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This research provided a model of genesis of soils in North-West Siberia connecting the stages of their development to the main environmental changes over the Late Pleistocene and the Holocene. The “soil memory” showed that the studied soils had a complex polygenetic origin. A gleyed paleosol with signs of solifluction found at a depth of 2 m was most probably formed during the Marine Isotope Stage (MIS) 3 that is the Karginsky interstadial. The following stage, i.e., MIS2 – the Sartanian cryochron was characterized by the eolian sedimentation of silty material. In the Late Sartanian, new soil formation began in the silty parent material, with a strong platy cryogenic aggregation and grain size sorting. The warmer and more humid climate in the early Holocene induced clay illuviation and allowed for the formation of the argic horizon. Finally, the modern climatic conditions have caused ooidal cryogenic aggregation within upper horizons, however recent frost action has not been as strong as it was during the previous cold stage. Additionally, the modern pedogenesis included spodic and stagnic processes as well as clay mineral transformation. We suppose that such a model of soil evolution could be extrapolated to the northern Cis-Ural region, but not to the west in the Baltic region, where the dynamics of pedogenesis were different.

This study aims to determine the palaeoenvironmental characteristics and activity patterns of Obrovac-type archaeological sites in Western Serbia, dated to the Late Neolithic/Early Eneolithic period, ∼5th millennium BC. These mound-like sites, enclosed by a wide ditch, that are not known in other parts of the central Balkan area, have long intrigued archaeologists investigating their origin and function over the last few decades. In this study, for the first time, organic-geochemical analysis of paleosol samples from the Obrovac-type sites was applied with the aim of palaeoenvironmental reconstruction. Additionally, organic carbon content and anion analysis of 58 subsoil samples from these settlements were performed to determine the use of space and activity zones. The analysis of biomarkers from selected sites suggests significant plant biodiversity in the Macva region during the Late Neolithic/Early Eneolithic. Distribution of n-alkanes with the maximum at n-C25 and predominance of C30 hop-22(29)-ene among hopanoids in samples from Obrovac type-sites indisputably indicates that macrophytes are a dominant source of organic matter, implying a marshy and floodplain depositional environment. On the other side, a strong signal of long-chain n-alkanes indicates the input of terrestrial plants into the precursor biomass, confirming that this environment was habitable for the first settlers in this region. Anion-based analysis delineates certain activity zones, demonstrating that Obrovac type-sites manifest rather complex spatial behavior despite their relatively small size and available space.

Subaerial physical, chemical and biological weathering processes are significant contributors to mountain landscape development worldwide, and over long time scales. This paper reports on pseudokarst features formed by different subaerial weathering processes on a high-elevation basalt plateau surface in the Maloti–Drakensberg mountains of eastern Lesotho, southern Africa. Different mesoscale landforms identified on this plateau surface include enclosed depressions (containing seasonal pools) that are morphologically similar to karstic solutional features. Such basalt pseudokarst landforms have not been previously described. This study uses field data on depression morphometry, sediments, water chemistry and rock surface hardness to explore the varied subaerial weathering and erosion processes contributing to pseudokarst depression development. Results show that physical, chemical and biological weathering and erosion processes in combination can impact on the basalt land surface in widening and deepening these depressions. An evolutionary model for pseudokarst depression development proposes that different weathering processes in combination within the ‘critical zone’ cause changes in depression morphology, and that there are significant feedbacks between bedrock, weathering, and the development of distinctive micromorphological forms. It is likely that similar pseudokarst landforms from other locations with non-carbonate substrates have been under-reported in the literature.

International audience; AimsRare earth elements (REEs) and normalized REE patterns determined in plant and soil samples represent powerful tools to trace biogeochemical processes during weathering, soil genesis and processes in the rhizosphere, and thus publications reporting REE concentrations and normalized REE patterns in soil systems and plants are rapidly increasing.MethodsA normalized REE pattern allows for the recognition of anomalous concentrations of an individual REE. In the literature, anomalies are predominantly reported/focused for/on the redox-sensitive elements cerium (Ce) and europium (Eu) that can shift their oxidation state during interactions with organic and inorganic soil phases and the biological processes affecting their mobility in soil and uptake by plants. Thus positive Eu anomalies in plants are often interpreted as a consequence of reduction of Eu3+ to Eu2+ in the rhizosphere followed by a preferential uptake of Eu2+.ResultsDue to an analytical artefact in ICP-MS analysis, a false Eu anomaly may be reported. This can be avoided by using a barium (Ba) interference correction. We draw attention to the possibility of this problem and to being aware of its potential occurrence when Eu anomalies are reported.ConclusionsWe recommend (i) including information on how this potential problem was dealt with in the Materials and Methods section of articles and (ii) how to implement Findable Accessible Interoperable and Reusability (FAIR) guiding principles in that section (including data availability in an open repository).

Wudalianchi is a typical continental Cenozoic volcanic group rich in potassic volcanic rocks (Northeast China). Five hydrologically connected barrier lakes (Lakes 5 to 1) and upwelling cold mineral springs occur, forming a complex lake-groundwater system. Clarifying the water-source contributions and the role of water-rock interactions in the hydrological cycling for barrier lakes remains a challenge from scientific and engineering perspectives. In this study, seasonal variations of multiple isotopes were analyzed. δ18O and δD data indicate that the Wudalianchi lakes were mainly fed by mineral springs. The values, however, were greatly influenced by precipitation (rain and snow) and varying evaporation intensities. In contrast, 87Sr/86Sr ratios varied little between seasons (0.70701–0.7079), suggesting similar water-rock interactions through time. Nonetheless, Sr isotopic mixing models suggested that shallow mineral springs generally contributed >50% of the water to lower reaches. In contrast, the upstream wetland contributed >50% to Lake 5 and decreased down-valley (10.3–53.6%). Calculations based on the δ18O and δD Rayleigh fractionation equation suggest that evaporation in upper reaches was higher than the lower reaches. The evaporation in July was generally higher than in October. This study demonstrates the homogenous water-rock interactions and the associated water mixing effects on the terrestrial volcanic area. HIGHLIGHTS 87Sr/86Sr ratios varied little across seasons; δD and δ18O varied significantly.; δD and δ18O values of lakes were impacted by evaporation and precipitation.; Four endmember sources were identified by geochemical and isotopic data.; Shallow mineral springs and wetland water contributed most to lake waters.; Water-rock interaction and water mixing effect were highlighted in terrestrial volcanic area in eastern China.

