Effect Of Lithology Research Articles

The spatial distribution of Benggang and the factors that influence it

AbstractBenggang, a fragmented landform induced by the overall collapse of soils on slopes, is one of the most serious land erosion problems in Southern China. The reasons for the concentrated development of Benggang and the major influencing factors are still unclear. The key driving factors for Benggang development in Fujian and Jiangxi Provinces were investigated by ArcGIS spatial analysis of the effects of rainfall, lithology, elevation, and geomorphology. It was found that Benggang density increases first and then decreases with annual average rainfall, elevation, and hypsometric integral value (HI) and that the regions with a density of greater than 0.2 Benggang km−2 are characterized with an average annual rainfall of 1,395–1,645 mm,an elevation of 200–400 m,and an HI of 0.14–0.30. Lithology and weathering crust exhibit an important influence on the development of Benggang, with the formation of 41.94% of Benggangs in 25.88% of the granite area. HI shows a significant positive correlation with elevation in the 1,680 watershed areas (r = .83, p < .01). In different HI value ranges, the annual average rainfall presents an opposite trend to the development density of Benggang. The HI values are consistent with the maximal number of Benggangs associated with granite, tuff, conglomerate, and sandstone, indicating a close relationship of the regional Benggang development with the stage of geomorphical development. The underlying surface conditions created by geomorphological development are the direct causes for Benggang, whereas human activities only accelerate or delay its occurrence.

Normal fault geometric attribute variations with lithology: examples from the Norwegian Barents Sea

Abstract The geometry of faults exposed in the field is at least partly controlled by host-rock lithology. However, little work has been published on the effect of lithology on the geometry of very large faults imaged in seismic data. This paper presents such a study for seismic-scale faults in the Norwegian Barents Sea. Gamma-ray data are used to extract clay volumes of the host rock. These clay volume logs are used to populate 3D seismic cubes with lithology information. Finally, the clay volume cubes are co-rendered with seismic coherence cubes using opacity blending. This makes it possible to visualize both lithology information and fault geometries in the same volume. Intervals of different lithologies are studied in order to compare fault geometries. The results show some differences between claystone-rich intervals and the more sandstone-dominated intervals. The fault zone is more segmented and wider in the claystones, while the sandy intervals are narrower and more localized with less segmentation. Larger displacement faults penetrate into deeper stratigraphic levels than smaller displacement faults, and their basal tips are unrelated to lithological decoupling.

Effects of lithology and geomorphology on sediment yield in karst mountainous catchments

Due to the characteristics of the lithology and the complexity of the geomorphology, the karst areas of Southwest China are experiencing severe soil erosion. Knowledge of the effects of lithology and geomorphology on sediment yield are therefore essential for developing measures to effectively control sediment delivery in this region. The objective of this study was to investigate the relative importance of lithological and geomorphological factors for sediment yield in 40 selected karst mountainous catchments in Southwest China. Because of the high co-dependence of these variables, a partial least squares regression (PLSR) model was used to explore the quantitative relationships between annual sediment yield and 30 lithological and geomorphological factors. Results showed that the lithology and geomorphology were critically important to annual sediment yield and could explain 65.9% of the total variance in sediment yield. The dominant lithological and geomorphological factors controlling annual sediment yield were karst coverage, drainage density, basin relief, plane curvature, elevation, maximum elevation, average slope, dolomite coverage, relative relief, and catchment area. This importance or these contributions of lithological and geomorphological factors to annual sediment yield provides a good reference for selecting key factors when developing soil erosion models. This study yields a greater understanding of the influences of lithology and geomorphology on sediment yield, and is helpful for better catchment management in karst regions.

Late Cenozoic uplift of the Sierra Nevada, California? A critical analysis of the geomorphic evidence

