Hasil untuk "Geology"

Qingxue Dong, Siqiong Luo, Zihang Chen et al.

Study region: The Tibetan Plateau (TP), China, contains the world’s largest permafrost area outside the Polar Regions. Study focus: This study investigates the precipitation-induced advective heat flux (EPre), which represents the energy transfer resulting from the temperature difference between rainfall and soil. Observational data from three permafrost monitoring sites (Qumalai, Xidatan, and Tanggula) were combined with simulations from the Community Land Model version 5.0 (CLM5.0) to quantify EPre precipitation infiltration depth, and the probability of infiltration reaching the frozen soil layer. The analysis further examines how precipitation amount, soil texture, soil moisture, and freeze–thaw state jointly control infiltration processes and influence the soil thermal regime. New hydrological insights for the region: Infiltration depth varies with initial soil moisture and precipitation duration, from shallow retention to deep percolation. EPre is generally negative, with maximum cooling of −84.14 W m⁻² at QML, −73.24 W m⁻² at XDT, and −56.63 W m⁻² at TGL, but becomes positive during prolonged summer rainfall, reaching 45.43 W m⁻² at QML. Diurnal soil temperature variations shift EPre from cooling by day to reduced cooling or warming at night. Across the TP, mean infiltration depth is ∼5 cm, higher in southeastern Tibet, with a regional mean EPre of −0.08 W m⁻². Warming effects are concentrated in the southeastern and central TP, while cooling dominates the arid west and high-elevation north.

Maxime Gautier, Matthieu Ferry, Stéphanie Gautier et al.

Abstract Deformed alluvial terraces are ubiquitous markers of a fault’s recent activity and may help assess its slip rate and associated seismic hazard. They are often considered as a nearly flat surface translated and rotated along a planar or listric fault. The present study challenges these assumptions by revealing uneven terrace treads and verticalization of the Topographic Frontal Thrust (TFT) in south-central Bhutan. We model this finding as combined variability in both the aggradation and geometry of the TFT. We estimate a Holocene slip rate of 19.6 ± 4.1 mm.yr−1, which confirms that the TFT accommodates most of the shortening across the range. Contrary to previous studies, we find an excess of slip over the last few centuries, which implies a lower seismic hazard. These results highlight the importance of considering the non-planar component in terrace shape, shallow abrupt changes in fault geometry, and aggradation in future morphotectonic studies worldwide.

J. Yu, J. Yu, J. Yu et al.

<p>Volatile organic sulfur compounds (VSCs), including carbon disulfide (CS<span class="inline-formula">₂)</span>, dimethyl sulfide (DMS), and carbonyl sulfide (COS), were surveyed in the seawater of the Bohai and Yellow seas and the overlying atmosphere during spring and summer of 2018 to understand the production and loss of VSCs and their influence factors. The concentration ranges of COS, DMS, and CS<span class="inline-formula">₂</span> in the surface seawater were 0.14–0.42, 0.41–7.74, and 0.01–0.18 nmol L<span class="inline-formula">⁻¹</span> during spring and 0.32–0.61, 1.31–18.12, and 0.01–0.65 nmol L<span class="inline-formula">⁻¹</span> during summer, respectively. The COS concentrations exhibited positive correlation with dissolved organic carbon (DOC) concentrations in seawater during summer, which verified the photochemical production of COS from chromophoric dissolved organic matter (CDOM). High DMS concentrations occurred near the Yellow River, Laizhou Bay, and Yangtze River estuary, coinciding with high nitrate and chlorophyll (Chl) <span class="inline-formula"><i>a</i></span> concentrations due to river discharge during summer. The COS, DMS, and CS<span class="inline-formula">₂</span> concentrations were the highest in the surface seawater and decreased with the depth. The mixing ratios of COS, DMS, and CS<span class="inline-formula">₂</span> in the atmosphere were 255.9–620.2, 1.3–191.2, and 5.2–698.8 pptv during spring and 394.6–850.1, 10.3–464.3, and 15.3–672.7 pptv in summer, respectively. The ratios of mean oceanic concentrations and atmospheric mixing ratios for summer to spring in COS, DMS, and CS<span class="inline-formula">₂</span> were 1.8, 3.1, 3.7 and 1.6, 4.6, 1.5, respectively. The ratios of the mean sea-to-air fluxes for summer to spring in COS, DMS, and CS<span class="inline-formula">₂</span> were 1.2, 2.1, and 4.3. The sea-to-air fluxes of VSCs indicated that the marginal seas are important sources of VSCs in the atmosphere. The results support a better understanding of the contribution of VSCs in marginal seas.</p>

