Search

Carbon is among the most abundant substances in the universe; although severely depleted on Earth, it is the primary structural element in biochemistry. Complex interactions between carbon and climate have stabilized the Earth system over geologic time. Since the modern instrumental CO2 record began in the 1950s, about half of fossil fuel emissions have been sequestered in the oceans and land ecosystems. Ocean uptake of fossil CO2 is governed by chemistry and circulation. Net land uptake is surprising because it implies a persistent worldwide excess of growth over decay. Land carbon sinks include ( a) CO2 fertilization, ( b) nitrogen fertilization, ( c) forest regrowth following agricultural abandonment, and ( d) boreal warming. Carbon sinks in both land and oceans are threatened by warming and are likely to weaken or even reverse as emissions fall with the potential for amplification of climate change due to the release of previously stored carbon. Fossil CO2 will persist for centuries and perhaps many millennia after emissions cease. ▪ About half the carbon from fossil fuel combustion is removed from the atmosphere by sink processes in the land and oceans, slowing the increase of CO2 and global warming. These sinks may weaken or even reverse as climate warms and emissions fall. ▪ The net land sink for CO2 requires that plants have been growing faster than they decay for many decades, causing carbon to build up in the biosphere over and above the carbon lost to deforestation, fire, and other disturbances. ▪ CO2 uptake by the oceans is slow because only the surface water is in chemical contact with the air. Cold water at depth is physically isolated by its density. Deep water mixes with the surface in about 1,000 years. The deep water does not know we are here yet! ▪ After fossil fuel emissions cease, much of the extra CO2 will remain in the atmosphere for many centuries or even millennia. The lifetime of excess CO2 depends on total historical emissions; 10% to 40% could last until the year 40,000 AD.

Natural gas is considered a bridging technology in the energy transition because it produces fewer carbon emissions than coal, for example. However, when leaks exist, methane is released into the atmosphere, leading to a dramatic increase in the carbon footprint of natural gas, as methane is a much stronger greenhouse gas than carbon dioxide. Therefore, we conducted a detailed study of methane emissions from gas-powered end-use appliances and then compared their climate impacts with those of electricity-powered appliances. We used the Munich Oktoberfest as a case study and then extended the study to 25 major natural gas consuming countries. This showed that electricity has been the more climate-friendly energy source at Oktoberfest since 2005, due to the extensive use of renewable electricity at the festival and the presence of methane emissions, particularly caused by the incomplete combustion of natural gas in cooking and heating appliances. By contrast, at the global level, our study shows that natural gas still produces lower end-use carbon emissions than electricity in 18 of the 25 countries studied. However, as the share of renewable energy in the electricity mix steadily increases in most countries, the carbon footprint of electricity will be lower than that of natural gas in these countries in the near future. These findings from our comparison of the total carbon emissions of electric and gas-powered end-use appliances can help inform the debate on how to effectively address climate change., Earth's Future, 11 (2), ISSN:2328-4277

The Sulawesi earthquake with a moment magnitude of Mw 7.5 struck the Central Sulawesi region of the Sulawesi Island, Indonesia, on September 28, 2018. The epicenter of the earthquake was located in the mountainous region of Donggala Regency, in the neck of the Minahasa Peninsula in the Central Sulawesi Province of Indonesia. Although the epicenter was located in Donggala Regency, the greatest devastating effects were observed about 70 km south of the epicenter in the Palu Valley. The event was the first of its kind to cause large-scale flowslides simultaneously at four key locations such as Balaroa, Petobo, Jono Oge, and Sibalaya with extensive ground displacements ranging from several hundred meters to more than 1 km. This article reviews the field observations of geotechnical failures and infrastructure damage caused by liquefaction resulting from the shallow strike-slip earthquake at Palu City, Donggala Regency, and Sigi Regency. A geo-spatial analysis was performed on data collected from aerial drone imagery, along with portable dynamic cone penetration testing (PDCPT) in the field. The investigation revealed a highly stratified ground with alternating soil layers of varying permeability and very low bearing resistance at shallow depths. The investigation also helped in assessing the extent of damage caused by geotechnical failure to the residential infrastructures, irrigation structures, and roads. Graphical Abstract

