Mud Deposits Research Articles

Classification and Control Factors of Reservoir Types in Hybrid Sedimentary Rocks: A Case Study on Lucaogou Formation in the Jimusaer Sag, Junggar Basin.

Hybrid sedimentary rocks (HSR) represent a significant reservoir type in fine-grained sediments. However, the classification and understanding of HSR reservoirs, including their storage mechanisms and identification of optimal "sweet spots," have been limited due to the lack of clarity regarding the multiple sources of components and their mixing processes. This study focuses on the Lucaogou formation of Jimusaer Sag and aims to highlight the reservoir classification principles, controlling factors, and evolutionary patterns associated with the components of HSR, beginning with examining the microscopic pore structure. The analysis of the microscopic pore structure characteristics reveals the presence of five distinct reservoir types within the HSR. The quality of these reservoirs is governed by various factors, including the composition and support mode of particles, diagenesis, provenance, and sedimentary microfacies. In regions near a provenance with strong hydrodynamic conditions, the HSR predominantly exhibits type I and type II reservoirs, characterized by numerous coarse-grained components and a granular-support mode. As the distance from the provenance increases, transitioning into medium hydrodynamic conditions, the HSR shifts to an interbedded-support mode, primarily developing type III reservoirs. In areas far from the provenance with weak hydrodynamic conditions, HSR reservoir types primarily consist of type IV and type V. Additionally, diagenetic effects such as compaction and calcite cementation further deteriorate intergranular and dissolution pores, consequently diminishing reservoir quality. Notably, during the mixing deposition processes of sand and dolomite, the developmental mode of HSR shifts from type I to type II and type III. Likewise, in the mixing deposition of mud and sand, the HSR transitions from type II to type III and type IV. Similarly, the mixing deposition of dolomite and mud leads to a change in the developmental mode of HSR from type III to type IV and type V. Moreover, this study effectively predicts the occurrence of "sweet spots" using reservoir classification, which reveals their continuous distribution. These findings provide a geological foundation for evaluating "sweet spots" and testing the oil production in HSR reservoirs.

Contour marks as potential indicators of evaporation rates in the early Permian continental vertebrate site Bromacker (Thuringia, Central Germany)

Reconstructing the climate of the past requires archives that bear proxy information on temperature, precipitation, or atmospheric composition, for example. In this study we use contour marks as potential water level marks in mud sediments to reconstruct local evaporation rates at the Bromacker lagerstaette site in the Early Permian. The measured values indicate a daily evaporation of 1.5–3.75 mm with a median value of 2.25 mm/day. The calculated evaporation rates are compared with modern ones to estimating moisture, precipitation and seasonal climate. For evaluating reconstructed precipitation and evapotranspiration rates, values simulated by global climate models and calculated from geochemical datasets are furthermore incorporated. For the first time, quantitative data and models elucidate the climate of the Tambach Formation and Bromacker lagerstaette against the background of the pivotal transition from the Carboniferous Ice House to the Permian Hothouse climate. Our results suggest a strongly seasonal climate with wet summers and dry winters in a mountainous region based on unexpectedly low temperatures (10.9–15.0 °C) considering the palaeo-location of the site in the tropical belt during the Early Permian. According to the modern vegetation model by Holdridge a moist forest biome is suggested for the Bromacker lagerstaette.

Delta initiation under low sediment discharge: Insights from Holocene incised valley fills north of Tokyo Bay, central Japan