A.V. Kasatkin, S.Yu. Stepanov, M.V. Tsyganko et al.

The Vorontsovskoe gold deposit (Northern Urals) is unique in both Russia and the world because of the diverse and original Tl–Hg–Mn–As–Sb–S mineralization. Based on the available literature and our data, we present a list of 210 minerals found at this deposit. Eight of them are new minerals discovered by the authors: vorontsovite, ferrovorontsovite, tsygankoite, gladkovskyite, luboržákite, pokhodyashinite, gungerite, and auerbakhite. In addition, 41 minerals are found for the first time in the Russian Federation and 89 minerals are new for the deposit. We defined nine major ore mineral assemblages, including seven ones related to carbonate breccias. They contain more than 70 rare sulfides, tellurides and sulfosalts, including 31, 12, and 9 minerals with Tl, Hg and Mn, respectively, as species-defining elements. The paper also describes these mineral assemblages and minerals of the Vorontsovskoe deposit.

Libo Han

On Jan. 8, 2022, a strong earthquake with surface magnitude up to MS6.9 occurred in Menyuan region, Qinghai Province. To understand its tectonic implication, focal mechanism and centroid depth of the major event are inverted by CAP method. The inversion results show that the event is dominated by a strike-slip focal mechanism with a very shallow centroid depth (3 km). Combining with the spatial orientations of relocated aftershocks, we confirm the rupture plane 284°/82°/21° (strike/dip/rake). The focal mechanism is different with those events including the 1986 and 2016 M6.4 Menyuan earthquakes, implying the complex crustal deformation in this region. The results provide fundamental information for seismic hazard in this region.

I.V. Filimonova, V.D. Kozhevin, V.Y. Nemov et al.

The article deals with the fundamental and conjuncture factors of the oil market equilibrium. The purpose of the study is to identify new economic indicators that affect the global pricing model in the oil market, and determine the effectiveness of the existing cartel agreement. The structure of net energy consumption, as well as features of demand for energy resources by regions of the world, is presented in the article. The study provides a comprehensive statistical analysis of the dynamics of changes in oil prices and production indicators of the largest oil producing countries in the world. The analysis highlights the factors of the oil market stabilization from the demand and supply side: production, technological and price factors. Relative indicators, such as the level of technology development and drilling efficiency in the respective segments, were found to have the greatest impact on the stability of energy prices, and long-term price stabilization is possible only if the US oil industry participates in OPEC+ agreement.

C. Grigné, M. Combes

Abstract Geochemical constraints on mantle temperature indicate a regular decrease by around 250 K since 3 Ga. However, models of Earth's cooling that rely on scaling laws for thermal convection without strong plates are facing a thermal runaway backwards in time, due to the power‐law dependence of heat loss on temperature. To explore the effect of surface dynamics on Earth's cooling rate, we build a two‐dimensional temperature‐dependent model of plate tectonics that relies on a force balance for each plate and on Earth‐like parameterized behaviors for the motion, creation, and disappearance of plate boundaries. While our model predicts the expected thermal runaway if plate boundaries are fixed, we obtain an average cooling rate consistent with geochemical estimates if the geometry of plate tectonics evolves through time. For a warmer mantle in the past, plates are faster but also larger (and less numerous) so that the average seafloor age and resulting heat flux always remain moderate. The predicted decrease in the number of plates backwards in time is in good agreement with recent plate reconstructions over the last 400 Myr. Our model also gives plate speed and subduction area flux consistent with these reconstructions. We finally compare the effect of parameters controlling mantle viscosity and individual plate speeds to the effect of localized surface processes, such as oceanization and subduction initiation. We infer that studies of Earth's thermal history should focus on surface processes as they appear to be key control parameters.