We developed a snowdrift model to evaluate the snowdrift height around snow fences, which are often installed along roads in snowy, windy locations. The model consisted of the conventional computational fluid dynamics solver that used the lattice Boltzmann method and a module for calculating the snow particles’ motion and accumulation. The calculation domain was a half channel with a flat free-slip boundary on the top and a non-slip boundary on the bottom, and an inflow with artificially generated turbulence from one side to the outlet side was imposed. In addition to the reference experiment with no fence, experiments were set up with a two-dimensional and a three-dimensional fence normal to the dominant wind direction in the channel center. The estimated wind flow over the two-dimensional fence was characterized by a swirling eddy in the cross section, whereas the wind flow in the three-dimensional fence experiment was horizontally diffluent with a dipole vortex pair on the leeward side of the fence. Almost all the snowdrift formed on the windward side of the two-dimensional and three-dimensional fences, although the snowdrift also formed along the split streaks on the leeward side of the three-dimensional fence. Our results suggested that the fence should be as long as possible to avoid snowdrifts on roads.

We investigated the number of references per page for different European Geosciences Union journals, which share the same text formatting. Although the journals formally all focus on geoscience, different disciplines are covered, from ocean science and biogeosciences to the technical description of numerical model development. In this study, we show that the number of references per page is remarkably constant across these journals. In addition, this value has remained constant in the last decade, despite the consistent increase in the number of pages and in the number of references in almost all journals considered. Independently of the quality of the references used in an article, we show that for the EGU (European Geosciences Union) journals the average number of references per page is 3.82 (1.87–6.18 at 90 % confidence level). This reveals that there is a consensus regarding optimum reference density, which depends on the journal's layout and not on the journal's discipline.

Communities in the Pamir Mountains of Central Asia are among the most vulnerable to climate change due to their geographic location and subsistence-based livelihoods. Historically, ecological calendars supported their agropastoral lifestyles which provided anticipatory capacity to seasonal changes. Due to decades of Soviet colonization and socioecological transformations, knowledge of these ecological calendars fell into disuse. In 2016, Savnob and Roshorv, two villages in the Bartang Valley of Tajikistan, began the revitalization of these calendars using a participatory action research process through knowledge co-generation. We undertook a comparative analysis to investigate the importance of context-specificity to ensure food security and reduce their vulnerability to climate change. A preliminary analysis of the temperature regime and local language terms, relating to the positioning and quality of land, framed our methods-of-analysis. We compared the villagers' ecological calendars by focusing on indicator species, potentially threatening weather events, land-use, livelihood activities, and the role of the vernal equinox. Despite their close geographic proximity, context-specificity determined by distinct microecologies influences the timing and practice of these communities' livelihood activities. These villages have different dependencies on biotic and abiotic events, crops, and land-use; all of which affect food security and survival. These differences contributed to mutual support between the two villages, increased the availability of food, and thereby, lowered their vulnerability to climate change. As Savnob's and Roshorv's ecological calendars are updated with changing climate, they can once again enhance their anticipatory capacity while reducing their vulnerability.

Burial driven recycling is an important process in the natural gas hydrate (GH) systems worldwide, characterized by complex multiphysics interactions like gas migration through an evolving gas hydrate stability zone (GHSZ), competing gas-water-hydrate (i.e., fluid-fluid-solid) phase transitions, locally appearing and disappearing phases, and evolving sediment properties (e.g., permeability, reaction surface area, and capillary entry pressure). Such a recycling process is typically studied in homogeneous or layered sediments. However, there is mounting evidence that structural heterogeneity and anisotropy linked to normal and inclined fault systems or anomalous sediment layers have a strong impact on the GH dynamics. Here, we consider the impacts of such a structurally complex media on the recycling process. To capture the properties of the anomalous layers accurately, we introduce a fully mass conservative, high-order, discontinuous Galerkin (DG) finite element based numerical scheme. Moreover, to handle the rapidly switching thermodynamic phase states robustly, we cast the problem of phase transitions as a set of variational inequalities, and combine our DG discretization scheme with a semi-smooth Newton solver. Here, we present our new simulator, and demonstrate using synthetic geological scenarios, (a) how the presence of an anomalous high-permeability layer, like a fracture or brecciated sediment, can alter the recycling process through flow-localization, and more importantly, (b) how an incorrect or incomplete approximation of the properties of such a layer can lead to large errors in the overall prediction of the recycling process. Key Points Structural heterogeneity linked to inclined fault systems or anomalous sediment layers have a strong impact on the gas hydrate dynamics The presence of anomalous high-permeability layers within gas hydrate stability zone alters the recycling process through flow-localization The presented discontinuous Galerkin scheme is able to accurately capture the gas hydrate recycling processes through strongly anisotropic materials