Human activities are changing the Arctic environment at an unprecedented rate resulting in rapid warming, freshening, sea ice retreat and ocean acidification of the Arctic Ocean. Trace gases such as nitrous oxide (N2O) and methane (CH4) play important roles in both the atmospheric reactivity and radiative budget of the Arctic and thus have a high potential to influence the region’s climate. However, little is known about how these rapid physical and chemical changes will impact the emissions of major climate-relevant trace gases from the Arctic Ocean. The combined consequences of these stressors present a complex combination of environmental changes which might impact on trace gas production and their subsequent release to the Arctic atmosphere. Here we present our current understanding of nitrous oxide and methane cycling in the Arctic Ocean and its relevance for regional and global atmosphere and climate and offer our thoughts on how this might change over coming decades. Supplementary Information The online version contains supplementary material available at 10.1007/s13280-021-01633-8.

Stable isotopes of hydrogen, carbon and oxygen are used to investigate numerous physical and chemical processes in the water and inorganic carbon cycles. Measuring and comparing natural isotopic variations requires reliable primary reference materials and consistent data treatment. However, these reference materials have changed over time, while advances in technology have led to better constrained isotopic compositions of the reference materials. In this Technical Review, we provide an overview of the historical evolution of such materials, and explain their relationships across time and isotopic scales. Recommendations are provided for the measurement and reporting of isotopic compositions against the consensual VPDB and VSMOW scales in light of the newest carbonate and water reference materials distributed by the International Atomic Energy Agency. Stable isotope fractionation factors and their temperature dependence in processes specific to the water cycle (2H, 18O, 17O) and the CO2–water–carbonate system (13C, 18O) are described, including for carbonate clumped isotope thermometry. Propagation of errors is also addressed for a consistent reporting of real uncertainties of isotopic measurements and calculations. Lastly, current gaps in knowledge on the behaviour of stable isotopes in the water cycle and the CO2–water–carbonate system are highlighted for future studies. The use of isotopes has provided key insights into the Earth system, but their use can be fraught with experimental and theoretical pitfalls. This Technical Review explains the use of and fractionation factors associated with hydrogen, carbon and oxygen isotopes in water cycle and CO2–carbonate–water system studies.

Yunnan at southeastern margin of the Tibetan Plateau is subject to frequent wildfires each year, while its wildfire history remains poorly known due to the lack of studies on palaeofire in the region. In this study, we report a local fire from the late Pliocene of northwestern Yunnan, based on macroscopic fossil charcoals recovered from the Sanying Formation of Lanping Basin. These sedimentary charcoals exhibit silky lustre in the light and complete homogenization of adjacent xylem cell walls, characterizing the result of incomplete combustion during the late Pliocene. Our preliminary taxonomic analysis indicates that the studied charcoals are dominated by conifers, suggesting higher importance of coniferous elements as fuel sources in the fire. We assert a conifer-rich source forest for the fire event by also considering plant remains of other types, i.e., needle fragments, small shoots, fruits and seeds, from the same sampling layer. Since conifers are commonly prone to wildfires, this type of forest might have a close link with the fire by serving highly flammable fuels. We consider that the regionally seasonal drought during the late Pliocene might also take responsibility, because in the dry season forest fuels such as ground litter would become ignitable after intensive desiccation. As modern wildfires in northwestern Yunnan are closely coupled with conifer-dominant forests and seasonally dry climate, we assume this correlation might have been established by the late Pliocene. Our study may bring attention to potential roles of wildfire on local and/or regional flora and vegetation evolution in this region.

Long-term carbon cycle models are critical for understanding the levels and underlying controls of atmospheric CO2 over geological time-scales. We have refined the implementation of two important boundary conditions in carbon cycle models, namely consumption by silicate weathering and carbon degassing. Through the construction of continental flooding maps for the past 520 million years (Myrs), we have estimated exposed land area relative to the present-day (fA), and the fraction of exposed land area undergoing silicate weathering (fAW-fA). The latter is based on the amount of exposed land within the tropics (±10°) plus the northern/southern wet belts (±40-50°) relative to today, which are the prime regions for silicate weathering. We also evaluated climate gradients and potential weatherability by examining the distribution of climate-sensitive indicators. This is particularly important during and after Pangea formation, when we reduce fAW-fA during times when arid equatorial regions were present. We also estimated carbon degassing for the past 410 Myrs using the subduction flux from full-plate models as a proxy. We further used the subduction flux to scale and normalize the arc-related zircon age distribution (arc-activity), allowing us to estimate carbon degassing in much deeper time. The effect of these refined modelling parameters for weathering and degassing was then tested in the GEOCARBSULFvolc model, and the results are compared to other carbon cycle models and CO2 proxies. The use of arc-activity as a proxy for carbon degassing brings Mesozoic model estimates closer to CO2 proxy values but our models are highly sensitive to the definition of fAW-fA. Considering only variations in the land availability to weathering that occur in tropical latitudes (corrected for arid regions) and the use of our new degassing estimates leads to notably higher CO2 levels in the Mesozoic, and a better fit with the CO2 proxies.

Remote sensing methods enable detection of solar-induced chlorophyll a fluorescence. However, to unleash the full potential of this signal, intensive cross-disciplinary work is required to harmonize biophysical and ecophysiological studies. For decades, the dynamic nature of chlorophyll a fluorescence (ChlaF) has provided insight into the biophysics and ecophysiology of the light reactions of photosynthesis from the subcellular to leaf scales. Recent advances in remote sensing methods enable detection of ChlaF induced by sunlight across a range of larger scales, from using instruments mounted on towers above plant canopies to Earth-orbiting satellites. This signal is referred to as solar-induced fluorescence (SIF) and its application promises to overcome spatial constraints on studies of photosynthesis, opening new research directions and opportunities in ecology, ecophysiology, biogeochemistry, agriculture and forestry. However, to unleash the full potential of SIF, intensive cross-disciplinary work is required to harmonize these new advances with the rich history of biophysical and ecophysiological studies of ChlaF, fostering the development of next-generation plant physiological and Earth-system models. Here, we introduce the scale-dependent link between SIF and photosynthesis, with an emphasis on seven remaining scientific challenges, and present a roadmap to facilitate future collaborative research towards new applications of SIF.

In this paper, we review both practical and theoretical assessments for evaluating radon geohazards from permafrost landforms in northern environments (>60º N). Here, we show that polar amplification (i.e. climate change) leads to the development of thawing permafrost, ground subsidence, and thawed conduits (i.e. Taliks), which allow radon migration from the subsurface to near surface environment. Based on these survey results, we conjecture that abruptly thawing permafrost soils will allow radon migration to the near surface, and likely impacting human settlements located here. We analyze potential geohazards associated with elevated ground concentrations of natural radionuclides. From these results, we apply the main existing legislation governing the control of radon parameters in the design, construction and use of buildings, as well as existing technologies for assessing the radon hazard. We found that at present, these laws do not consider our findings, namely, that increasing supply of radon to the surface during thawing of permafrost will enhance radon exposure, thereby, changing prior assumptions from which the initial legislation was determined. Hence, the legislation will likely need to respond and reconsider risk assessments of public health in relation to radon exposure. We discuss the prospects for developing radon geohazard monitoring, methodical approaches, and share recommendations based on the current state of research in permafrost effected environments.