Modern delta formation initiated as a result of the deceleration in the rate of sea-level rise during the middle Holocene. In Asia, many deltas initiated at the mouths of rivers with large sediment discharge at 8 ka, early in the middle Holocene, when the volume of sediment supply exceeded that of the accommodation space created by sea-level rise. However, in the Japanese Islands, even some deltas formed by rivers with quite small sediment discharges initiated at 8 ka. In the area north of Tokyo Bay, a narrow, 70-km-long bay was formed during the last deglacial sea-level rise. The Tone and Watarase rivers flowed into this bay from the west and east, respectively. We carried out facies analysis and radiocarbon dating of two sediment cores obtained in the vicinity of the Watarase River mouth. The delta that formed at the tide-dominated Watarase River mouth was characterized by bay mud sediments with a narrow sand body along the axis. This deltaic sand body, which is 5–15 m thick and coarsens upward, filled a tidal channel that was 1–3 km wide and 30 km long. At the mouth of the sediment-starved Watarase River, the delta initiated at the onset of the sea-level stillstand at 7 ka. In contrast, at the mouth of the sediment-rich Tone River, a delta initiated at 8 ka, when the rate of sea-level rise decreased from 14 to 7 m/kyr. By reviewing delta initiations in the area north of Tokyo Bay and in 17 coastal lowlands of the Japanese Islands, we demonstrate that the sediment discharge threshold governing whether delta initiation occurred at 8 or 7 ka was equivalent to a mean annual water discharge of 100 m3/s.

Link between Lesser Himalayan Neoproterozoic Krol succession and the Adelaide rift complex of Australia ‒ evidence from the mudstone deposits of Krol succession, Himachal Pradesh, India

The mudstone deposits, a major constituent of the Lesser Himalayan Krol succession, represents the terminal phase of Marinoan snowball melting, an important part of the most significant events of the Proterozoic time, the Cryogenian Snowball Earth. The Facies analysis suggests that the sediments were supplied to the shelf by meltwater flows, and were later dispersed to the deeper part of the shelf by current/wave-enhanced bottom currents. The upper part of the deposit bears the signature of gradual shallowing of the basin caused due to glacioisostatic rebound. Petrographic study of the samples, randomly collected from different parts of the deposit, reveals that the mud deposit is composed of silt-sized particles of quartz and dolomite, and argillaceous material. Besides the variation in proportion of these constituent components, no other material was found within this deposit. This compositional homogeneity of this huge deposit primarily suggest derivation from some preexisting sediments. Mineralogical similarity and perfect match in trace and Rare Earth elements composition suggest that this mud was derived from the periglacial loess deposits of the Nuccaleena Formation of South Australia. This is in agreement with the provenance of the underlying Krol Sandstone. The mudstones, along with the underlying Krol Sandstone, thus suggest that the Lesser Himalayan Krol succession represent an extended part of the Adelaide rift system of South Australia. The relative position of India and Australia during Neoproterozoic, as per the reconstructed configuration of the Rodinia supercontinent, corroborates this inference.

Global Warming Potential of Carbon dioxide and Methane Emission from Mangrove Sediment in Waiheru Coastal, Ambon Bay.

Mangroves can store carbon. However, it also produces carbon emissions by degrading organic matter in mangrove sediments. This research was conducted in a mangrove ecosystem at Waiheru, in the inner Ambon bay, to determine CO2 and CH4 emissions and their potential for global warming (GWP) from mangrove sediments. Gas is taken through a syringe mounted on the hood. Gas concentration analysis used the gas chromatography method, while the average gas concentration in each sediment was tested using ANOVA Single Factor. The results showed that the average concentration of CO2 gas was significantly different for each sediment (P-value <0.05), while the average concentration of CH4 gas was not significantly different (P-value >0.05). The largest CO2 gas emission in mangrove sediments in Waiheru Village was found in sandy mud sediments with an emission value of 136.99 mg.m−2.h−1, and the lowest was in sand sediments, namely 13.01 mg.m−2.h−1. Meanwhile, the largest emission of CH4 gas was in silty sand sediments, namely 0.32 mg.m−2.h−1, and the lowest was in sandy mud sediments, namely 0.15 mg.m−2.h−1. Fluctuations in carbon gas emissions in each sediment are inversely proportional, which indicates that the formation of CH4 gas is obtained through ethanol reduction, which utilizes CO2 gas concentrations. The total GWP in the mangrove sediments of Waiheru Village is 231.58 mg.m−2.h−1. The GWP contributed by the type of sandy silt sediment was 140.72 CO2-eq mg.m−2.h−1, muddy sand was 70.95 mg.m−2.h−1, and sand sediment was 19.91 CO2-eq mg.m−2. h−1.

