Factors determining changes in the network of marked hiking trails in the Sudetes

Hiking trails are a basic type of tourist infrastructure,which,on the one hand,make areas available for tourist traffic,and on the other hand,can contribute to the protection of the natural environment(if they are well designed and maintained).Owing to the variety of performed functions,their designation is determined by several factors:natural,technical,economic,social.Networks of trails change constantly.The aim of this article is to determine exactly what factors influence transformations within the hiking trail networks and what is their significance.To this end,three study areas in the Sudetes were analysed:one on the Polish side of the Sudetes-the Table(Stołowe)Mountains,and two on the Czech side-the rock town near the village of Sloup vČechách and the central part of Zlatohorskávrchovina.An analysis of changes in the shape of the networks over time was carried out,as well as surveys of institutions that were responsible for or influenced these transformations.These areas are characterised by a significant level of changes in the trail network.Among the factors influencing these changes,the tourist attractiveness of the area,the resilience of the environment,the intensity of tourism traffic,the environmental transformations associated with it,the history of tourism development and land ownership changes should be considered the most important.At each stage of forming networks,the key factor should be tourists’needs,including the desire to escape the urbanised environment.For this reason,trails should avoid roads with artificial(hard)surfaces and heavy automobile traffic.

Petrographic, Geochemical and Metallogenical Context of the Geological Formations of the Goumere Region (North-East of Cote D’Ivoire): Implication to the Knowledge of Gold Mineralization

The Gouméré region is located in the North-East of Côte d’Ivoire and is located in the South-West of the Bui furrow. In order to highlight the geology of the area studied, 14 samples were taken for studies using petrographic, geochemical and metallogenic methods. The study of macroscopic and microscopic petrography made it possible to highlight two major lithological units: 1) a volcano-plutonic unit, formed of gabbros, basalt, volcaniclastics and rhyodacite;2) a sedimentary unit (microconglomerate). From a geochemical point of view, the results obtained indicate that the plutonites are gabbro and gabbro diorite while the volcanics have compositions of basaltic andesites, rhyolite and dacites. The sediments have a litharenitic to sublitharenitic character. The metallogenic study made it possible to highlight hydrothermal alterations and metalliferous paragenesis on the formations studied. Hydrothermal alteration is characterized by the presence of carbonation, silicification, sericitization, sulfidation and to a lesser degree chloritization. Metalliferous paragenesis consists of pyrite, chalcopyrite, hematite and magnetite.

Soft-sediment Deformation Structures Related to Earthquake from the Devonian of the Eastern North Qilian Mts.and Its Tectonic Significance

Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin triggered a intense earthquake, and formed seismites and earthquake-related soft-sediment deformation. The soft-sediment deformation structures of Devonian in the eastern North Qilian Mts. consist of seismo-cracks, sandstone dykes, syn-depositional faults, microfoids （micro-corrugated lamination）, fluidized veins, load casts, flame structures, pillow structures and brecciation. The seismo-cracks, syn-depositional faults and microfolds are cracks, faults and folds formed directly by oscillation of earthquake. The seismic dykes formed by sediment instilling into seismic cracks. Fluidized veins were made by instilling into the seismo-fissures of the fluidized sands. The load casts, flame structures and pillow structures were formed by sinking and instilling caused from oscillation of earthquake along the face between sandy and muddy beds. The brecciation resulted from the oscillation of earthquake and cracking of sedimentary layers. The seismites and soft-sediment deformations in Devonian triggered the earthquake related to tectonic activities during the orogeny and uplift of North Qilian Mts.

Distribution of Rare Earth Elements in Early Permian Reef-Island Ocean Sediments in Eastern Kunlun

Abstract: Based on the study of stratigraphy and fossils, the Early Permian ocean in eastern Kunlun is recognized as a kind of reef-island ocean, in which there exist many different kinds of sediment, including patch carbonate platform, reef facies, transitional facies and deep basin sediments. It has been found that the total contents of REEs increase gradually from carbonate platform facies to deep basin facies. Meanwhile, sediments of different facies have different REE distribution patterns and different Ce anomalies. Most of the sediments of patch carbonate platform facies or reef facies are characterized by extremely negative Ce anomalies or moderately negative Ce anomalies (Ce/Ce*=0.33 to 0.55), and medium or thin-bedded limestones of transitional facies by moderately negative Ce anomalies (Ce/Ce*=0.49 to 0.60). However, sediments of deep basin facies show weak or no negative Ce anomalies (Ce/Ce*=0.69 to 1.47), among which the value of Ce/Ce* in the radiolarian chert is 1.47.