From the earliest days of California geology, the ramp-like profile of the northern half of the Sierra Nevada mountains and putative signs of recent incision have been interpreted as evidence that the range was formed by the tilting of a rigid block in the late Cenozoic. Over the years, various geomorphic analyses have been used to quantify the magnitude of uplift and to establish its timing, such as analyzing the gradients of ancient channels, examining the tilt of sedimentary beds, and reconstructing the incisional history of rivers. Most studies that have used these methods have supported substantial (>500 m) recent uplift of the Sierra. In contrast, investigations based on other sources of paleotopographic information, such as isotope records, thermochronology, and detrital zircon geochronology, have found that the Sierra have been at high elevations for much of the Cenozoic. This set of contradictory results motivates a re-examination of the geomorphic evidence for late Cenozoic uplift. A critical assessment of these geomorphic studies, based on new topographic analyses and field investigations, reveals that their conclusions are not well supported. For example, several studies based their results on reconstructions of ancient channels that would have flowed up and over bedrock ridges as high as 190 m, a physical impossibility. Other weaknesses include unjustified assumptions regarding the original tilt of fluvial deposits, misinterpretations of stratigraphic relationships, and inadequate recognition of the effect of lithology on channel profiles. The studies supporting recent tilting in the northern Sierra Nevada are inconclusive and rely on observations not unique to tectonic forcing. Indeed, much of the evidence based on the paleogradients of the Tertiary channels is consistent with an early trellis drainage network formed across alternating bands of resistant and weak lithologies. In addition, analyses are presented to demonstrate that deep northern Sierran canyons thought to have been recently incised were, instead, cut as early as the Eocene-Oligocene. Two geomorphic studies from the southern Sierra are consistent with late Cenozoic tilting and uplift although ongoing tectonic activity may be insignificant. Finally, I present a conceptual model of the evolution of the Sierran landscape, applicable primarily to the northern half of the range, illustrating the development of three different drainage networks since the late Jurassic.

Effect of catchment lithology on dissolved inorganic carbon budgets in suburban streams of Baltimore, Maryland, during rainfall minima

Urbanization has the potential to affect riverine carbon exports, but relatively few studies have evaluated the potential effect of lithology on carbon fluxes in urban settings. To address this gap, four first-order streams in the Baltimore metropolitan area exhibiting different levels of impervious surfaces and catchment lithologies were examined for a span of ten weeks during a period of rainfall minima with the purpose of identifying sources and magnitudes of inorganic carbon transported by these streams during base flow conditions. Discharge, alkalinity, pH, temperature, and dissolved oxygen were measured in situ, whereas the carbon isotopic composition of dissolved inorganic carbon (DIC) was determined in the laboratory. Abundances of DIC and pCO2 were estimated from the collected data, revealing that the stream with an increased forest coverage and a calcareous catchment consistently had the highest values for DIC, pCO2, alkalinity, and stable isotope ratios. DIC yields for the four studied streams were relatively low, ranging from 2.6 to 21.8 mmol C/m2-yr, and calculated pCO2 evasion rates were some of the lowest recorded values in temperate and boreal regions, ranging from 184 to 6451 g C/day. These low values possibly resulted from the low rainfall amount that prevailed during the sampling period, which limited both the transfer of soil-derived DIC to the studied streams and the subsequent emission of CO2 to the atmosphere. Stable isotope data linearly correlated with DIC, and this relation could reflect the lithological control of inorganic carbon in the studied streams, with a 13C-enriched source of DIC probably representing the dissolution of calcareous metamorphic rocks and some contribution of soil-respired CO2 and with a 13C-depleted source interpreted to result from a predominant contribution of soil-respired CO2. Thus, our results point to the dominant effect of catchment lithology in regulating stream DIC budgets in the studied suburban streams during low discharge conditions.

Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Abstract. Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150 km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60 % of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.

Effect of Ore Mineralogy and Bedrock Lithology on Metal Loading Rates and Acid-Mine Drainage: Bayhorse Creek, Idaho and the North Fork of the American Fork River, Utah

Metal contamination of the water in two streams was investigated at the Ramshorn Mine along Bayhorse Creek in Idaho, and the Pacific Mine along the North Fork of the American Fork River in Utah. The studies were conducted to determine what remediation measures should be implemented at each site to reduce metal loads in the streams. Discharge measurements and chemical analyses of filtered and unfiltered water samples allowed dissolved and total metal loads to be calculated. Copper, Fe, Mn, Pb, Zn, and As were found at both sites, and Cd also was present at the Utah site. Of these, Fe had the highest dissolved and total loading rates at the Ramshorn Mine, with Mn and Zn having intermediate rates; Fe and Zn had the highest loading rates at the Pacific Mine. Hydrous ferric oxides, particularly ferrihydrite, are abundant at both sites. Pyrite is the iron source at the Pacific Mine, while it is siderite at the Ramshorn Mine. The lack of sulfide at the latter site inhibits acid mine drainage (AMD) formation, and the presence of dolomite provides abundant alkalinity to neutralize any AMD that might be generated. PHREEQC was used to gain insight into the metal phases and oxidation states, to calculate saturation indices, and to perform surface sorption modeling. The results suggest that most of the metals at both sites are transported in the suspended rather than dissolved state, As occurs exclusively in the less toxic As5+ form, and several metals are likely sorbed to ferrihydrite. Based in part on the results of these studies, the US Forest Service removed the tailings at the Pacific Mine site, but only capped and regraded the tailings pile at the Ramshorn Mine.