S. Ali, S. Ali, P. Biermanns et al.

<p>The Karakoram Highway (KKH) is an important route, which connects northern Pakistan with Western China. Presence of steep slopes, active faults and seismic zones, sheared rock mass, and torrential rainfall make the study area a unique geohazards laboratory. Since its construction, landslides constitute an appreciable threat, having blocked the KKH several times. Therefore, landslide susceptibility mapping was carried out in this study to support highway authorities in maintaining smooth and hazard-free travelling. Geological and geomorphological data were collected and processed using a geographic information system (GIS) environment. Different conditioning and triggering factors for landslide occurrences were considered for preparation of the susceptibility map. These factors include lithology, seismicity, rainfall intensity, faults, elevation, slope angle, aspect, curvature, land cover and hydrology. According to spatial and statistical analyses, active faults, seismicity and slope angle mainly control the spatial distribution of landslides. Each controlling parameter was assigned a numerical weight by utilizing the analytic hierarchy process (AHP) method. Additionally, the weighted overlay method (WOL) was employed to determine landslide susceptibility indices. As a result, the landslide susceptibility map was produced. In the map, the KKH was subdivided into four different susceptibility zones. Some sections of the highway fall into high to very high susceptibility zones. According to results, active faults, slope gradient, seismicity and lithology have a strong influence on landslide events. Credibility of the map was validated by landslide density analysis (LDA) and receiver operator characteristics (ROC), yielding a predictive accuracy of 72&thinsp;%, which is rated as satisfactory by previous researchers.</p>

B. Rastogi, M. Berkelhammer, S. Wharton et al.

<p>Carbonyl sulfide (OCS) has recently emerged as a tracer for terrestrial carbon uptake. While physiological studies relating OCS fluxes to leaf stomatal dynamics have been established at leaf and branch scales and incorporated into global carbon cycle models, the quantity of data from ecosystem-scale field studies remains limited. In this study, we employ established theoretical relationships to infer ecosystem-scale plant OCS uptake from mixing ratio measurements. OCS fluxes showed a pronounced diurnal cycle, with maximum uptake at midday. OCS uptake was found to scale with independent measurements of <span class="inline-formula">CO₂</span> fluxes over a 60&thinsp;m tall old-growth forest in the Pacific Northwest of the US (45<span class="inline-formula">^∘</span>49<span class="inline-formula">^′</span>13.76<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><msup><mi/><mrow><mo>′</mo><mo>′</mo></mrow></msup></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="6pt" class="svg-formula" dspmath="mathimg" md5hash="72877009115e133fe632a10b0040889b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-15-7127-2018-ie00001.svg" width="8pt" height="6pt" src="bg-15-7127-2018-ie00001.png"/></svg:svg></span></span>&thinsp;N, 121<span class="inline-formula">^∘</span>57<span class="inline-formula">^′</span>06.88<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><msup><mi/><mrow><mo>′</mo><mo>′</mo></mrow></msup></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="6pt" class="svg-formula" dspmath="mathimg" md5hash="9162d003e0ed94af8b7d2b4a38708019"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-15-7127-2018-ie00002.svg" width="8pt" height="6pt" src="bg-15-7127-2018-ie00002.png"/></svg:svg></span></span>&thinsp;W) at daily and monthly timescales under mid–high light conditions across the growing season in 2015. OCS fluxes were strongly influenced by the fraction of downwelling diffuse light. Finally, we examine the effect of sequential heat waves on fluxes of OCS, <span class="inline-formula">CO₂</span>, and <span class="inline-formula">H₂O</span>. Our results bolster previous evidence that ecosystem OCS uptake is strongly related to stomatal dynamics, and measuring this gas improves constraints on estimating photosynthetic rates at the ecosystem scale.</p>