Pemetaan Sebaran Habitat Dasar Perairan Laut Dangkal Menggunakan Citra Sentinel-2A di Teluk Gilimanuk

West Bali National Park is a conservation area with such a high biodiversity. That includes mangrove forest, coastal, and shallow water ecosystem. As a conservation area, a distribution map of the shallow water habitat is necessary for decision making in the conservation’s benthic habitat developing program. One of the mapping method is remote sensing and requires Sentinel-2A Level 1C satelitte image. Sentinel-2A Level 1C is used due to its high resolution which is 10x10 meters for a single pixel. The aim for this research is for mapping the distribution of the shallow water habitat in Gilimanuk Bay while also assesses the accuracy of Sentinel-2A image. This research uses the Quantum GIS and SAGA GIS software to analyze the Sentinel-2A image. The image is transformed using Depth Invariant Index to reduce the scattering effect on the reflectance. After the image is being transformed by the Depth Invariant Index, it is classified using maximum likelihood method. The classification showed, the area of each classes are 56.59 hectares of corals, 18.01 hectares of seagrass, 128.97 hectares of waters, 45.76 hectares of mud sediment, 78.95 hectares of macro algae, and 26.67 hectares of sands. Overall accuracy assessment for this research calculated using confusion matrix and the result is 65.1% and considered good enough due to Coral Ecosystem Remote Sensing Data Analysis Guide by National Institute of Aeronautics and Space (LAPAN), in which the tolerance of the accuracy is 60%. Accuracy levels are influenced by number of classes, image resolution, class resemblance, turbidity, and seafloor material.

Foraminifera assemblages from Fantangisña serpentinite mud seamount in the NW Pacific Ocean during the Pleistocene (IODP Expedition 366).

The Mariana forearc system, in the northwestern Pacific, is known as the only convergent margin setting with currently active serpentine mud volcanism. The Fantangisña serpentinite mud volcano lies 62 km west of the Mariana trench, within the influence of the North Equatorial Current (NEC). Cores recovered by International Ocean Discovery Program (IODP) Expedition 366 contain pelagic sediments overlying layered serpentinite mud deposits. At the bottom of the sequence, nannofossil-rich forearc deposits were recovered from under the seamount edifice. In this study, we investigated 47 samples from Site U1498A on the southern flank of the seamount for benthic and planktonic foraminifera assemblages. Statistical analyses on planktonic assemblages differentiated two sample groups related to the ratio between thermocline/mixed layer taxa, which indicate fluctuations in the depth of the thermocline (DOT) during the Pleistocene. Variations in the DOT reflect changes in the intensity of the NEC associated with El Niño/La Niña conditions. Mudflows do not influence the ecology of planktonic foraminifera but possibly enhance their preservation against dissolution, which was instead detected in the pelagic deposit as suggested by common Globigerinoides conglobatus. Benthic foraminifers were rare in serpentinite mud deposits as they are severely affected by mudflows. Conversely, they showed high diversity pre-/post-mud-volcanism, and indicate oligotrophic bottom-water conditions.