Spatial data mining helps to find hidden but potentially informative patterns from large and high-dimensional geoscience data. Non-spatial learners generally look at the observations based on their relationships in the feature space, which means that they cannot consider spatial relationships between regionalised variables. This study introduces a novel spatial random forests technique based on higher-order spatial statistics for analysis and modelling of spatial data. Unlike the classical random forests algorithm that uses pixelwise spectral information as predictors, the proposed spatial random forests algorithm uses the local spatial-spectral information (i.e., vectorised spatial patterns) to learn intrinsic heterogeneity, spatial dependencies, and complex spatial patterns. Algorithms for supervised (i.e., regression and classification) and unsupervised (i.e., dimension reduction and clustering) learning are presented. Approaches to deal with big data, multi-resolution data, and missing values are discussed. The superior performance and usefulness of the proposed algorithm over the classical random forests method are illustrated via synthetic and real cases, where the remotely sensed geophysical covariates in North West Minerals Province of Queensland, Australia, are used as input spatial data for geology mapping, geochemical prediction, and process discovery analysis.

The episodic growth of high-elevation orogenic plateaux is controlled by a series of geodynamic processes. However, determining the underlying mechanisms that drive plateau growth dynamics over geological history and constraining the depths at which growth originates, remains challenging. Here we present He-CO2-N2 systematics of hydrothermal fluids that reveal the existence of a lithospheric-scale fault system in the southeastern Tibetan Plateau, whereby multi-stage plateau growth occurred in the geological past and continues to the present. He isotopes provide unambiguous evidence for the involvement of mantle-scale dynamics in lateral expansion and localized surface uplift of the Tibetan Plateau. The excellent correlation between 3He/4He values and strain rates, along the strike of Indian indentation into Asia, suggests non-uniform distribution of stresses between the plateau boundary and interior, which modulate southeastward growth of the Tibetan Plateau within the context of India-Asia convergence. Our results demonstrate that deeply-sourced volatile geochemistry can be used to constrain deep dynamic processes involved in orogenic plateau growth., Deeply-sourced volatiles are releasing from orogenic plateau regions, providing windows to plateau growth dynamics occurring at variable depths. Here the authors show that mantle-derived volatiles reveal the involvement of mantle dynamics in southeastward growth of the Tibetan Plateau.

The necessity of a comprehensive description of greenhouse gas fluxes on different types of soils, the methodology for creating “carbon polygons” and “carbon farms” with the use of modern methods for assessing carbon fluxes in ecosystems, taking into account the specifics of the natural conditions of Russia and competitive advantages, are substantiated. Directions for developing national methods for calculating carbon fluxes are given, which should be subjected to verification by the interested parties of the Paris Agreement adopted by the Russian Federation. Such issues are considered as the role and potential of the Russian soil cover in the carbon balance of the planet, factors of reducing carbon stocks from the upper 1 meter depth layer of the soil, competitive edge in the EU and the Western world in the questions of natural and climatic changes, the use of remote sensing of the Earth from space in order to obtain regular, complete and reliable estimates of the absorption of greenhouse gases.

Mixedwood forest composition, or co-dominance of hardwood and softwood species, has been interpreted as both stable and unstable. Through review of existing theory, we propose a conceptual model to understand mixedwood compositional stability in boreal and temperate forests of eastern North America. We first review the current theory that the strength of neighborhood effects (i.e., species ability to self-replace under their own canopy) is essential to understanding stability such that when self-replacement is strong for both dominant hardwood and softwood species, composition is stable except at extreme disturbance severities. In contrast, when mixedwood forests are dominated by negligible or weak affinities to self-replace, composition is unstable and sensitive to changes in disturbance. Our new concept further posits that changes in both the disturbance severity and its vertical direction are essential to understanding stability. For example, where moderate-severity surface fires (which impact forests from below) cease and are replaced by moderate-severity blowdowns (which impact forests from above), instability can occur even when disturbance severity is unchanged. We therefore pose and discuss an extension to current theory to provide a new unifying concept of stability for mixedwood forests and, more broadly, for mixed-species forests.

The paper provides initial materials characterizing the complicated history of formation, natural soils and lithological-geomorphological conditions of the Jizzakh steppe before the beginning of reclamation development. It is shown that on the basis of soil-lithological and geomorphological zoning, the Jizzakh steppe is divided into a number of natural regions belonging to different levels (altitude levels) of the piedmont plain. In total, 22 districts have been identified within the Jizzakh steppe, including the foothill margins. On the piedmont plain itself, the regions are combined into two high-altitude levels: the upper step and the lower step or blanket zone. These two levels differ sharply in terms of drainage conditions and soil salinity. The upper level, covering the upper and middle parts of the alluvial fan, the high interconal Zaamin-Sanzar plain and the Lomakino plateau, is characterized by a weak manifestation of salinity due to relatively good drainage, except for the sloping depressions of the Lomakino plateau. In contrast to the upper level, the lower level, located in the blanket zone of the piedmont plain, is characterized by active natural salinization because of the poor drainage. The saline sediments of the Zaamin cone delta are characterized by the greatest thickness. To a lesser extent, the rocks of the Sanzar cone delta, which are drained by deep gullies, are salinized. The Khavast sloping plain is characterized by a strongly saline upper two-meter layer, with salt and gypsum content decreasing with depth. Thus, it is shown that high salinity and gypsum bearing rocks, as well as high groundwater salinity of the cone delta zone are the source of modern salt accumulation in soils of foothill Golodnostepskaya plain, as well as in soils of the cone delta zone of Djizak steppe.

The purpose of the study is to analyze the possibility to identify the pollution genesis of the underground hydrosphere based on the data on polyarenes as geochemical markers. Their marker role is due to their toxicity, persistence and confinement to specific pollution sources and natural and technogenic processes. The main research method is the analysis of indicator ratios of polyarenes. The object of research is groundwater from different regions of the world, which are polluted by natural and anthropogenic polyarenes. The main directions of domestic and foreign researches as well as the problems of their implementation are shown. The use of indicator ratios enabled successful identification of pyro- and petrogenically polluted samples of groundwater also the examples of the study of polyarenes as geochemical markers were demonstrated. The polyarenes are shown to be an effective indicator of the pollution genesis in the underground hydrosphere. However, their analysis requires the use of modern methods of sampling, sample preparation and extraction, which significantly complicates research in practice.