Management of hydropower plants strongly influences streamflow dynamics and hence the interaction between surface water and groundwater. As dam operations cause variations in river stages, these can result in changes in the groundwater level at multiple temporal scales. In this work, we study the case of an Alpine aquifer, where weekly fluctuations are particularly pronounced. We consider an area with four river reaches differently impacted by reservoir operations and investigate the influence of these rivers on the common aquifer. Using continuous wavelet transform and wavelet coherence analysis, we show that weekly fluctuations in the groundwater table are particularly pronounced in dry years, in particular in the winter season, although the area of the aquifer impacted by dam operations remains almost unchanged. We thus observe that in Alpine catchments, surface water‐groundwater interaction is sensitive to the conditions determined by a specific hydrological year. We also investigate the influences of the river‐aquifer water fluxes and show that under dry conditions hydropeaking mainly affects their temporal dynamics. Our observations have significant consequences for predicting nutrient and temperature dynamics/regimes in river‐aquifer systems impacted by hydropower plant management., Plain Language Summary: The operation of hydropower plants affects the water level in the downstream part of the river, which in turn can alter the groundwater level. In this work, we study an Alpine aquifer crossed by rivers differently impacted by hydropower production. We use statistical tools to analyze the interaction between the rivers and the groundwater, and observe that this interaction is sensitive to the conditions of the hydrological year, such as dry periods., Key Points: Wavelet power spectrum and coherence analysis is used to study river‐aquifer interactions under dam operations in an Alpine catchment. The impact of reservoir operations on the aquifer is strongest under low flow conditions but the area impacted shows little variation. Under low flow conditions, dam operations considerably influence the frequency of the water exchange between rivers and aquifer., Consejo Nacional de Ciencia y Tecnología http://dx.doi.org/10.13039/501100003141, Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Consejo Veracruzano de Investigación Científica y Desarrollo Tecnológico, https://doi.org/10.17632/97jchhz4s8.2

Seismic and rock physics play important roles in gas hydrate exploration and production. To provide a clear cognition of the applications of geophysical methods on gas hydrate, this work presents a review of the seismic techniques, rock physics models, and production methods in gas hydrate exploration and exploitation. We first summarize the commonly used seismic techniques in identifying the gas hydrate formations and analyze the limitations and challenges of these techniques. Then, we outline the rock physics models linking the micro-scale physical properties and macro-scale seismic velocities of gas hydrate sediments, and generalize the common workflow, showing the frequently-used procedures of building models with detailed analysis of the potential uncertainties. Afterwards, we summarize the production techniques of gas hydrate and point out the problems regarding the petrophysical basis and abnormal seismic responses. In the end, considering the geological and engineering problems, we come up with several aspects of using geophysical techniques to solve the problems in gas hydrate exploration and production, hopefully to provide some important clues for future studies of gas hydrate.

Fe is a common substituent in palygorskites (Plg), but its effect on the microscopic properties is unclear. In the current study, molecular dynamics (MD) simulations were carried out to investigate the effect of Fe on the properties of the nano-pores in Plg. The structures and dynamics of water and Na+ ions in the pores were computed by analyzing the MD trajectories. The results revealed that for both Fe-containing and ordinary Plg, zeolitic water molecules can diffuse into the pores with very low mobility whereas Mg-coordinated water fails to escape. Na+ ions show no obvious diffusivity because they are fixed above the Si–Osix-membered rings. Detailed comparison indicates that Fe-substitution has no significant influence on the pore properties of Plg.