Estimation of postseismic deformation parameters from continuous GPS data in northern Sumatra after the 2004 Sumatra-Andaman earthquake

Continuous global positioning system （GPS） in northern Sumatra detected signal of the ongoing physical process of postseismic deformation after the M9.2 2004 Sumatra-Andaman earthquake. We analyze the character- istics of postseismic deformation of the 2004 earthquake based on GPS networks operated by BIG, and the others named AGNeSS, and SuGAr networks located in northern Sumatra. We use a simple analytical logarithmic and exponential function to evaluate the postseismic deforma- tion parameters of the 2004 earthquake. We find that GPS data in northern Sumatra during time periods of 2005-2012 are fit better using the logarithmic function with dog of 104.2 ± 0.1 than using the exponential function. Our result clearly indicates that other physical mechanisms of post- seismic deformation should be taken into account rather than a single physical mechanism of afterslip only.

Genetic Relationship of Minerals and Carbonate Units of Stratigraphy Sequence in the Ahmadabad Deposit (NE of Bafq) Using Data Related to Rare Earth Elements

Ahmadabad Pb-Zn ore deposit is located in the mineral area of Bahabad in Central Iran Zone. This ore deposit like other metallogenic areas in Bahabad is found in Triassic carbonate rocks. Carbonate rocks in Shotori formation have the highest frequency in the regional sequence stratigraphy. This formation is composed of TRSh1, TRSh2, TRSh3 and TRSh4 units. The TRSh3 unit hosts minerals in ore deposit Ahmadabad. Microcrystalline particles are the main constituent of these rocks. The most important minerals in this ore deposit include calamine Celestine, Cerussite and Wulfenite. The comparison of normalized ore patterns and carbonate sequence indicates that they have a specified genetic relationship. Here the TRSh2 unit is more similar to minerals.

Effect of tectonic-climatic controllers on the transition of Endorheic to Exorheic Basins in the Zagros mountain range

Endorheic basins(ENBs) are inland drainage basins allowing no outflow to oceans.These basins in the active mountain chains of the convergence zones are under the influence of compressional tectonic activity and climate condition.The Zagros Mountains of Iran is one of the youngest convergence zones in which continental-continental collision has occurred.In this paper we hypothesize the formation of ENBs among the Zagros range after the epeirogenic stage in the Late Paleogene-Early Neogene.Due to tectonic activity and Quaternary climatic conditions,the ENBs pass the transition stage to exorheic,and still,some tectonic depressions are not linked to the evolutionary process of exorheic drainage of Zagros.The geometry of the drainage network of Kul and Mond basins in Fars arch shows that 67% of their water gaps are located along the thrusts and transverse basement faults in the east and west of the Fars arch.Geometrically,the Kul and Mond basins form triangles with their sides matching with the edges of the Arabian Plate where the major inherited faults of Arabian plate controls the shape of the Zagros basin and a low strain zone along the Razak fault with lower salt tectonic activity,where the wind gaps are created.The ENBs are located in the rainshadow slopes,but the Kul and Mond basins are located in the upwind slopes of rain waves.This factor and the heavy rains of the basin lead to increase of the erosion potential,destruction of depressions,and floods and consequently,the funnel-shaped gaps have a significant impact on the flood flow.