Permafrost and active layer research on James Ross Island: An overview

This study summarizes the current state of the active layer and permafrost research on James Ross Island. The analysis of climate parameters covers the reference period 2011–2017. The mean annual air temperature at the AWS-JGM site was -6.9°C (ranged from -3.9°C to -8.2°C). The mean annual ground temperature at the depth of 5 cm was -5.5°C (ranged from -3.3°C to -6.7°C) and it also reached -5.6°C (ranged from -4.0 to -6.8°C) at the depth of 50 cm. The mean daily ground temperature at the depth of 5 cm correlated moderately up to strongly with the air temperature depending on the season of the year. Analysis of the snow effect on the ground thermal regime confirmed a low insulating effect of snow cover when snow thickness reached up to 50 cm. A thicker snow accumulation, reaching at least 70 cm, can develop around the hyaloclastite breccia boulders where a well pronounced insulation effect on the near-surface ground thermal regime was observed. The effect of lithology on the ground physical properties and the active layer thickness was also investigated. Laboratory analysis of ground thermal properties showed variation in thermal conductivity (0.3 to 0.9 W m-1 K-1). The thickest active layer (89 cm) was observed on the Berry Hill slopes site, where the lowest thawing degree days index (321 to 382°C·day) and the highest value of thermal conductivity (0.9 W m-1 K-1) was observed. The clearest influence of lithological conditions on active layer thickness was observed on the CALM-S grid. The site comprises a sandy Holocene marine terrace and muddy sand of the Whisky Bay Formation. Surveying using a manual probe, ground penetrating radar, and an electromagnetic conductivity meter clearly showed the effect of the lithological boundary on local variability of the active layer thickness.

Transitional impact craters on the Moon: Insight into the effect of target lithology on the impact cratering process

AbstractWe studied a data set of 28 well‐preserved lunar craters in the transitional (simple‐to‐complex) regime with the aim of investigating the underlying cause(s) for morphological differences of these craters in mare versus highland terrains. These transitional craters range from 15 to 42 km in diameter, demonstrating that the transition from simple to complex craters is not abrupt and occurs over a broad diameter range. We examined and measured the following crater attributes: depth (d), diameter (D), floor diameter (Df), rim height (h), and wall width (w), as well as the number and onset of terraces and rock slides. The number of terraces increases with increasing crater size and, in general, mare craters possess more terraces than highland craters of the same diameter. There are also clear differences in the d/D ratio of mare versus highland craters, with transitional craters in mare targets being noticeably shallower than similarly sized highland craters. We propose that layering in mare targets is a major driver for these differences. Layering provides pre‐existing planes of weakness that facilitate crater collapse, thus explaining the overall shallower depths of mare craters and the onset of crater collapse (i.e., the transition from simple to complex crater morphology) at smaller diameters as compared to highland craters. This suggests that layering and its interplay with target strength and porosity may play a more significant role than previously considered.

Comparative study of pseudotachylite microstructures in felsic and mafic rocks from the Vredefort impact structure, South Africa. Implications for the experimental studies

Abstract While the formation of tectonic PTs is widely accepted as related to friction melting for all rock types, the mechanism of formation of impact-related pseudotachylites (PTs) is strongly debated. Moreover, the influence of the target lithology on the initial impact PT formation, development and deformation has not been considered in detail, even though impact PTs in the Vredefort structure are found in various lithologies. Here, we investigate PTs that occur in felsic (granite) and mafic (dolerite) rocks that are in contact with one another in the core of the Vredefort impact structure. In this unique outcrop, multiple granitic clasts are observed inside the PTs hosted by dolerite, which indicates material exchange between PTs in the two lithologies, pointing to simultaneous shock deformation in the adjacent rock phases. This outcrop thus provides an unusual opportunity for studying the effect of host lithology on the formation and deformation of PT. Our investigations demonstrate that microstructures and textures in PTs and their chemical composition largely depend on the host rock, suggesting particular rheological syn- and post-formation behaviour of the melt veins of different composition. In granite, melt initiates due to preferential decomposition of mafic and hydrous minerals, and subsequent ductile deformation of quartz and feldspars. In dolerite, melt initiates as a result of comminution of the bulk rock. Due to the different mineral composition of rocks, and corresponding various fracture toughness of different minerals, granitic PTs contain abundant monomineralic clasts composed of more refractory phases, most often quartz, while PT veins in dolerite contain fewer, usually lithic clasts, representing fragments of the host rock. PTs in granite are chemically zoned, which has not been observed for PTs in dolerite. In felsic rocks, PTs are often framed by an ultramylonite and are associated with post-shock ductile features, such as sigmoidal-shaped clasts and dragged edges of the veins, whereas in mafic rocks, PTs are found to be associated with brittle features only, such as (ultra)cataclasites and micro-faults. These differences in initiation and development of PTs based on rock type are consistent with previous experimental studies and must be considered when discussing the formation mechanisms of impact-generated PTs.