Forests mitigate climate change by storing carbon and reducing emissions via substitution effects of wood products. Additionally, they provide many other important ecosystem services (ESs), but are vulnerable to climate change; therefore, adaptation is necessary. Climate‐smart forestry combines mitigation with adaptation, whilst facilitating the provision of many ESs. This is particularly challenging due to large uncertainties about future climate. Here, we combined ecosystem modeling with robust multi‐criteria optimization to assess how the provision of various ESs (climate change mitigation, timber provision, local cooling, water availability, and biodiversity habitat) can be guaranteed under a broad range of climate futures across Europe. Our optimized portfolios contain 29% unmanaged forests, and implicate a successive conversion of 34% of coniferous to broad‐leaved forests (11% vice versa). Coppices practically vanish from Southern Europe, mainly due to their high water requirement. We find the high shares of unmanaged forests necessary to keep European forests a carbon sink while broad‐leaved and unmanaged forests contribute to local cooling through biogeophysical effects. Unmanaged forests also pose the largest benefit for biodiversity habitat. However, the increased shares of unmanaged and broad‐leaved forests lead to reductions in harvests. This raises the question of how to meet increasing wood demands without transferring ecological impacts elsewhere or enhancing the dependence on more carbon‐intensive industries. Furthermore, the mitigation potential of forests depends on assumptions about the decarbonization of other industries and is consequently crucially dependent on the emission scenario. Our findings highlight that trade‐offs must be assessed when developing concrete strategies for climate‐smart forestry., Plain Language Summary: Forests help mitigate climate change by storing carbon and via avoided emissions when wood products replace more carbon‐intensive materials. At the same time, forests provide many other “ecosystem services (ESs)” to society. For example, they provide timber, habitat for various species, and they cool their surrounding regions. They are, however, also vulnerable to ongoing climate change. Forest management must consider all these aspects, which is particularly challenging considering the uncertainty about future climate. Here, we propose how this may be tackled by computing optimized forest management portfolios for Europe for a broad range of future climate pathways. Our results show that changes to forest composition are necessary. In particular, increased shares of unmanaged and broad‐leaved forests are beneficial for numerous ESs. However, these increased shares also lead to decreases in harvest rates, posing a conflict between wood supply and demand. We further show that the mitigation potential of forests strongly depends on how carbon‐intensive the replaced materials are. Consequently, should these materials become “greener” due to new technologies, the importance of wood products in terms of climate change mitigation decreases. Our study highlights that we cannot optimize every aspect, but that trade‐offs between ESs need to be made., Key Points: Strategies for climate‐smart forestry under a range of climate scenarios always lead to trade‐offs between different ecosystem services (ESs). Higher shares of unmanaged and broad‐leaved forests are beneficial for numerous ESs, but lead to decreased timber provision. The mitigation potential of forests strongly relies on substitution effects which depend on the carbon‐intensity of the alternative products., European Forest Institute (EFI) Networking Fund http://dx.doi.org/10.13039/501100013942, Bayerisches Staatsministerium für Wissenschaft und Kunst, Bayerisches Netzwerk für Klimaforschung (BayKliF) http://dx.doi.org/10.13039/501100004563, Swedish Research Council Formas, German Federal Office for Agriculture and Food (BLE), https://doi.org/10.5281/zenodo.6667489, https://doi.org/10.5281/zenodo.6612953