Contribution of biophysical and climate variables to the spatial distribution of wildfires in Iran

This study investigated the relationship between climate and biophysical variables in burned areas in Iran.The fire burned area(FBA)product(Fire CCI 5.1.1),land surface temperature(MOD11C3C),vegetation index(MOD13A1),and climate variables such as temperature,wind speed,relative humidity,and volumetric soil moisture from the ERA5 reanalysis dataset were used.Pearson correlation coefficient was used to determine the relationship between biophysical and climate variables and fire occurrence.The results show that FBA increased by 1.7 hectares/decade from 2001 to 2020.The high FBA in 2010(the black summer of Iran)was due to high temperatures and significant heatwaves that led to extensive wildfires.Although anthropogenic activities are considered a significant cause of wildfires,several variables,including increased temperatures,less precipitation,relative humidity,and wind speed and direction,contribute to the extent and occurrence of wildfires.The country’s FBA hotspot is in the Arasbaran region during the summer season.Temperature and relative humidity are the most significant variables influencing the occurrence of wildfires.The results show the vulnerability of Iran s forests and their high potential for fires.Considering the frequency of fire occurrences in Iran and the limited equipment,fire prevention plans should be carried out by applying proper management in high-risk regions.

Biostratigraphy,Microfacies,Sedimentary Environments and Sequence Stratigraphy of the Late Devonian-Carboniferous Deposits at the Anarak Section,Central Iran

The Late Devonian-early Carboniferous deposits of the Anarak section in northeastern Isfahan,Central Iran,evaluated based on conodont biostratigraphy,sedimentary environment and sequence stratigraphy.According to the field observations,five lithological units were identified.Investigating the conodont fauna of the Late Devonian-Carboniferous(Mississippian-Pennsylvanian)deposits of Bahram,Shishtu,and Qaleh(Sardar 1)formations in Anarak section led to the identification of 67 species of 18 conodont genera,and accordingly 22 conodont biozones were differentiated.The correlation of sea-level change curves,regarding to the conodont biofacies with the global sea-level curve,demonstrates the relative correlation in the mentioned times due to the shallow condition of the central Iran basin compared to the European and American basins.The microfacies analysis led to the identification of 12 microfacies related to the open sea,bioclastic barrier,lagoon and tidal flat sub-sedimentary environments in a homoclinal carbonate ramp environment.Based on sequence stratigraphy studies,three 3rd order sequences were identified.The first sequence,which is of the Late Devonian(upper part of the Bahram Formation,32.5 m),the second sequence(12.5 m)is the Late Devonian(uppermost part of the Bahram Formation),and the third sequence(68 m)is the early Carboniferous(the Shishtu I Formation).

Local geoid modeling in the central part of Java, Indonesia, using terrestrial-based gravity observations

The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.

Insights into the adsorption performance and mechanism of Cr(Ⅵ)onto porous nanocomposite prepared from gossans and modified coal interface:Steric,energetic,and thermodynamic parameters interpretations

Herein,iron oxide/hydroxides deposits(gossans)were utilized,for the first time,in the fabrication of magnetite nanoparticles(MNPs)to load modified coal(MC).The as-synthesized MNPs@MC composite was characterized via different techniques and utilized for the Cr(Ⅵ)remediation.Experimental studies supported by theoretical treatment were applied to offer a new overview of the Cr(Ⅵ)adsorption geometry and mechanism at 25-45℃.Experimental results suggested that the Cr(Ⅵ)uptake was mainly governed by adsorption-reduction coupled mechanism.The Langmuir model fitted well the Cr(Ⅵ)adsorption data with maximum adsorption capacities extended from 115.24 to 129.63 mg·g^(-1).Theoretical calculations indicated that Cr(Ⅵ)ions were adsorbed on the MNPs@MC following the theory of the advanced monolayer statistical model.The number of ions removed per site ranged from 1.88 to1.23 suggesting the involvement of vertical geometry and multi-ionic mechanism at all temperatures.The increment of the active sites density and the adsorption capacity at saturation with improving temperature reflected an endothermic process.Energetically,the Cr(Ⅵ)adsorption was controlled by physical forces as the adsorption energies were less than 40 kJ·mol^(-1).The calculated free enthalpy,entropy.and internal energy explained the spontaneous nature and the viability of Cr(Ⅵ)adsorption on the MNPs@MC adsorbent.These results offer a new approach in utilizing the iron-rich deposits as gossans in the preparation of magnetic and low-cost adsorbents for wastewater remediation.