Seyedfoad Aghamiri, Mohsen Tamtaji, Mohammad Javad Ghafoori

This paper proposed a new empirical K-value equation is developed to calculate dew pressure for gas condensate reservoirs. This equation is applicable in the wide ranges of composition, temperature, and pressure by considering the effect of composition via two equations for normal boiling point and critical temperature of the mixture. The range of dew pressure, temperature, heptane plus mole fraction, methane mole fraction, N2 mole fraction, CO2 mole fraction, and H2S mole fraction are fallen into 2666.7–9655 Psia, 40–350.87 °F, 0.0021–0.213, 0.3344–0.9668, 0–0.4322, 0–0.0864, and 0–0.942 respectively. As an important point, the proposed equation has any adjustable parameters, in addition, this equation indicates that in order to predict of dew pressure of gas condensate reservoirs, trial and error was not needed and therefore, computational speed increases beyond the accuracy. Moreover, the accuracy is validated by comparing against the experimental data of 81 gas condensate reservoirs samples from published literature and the results of Wilson, Whitson, and Ghafoori equations. Compared to the experimental data, the absolute average deviations of dew pressure calculations for the proposed equation, Wilson, Whitson, and Ghafoori were 7.6%, 97.6%, 99.4%, and 94.9% respectively. Keywords: Dew point pressure, Gas condensate reservoirs, K-value, Wilson

Bertha Oliva Aguilar-Reyes, Mikhail Ostrooumov, Emmanuel Fritsch

Este trabajo presenta los resultados del primer estudio mineralógico del fenómeno de desestabilización por blanqueamiento en ópalos mexicanos de origen volcánico. En los espectros Raman de las muestras de ópalo estudiadas se observan bandas características de grupos moleculares de H2O en dos regiones diferentes: alrededor de 3,200 cm-1 para la parte no afectada por la desestabilización (de color naranja) y alrededor de 2,900 cm-1 para la parte desestabilizada (de color blanco). La forma e intensidad de las bandas presentes a 960 cm-1 (grupos Si–OH) y 1,600 cm-1 (grupos moleculares de H2O) constatan esta modificación debida al agua. El análisis térmico diferencial (ATD/ATG) mostró que el contenido total de agua es de 6 a 85% menor en la parte desestabilizada que en la parte naranja inalterada; el agua presente en la parte de color blanco es también más móvil, ya que su eliminación comienza por debajo de los 100 °C. Asimismo, mediante la medición de la superficie específica (método BET) se pudo constatar que, sistemáticamente, la superficie específica es entre 2 y 30 veces más grande para la parte desestabilizada. La microscopia electrónica de barrido (MEB) ha permitido verificar diferencias microestructurales entre las dos partes del ópalo, observándose que en la parte desestabilizada ocurre una descompactación del material. Los resultados obtenidos muestran que la causa de la desestabilización está relacionada con una transformación estructural que involucra la formación de cristobalita de recristalización y la incorporación de grupos H2O moleculares a la estructura de los ópalos volcánicos.  