Authigenic greigite in late MIS 3 sediments: Implications for the Yellow Sea Cold Water Mass and Yellow Sea Warm Current evolution

Yellow Sea current conditions during the late Marine Isotope Stage 3 (late MIS3, 40–30 ka B.P.) highstand remain unknown. Here, environmental magnetism, geochemistry, particle size, and scanning electron microscope methods are employed to analyze core YS01A with a basal age of 40 kyr from the South Yellow Sea mud deposits. Greigite formed in marine sedimentary layers with thickness >7 m during early diagenesis. Greigite formation is related to the redox state and total organic content (TOC) availability, which are controlled, respectively, by the Yellow Sea Cold Water Mass (YSCWM) and the Yellow Sea Warm Current (YSWC). In MIS1 (7–0 ka B.P.), a strong YSWC brought greater TOC, and a strong YSCWM (thickness of 48 m) resulted in a strongly reducing low-oxygen environment. This led to massive magnetite dissolution and pyrite preservation. In late MIS3 (37–31 ka B.P.), the weak Kuroshio Current and East Asian Winter Monsoon (EAWM) resulted in a low-intensity YSWC that provided less TOC. A weak YSCWM (thickness of 35 m), caused by shallow water depths and a weak EAWM, contributed to a less reducing sedimentary environment. Thus, pyritization was interrupted and greigite was preserved. Greigite content can, thus, be used to trace the development of Yellow Sea currents. During a period of slow sea level rise at 41–37 ka B.P., minor greigite formed with most magnetite being preserved, which indicates that the environment started to become reducing. This can be interpreted as due to initial formation of a thin and weak YSCWM. During the 37–31 ka B.P. highstand, the greigite content increased, which suggests more reducing conditions related to establishment of a thicker and intensified YSCWM. In addition, the greigite content decreased progressively, which may have resulted from YSWC weakening. Our results suggest that greigite can be used as a simple tool to reflect current evolution in the Yellow Sea, which can give a better understanding of continental shelf environment change.

Depositional and diagenetic conditions during early South Atlantic opening: Evidence from the upper Aptian Oiteirinhos Member, Muribeca Formation, Sergipe-Alagoas Basin, NE Brazil

The Muribeca Formation from the Sergipe-Alagoas Basin, northeastern Brazil, records the transition from continental to marine conditions during the initial South Atlantic opening. The formation is constituted by the basal coarse clastics of the Carmópolis Member, covered by the Ibura Member evaporites, and the Oiteirinhos Member. The Oiteirinhos Member presents a wide lithological variation, including siliciclastic, carbonate, and hybrid deposits. Considering the scientific importance of understanding the conditions during this key time in South Atlantic evolution, very few sedimentological studies were performed on the Oiteirinhos Member. This article presents a petrological characterization, integrated with sedimentological data from five onshore wells. The studied rocks include siliciclastic sandstones, siliciclastic-carbonate hybrid arenites, marls, microbialites, calcarenites, and calcilutites. The composition of the sandstones is rich in low-grade metasedimentary fragments from the erosion of upper Proterozoic supracrustal orogenic terrains. Intrabasinal carbonate constituents include ooids, peloids, oncoids, intraclasts, bioclasts of ostracodes, benthic foraminifers, and echinoderms. Carbonate microbialites occur associated with laminated organic mud deposits, commonly rich in carbonaceous and phosphate fragments. The main diagenetic process occurred near-surface, under the influence of an evaporitic, dry climate under continental and marine conditions. The depositional and diagenetic aspects reveal progressively less evaporitic conditions during the deposition of the Oiteirinhos Member, with anhydrite followed by siliciclastic and hybrid deposits and finally by marine carbonates.

Depositional history of the subaqueous delta off the southeastern coast of Korea during the post-glacial period