Relationship between gravitational flap structures in the backlimb of anticlinal breakthrough Fault-Propagation Folds:case study of the Southern-Central Tunisian Atlas

The development of orogenic belts structures in the Southern-Central Tunisian Atlas is influenced by the evolution of tectonic activities during different phases,which are also closely linked to the formation of gravitational collapse structure.The typical example is that of the northern flank of the Jebel Orbata particularly the Ben Zannouch fold.It is an asymmetrical anticline interpreted by the model of“Fault Propagation Folds”.The development of the Ben Zannouch structures is resulted from landslides,scree falls and inverted layers plunging to the south.The direction of resulted gravitational structure is parallel to the main thrust direction of the Bou Omrane anticline.The thrust activity of Bou Omrane fault is associated to the important paleo-slope facing south and plastic lithology(incompetent marl layers)of outcropped series,facilitates the development of the Ben Zannouch Flap structure.The definition of gravitational collapse structures for the first time in Tunisia particularly in the northern flank of the Jebel Orbata is controlled by many principal structural conditions:fragmentation of the landslide surfaces,rheology and topography.Other regional factors can be distinguished in the Southern-Central Tunisian Atlas as the seismic activity of the pre-existing Gafsa fault reactivated during compressive phases and the weather conditions during the postglacial period.

Integration of Sequence Stratigraphic Analysis and 3D Geostatistical Modeling of Pliocene–Pleistocene Delta,F3 Block,Netherlands

This research is focused on the analysis of the sequence stratigraphic units of F3 Block,within a wave-dominated delta of Plio–Pleistocene age.Three wells of F3 block and a 3D seismic data,are utilized in this research.The conventional techniques of 3D seismic interpretation were utilized to mark the 11 surfaces on the seismic section.Integration of seismic sequence stratigraphic interpretation,using well logs,and subsequent 3D geostatistical modeling,using seismic data,aided to evaluate the shallow hydrocarbon traps.The resulting models were obtained using System Tract and Facies models,which were generated by using sequential stimulation method and their variograms made by spherical method,moreover,these models are validated via histograms.The CDF curve generated from upscaling of well logs using geometric method,shows a good relation with less percentage of errors(1 to 2 for Facies and 3 to 4 for System Tract models)between upscaled and raw data that complements the resulted models.These approaches help us to delineate the best possible reservoir,lateral extent of system tracts(LST and/or HST)in the respective surface,and distribution of sand and shale in the delta.The clinoform break points alteration observed on seismic sections,also validates the sequence stratigraphic interpretation.The GR log-based Facies model and sequence stratigraphy-based System Tract model of SU-04-2 showed the reservoir characteristics,presence of sand bodies and majorly LST,respectively,mainly adjacent to the main fault of the studied area.Moreover,on the seismic section,SU-04-2 exhibits the presence of gas pockets at the same location that also complements the generated Facies and System Tract models.The generated models can be utilized for any similar kind of study and for the further research in the F3 block reservoir characterization.

Mapping and Petro-Structural Study of the Geological Formations of the Alépé Region (South-East of Côte d’Ivoire)

This study focuses on the petrographic and structural characteristics of the geological formations of the Alépé region in the Comoé basin. The petrographic characterization allows us to retain that the study area abounds in a variety of lithologies: amphibole metagranite, metadiorite, amphibolite and metagrauwacke. The lineament map attests that the study area was affected by polyphase tectonics (ductile and brittle), all these deformations have NW-SE to NNW-SSE;NW-ESE to NW-SE;ENE-OSW and NE-SW directions. Coupled geochemical data show that the protoliths of the studied rocks evolve between granites and gabbros that are weakly to moderately be altered. They would originate from continental crust and mantle and would be emplaced in collision contex.