The Subglacial Antarctic Lakes Scientific Access (SALSA) Project accessed Mercer Subglacial Lake using environmentally clean hot-water drilling to examine interactions among ice, water, sediment, rock, microbes and carbon reservoirs within the lake water column and underlying sediments. A ~0.4 m diameter borehole was melted through 1087 m of ice and maintained over ~10 days, allowing observation of ice properties and collection of water and sediment with various tools. Over this period, SALSA collected: 60 L of lake water and 10 L of deep borehole water; microbes >0.2 μm in diameter from in situ filtration of ~100 L of lake water; 10 multicores 0.32–0.49 m long; 1.0 and 1.76 m long gravity cores; three conductivity–temperature–depth profiles of borehole and lake water; five discrete depth current meter measurements in the lake and images of ice, the lake water–ice interface and lake sediments. Temperature and conductivity data showed the hydrodynamic character of water mixing between the borehole and lake after entry. Models simulating melting of the ~6 m thick basal accreted ice layer imply that debris fall-out through the ~15 m water column to the lake sediments from borehole melting had little effect on the stratigraphy of surficial sediment cores.

International audience; The Oligocene-Miocene boundary Asian climatic reorganization linked to the northward migration of the East Asian monsoon into subtropical China is a potentially important but poorly constrained atmospheric CO2 consumption process. Here, we performed a first-order estimate of the CO2 consumption induced by silicate chemical weathering and organic carbon burial in subtropical China related to this climatic reorganization. Our results show that an increase in long-term CO2 consumption by silicate weathering varies from 0.06×1012 to 0.87×1012 mol yr−1 depending on erosion flux reconstructions, with an ~50% contribution of Mg-silicate weathering since the late Oligocene. The organic carbon burial flux is approximately 25% of the contemporary CO2 consumption by silicate weathering. The results highlight the significant role of weathering of the Mg-rich upper continental crust in East China, which would contribute to the rapid decline in atmospheric CO2 during the late Oligocene and the Neogene rise in the seawater Mg content. If this climatic reorganization was mainly induced by the Tibetan Plateau uplift, our study suggests that the growth of the Himalayan-Tibetan Plateau can lead to indirect modification of the global carbon and magnesium cycles by changing the regional hydrological cycle in areas of East Asia that are tectonically less active.

Phosphorus (P) is essential for life, but most of the global surface ocean is P depleted, which can limit marine productivity and affect ecosystem structure. Over recent decades, a wealth of new knowledge has revolutionized our understanding of the marine P cycle. With a revised residence time (~10–20 kyr) that is similar to nitrate and a growing awareness that P transformations are under tight and elaborate microbial control, the classic textbook version of a tectonically slow and biogeochemically simple marine P cycle has become outdated. P moves throughout the world’s oceans with a higher level of complexity than has ever been appreciated before, including a vast, yet poorly understood, P redox cycle. Here, we illustrate an oceanographically integral view of marine P by reviewing recent advances in the coupled cycles of P with carbon, nitrogen and metals in marine systems. Through this lens, P takes on a more dynamic and connected role in marine biogeochemistry than previously acknowledged, which points to unclear yet profound potential consequences for marine ecosystems, particularly under anthropogenic influence. Phosphorus plays a dynamic and complex role in marine biogeochemistry, which is closely connected to carbon, nitrogen and metal cycling, according to a literature synthesis on recent advances in understandings of the marine phosphorus cycle.

The Great Oxygenation Event (GOE), ca. 2.4 billion years ago, transformed life and environments on Earth. Its causes, however, are debated. We mathematically analyze the GOE in terms of ecological dynamics coupled with a changing Earth. Anoxygenic photosynthetic bacteria initially dominate over cyanobacteria, but their success depends on the availability of suitable electron donors that are vulnerable to oxidation. The GOE is triggered when the difference between the influxes of relevant reductants and phosphate falls below a critical value that is an increasing function of the reproductive rate of cyanobacteria. The transition can be either gradual and reversible or sudden and irreversible, depending on sources and sinks of oxygen. Increasing sources and decreasing sinks of oxygen can also trigger the GOE, but this possibility depends strongly on migration of cyanobacteria from privileged sites. Our model links ecological dynamics to planetary change, with geophysical evolution determining the relevant time scales., The Great Oxygenation Event (GOE) 2.4 billion years ago is believed to have been critical for the evolution of complex life. Here, Olejarz et al. propose a model suggesting that competition between major bacterial groups could have triggered the GOE in a feedback loop with geophysical processes.

Geoscience organizations shape the discipline. They influence attitudes and expectations, set standards, and provide benefits to their members. Today, racism and discrimination limit the participation of, and promote hostility towards, members of minoritized groups within these critical geoscience spaces. This is particularly harmful for Black, Indigenous, and other people of color in geoscience and is further exacerbated along other axes of marginalization, including disability status and gender identity. Here we present a twenty-point anti-racism plan that organizations can implement to build an inclusive, equitable and accessible geoscience community. Enacting it will combat racism, discrimination, and the harassment of all members., Racism thrives in geoscience. We present an antiracism plan to support the recruitment, retention and success of Black, Indigenous, and other people of color in geoscience. Our action plan can be adapted by any organization to remove barriers to participation for all marginalized geoscientists.

The landscape index is a quantitative index which reflects characteristics of structure composition and spatial pattern in landscape studies, it is, therefore, expected to describe the spatial pattern of scientific research in bibliometric analysis. In this study, a novel attempt to regard scientific research as a kind of ‘landscape’ was made, and landscape indices were improved for bibliometric analysis to measure the spatial pattern of scientific research. For illustrating the feasibility of our method, global geoscience research from 1994 to 2018 was presented as a case. Moreover, spatiotemporal migration of landscape centroids was visualized. The results indicated that global geoscience publications increased steadily and articles were highly concentrated at the country level. The top 10 countries published 69.93% of total articles and 84.68% of geoscience articles were from top 20 productive countries. The spatial migration of centroids was mainly reflected in the longitude because of significant increasing of articles in eastern countries, especially in China with the growth rate of 747.14%. At the patch scale, the change trend of improved landscape indices verified the spatiotemporal changes of global distribution of geoscience articles. At the landscape scale, the strengthening of global international collaboration is the main driving forces of spatial heterogeneity of global geoscience research. This study is expected to help readers to understand global trends of geoscience research in the past 25 years, and to promote the development of bibliometric analysis towards the directions of spatialization and visualization.