The distal mud deposit (DMD) of the Korea Strait Shelf, located along the southeastern coast of Korea and detached from the main sediment source, the mouth of the Nakdong River, is considered a subaqueous delta system. The complex spatiotemporal changes in the stratigraphic architecture of the DMD were reconstructed, based on combined seismic and sediment core data, according to the three stages of post-glacial sea-level rise. During the early transgressive stage (from ca. 19 to 10.9 ka), transgression occurred at a relatively deeper northern outer shelf of the DMD, where Unit A began to be deposited in an aggradational stratal stacking pattern. During the late transgressive stage (ca. 10.9 to 8 ka), further sea-level rise provided sufficient accommodation for DMD, but an insufficient sediment supply from the Nakdong River might have prevented sedimentation. At the highstand stage (ca. 8 ka to the present), the increased supply of suspended sediments from the Nakdong River coupled with the entrance of the Tsushima Warm Current through the Korea Strait may have enabled the along-shore lobate progradation of Unit B on the flat and wide southern shelf. After appoximately 2 ka, as Unit B proceeded into the narrow, steep northern shelf, it started to prograde in a shore-normal direction, controlled by a rapid downslope decrease in near-bed shear stress. Over the last 700 years, sediments have been actively deposited at the depocenter of the DMD by frequent storm surges during the summer season. The reconstructed depositional history of the DMD demonstrates the importance of the pre-existing shelf morphology, along-shore currents, and storm surges in offshore sediment transport for a subaqueous delta in a microtidal shelf with a relatively small riverine sediment load.

Assessment of the environmental radiological impact in the emergency exposure phase through the simulation of a uranium mining tailings dam breach

This work is aiming at estimating the radiation doses to members of the public in case of an emergency exposure situation related to a hypothetical uranium mining tailings dam rupture at the UDC - Decommissioning Unit of Caldas, MG, Brazil. The calculations will help to managing the exposures of emergency workers and residents in the region downstream the dam. The computer code chosen to perform the simulations was FLO-2D@ software. Due to the uncertainties involved, mainly regarding the waste rheology and activity concentrations and in parameters values to be used in the dose assessment, considerations were made for the study to present results derived from conservative assumptions. Through the creation of flood maps, it was possible to estimate the extent of the areas affected by the released materials. The results showed that in a scenario of the tailings dam breach, deposition of mud shall extend over 20 km downstream affecting an area of nearly 3 km2. Total dose for a member of the public living in most affected areas would be around 43 mSv/y in the early phase after the accident. Although only shielding would be recommended under current radiation protection regulation, evacuation/relocation is suggested due to the presence of long-lived radionuclides. This protective measure would probably already be indicated by the accident itself, regardless of radiological reasons. More realistic assessment should be performed before returning people, considering long-term environmental transport and uses of the area. It must also be considered that long-term exposures have more restricted recommended acceptable levels than those for the emergency phase.

Changjiang coastal mud‐belt deposits in Taiwan Strait: Controls on its distribution and facies

ABSTRACTCoastal mud belts, which lie parallel to the coast just seaward of the shoreface, are one of the most important settings where shallow‐marine muddy deposits accumulate. However, sedimentary processes and facies distributions of coastal mud belts remain largely uninvestigated. This study uses process‐oriented sedimentology, coupled with provenance analysis and organic geochemistry of sedimentary records at the northern entrance to the Taiwan Strait, to investigate one of the largest such systems in the world, the Changjiang coastal mud belt. Carbon‐14 dates indicate that deposition has been intermittent throughout Marine Isotope Stages 1, 2 and 3, with several cryptic gaps in the muddy succession as a result of exposure or transgressive erosion during periods of lower or rising sea level, respectively. The palaeowater depth of each depositional unit was roughly estimated based on a global sea‐level curve and the elevation and age of the depositional units. Integrated provenance and sedimentology studies suggest that an incised valley most likely cut by the Minjiang, a nearby river draining the Chinese mainland, probably during Marine Isotope Stage 6, was filled with shelf mud during Marine Isotope Stage 3. These results demonstrate that deposition of mud on the Changjiang coastal mud belt was influenced by sea‐level changes that controlled water depth and flow patterns through Taiwan Strait. The Changjiang coastal mud belt migrates landward when sea level rises and moves seaward when sea level drops. In addition, changes in oceanic circulation associated with opening and closing of Taiwan Strait due to sea‐level changes causes significant changes in the source of the mud, with an alternation between sediment contributions from the Changjiang in the north, the nearby Minjiang, and the island of Taiwan to the south‐east. This study also reveals that the Changjiang coastal mud belt deposits are composed of both shallower‐water and deeper‐water facies. The shallower‐water facies predominantly comprises abundant fluid‐mud beds generated by waves and tidal currents. The deeper‐water facies contains shell‐rich mud and bioturbated mud, which were likely deposited by the Chinese coastal current and Taiwan Warm current. The bed types and interpretation of sedimentary processes of the Changjiang coastal mud belt are useful for recognition of ancient deposits of coastal mud belts elsewhere.