Platform Evolution in an Oligo-Miocene Back-arc Basin:An Example from the Central Iran Basin

The Qom Formation is the most important hydrocarbon reservoir target in Central Iran.The Qom platform developed in a back-arc basin during the Oligo-Miocene due to the closing of the Tethyan Seaway.This formation consists of a variety of carbonate and non-carbonate facies deposited on a platform ranging from supratidal to basin.A combination of tectonic and eustatic events led to some lateral and vertical facies variations in the study area.Six third-order depositional sequences and related surfaces were identified regarding vertical facies changes in the studied sections of this Oligo-Miocene succession.According to all results and data,this succession was initially deposited during the Chattian upon a distally steepened ramp of siliciclastic-carbonate composition,including the Bouma sequence.Then,from the late Chattian to the Aquitanian,the platform changed into a homoclinal carbonate ramp with a gentle profile.With respect to tectonic activity,this phase was a calm period during the deposition of the Qom Formation.Finally,a drowned carbonate platform and a rimmed shelf emerged during the Burdigalian,terminated by the continental deposits of the Upper Red Formation.Regarding all geological characteristics,three main tectono-eustatic evolutionary phases have been recognized in the Qom back-arcbasin.

Temporal-Spatial Structure of Intraplate Uplift in the Qinghai-Tibet Plateau

The intraplate uplift of the Qinghai-Tibet Plateau took place on the basis of breakup and assembly of the Precambrian supercontinent, and southward ocean-continent transition of the Proto-, Paleo-, Meso- and Neo-Tethys during the Caledonian, Indosinian, Yanshanian and Early Himalayan movements. The intraplate tectonic evolution of the Qinghai-Tibet Plateau underwent the early stage of intraplate orogeny characterized by migrational tectonic uplift, horizontal movement and geological processes during 180-7 Ma, and the late stage of isostatic mountain building characterized by pulsative rapid uplift, vertical movement and geographical processes since 3.6 Ma. The spatial-temporal evolution of the intraplate orogeny within the Qinghai-Tibet Plateau shows a regular transition from the northern part through the central part to the southern part during 180-120 Ma, 65-35 Ma, and 25-7 Ma respectively, with extensive intraplate faulting, folding, block movement, magmatism and metallogenesis. Simultaneous intraplate orogeny and basin formation resulted from crustal rheological stratification and basin-orogen coupling that was induced by lateral viscous flow in the lower crust. This continental dynamic process was controlled by lateral flow of hot and soft materials within the lower crust because of slab dehydration and melted mantle upwelling above the subducted plates during the southward Tethyan ocean-continent transition processes or asthenosphere diapirism. Intraplate orogeny and basin formation were irrelevant to plate collision. The Qinghai-Tibet Plateau as a whole was actually formed by the isostatic mountain building processes since 3.6 Ma that were characterized by crust-scale vertical movement, and integral rapid uplift of the plateau, accompanied by isostatic subsidence of peripheral basins and depressions, and great changes in topography and environment. A series of pulsative mountain building events, associated with gravity equilibrium and isostatic adjustment of crustal materials, at 3.6 Ma, 2.5 Ma, 1.8-1.2 Ma, 0.9-0.8 Ma and 0.15-0.12 Ma led to the formation of a composite orogenic belt by unifying the originally relatively independent Himalayas, Gangdise, Tanghla, Longmenshan, Kunlun, Altyn Tagh, and Qilian mountains, and the formation of the complete Qinghai-Tibet Plateau with a unified mountain root after Miocene uplift of the plateau as a whole.

Magnetostratigraphy and Anisotropy of Magnetic Susceptibility of the Lulehe Formation in the Northeastern Qaidam Basin