Characterizing lithological effects on large scale borehole heat exchangers during cyclic heating of the subsurface

This paper presents the results of a study where subsurface temperatures were monitored adjacent to the u-tube of a central borehole of a large scale 144 borehole heat exchanger (BHE) at multiple depths. This was an effort to develop a method to characterize the variability of thermal properties of the various lithological units surrounding the BHEs of large scale ground coupled heat pump systems during the operation of the system. Saturation of the units and lithology was shown to affect the performance of the BHE resulting variable temperature fluctuations and heat flux at different depths within the borehole. Median heat flux tended to increase with decreasing temperature ranges measured by the sensors. The lowest median heat flux was in the location nearest to the surface in the least saturated zone. In the more saturated zone, the highest median heat flux were at locations where the lithological units were composed of 75 percent or greater dolomite while the lowest median heat flux where in lithological units composed of 30 percent or greater chert.

The effects of lithology on trace element and REE behavior during tropical weathering

The thick regolith developed in the humid tropics represents an endmember of critical zone evolution, where shallow and deep biogeochemical cycles can be decoupled in terms of the predominant source of trace elements (atmospheric input at the surface, weathering at depth) and of the processes that control their cycling. To investigate the influence of lithology on trace element behavior and in this potential decoupling, we studied two deep (9.3 and 7.5 m), highly-leached, ridgetop regolith profiles at the Luquillo Critical Zone Observatory, Puerto Rico. These profiles have comparable internal (degree of weathering, topography) and external (vegetation, climate) characteristics, but differ in their underlying bedrock (andesitic volcaniclastic and granitic). At these two sites, we analyzed a large suite of trace elements and used the rare earth elements and yttrium (REY) as tracers of critical zone processes because they are fractionated by the chemical reactions involved in weathering and pedogenesis (e.g., sorption, dissolution, colloidal transport) and by redox fluctuations.We found that both regolith profiles show atmospheric inputs of trace elements at the surface and evidence of bedrock dissolution at depth, as expected. We also found noticeable differences in the re-distribution of trace elements and REY within the profiles, indicative of different geochemical environments with depth and lithology. In the volcaniclastic profile, trace element and REY behavior is controlled mainly by redox-mediated, sorption/desorption reactions, whereas pH-controlled dissolution/precipitation and sorption reactions predominate in the granitic profile. The most noticeable difference between the two regolith profiles is in the long-term redox conditions, inferred from redox-sensitive elements and Ce anomaly variations, which are more variable and stratified in the volcaniclastic profile and change gradually with depth in the granitic profile. The contrasting redox conditions and the different sources of elements (dust vs. bedrock) produce a decoupling between the surface and deep geochemical environments of the volcaniclastic regolith. The difference in redox conditions between the two lithologies likely stems from the finer grain size and higher clay content of the volcaniclastic regolith.