Detailed imaging of accretionary wedges reveals splay fault networks that could pose a significant tsunami hazard. However, the dynamics of multiple splay fault activation during megathrust earthquakes and the consequent effects on tsunami generation are not well understood. We use a 2‐D dynamic rupture model with complex topo‐bathymetry and six curved splay fault geometries constrained from realistic tectonic loading modeled by a geodynamic seismic cycle model with consistent initial stress and strength conditions. We find that all splay faults rupture coseismically. While the largest splay fault slips due to a complex rupture branching process from the megathrust, all other splay faults are activated either top down or bottom up by dynamic stress transfer induced by trapped seismic waves. We ascribe these differences to local non‐optimal fault orientations and variable along‐dip strength excess. Generally, rupture on splay faults is facilitated by their favorable stress orientations and low strength excess as a result of high pore‐fluid pressures. The ensuing tsunami modeled with non‐linear 1‐D shallow water equations consists of one high‐amplitude crest related to rupture on the longest splay fault and a second broader wave packet resulting from slip on the other faults. This results in two episodes of flooding and a larger run‐up distance than the single long‐wavelength (300 km) tsunami sourced by the megathrust‐only rupture. Since splay fault activation is determined by both variable stress and strength conditions and dynamic activation, considering both tectonic and earthquake processes is relevant for understanding tsunamigenesis., Plain Language Summary: In subduction zones, where one tectonic plate moves beneath another, earthquakes can occur on many different faults. Splay faults are relatively steep faults that branch off the largest fault (the megathrust) in a subduction zone. As they are steeper than the megathrust, the same amount of movement on them could result in more vertical displacement of the seafloor. Therefore, splay faults are thought to play an important role in the generation of tsunamis. Here, we use computer simulations to study if an earthquake can break multiple splay faults at once and how this affects the resulting tsunami. We find that multiple splay faults can indeed fail during a single earthquake due to the stress changes from trapped seismic waves, which promote rupture on splay faults. Rupture on splay faults results in larger seafloor displacements with smaller wavelengths, so the ensuing tsunami is bigger and results in two main flooding episodes at the coast. Our results show that it is important to consider rupture on splay faults when assessing tsunami hazard., Key Points: Multiple splay faults can be activated during a single earthquake by megathrust slip and dynamic stress transfer due to trapped waves. Splay fault activation is facilitated by their favorable orientation with respect to the local stress field and their closeness to failure. Long‐term geodynamic stresses and fault geometries affect dynamic splay fault rupture and the subsequent tsunami., Volkswagen Foundation (VolkswagenStiftung) http://dx.doi.org/10.13039/501100001663, Royal Society (The Royal Society) http://dx.doi.org/10.13039/501100000288, EC | H2020 | H2020 Priority Excellent Science | H2020 European Research Council (ERC) http://dx.doi.org/10.13039/100010663, Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659, National Science Foundation (NSF) http://dx.doi.org/10.13039/100000001, https://github.com/TUM-I5/SWE, https://doi.org/10.5281/zenodo.6969455

In this article, we review the current knowledge of the glacial recession and related glacial lake development in the Andes of South America. Since the mid-1980s, hundreds of glacial lakes either expanded or formed, and predictions show that additional hundreds of lakes will form throughout the 21st century. However, studies on glacial lakes in the Andes are still relatively rare. Many glacial lakes pose a potential hazard to local communities, but glacial lake outburst floods (GLOFs) are understudied. We provide an overview on hazards from glacial lakes such as GLOFs and water pollution, and their monitoring approaches. In real-time monitoring, the use of unmanned aerial systems (UASs) and early warning systems (EWSs) is still extremely rare in the Andes, but increasingly authorities plan to install mitigation systems to reduce glacial lake risk and protect local communities. In support, we propose an international remote sensing-based observation initiative following the model of, for example, the Global Land Ice Measurements from Space (GLIMS) one, with the headquarters in one of the Andean nations.

The present study of Anisian (Middle Triassic) conodonts from the Kocaeli Peninsula (western Turkey) encompasses over 10 species of the families Gondolellidae and Gladigondolellidae, providing Early and Middle Triassic time constraints, Chiosella timorensis (Nogami, 1968); Cornudina oezdemirae Gedik, 1975; Gladigondolella tethydis (Huckriede, 1958); Neostrachanognathus tahoensis Koike, 1998; Paragondolella aegaea (Bender, 1970); Paragondolella bulgarica Budurov and Stefanov, 1975; Nicoraella kockeli (Tatge, 1956); P. hanbulogi (Sudar and Budurov, 1979), and Gladigondolella sp. A. Newly established are Paragondolella hirschii n. sp. Kilic and Budurov; P. praecornuta n. sp. Kilic, Budurov, Petrunova and Mir0103uţ0103; and P. ebruae n. sp. Kilic. The Kocaeli Anisian conodonts show a faunal affinity with Bulgaria. The present Anisian fauna is characteristic of the Tethys. The strong homeomorphy that characterizes the Anisian in western North America is discussed.