Evaluation of the Foundation Beds Liquidation by Using Soil Modeling for El-Burullus Power Plant Area, Kafr El-Sheikh, Egypt

In this study, the soil has been numerically modeled as the Mohr-Columb model because it is simple to capture essential features of soil behavior. Plaxis 2D software program has been used for modeling. The dynamic analyses depend on some data, such as grain size gradation for materials, stiffness and water level. This data has been used in the calculation process. Simple applications have been chosen to calculate the relations. The program computes entered data automatically. Earthquakes result in dynamic loading on soil which has a significant effect on the soil properties. The model is formed of five soil layers. Sands and mud deposits covered the area and Delta also. Some of the study results can be estimated by using the modeling method. The applied load value is 100 kN/m2. The amplification factor (S %) to the soil in the study area is 108 % when soil is without the foundation load and 150 % when soil with foundation load. Thus, the soil is classified as type – D (Moderate) and no liquefaction is expected in the results, but subduction or landslide, so piling foundations are recommended within the area of study. As well, numerical modeling is recommended in several locations in Egypt to obtain suitable areas for the foundation constructions.

Always a White Christmas in the Bahamas: temperature and hydrodynamics localize winter mud production on Great Bahama Bank

ABSTRACTWhitings, or occurrences of fine-grained carbonate in the water column, have been observed in modern environments with salinities ranging from fresh to marine conditions, and thick deposits of lime mud are described throughout the geological record. Despite their ubiquity, the trigger for whitings has been debated for more than eighty years. Satellite data reveal that most whitings are restricted to the northwestern part of Great Bahama Bank (GBB) which occupies &amp;lt; 10% of the platform area. Even here, whitings are further focused. More than 35% of them occur in a zone which occupies just 1% of the platform. We propose a three-step process for the existence of this zone of peak whitings and why the whitings in it are both more frequent and larger in winter than summer. First, the temperature differential between on- and off-platform waters is highest in the winter, setting up a disparity between dissolved CO2 concentrations in the two water masses. Second, hydrodynamic mixing of these two water masses increases the degree of aragonite saturation of the platform-top waters, as colder on-platform waters with theoretically higher concentrations of dissolved gases are warmed via mixing with the warmer off-platform waters. Finally, spatial heterogeneity in the degree of aragonite saturation is higher in the winter, and the zone of peak whitings is situated in an area of locally enhanced saturation state. Hydrodynamic simulation suggests that the whitings zone is located by tidal inflow of off-platform waters across the western margin of GBB, as well as inflow from the Tongue of the Ocean to the north of Andros Island. Despite thermodynamic forcing mechanisms that predict higher frequency of whitings in the summer, the environmental, hydrodynamic, geochemical, and kinetic conditions in the whitings zone appear to support the Goldilocks configuration that enhances the formation of wintertime whitings on Great Bahama Bank. This phenomenon has implications for the interpretation of whitings mud in the geological record, including the geochemical signatures within it.