The effect of heterogeneity on NMR derived capillary pressure curves, case study of Dariyan tight carbonate reservoir in the central Persian Gulf

The porous network controls the behavior of fluids in the reservoir rocks. In carbonate reservoirs fluid flow characteristics do not certainly follow initial sedimentary fabrics. Therefore in these reservoirs, the properties of the porous network should be used in determining the facies. In this study, using a combination of petrographic, reservoir petrophysical and reservoir engineering data, porous network in Aptian-Albian Dariyan carbonates have been studied in one of the central Persian Gulf fields. Accordingly, four pore facies were determined by capillary pressure curves from mercury injection and nuclear magnetic resonance data in four different types of lithology with different microfacies. Also, 13 different petrophysical parameters of these curves derived from both methods and compared with each other. A clear trend was observed in reducing the reservoir quality from pore facies 1 to pore facies 4. The performance of the capillary pressure curves obtained from mercury injection and nuclear magnetic resonance and their derived parameters in 4 facies and the effect of lithology on these curves have been investigated. Results showed that the porosity of the NMR is completely independent of lithology and complexity of the porous system, while the permeability-dependent parameters are largely influenced by both lithology and pore system structure. It was also shown that the NMR curves are a suitable tool for determining the pore facies and their petrophysical parameters in homogeneous tight carbonate lithology with a simple porous system.

Effects of test procedures and lithology on estimating the mode I fracture toughness of rocks using empirical relations

AbstractEmpirical estimation is a common method for getting mode I fracture toughness KIC of rock. By collecting data from tests in this study and literature, 204 sets of KIC and tensile strength σt test data are obtained for new empirical KIC‐σt relations regression. The empirical relations make the estimation of KIC values from σt conveniently, but test procedures and lithology will influence its reasonability and reliability. Results indicate that the empirical KIC‐σt relations obtained from the four different suggested KIC test methods are all in good but obviously different linear relationship. The analyses show that cracked chevron notch Brazilian disc specimen (CCNBD) test‐based empirical relation is more accurate for estimating KIC than the other three test‐based empirical relations. As to different lithology, isotropic rocks such as sandstone and carbonatite may be more appropriate for the application of empirical estimation method. However, for coarse grained or anisotropic rocks such as granite and marble, estimation method should be applied carefully because of possibly weak KIC‐σt relations.

Heavy minerals distribution and provenance in modern beach sands of Campania, Italy

The Campania region (southern Italy) is an excellent area to determine the effects of multiple source lithology (volcanic+sedimentary), climate, weathering, transport anddepositional environment on heavy minerals enrichments in the sandy beaches of the coastline between Pozzuoli and Bacoli, and at the Volturno river-mouth. The heavy mineral (HM) assemblage should reflect the clastic supply from the potassic to ultrapotassic lavas and pyroclastic rocks of the Campania and of the Roman Magmatic provinces (Phlegrean Fields, Roccamonfina volcano), and from the recycling of sedimentary - both carbonate and siliciclastic - terranes of the Apennine thrust belt. Opaque oxides, pyroxene and amphibole assemblage dominates in the beach placers of the Campania shoreline - from Bacoli to Pozzuoli - as well as in the Volturno river mouth sands to the north. Modern heavy minerals assemblages reflect clastic contribution from magmatic source rocks whereas contributionfrom sedimentary terranes - exposed extensively in the Volturno river drainage - provide no recycled heavy minerals to the river-mouth sand. Thus, heavy minerals linked to a provenance from the Apennine thrust belt source rocks result diluted and/or unrecognizable using the only HM approach with respect to the minerals provenance sourced by the potassic volcanic fields of Latium and Campania. Thediverse detrital heavy minerals have been characterized describing major stages of progressive chemical weathering, from unweathered to corroded to etched morphologies, a process - in this case-history - playing a minor role in reducing HM diversity through dissolution of moderately stable mineral species.

Controls on spatial variations of glacial erosion in the Qilian Shan, northeastern Tibetan Plateau

Understanding interactions between topography and glacial erosion is a key to advancing knowledge of mountain landscape evolution and is often hampered by the lack of quantitative data for glacial erosion. Here, we examine spatial variations in glacial erosion in the Qilian Shan using a power law model (y = axb) fit to cross profiles of glacial valleys. We further analyze the impacts of glacial dynamics, topography, and lithology on the degree of glacial erosion using qualitative and quantitative methods. Although the distribution of glacial erosion is controlled by the combined effects of glacial dynamics, topography, and lithology, average glacier size or ice flux and mean slope above the equilibrium line altitude are dominant controls. In addition, the topographic data analyzed through a b-FR diagram suggests two opposite types of glacial valley cross-profile development: temperate (maritime) glacier valleys are mainly dominated by overdeepening; while continental glacier valleys are mainly dominated by a widening process, although this varies with lithology.