Canérot Joseph

Contrary to recent conceptual models, we evidence that the Mauléon Basin does not only result from the Pyrenean tectonic inversion of an aborted Albian rift involving a N-S extreme crust thinning, with related detachment and mantle exhumation. It actually corresponds to an element of this rift system where E-W dominant regional sinistral strike slip faulting between its European and Iberian margins generated as early as the Latest Aptian (Clansayesian) an oblique pull apart-type basin: the Tardets-Sorholus Trough. Then, towards the Late to Latest Albian period, the active transverse, SW-NE oriented, Barlanès and Saison listric faults provided the main crustal thinning leading locally (Urdach) to mantle exhumation. Finally, at the beginning of the Late Cretaceous, the trough widened through transtension motion (N-S distension associated with E-W sinistral strike slip) leading to the creation of the Mauléon Basin. This geodynamic evolution gives to the Mauléon Basin its logical place between the western Bilbao Basin where oceanic crust developed through dominant N-S extension process and the central and eastern north Pyrenean basins where dominant E-W left lateral strike slip then transpressive motion preclude mantle denudation. From the Late to Latest Cretaceous, the inverted motion turning to generalized regional transpression led to the closure of the trough, then, by gradual uplift from east to west, to the formation of the Pyrenean range.

Pazik Paulina M., Chmielewski Tomasz, Glass Hylke J. et al.

Cobalt is recognized as a strategic metal and also E-tech element, which is crucial for worlds development. An increasing demand for cobalt forces for searching of new resources that could be explored in European countries. There are many examples of cobalt recoveries, mostly from laterite and sulphide deposits. However, the accurate choice of the technology depends on many factors. The Kupferschiefer stratiform copper ore located in Poland is the biggest deposit of cobalt in Europe. Although KGHM Polska Miedz S.A. recovers many precious metals from this ore, cobalt is not recovered yet. This metal occurs as an accompanying element, mostly in the form of cobaltite (CaAsS), with the average content of 50–80 g/Mg. In this paper a possible recovery of cobalt from the Kupferschiefer ore, with the use of hydrometallurgical methods, was investigated.

W. J. Arkell

K. Emery, E. Uchupi

Poulsen, N., Bocin-Dumitriu, A., Holloway, S. et al.

J. Douglas, J. A. Ferguson

R. Douglas

Elisa Falasco, Luc Ector, Marco Isaia et al.

In scarcity of light and primary producers, subterranean ecosystems are generally extremely oligotrophic habitats, receiving poor supplies of degradable organic matter from the surface. Human direct impacts on cave ecosystems mainly derive from intensive tourism and recreational caving, causing important alterations to the whole subterranean environment. In particular, artificial lighting systems in show caves support the growth of autotrophic organisms (the so-called lampenflora), mainly composed of cyanobacteria, diatoms, chlorophytes, mosses and ferns producing exocellular polymeric substances (EPSs) made of polysaccharides, proteins, lipids and nucleic acids. This anionic EPSs matrix mediates to the intercellular communications and participates to the chemical exchanges with the substratum, inducing the adsorption of cations and dissolved organic molecules from the cave formations (speleothems). Coupled with the metabolic activities of heterotrophic microorganisms colonising such layer (biofilm), this phenomenon may lead to the corrosion of the mineral surfaces. In this review, we investigate the formation of biofilms, especially of diatom-dominated ones, as a consequence of artificial lighting and its impacts on speleothems. Whenever light reaches the subterranean habitat (both artificially and naturally) a relative high number of species of diatoms may indeed colonise it. Cave entrances, artificially illuminated walls and speleothems inside the cave are generally the preferred substrates. This review focuses on the diatom flora colonising subterranean habitats, summarizing the information contained in all the scientific papers published from 1900 up to date. In this review we provide a complete checklist of the diatom taxa recorded in subterranean habitats, including a total of 363 taxa, belonging to 82 genera. The most frequent and abundant species recorded in caves and other low light subterranean habitats are generally aerophilic and cosmopolitan. These are, in order of frequency: Hantzschia amphioxys, Diadesmis contenta, Orthoseira roeseana, Luticola nivalis, Pinnularia borealis, Diadesmis biceps and Luticola mutica. Due to the peculiarity of the subterranean habitats, the record of rare or new species is relatively common. The most important environmental factors driving species composition and morphological modifications observed in subterranean populations are analysed throughout the text and tables. In addition, suggestions to prevent and remove the corrosive biofilms in view of an environmentally sustainable cave management are discussed.

S. Chough