Since the discovery of glacial features on sub-Antarctic Marion Island, the character and extent of a historic glacial period have remained an important research focus for earth science investigations. Previous glacial reconstructions were limited to mostly pre-GPS field observations and pre-digital mapping through a Geographic Information System. With the aid of GPS field mapping, high-resolution satellite imagery and a digital surface model with a 1 × 1 m cell resolution, this paper provides a comprehensive, geo-rectified spatial geodatabase and map of Marion Island’s glacial geomorphology. The geodatabase includes an inventory of glacial erosional (e.g. striations) and depositional (e.g. moraines) features compiled from existing records as well as new features mapped from recent field observations. The final map and the geodatabase, which is downloadable as ESRI layer-package files, will aid future field investigations and modelling applications to understand Marion Island’s Quaternary landscape evolution and post-glacial ecological succession.

Even though the biological crusts are critical to dust emissions, no sand and dust forecast model have considered the impacts of the biological crust in dust emission scheme. This situation mainly comes from two scientific difficulties: there is no large scale regional biological crust data available that can be used in the forecast model; there is no quantification of how biological crusts impact on sand emission. In this way, we studied the distribution of biological soil crust in sand and dust storm source areas of Central and East Asia using Moderate Resolution Imaging Spectroradiometer satellite surface reflectance data collected in 2000–2019 to determine its potential impact on dust emission according to two empirical schemes. We further evaluated the relationships between soil crust coverage, roughness length, and dust emission to study SDS source areas. We found that biological crust is widely distributed in SDS source areas of Central and East Asia, with coverage rates of 19.8% in Central Asian deserts, 23.1% in the Gobi Desert, and 17.3%–32.8% in Chinese deserts (p > 0.05). Cyanobacteria and lichen coverage has increased in Chinese deserts, reflecting the recent impacts of the Project of Returning Farmland to Grassland and Farmland to Forests. However, biological soil crust coverage has not increased in Central Asian deserts or the Gobi Desert, and that in Central Asian deserts continues to decrease, demonstrating the complexity of the combined effects of human activities and climate change on its distribution. Biological soil crust increased the roughness length of Central and East Asian SDS source areas by 0.14–0.62 mm. The suppression of dust emission due to biological soil crust did not change among years during the study period. The horizontal and vertical dust flux inhibition coefficient (DFIC) were 2.0–11.0 and 1.7–2.9 (p > 0.05), respectively, clearly showing a suppressive effect. Improvement of the ecological environment in some deserts can lead to the ability of these crusts to inhibit dust erosion errors that must be considered in the dust emission scheme for areas where crust coverage has improved.

In the last years we have witnessed the fields of geosciences and remote sensing and artificial intelligence to become closer. Thanks to both the massive availability of observational data, improved simulations, and algorithmic advances, these disciplines have found common objectives and challenges to advance the modeling and understanding of the Earth system. Despite such great opportunities, we also observed a worrying tendency to remain in disciplinary comfort zones applying recent advances from artificial intelligence on well resolved remote sensing problems. Here we take a position on research directions where we think the interface between these fields will have the most impact and become potential game changers. In our declared agenda for AI on Earth sciences, we aim to inspire researchers, especially the younger generations, to tackle these challenges for a real advance of remote sensing and the geosciences., Comment: In press at IEEE Geoscience and Remote Sensing Magazine

In geological history, one major life explosion and five mass extinction events occurred. These major biological and environmental events affected the evolution of the Earth ecosystem and controlled the formation of organic-rich strata. The life explosion occurred in Cambrian and the five mass extinction events happened at the end of Ordovician, Late Devonian, end of Permian, end of Triassic, and end of Cretaceous, respectively. They are corresponded to the formation of multiple suites of organic-rich strata globally, which are crucial to the formation, evolution and distribution of the fossil energy on Earth. China’s energy is characterized by “unlimited new energy, rich in coal but insufficient in oil and gas “, and it is determined to rely on new energy sources to achieve” energy independence “and carbon neutrality. From the perspective of the Earth system evolution, we investigate the multiple relationships between energy and Earth, energy and environment, as well as energy and human beings, and carry out comprehensive research on energy. Energy science refers to the science of studying the various energy sources formation and distribution, evaluation and selection, production and utilization, orderly replacement, development prospects, etc. in temporal and spatial scales based on the evolution of the Earth system. The connotation of energy science includes three core contents: (1) The relationship between the Earth and energy, including the formation of energy in the Earth system and the feedback of energy consumption to the Earth’s climate and environment; (2) The relationship between the Earth environment and the human beings, including the Earth environment breeding human beings and human activities transforming the earth environment; (3) The relationship between the energy and the human beings, including the development of energy technology by human beings and the progress of human society driven by energy utilization. The energy science focuses on the formation and development of fossil energy, development and orderly replacement of new energy, exploration and utilization of energy in deep earth and deep space, and energy development strategy and planning. The proposal of energy science is of great significance for improving the discipline system, promoting energy development, clarifying the development direction of energy transition, driving the carbon neutral geology research and constructing a habitable Earth.

The Greenland Ice Sheet harbours a wealth of microbial life, yet the total biomass stored or exported from its surface to downstream environments is unconstrained. Here, we quantify microbial abundance and cellular biomass flux within the near-surface weathering crust photic zone of the western sector of the ice sheet. Using groundwater techniques, we demonstrate that interstitial water flow is slow (~10−2 m d−1), while flow cytometry enumeration reveals this pathway delivers 5 × 108 cells m−2 d−1 to supraglacial streams, equivalent to a carbon flux up to 250 g km−2 d−1. We infer that cellular carbon accumulation in the weathering crust exceeds fluvial export, promoting biomass sequestration, enhanced carbon cycling, and biological albedo reduction. We estimate that up to 37 kg km−2 of cellular carbon is flushed from the weathering crust environment of the western Greenland Ice Sheet each summer, providing an appreciable flux to support heterotrophs and methanogenesis at the bed., Microbes that colonise ice sheet surfaces are important to the carbon cycle, but their biomass and transport remains unquantified. Here, the authors reveal substantial microbial carbon fluxes across Greenland’s ice surface, in quantities that may sustain subglacial heterotrophs and fuel methanogenesis.

Geologic maps are foundational products for natural hazard assessments but developing them for submarine areas is challenging due to a lack of physical access to the study area. In response, submarine geomorphologic maps are used to provide geologic context and spatial information on landforms and related geo-hazards for risk management. These maps are generated from remotely sensed data, e.g. digital elevation models (DEMs), which introduce unique hurdles to submarine mapping. To address this issue, we produced a workflow for applying planetary geologic mapping methods to submarine data. Using this, we created an onshore-offshore geomorphologic map of the Christiana-Santorini-Kolumbo Volcanic Group, Greece. This product can be used to enhance hazard assessments on Santorini, which is a tourist hot-spot at high risk for volcanically- and seismically-induced hazards. We present this workflow as a tool for generating uniform geomorphologic map products that will aid natural hazard assessments of submarine environments.