Tectonic Study of Lineaments for Part of Zagros Belt, Northeast Iraq

The study area situated in the western part of Zagros fold-thrust belt, north east (NE) Iraq. Google earth image for study area was used to build up lineaments map. Studying and processing of these lineaments revealed that there are two dominant directions of lineaments northeast-southwest (NE-SW) and northwest- southeast (NW-SE), compatible with the main regional stress direction and Zagros belt direction respectively. It was found that there is no significant change of lineaments density in different tectonic zones and there is no obvious effect of lithology on lineament density in the study area. Length rose diagrams showed an obvious increase in the value of NW-SE lineaments direction, starting from low folded zone toward NE, despite frequency rose diagrams of different tectonic zones showed no significant change of the main prevailing direction. It is found that some lineaments shifted or bended some folds or ridges in the study area. Field observations demonstrated that some lineaments of study area had field criteria of faults while they did not described in tectonic map.

Investigation of gas seepages in Thessaloniki mud volcano in the Mediterranean Sea

Gas seepages are commonly observed in marine environment. Especially, gas seepages due to anthropogenic gas hydrate dissociation are big concerns recently. In the Eastern Mediterranean Sea, Thessaloniki mud volcano was detected. Gas hydrate stability conditions in this mud volcano is very fragile. For this reason, in this study, gas seepages were predicted by using HydrateResSim at different seafloor temperature increments varying from 1 to 5 °C and different sediment permeability values varying from 0.1 mD to 5mD in Thessaloniki mud volcano. Both the effect of temperature increment (above 1 °C increment) and the increase in permeability cause faster gas hydrate dissociation. The gas seepages on the seafloor of Thessaloniki mud volcano was investigated in this study by using the bubble rise theory. It was found that the effect of gas bubble diameter is high on the height of gas flare in the study area. The effect of permeability and lithology near seafloor on gas release after gas hydrate dissociation is huge. Generally, in Thessaloniki MV, clays are dominant so it is advantageous for environment because even if gas hydrate dissociates, free gas reaches to the seafloor slowly. Moreover, since the next 100 years, it is expected that temperature will increase by +2 °C on the seafloor of Thessaloniki MV. It was indicated that gas release will be obvious if temperature increment is above 1 °C in this area according to the numerical simulations with HydrateResSim.

A simple apparatus to study the effect of lithology, permeability, and wettability on spontaneous imbibition

The spontaneous imbibition phenomenon is an important process in hydrocarbon recovery. Laboratory study of imbibition is affected by many parameters including, rock characteristics, boundary conditions, length of the sample, variable interfacial tension, and sample heterogeneity. Investigating spontaneous imbibition enhances our understanding of the imbibition mechanism and, hence, helps improve waterflooding used in the oil industry. A simple apparatus has been developed to resemble naturally fractured reservoirs. Using the developed apparatus, the effects of lithology, permeability, and wettability on spontaneous imbibition have been experimentally investigated. Some encountered unexpected technical problems during the experiments are overcome and reported in this paper. Details of the developed apparatus are shown and spontaneous imbibition results are presented. First, the effect of permeability on the oil recovery rate is presented. In addition, obtained curves of oil recovery by water spontaneous imbibition using different lithology are presented. Finally, results of oil recovery from Berea sandstone core sample before and after wettability alteration are shown.

The effects of lithology and base level on topography in the northern alpine foreland

The evolution of topography is driven by climate and tectonics, and strongly influenced by substrate properties and different base levels. The contributions of these factors may vary in space and time and are thus difficult to disentangle. Our study area, the Hausruck-Kobernaußerwald range, has a rather uniform climatic and tectonic history but is drained by rivers with different base levels and consists of contrasting sedimentary rocks, mainly due to different sedimentation environments. This makes them an ideal location to study the effects of lithology and base level on topography.To decipher the roles of these influences, we used a high-resolution digital elevation model and performed a series of morphometric analyses. Longitudinal river profiles indicate that all channels in the study area, independent from base level, bed rock and overall morphological expression, are well graded. Hypsometry shows no evidence for base level effects on the present topography, while variations in the hypsometric curves coincide with lithological differences. This is also reflected in contrasts of mean elevation and slope distributions. Lithology-dependent variations in channel concavity and catchment-wide hypsometric integrals show that lithology controls both channel incision and hillslope processes in the study area. Our results further indicate that variations in channel and catchment metrics are not linked to the prevalence of different rock types alone, but to different successions of lithological units along the channels and within the catchments. Variations in channel slope and geomorphological mapping suggest that lithology-dependent landsliding is the dominant process causing the observed large-scale landscape diversity in the Hausruck-Kobernaußerwald range.