The timing of onset of deposition of the Lulehe Formation is a significant factor in understanding the genesis of the Qaidam basin and the evolution of the Tibetan Plateau. Here, we describe a detailed magnetostratigraphic and magnetic fabric study of the middle and lower parts of the Lulehe Formation. A total of 234 samples were collected from 117 sites throughout a thickness of almost 460 m of fluvial and lacustrine deposits at the Xitieshan section in the northeastern Qaidam basin. Out of these sites, 94 sites yielded well-defined characteristic remanent magnetization components by stepwise thermal demagnetization and were used to establish the magnetostratigraphy of the studied section. Based on correlation with the geomagnetic polarity timescale, the studied section spans the period from 53.8 Ma to 50.7 Ma. Our results show a three-fold decrease in sedimentation rates as well as marked change in facies from braided river to delta and shore-shallow lake around 52.6 Ma, which suggests tectonic uplift of the northeastern Qaidam basin margin ridge was rapid at the onset of formation of the Qaidam basin and subsequently weakened after 52.6 Ma. The anisotropy of magnetic susceptibility results indicate that tectonic compression stress had reached the northeastern Tibetan Plateau by the early stages of Indo-Eurasian plate collision and that the direction of stress in the study area was NE-SW. Furthermore, a weakening of tectonic compression stress around 52.6 Ma is consistent with sedimentary records. The age of initial deposition of the Qaidam basin （around 53.8 Ma） was almost synchronous with that of the Qiangtang, Hoh Xil, Xining, and Lanzhou basins, which implies that stress was transferred rapidly through the Tibetan Plateau during or immediately after the onset of Indo-Eurasian collision.

Reconstruction of Ore-controlling Structures Resulting from Magmatic Intrusion into the Tongling Ore Cluster Area during the Yanshanian Epoch

The Tongling ore cluster area experienced intensive compression and associated shearing during the Indosinian-Yanshanian Epoch, which formed a trunk ore-controlling fold and fault system in the caprock. The magmatic intrusion in the Yanshanian Epoch induced a multi-stage unmixing of poly-phase fluids, resulting in mineralization characterized by multi-layer, wide-range, and multiform styles. The magmatic intrusion in the Tongling area not only supplied the essential ore-forming materials, but also reconstructed the ore-controlling structures according to a trend surface simulation of the following five strata boundaries： Silurian-Devonian, Devonian-Carboniferous, Carboniferous- Permian, Middle Permian-Upper Permian and Permian -Triassic. The result of this simulation shows that there exists a significant difference between the strata in the upper part and those in the lower. The lower trend surfaces are antiform whereas the upper trend surfaces are synform. In addition, superposing of the trend surfaces of adjacent bed boundaries （such as, Silurian-Devonian boundary superposed upon Devonian-Carboniferous boundary） shows that the lower trend surface always pierces the one above. Moreover, the position and orientation of the pierced parts of the different superposed trend surfaces are similar and show E-W-trending zonal distribution in accordance with the distribution of the regional E-W-trending magmatic-metallogenic belt. Based on comprehensive analysis of the mechanical properties of the strata, structural deformation mechanisms, and field phenomena, it seems that the special characteristics of the stratal trend surface resulted from jacking due to magmatic intrusion into the caprock previously controlled by an E-W-trending basement fault. Therefore, it is deduced that the major ore-controlling structures, which formed during regional horizontal compression, were reconstructed by the vertical jacking function of ore-forming magmas during the Yanshanian Epoch. During the ore-forming process, the local vertical jacking of magmas, coupled with the regional horizontal compression, optimized an extensive environment in the fluid- conduit network and accelerated the unmixing of poly-phase fluids following magmatic emplacement. Jacking also strengthened the vertical and lateral fluid-guiding structures, supplying more suitable physical conditions for multi-layer emplacement and wide-ranging transport of poly-phase fluids.

Behavior of REE Fractionation during Weathering of Dolomite Regolith Profile in Southwest China

REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The weathering of dolomite is divided into two stages：the pedogenesis stage and soil evolution stage,corresponding to the saprolites and soils respectively in the regolith profile. SiO_2,TiO_2,P_2O_5,Zr,Hf,Nb and Ta were immobile components during the weathering by and large, while Al_2O_3,K_2O and Fe_2O_3 were lost during the soil evolution stage in the physical form（clay minerals probably）.REE were fractionated during the whole weathering of dolomite.The field weathering profile and the lab acid-leaching experiments on dolomite indicate that MREE were enriched clearly relative to other REE during the pedogenesis stage in a ＂capillary ascending-adsorption＂ mechanism, but they did not fractionate clearly in the soil evolution stage.REE were lost and accumulated in the weathering front of dolomite during the soil evolution stage in a ＂physical-chemical leaching＂ mechanism.