Throughout the Ediacaran Period, variable water-column redox conditions persisted along productive ocean margins due to a complex interplay between nutrient supply and oceanographic restriction. These changing conditions are considered to have influenced early faunal evolution, with marine anoxia potentially inhibiting the development of the ecological niches necessary for aerobic life forms. To understand this link between oxygenation and evolution, the combined geochemical and palaeontological study of marine sediments is preferable. Located in the Yangtze Gorges region of southern China, lagoonal black shales at Miaohe preserve alga and putative metazoans, including Eoandromeda, a candidate total-group ctenophore, thereby providing one example of where integrated study is possible. We present a multi-proxy investigation into water-column redox variability during deposition of these shales (c. 560–551 Ma). For this interval, reactive iron partitioning indicates persistent water-column anoxia, while trace metal enrichments and other geochemical data suggest temporal fluctuations between ferruginous, euxinic and rare suboxic conditions. Although trace metal and total organic carbon values imply extensive basin restriction, sustained trace metal enrichment and δ15Nsed data indicate periodic access to open-ocean inventories across a shallow-marine sill. Lastly, δ13Corg values of between −35‰ and −40‰ allow at least partial correlation of the shales at Miaohe with Member IV of the Doushantuo Formation. This study provides evidence for fluctuating redox conditions in the lagoonal area of the Yangtze platform during late Ediacaran time. If these low-oxygen environments were regionally characteristic, then the restriction of aerobic fauna to isolated environments can be inferred.

Throughout Earth's history, CO2 is thought to have exerted a fundamental control on environmental change. Here we review and revise CO2 reconstructions from boron isotopes in carbonates and carbon isotopes in organic matter over the Cenozoic—the past 66 million years. We find close coupling between CO2 and climate throughout the Cenozoic, with peak CO2 levels of ∼1,500 ppm in the Eocene greenhouse, decreasing to ∼500 ppm in the Miocene, and falling further into the ice age world of the Plio–Pleistocene. Around two-thirds of Cenozoic CO2 drawdown is explained by an increase in the ratio of ocean alkalinity to dissolved inorganic carbon, likely linked to a change in the balance of weathering to outgassing, with the remaining one-third due to changing ocean temperature and major ion composition. Earth system climate sensitivity is explored and may vary between different time intervals. The Cenozoic CO2 record highlights the truly geological scale of anthropogenic CO2 change: Current CO2 levels were last seen around 3 million years ago, and major cuts in emissions are required to prevent a return to the CO2 levels of the Miocene or Eocene in the coming century. ▪ CO2 reconstructions over the past 66 Myr from boron isotopes and alkenones are reviewed and re-evaluated. ▪ CO2 estimates from the different proxies show close agreement, yielding a consistent picture of the evolution of the ocean-atmosphere CO2 system over the Cenozoic. ▪ CO2 and climate are coupled throughout the past 66 Myr, providing broad constraints on Earth system climate sensitivity. ▪ Twenty-first-century carbon emissions have the potential to return CO2 to levels not seen since the much warmer climates of Earth's distant past.

We present polar ice core organic matter (OM) fluorescence signatures to reconstruct ancient and modern atmospheric compositions and relate OM signals to past ecological changes. OM composition from three Arctic ice cores (Canada and Greenland) was characterized by fluorescence spectroscopy and compared to an Antarctic OM record. Diverse OM was measured in ancient and modern ice in both hemispheres and similarities existed across vast spatiotemporal scales. We determined three OM markers, indicating paleoclimate and modern carbon trends: (i) ‘humic-like’, detected in Holocene ice of more complex and aromatic character, supporting trends of higher plant influences in warmer climates, (ii) monolignol- and non-amino acid-like, describing simple, lignin-like OM precursors ubiquitous in the environment and the microbial degradation products of more complex materials from plants/soils, and (iii) amino acid- and tannin-like, indicating microbial degradation of simple OM chemical species, compared to the other markers. Concentration trends were inferred from fluorescence intensities of individual OM types and related to warmer temperatures. No indicators of freshly produced OM by microbes were detected; signals were interpreted as materials externally produced from the ice and transported to polar regions. This marks the first global comparison of atmospheric reconstructions from OM across vast spatiotemporal scales.

Since the beginning of the 21st century, the geoscience research has been entering a significant transitional period with the establishment of a new knowledge system as the core and with the drive of big data as the means. It is a revolutionary leap in the research of geoscience knowledge discovery from the traditional encyclopedic discipline knowledge system to the computer-understandable and operable knowledge graph. Based on adopting the graph pattern of general knowledge representation, the geoscience knowledge graph expands the unique spatiotemporal features to the Geoscience knowledge, and integrates geoscience knowledge elements, such as map, text, and number, to establish an all-domain geoscience knowledge representation model. A federated, crowd intelligence-based collaborative method of constructing the geoscience knowledge graph is developed here, which realizes the construction of high-quality professional knowledge graph in collaboration with global geo-scientists. We also develop a method for constructing a dynamic knowledge graph of multi-modal geoscience data based on in-depth text analysis, which extracts geoscience knowledge from massive geoscience literature to construct the latest and most complete dynamic geoscience knowledge graph. A comprehensive and systematic geoscience knowledge graph can not only deepen the existing geoscience big data analysis, but also advance the construction of the high-precision geological time scale driven by big data, the compilation of intelligent maps driven by rules and data, and the geoscience knowledge evolution and reasoning analysis, among others. It will further expand the new directions of geoscience research driven by both data and knowledge, break new ground where geoscience, information science, and data science converge, realize the original innovation of the geoscience research and achieve major theoretical breakthroughs in the spatiotemporal big data research.

Time-distinctive features within carbonate rocks, specifically the presence, abundance and distribution of stromatolites, molar-tooth fabric and specific morphologies of marine cement, have been identified as potential indicators of global-scale changes in the chemistry of marine environments. Recently, Cantineet al.(2019) introduced a database approach seeking to quantify spatial and temporal patterns in these carbonate features through the Precambrian. Despite the coarse temporal scale, results support earlier inferences of temporal change in carbonate sedimentation. Here, we use original field notes to dissect late Mesoproterozoic (˜1.3 to 1.0 Ga) carbonate strata at a high resolution, analyse time-distinctive carbonate fabrics within a database context and compare sedimentological patterns within this narrow time range to observations of the Proterozoic as a whole. Late Mesoproterozoic strata contain a variety of features (e.g. stromatolites, seafloor precipitates, herringbone carbonate, molar-tooth carbonate), often in close spatial and temporal proximity, that are commonly considered to be temporally restricted during the Precambrian. The spatial distribution of such features within Mesoproterozoic basins demonstrates the importance of recognizing even rare occurrences of time-distinctive facies and permits inference of environmental drivers that may have interacted to affect carbonate precipitation. Such spatial variability reflects a subtle division of Mesoproterozoic carbonate platform environments driven by globally high sea level, elevated carbonate saturation and a low-oxygen water column. The heterogeneous, mosaic nature of environments appears to be a hallmark of Mesoproterozoic carbonate sedimentation and emphasizes the importance of these basins in understanding longer-term trends in carbonate deposition.