Defect Size Characterization in Unidirectional Curved GFRP Composite by TSR Processed Pulse and Lock in Thermography: A Comparison Study

Glass fiber reinforced polymer (GFRP) curved composite is widely used in industries due to its high corrosive resistance nature. GFRP curved composites are involved in many industries like petrochemical industries for handling oil and gas at offshore platforms, chemical processes such as chemical storage tanks, desalination, and water treatment. Since alloy steel materials get corroded by environmental factors such as excess salinity in the surrounding environment, mud deposition, and sulfur crude accumulation makes alloy steel pipes are expensive to maintain. Every year billions of dollars can be saved by corrosion prevention using Glass Fiber Reinforced Polymer (GFRP) pipes instead of alloy steel pipes. In-service stage of the GFRP pipe or tank, different types of defects are forming such as void, delamination, and wall loss (pits). Among all these defects, pits or wall loss is one of the severe defects which may lead to leakage accidents. The objective of the study is the quantification of defect size by using TSR processed pulsed and lock-in thermography and analyses their capabilities in defect size quantification. TSR processed the PT image and the signal to noise ratio was used to estimate the defect size quantification. For defect size measurement, the TSR-processed PT thermal results are recommended and the near-surface defects can be measured with high accuracy in LT.

Sustaining and Development of Physiotherapy as an Important Condition for Health Resort Treatment Effectiveness Increasing: a Review

AIM. To focuses on the relevance of using, along with natural healing factors, traditional and innovative transformed physical factors, which can significantly improve the effectiveness of health resort treatment. INTRODUCTION. Globally recognized achievements of Russian balneology are first of all connected with strictly scientific approaches to development of therapeutic methods and complex programs of physiotherapeutic treatment, implemented for many decades in health resort organizations throughout the country. The richest deposits of natural mineral waters and mud were mastered, studied and adapted for treatment of chronic diseases of inflammatory and degenerative-dystrophic nature, for rehabilitation of patients after vascular accidents, injuries and operations, as well as for rehabilitation of virtually healthy persons with reduced functional reserves. The results obtained on the basis of randomized clinical trials represent the evidence base for inclusion of various methods of physiotherapy in the Clinical Guidelines for various nosologies. The successful development of physiotherapy requires not only a profound scientific approach, consolidation of researchers, manufacturers of physiotherapy equipment and practitioners, but also further improvement of the regulatory framework. Thus, a great achievement of 2022 can be considered the drafting of an Order on providing medical care to the population in the profile of «physiotherapy».

Ecotourism development strategies of Lusi Island in Kedungpandan-Jabon Sidoarjo using SWOT Analysis

Lusi Island is a nature-based ecotourism site located in Sidoarjo, with its own uniqueness compared to the surrounding islands because it began as a dumping ground for Lapindo mud sediment. Lusi Island is providing several facilities to be used in protection, education, and recreation activities. The purpose of this study is to determine the development strategy of the Lusi Island tourist attraction by analyzing the existence of potential using the strength, weakness, opportunity, and threat (SWOT) analysis method at the ecotourism location. The results showed that the ecotourism development strategy of Lusi Island can be achieved by establishing cooperation between managers and various parties, controlling the impact of tourist attraction development, and adding adequate facilities and infrastructure to support better ecotourism.

Linking top and subsoil types, alteration and degassing processes at Rotokawa geothermal field, New Zealand

