average orientation,the density,and the trace length)among different subzones.Moreover,the density of fracture sets,which is approximately parallel to the slope surface,exhibits a notably higher value compared to other fracture sets across all subzones.To improve the accuracy of the DFN modeling,the effects of three common phenomena resulting from vegetation and rockfalls are qualitatively analyzed and the corresponding quantitative data processing solutions are proposed.Subsequently,the 3D fracture geometric parameters are determined for different areas of the high-steep rock slope in terms of the subzone dimensions.The results show significant variations in the same set of 3D fracture parameters across different regions with density differing by up to tenfold and mean trace length exhibiting differences of 3e4 times.The study results present precise geological structural information,improve modeling accuracy,and provide practical solutions for addressing complex outcrop issues.
文摘For the purpose of reservoir characterization of oilfields discovered in Albertine Graben, it is necessary to study the regional stratigraphy and sedimentary characteristics. The Semliki outcrops display a complete stratigraphy of Miocene, and the sediments are likely to provide valuable analogues for the reservoirs at Albertine Graben oilfields. The outcrops were observed and described in detail, mainly including lithology, colour, thickness, grain size and sedimentary structure. The sedimentology, depositional environment, climate, reservoir geometries and dimensions were analyzed. The Miocene stratigraphic section of Semliki basin was finally established, with lithology, sedimentary structure, sedimentary cycle, interpretation and climate information on it. It provides an analogy for the reservoir characterization, especially provides a basis for appropriate prediction of reservoir geometries in the field.
文摘The highest volcano in Mexico,at the same time the third largest mountain in North America(Citlaltépetl,5610 m a.s.l.),is home to the largest glacier in the country.Because of the extinction of the Popocatépetl glacier(5500 m a.s.l.)caused by eruptive activity,and the almost disappearance of the Iztaccíhuatl glaciers(5220 m a.s.l.)due to the lower elevation of the mountain,the Glaciar Norte of Citlatépetl has been the only glacier that has shown a certain degree of stability as a response to the altitude in which it is located.However,as occurs in almost all glaciers on the planet,the retreat of its glacier terminus has been continuous.Furthermore,during the last years the thickness of its upper part began to decrease rapidly until its bedrock was exposed for the first time in 2019.Due to its ecosystem importance and because it is the main glacier in Mexico,as well as the only one in the world located at latitude 19°N,in this work its current dimensions are updated,as well as the local climatology that governs the current state of the glacier is pointed out.The study was based on the analysis of high-resolution Sentinel-2 optical images,as well as through Sentinel-1 SAR images,with the support of climatological information from the study area.Therefore,the outcropping of the bedrock in the accumulation zone and the consequent horizontal retreat of the upper part of the glacier are documented;at the same time,the decrease in the thickness of the ice along it is noted.The rocky outcrop in the accumulation zone suggests that the flow dynamics of the ice towards the ablation zone will be considerably less,accelerating the retreat of the glacier terminus.Finally,the ascent of the glacial front to 5102 m a.s.l.and the modelled altitude of the equilibrium line to 5276 m a.s.l.are reported as a warning signal in terms of snow catchment and mass balance;likewise,the decrease of 23%of its surface is also indicated regarding the surface reduction monitoring that has been done until 2017.These findings may indicate that the future of this glacier is related to its possible extinction sooner than previously thought,with severe environmental consequences,especially in terms of the provision of drinking water for thousands of inhabitants of the slopes of the volcano.This research is expected to help reflect on the impacts of current climate variability and at the same time serve as a reference for the tropical glaciers on the planet.