The coupling between chemical weathering (including silicate, carbonate and pyrite weathering) and physical erosion is of high interest in active mountain belts. Participation of pyrite weathering which, results in CO2 emission to the atmosphere, also is of great research attention. Nevertheless, the responses of the (de-)couplings to landslide and typhoon are unclear. We used records of riverine TDS (total dissolved solids) and TSS (total suspended solids) with high-frequency sampling during typhoons to estimate chemical denudation rates of silicate (CDRsil), carbonate (CDRcarb), pyrite (CDRpyrite) and physical denudation rates (PDR) in two adjacent catchments, eastern Taiwan. Results show that the CDRsil in the two catchments is approx. 10-fold higher than the global mean, whereas the CDRcarb, CDRpyrite and PDR are over 15-fold higher than the global averages. Landslides likely elevate carbonate and sulfate dissolution, and streamflow is a kinetic control on the CDRs. Among CDRs, CDRsil remains constant with various landslides and typhoons. Yet, CDRcarb and CDRpyrite rapidly respond to typhoons and then contribute more CO2 emission. In sum, landslides expose fresh minerals to enhance chemical weathering; typhoons, which transport the dissolved solids within a short time and prompt new rainwater for weathering, are also dominant agents. We demonstrate the importance of dynamic partitioning of sulfuric and carbonic acid on silicate weathering for quantitative estimation of weathering-associated CO2 budget in active mountain belts.

Oil field A, situated in Bohai Bay, was discovered in 1999 and has been developed as one of the most productive oil assets in China. It continues to hold significant growth potential for the future. Though the field contains a large amount of resources remaining to be developed, seismic imaging has been challenging in area 5, resulting in structural uncertainty for reservoir interpretation and well planning. In the past three decades, several 2D and 3D seismic surveys have been acquired, processed, and reprocessed in this area. However, due to the existence of complicated gas clouds, which are shallow, multilayered, and extensive, obscured sub-gas-cloud images appear in all legacy seismic results, making fault interpretation under the gas clouds almost impossible. To improve the sub-gas-cloud image and overall structural interpretability, a narrow-azimuth full-field ocean-bottom cable (OBC) acquisition was conducted in field A during 2018 and 2019, and later, a compressive seismic imaging (CSI)-based full-azimuth and large-offset OBC infill survey was acquired in area 5, covering the widest gas cloud. Through high-fidelity signal processing, full-waveform inversion (FWI)-driven velocity model building, and imaging using both Kirchhoff migration and reverse time migration (RTM), the seismic image quality beneath complicated gas clouds is improved significantly. It is the first time that sub-gas-cloud faults and the Base of Guantao event have been imaged by seismic without significant dim zones. CSI acquisition, FWI, and RTM are the key elements to resolve gas-cloud-related challenges in area 5.

We use a sedimentological approach to examine the formation and deformation processes associated with the accumulation of shell deposits in two major clusters of shell mounds, the Weipa group in the monsoonal environment of Albatross Bay in the Cape York Peninsula of northern Queensland, Australia, and the Farasan Islands group in the semi-arid environment of the southern Red Sea sector of Saudi Arabia. The comparison of such disparate case studies is deliberate, intended to highlight generic issues of shell accumulation and degradation irrespective of the taxonomic composition of the shells or cultural and environmental histories. It also reflects recent fieldwork in both regions conducted in parallel with collaborative arrangements for sharing of ideas and approaches and exchange of personnel in order to establish a common baseline for comparison. Comparative analysis of shell composition, fragmentation, and accumulation highlights similarities despite the different cultural and environmental contexts of the two case studies. These similarities suggest that the size and form of shell deposits are altered by a combination of processes reflecting ongoing changes in deposit composition unrelated to human actions of shell discard. Even where large shell deposits are visible and available for sampling, what is preserved is neither a static reflection of initial deposition nor of undisturbed or “completed” form. We consider the influence of such processes on assessments of rates of deposition and the interpretation of variations in the shape and size of shell deposits.

Martian lava tube caves resulting from a time when the planet was still volcanically active are proposed to contain deposits of water ice, a feature that may increase microbial habitability. In this study, we taxonomically characterized and directly measured metabolic activity of the microbial communities that inhabit lava tube ice from Lava Beds National Monument, an analogue environment to martian lava tubes. We investigated whether this environment was habitable to microorganisms by determining their taxonomic diversity, metabolic activity, and viability using both culture-dependent and culture-independent techniques. With 16S rRNA gene sequencing, we recovered 27 distinct phyla from both ice and ice-rock interface samples, primarily consisting of Actinobacteria, Proteobacteria, Bacteroidetes, Firmicutes, and Chloroflexi. Radiorespiration and Biolog EcoPlate assays found these microbial communities to be metabolically active at both 5°C and -5°C and able to metabolize diverse sets of heterotrophic carbon substrates at each temperature. Viable cells were predominantly cold adapted and capable of growth at 5°C (1.3 × 10

The equatorial tropics house some of the earliest rock art yet known, and it is weathering at an alarming rate. Here we present evidence for haloclasty (salt crystallisation) from Pleistocene-aged rock art panels at 11 sites in the Maros-Pangkep limestone karsts of southern Sulawesi. We show how quickly rock art panels have degraded in recent decades, contending that climate-catalysed salt efflorescence is responsible for increasing exfoliation of the limestone cave surfaces that house the ~ 45 to 20-thousand-year-old paintings. These artworks are located in the world’s most atmospherically dynamic region, the Australasian monsoon domain. The rising frequency and severity of El Niño-induced droughts from anthropogenic climate change (that is, higher ambient temperatures and more consecutive dry days), combined with seasonal moisture injected via monsoonal rains retained as standing water in the rice fields and aquaculture ponds of the region, increasingly provide ideal conditions for evaporation and haloclasty, accelerating rock art deterioration.