Surface geothermal expressions such as mud pools, fumaroles, mineral deposits, collapse pits, and hydrothermal eruption craters vary in scale and type over space and time. The evolution in space and time of these surficial thermal features strongly relates to alteration processes caused by hydrothermal fluids. The changes in the physical and mechanical properties of top and subsoils that can control fluid flow, degassing patterns, and occurrence of geothermal hazards remain understudied. The thermal area located south of the Rotokawa geothermal field (New Zealand) includes a variety of major natural surface thermal features and widespread sulphur deposits precipitated by acid–sulphate fluids in steam-heated zones. Decades of sulphur mining induced the formation of new thermal features. Such a setting represents an exemplary case study for investigating old and recently formed thermal features, soil characteristics, types and patterns of superposed hydrothermal alteration, and degassing processes. We combined field and laboratory methods to define groups of thermal features, soil types, and associated alteration. Their spatial distribution indicates that fluid circulation, alteration intensity, and degassing are strongly influenced by the local and regional geological and structural settings, as well as by mining activity. We found that at the water table level and within excavated areas, acidic fluids led to the deposition of mud deposits, sinters, and stromatolites around warm springs and mud pools. In the vadose, steam-heated portions, fluids generally leach and degrade the Taupo Pumice, resulting in broad unstable grounds and collapse structures, while extensive sulphur-encrusted grounds and sulphur-rich soils formed in excavated sites. In this framework, the degassing and fluid circulation within the top and subsoils are strongly affected by the dominant soil layer type, and in turn by its granulometry, texture, and alteration state. Our study of top and subsoils yields precious insights into surface expression variability, fluid–rock interaction processes, and sulphur deposition patterns within steam-heated zones. Processes at such a scale may strongly influence the migration of thermal manifestations, gas outputs, and ground subsidence within geothermal environments. From a broader perspective, our results will help assess the evolution of geothermal activity and related hazards in similar areas worldwide.

Holocene transgression and sea level change offshore Peninsular Malaysia (innermost Sunda Shelf) as indicated by benthic foraminiferal, lithologic and geochronologic data

The history of Holocene sedimentation on the Sunda Shelf (southern South China Sea), one of the largest shelves in the world, has received little attention, particularly off Peninsular Malaysia. We present here evidence of Holocene transgression from most of the inner shelf of Peninsular Malaysia, based on lithologic and foraminiferal analyses of 24 cores from 13.5 m to 46.8 m water depth encompassing the coastal sand wedge and the immediately adjacent shelf. Six benthic foraminifera biofacies occur within these cores and, together with lithologic data and five AMS radiocarbon age estimates, enable recognition of three units previously defined in cores taken from 52 m to 77 m water depth. Eleven of 24 cores contain Unit 3, earliest Holocene coastal plain semi-consolidated peaty, sandy clay deposits that represent the lowest part of the post-last glacial maximum transgressive systems tract (TST). In a single core, Unit 4 open marine, inner shelf sandy mud deposits of the early Holocene upper part of the TST overlie Unit 3. In 23 cores Unit 3 is directly overlain by Unit 5, open marine, inner shelf sandy mud deposits of the highstand systems tract (HST) and laterally equivalent sediments within the coastal sand wedge that accumulated after the mid-Holocene sea-level maximum.

Natural resource factors in assessing the competitiveness of the tourism and recreation sector of the Carpathian region of Ukraine

The article examines how natural conditions and resources influence the competitiveness of the tourism and recreation sector of the Carpathian region of Ukraine. It highlights the methodological approaches to their assessment in the system of competitiveness factors in the studied sector of the regions on a national level. To calculate the competitiveness indices, the following dominant indicators are suggested: forested areas, mountainous areas, objects in the nature reserve fund, UNESCO World Heritage sites, medicinal mineral waters, deposits of therapeutic mud, ozokerite, lakes and estuaries with therapeutic brine, density of the river system, area of lakes, ponds and reservoirs, availability of sea beaches, number of hunting sites on the territory of hunting grounds. In addition to the partial indices for Ukraine’s regions based on individual indicators of natural resource factors, integral indices of regions are calculated. According to the indicators of integral indices of the impact of natural resource factors on the competitiveness of the tourism and recreation sector, the rating of the oblasts of the Carpathian region is determined, in particular: Zakarpatska (4.3) and Lvivska (3.4) oblasts are ranked first and second, Ivano-Frankivska – fifth (3.1), and Chernivetska – seventeenth. In general, natural conditions and resources offer significant competitive advantages to the region’s oblasts in providing wellness, tourism and wellness (especially in Lvivska and Zakarpatska oblasts), tourism and recreation, and tourism and sports services, particularly in skiing. The article reveals that the combination of natural conditions and resources available in the Carpathian region provides significant competitive advantages for its oblasts in the tourism and recreation sector at the national level.