Archaeobotanical analyses together with historical records can provide unique information about the cargoes and histories of sunken ships, which are found as wrecks at the bottom of the seas all over the world. An interdisciplinary research project was undertaken on the Vrouw Maria (Lady Mary), a Dutch wooden two-masted merchant ship that sank on October 9th in 1771 in the Finnish Baltic Sea. She rested at a depth of 41 m and was in good condition when discovered. Based on written sources and archaeological research, the ship was carrying a valuable cargo including, for example, sugar, dyes, cloth, porcelain, wood and goods that the Russian nobility had ordered. Among them were paintings that the Russian Empress Catherine the Great (1729–1796) had bought at an auction in Amsterdam. Samples from four wooden barrels and from one wooden packing crate among the ship’s cargo were investigated. Botanical analysis revealed products such as stimulants, dyes and fruits originating from the Mediterranean, India, Africa and South America. One of the most intriguing finds from the cargo was Indigofera tinctoria L. (true indigo), a valuable dye plant. Our paper presents the botanical data analysed from the barrels and summarizes the plants mentioned in the historical records on the cargo of the Vrouw Maria.

This paper presents the first archaeobotanical results on plant macroremains other than charcoal from the Early and Middle Epipalaeolithic site of Kharaneh IV in the Azraq basin, one of the largest Epipalaeolithic sites in the southern Levant and one of the few with evidence for multiple phases of occupation. The analysis of the substantial archaeobotanical assemblage from the site provides new insights into the local environmental conditions and how these changed throughout occupation, potentially affecting the use of the site, and it further contributes to debates about hunter-gatherer lifeways during the earlier Epipalaeolithic. A variety of potential food plant resources was identified, including several starch-rich seeds and tissues, fruits and various other wild seeds and grains. Comparison of the Kharaneh IV archaeobotanical assemblage with those from other Epipalaeolithic sites in the southern Levant reveals a number of similarities and differences. These comparisons, and especially with the contemporary nearby site of Wadi Jilat 6, support the emerging picture of an ecological mosaic within the Epipalaeolithic Azraq basin, and a general pattern of local resource use across the wider region.

Almost all aspects of conodont research rely on a sound taxonomy based on comparative analysis. This is founded on hypotheses of homology which ultimately rest on knowledge of the location of elements in the apparatus. Natural assemblages—fossils that preserve the articulated remains of the conodont skeletal apparatus—provide our only direct evidence for element location, but very few are known from the Late Triassic. Here we describe fused clusters (natural assemblages) from the late Norian limestone beds of the Nanshuba Formation in Baoshan, Yunnan Province, southwestern China. Recurrent arrangements and juxtaposition of S and M elements in multiple clusters reveal the composition of the apparatus of Mockina and, probably, Parvigondolella. They indicate that these taxa had a standard 15 elements ozarkodinid apparatus, and provide new insights into the morphology of the elements occupying the P2, M and S locations of the apparatus. The apparatus comprised a single alate (hibbardelliform) S0 element, paired breviform digyrate (grodelliform) S1 and (enantiognathiform) S2 elements, paired bipennate (hindeodelliform) S3 and S4 elements, paired breviform digyrate (cypridodellifrom) M elements, paired, modified-angulate P2 elements (with reduced or lacking ‘posterior’ process) and segminiplanate (mockiniform and parvigondolelliform) P1 elements. Our results will allow testing of the hypothesis that Mockina, Parvigondolella and Misikella—critical taxa in Late Triassic biostratigraphy—are closely related and possessed morphologically similar elements in homologous locations.

Past sea-level change represents the large-scale state of global climate, reflecting the waxing and waning of global ice sheets and the corresponding effect on ocean volume. Recent developments in sampling and analytical methods enable us to more precisely reconstruct past sea-level changes using geological indicators dated by radiometric methods. However, ice-volume changes alone cannot wholly account for these observations of local, relative sea-level change because of various geophysical factors including glacio-hydro-isostatic adjustments (GIA). The mechanisms behind GIA cannot be ignored when reconstructing global ice volume, yet they remain poorly understood within the general sea-level community. In this paper, various geophysical factors affecting sea-level observations are discussed and the details and impacts of these processes on estimates of past ice volumes are introduced.

The purpose of this contribution is to highlight four topics of regional and worldwide mineral resource prediction: (1) use of the jackknife for bias elimination in regional mineral potential assessments; (2) estimating total amounts of metal from mineral potential maps; (3) fractal/multifractal modeling of mineral deposit density data in permissive areas; and (4) worldwide and large-areas metal size-frequency distribution modeling. The techniques described in this paper remain tentative because they have not been widely researched and applied in mineral potential studies. Although most of the content of this paper has previously been published, several perspectives for further research are suggested.

The idea of mineral exploration, which is called "exploration philosophy" in the Western countries, is the thoughts, the methodology, technology, goals and organization that guide mineral exploration. The three basic elements of mineral exploration are "what to find", "where to find" and "how to find". The concept of mineral exploration is gradually changing with the development of these three elements that provide a powerful driving force to change mineral exploration concepts, methods and technology. Innovation of mineral exploration concepts is the result of continuing exploration and development keeping pace with the times. The combination of "mathematical geology" and "information technology" can be called "digital geology". Digital geology is the data analysis component of geological science. Geological data science is a science that uses the general methodology of data to study geology based on the characteristics of geological data and the needs of geological field work. Digital mineral exploration is the application of digital geology in mineral exploration to reduce ore-finding uncertainty.

This study focuses on the evolution of flood risk in the Yangtze River Basin under climate change, which is a critical issue for socioeconomic development in future. In this study, we (1) compared the 1998 and 2020 floods and found that the destructiveness of a given discharge is now greater than before; (2) revealed three issues related to the above finding; and (3) prospected the future development of up-to-date technologies to better address the issue that floods with high water levels will frequently threaten us. The outcomes of this study would be of great significance to future flood control operation of large river basins.

Lithium has limited biological activity and can readily replace aluminium, magnesium and iron ions in aluminosilicates, making it a proxy for the inorganic silicate cycle and its potential link to the carbon cycle. Data from the North Pacific Ocean, tropical Indian Ocean, Southern Ocean and Red Sea suggest that salinity normalized dissolved lithium concentrations vary by up to 2%–3% in the Indo‐Pacific Ocean. The highest lithium concentrations were measured in surface waters of remote North Pacific and Indian Ocean stations that receive relatively high fluxes of dust. The lowest dissolved lithium concentrations were measured just below the surface mixed layer of the stations with highest surface water concentrations, consistent with removal into freshly forming aluminium rich phases and manganese oxides. In the North Pacific, water from depths >2,000 m is slightly depleted in lithium compared to the initial composition of Antarctic Bottom Water, likely due to uptake of lithium by authigenically forming aluminosilicates. The results of this study suggest that the residence time of lithium in the ocean may be significantly shorter than calculated from riverine and hydrothermal fluxes., Key Points: Li/Na ratios vary by up to 2%–3% in the Indian and Pacific Oceans. Authigenic formation of aluminosilicates slightly deplete deep‐water lithium concentrations in the North Pacific. The residence time of lithium in the ocean is 240,000 ± 70,000 years, based on removal from North Pacific deep‐water., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, MoES, Indian National Centre for Ocean Information Services http://dx.doi.org/10.13039/501100004814, National Science Foundation USA, https://doi.pangaea.de/10.1594/PANGAEA.941888

Over the past decade or so, geochemical techniques have been applied to the study of modern and past tsunamis. Seawater incursions and the introduction of marine organic matter can be detected through geochemical analysis, providing strong evidence that an event deposit was formed by saltwater inundation. Furthermore, the marine geochemical signature of an event may reveal the full extent of tsunami inundation far more precisely than can be obtained from sediment alone. Based mainly on literature published during the last 4 years, this paper summarizes the latest advances in and some problems with tsunami geochemical research, and specifically addresses organic and inorganic proxies with high preservation potential, geochemical characteristics of invisible tsunami deposits, handling of data from core scanners, and offshore environmental impacts. Recent studies have proposed that some organic and inorganic geochemical proxies have high preservation potential, and sometimes such evidence can be recognized from invisible tsunami deposits. Quantitative assessments of biomarkers are also effective for detecting allochthonous materials. Organic and inorganic proxies can be applied both to identify tsunami deposits and to accurately reconstruct tsunami inundation areas; however, there are as yet no universal criteria for accurate reconstruction of tsunami inundation areas by detecting invisible tsunami deposits using geochemical approaches. For deeper understanding of the behavior of geochemical characteristics derived from tsunami events, additional knowledge of the geochemical substances associated with modern and paleo-tsunami events is required. Specifically, further work is required on assessment of the environmental selectivity of geochemical proxies and refinement of core-scanner analysis for both organic and inorganic substances.

The Olenekian-Anisian Boundary (OAB) interval is an important time in Earth history, reflecting the last phase of marine ecosystem recovery in the aftermath of the end-Permian mass extinction. Despite this, the Global Stratotype Section and Point (GSSP) for the base of the Anisian remains undefined. The first appearance of the conodont Chiosella timorensis has been proposed as a potential index for the boundary; however, the discovery of this conodont with ammonoids traditionally considered to be Spathian has generated doubts about its suitability. The taxonomy and relationships of early Anisian conodonts, including species of Chiosella, remain understudied, which leads to difficulties in correlation. New species of Neogondolella (N. gradinarui) and Magnigondolella (M. n. sp. D) have been recognized from the leading GSSP candidate section for the OAB at Desli Caira, and from an additional OAB section at Guandao. Furthermore, several species previously identified in Canada and the USA can be recognized from these sections, improving correlation between Tethys and North America. One of these species may serve as a suitable alternative proxy for the OAB; for instance, N. curva appears just below the first Anisian ammonoids in Desli Caira, and just above the first appearance of C. timorensis in both Desli Caira and Guandao. Continued work on sections other than the candidate sections, and on the taxonomy of species outside of those traditionally proposed as indices, is required.

The age of the Silurian Lower Red Beds in the Upper Yangtze region remains debatable. Twenty-four samples were collected for conodont biostratigraphical studies from the Paiyunan Formation in the Sanbaiti Section, Huaying, Sichuan Province. The conodont fauna from the Paiyunan Formation, together with the graptolites from the underlying Lungmachi Formation, indicates that the Lower Red Beds at Sanbaiti correspond to the lower Telychian. Comparative analysis indicates that most exposures of the Lower Red Beds in the Upper Yangtze region can be assigned, in general, to the Telychian Stage, except for several localities, where the Lower Red Beds can be roughly dated as an interval between the upper Aeronian and lower Telychian.

Paleoethnobotanical assemblages from the Northwestern region of North America often yield geophyte subterranean organs, but these carbonized remains are difficult to identify to species or genus level. We examine 11 species (8 genera) of the most ethnographically prevalent Northwest geophyte foods for macro- and micro-morphologic geophyte features, with a focus on bulbs from the Asparagales and Liliales orders. In this contribution, we discuss ethnographic practices which may affect archaeological material and provide digital photographic and quantitative references for both fresh and carbonized geophytes. We determine that pavement epidermal cells are the most diagnostic criteria for identifying bulbs in paleoethnobotanical assemblages. These identification standards provide researchers with comparative material to address questions of plant use, preparation, and stewardship across the greater Northwest Coast and Columbia-Fraser Plateau cultural and geographic regions.

Despite several regional glacier and glacier lake inventories, the relationship between receding glacier, glacial lake evolution (glacial-lake interactions) and their sensitivity to different forcing factors have not been properly understood yet. To better understand these processes, we used satellite images collected in 1994, 2015 and 2017 to monitor the spatially-explicit evolution of glacial lakes and glacier changes. The results show a total of 1 353 glacial lakes covering an area of 7.96 km2 in the year 2015. Out of these, a total of 137 glacial lakes having an area of >0.01 km2 and located within 2 km periphery of mother glacier have been selected for the monitoring of spatial development between 1994 and 2017. We found an increase in the total lake area from ∼4.9 to ∼7.73 km2 between 1994 and 2017, corresponding to an overall expansion of ∼57%. The total area covered by the glaciers associated with these lakes reduced from ∼365 km2 in 1994 to ∼358 km2 in 2017, accounting for a glacier loss of ∼7 km2 and corresponding to ∼1.92% reduction. Our study results are in agreement with global glacier behavior, revealing a rapid glacier recession and accelerated glacial lake expansion under an unprecedented climate change scenario. In addition, the results suggest a significant reduction in the glacier area and a close relationship between the glacier melting and lake changes.

Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28‐day incubations. We incubated late‐summer stream water from 23 locations nested in seven northern or high‐altitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two‐way interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways., Key Points Dissolved organic matter (DOM) from diverse circumpolar regions showed compositional and optical commonalitiesAdded acetate and nutrients suppressed background DOM degradation but accelerated colored DOM breakdownDisconnect between DOM composition and function indicates intrinsic and extrinsic conditions interact to regulate DOM dynamics