Structural studies in active caldera systems are widely used in geothermal exploration to reconstruct volcanological conceptual models. Active calderas are difficult settings to perform such studies mostly because of the highly dynamic environment, dominated by fast accumulation of primary and secondary volcanic deposits, the variable and transient rheology of the shallow volcanic pile, and the continuous feedbacks between faulting, secondary porosity creation, and geothermal fluid circulation, alteration and cementation that tend to obliterate the tectonic deformation structures. In addition, deformation structures can be also caused by near- and far-field stress regimes, which include magmatic intrusions at various depths, the evolving topography and regional tectonics. A lack of consideration of all these factors may severely underpin the reliability of structural studies. By rebutting and providing a detailed discussion of all the points raised by the comment of Norini and Groppelli (2020) to the Urbani et al. (2020) paper, we take the opportunity to specify the scientific rationale of our structural fieldwork and strengthen its relevance for geothermal exploration and exploitation in active caldera geothermal systems in general and, particularly, for the Holocene history of deformation and geothermal circulation in the Los Humeros caldera. At the same time, we identify several major flaws in the approach and results presented in Norini and Groppelli (2020), such as (1) the lack of an appropriate ranking of the deformation structures considering an inventory method for structural analysis; (2) the misinterpretation and misquoting of Urbani et al. (2020) and other relevant scientific literature; and (3) irrelevant and contradictory statements within their comment.

The importance of the Red Data Book of Soils compilation is substantiated. The idea is based on some fundamental principles interpreted for the regional level: phenomenological, of the equivalence of components, the priority of virgin soil objects, representativeness, rarity of soil cover components, regional, zonal, azonal, catenary, and natural-historical. The main soil objects, which correspond to the zonal standards, i.e. rare, unique and endangered soils of high priority to be included in these environmental documents, have been identified by the example of the soil cover of Kirov oblast. It is proposed to assign podzolic, soddy-podzolic, and gray soils on mantle loams widely spread in the region to the zonal standards of the middle and southern taiga and mixed forests. Polygenic soils with a complicated humus profile, which includes the second relic residual and buried humus horizons are rare soils, which should be included in the regional Red Data Soil Book. A specific list of priority objects for the future regional Red Data Soil Book is presented, and the main areas of their occurrence are specified. In addition to soil reserves, it is proposed to distinguish the category of pedogenic natural monuments in places accessible for a direct observation of scientifically valuable soil objects, outcropping in river valley banks. These materials may be used to develop a local network of protected areas by including in it a new category of natural heritage: soil. These materials are of interest for environmental services of Kirov oblast and for other members of the Russian Federation.

Plate tectonics drives variation in sea-level, over intervals of approximately107–108years. These variations may have significant effects on the pace of (biological) evolution through the elimination of terrestrial niches and the expansion of shallow-water marine niches. However, within the solar system, only the Earth experiences this kind of tectonism. Venus displays regional tectonism, characterized by rising diapirs within the plastic mantle. Impinging on the lithosphere, these plumes produce a range of structures of varying dimensions; the uplift of which would raise sea-level, were Venus to have oceans. Using Magellan observations of Venus, we model the impact of regional tectonism on sea-level for given areas of Venusian ocean, then compare the effect with terrestrial tectonic processes for similar oceanic area. We show that despite variation in the geographical extent of Venusian-style tectonic processes, the styles of regional tectonism on Venus can produce the same order of magnitude changes in sea-level, for a given area of ocean, as plate tectonics. Consequently, we examine some of the impacts of marine transgression on habitability and the evolution of life.

The existence of freshwater ferromanganese concretions has been known for decades, but we are not aware of a generally accepted explanation for their formation, and there has been little research into their potential use as records of Holocene climate and paleohydrology. A conceptual model is presented to describe the environmental and geochemical processes which result in the formation and growth of freshwater ferromanganese concretions. In order to evaluate their potential as historical geochemical records, a concretion from Magaguadavic Lake, New Brunswick, Canada is the focus of a detailed geochronological and geochemical investigation. The radiocarbon data provide a coherent growth curve and a maximum age for the concretion of 8448 ± 43 years, consistent with the establishment of Magaguadavic Lake as a stable post-glacial lacustrine system. The data suggest accretion rates of 1.5 and 3.4 mm per 1000 years during the Northgrippian and Meghalayan stages of the Holocene, respectively. The abrupt change in growth rate observed at the stage boundary may be an indicator of Holocene climate change. These features are consistent with inferences from previous research that warmer climate in the Northgrippian led to eutrophication in some lakes in eastern North America. The results confirm that freshwater Fe–Mn concretions may yield important information about past climatic and environmental conditions.

For more than half a century, exploring a complete sequence of the oceanic crust from the seafloor through the Mohorovičić discontinuity (Moho) and into the uppermost mantle has been one of the most challenging missions of scientific ocean drilling. Such a scientific and technological achievement would provide humankind with profound insights into the largest realm of our planet and expand our fundamental understanding of Earth's deep interior and its geodynamic behavior. The formation of new oceanic crust at mid-ocean ridges and its subsequent aging over millions of years, leading to subduction, arc volcanism, and recycling of some components into the mantle, comprise the dominant geological cycle of matter and energy on Earth. Although previous scientific ocean drilling has cored some drill holes into old (> 110 Ma) and young (< 20 Ma) ocean crust, our sampling remains relatively shallow (< 2 km into intact crust) and unrepresentative of average oceanic crust. To date, no hole penetrates more than 100 m into intact average-aged oceanic crust that records the long-term history of seawater–basalt exchange (60 to 90 Myr). In addition, the nature, extent, and evolution of the deep subseafloor biosphere within oceanic crust remains poorly unknown. To address these fundamentally significant scientific issues, an international workshop “Exploring Deep Oceanic Crust off Hawai`i” brought together 106 scientists and engineers from 16 countries that represented the entire spectrum of disciplines, including petrologists, geophysicists, geochemists, microbiologists, geodynamic modelers, and drilling/logging engineers. The aim of the workshop was to develop a full International Ocean Discovery Program (IODP) proposal to drill a 2.5 km deep hole into oceanic crust on the North Arch off Hawai`i with the drilling research vessel Chikyu. This drill hole would provide samples down to cumulate gabbros of mature (∼ 80 Ma) oceanic crust formed at a half spreading rate of ∼ 3.5 cm a−1. A Moho reflection has been observed at ∼ 5.5 km below the seafloor at this site, and the workshop concluded that the proposed 2.5 km deep scientific drilling on the North Arch off Hawai`i would provide an essential “pilot hole” to inform the design of future mantle drilling.

The subsurface is among Earth’s largest biomes, but the extent to which microbial communities vary across tectonic plate boundaries or interact with subduction-scale geological processes remains unknown. Here we compare bacterial community composition with deep-subsurface geochemistry from 21 hot springs across the Costa Rican convergent margin. We find that cation and anion compositions of the springs reflect the dip angle and position of the underlying tectonic structure and also correlate with the bacterial community. Co-occurring microbial cliques related to cultured chemolithoautotrophs that use the reverse tricarboxylic acid cycle (rTCA) as well as abundances of metagenomic rTCA genes correlate with concentrations of slab-volatilized carbon. This, combined with carbon isotope evidence, suggests that fixation of slab-derived CO2 into biomass may support a chemolithoautotrophy-based subsurface ecosystem. We calculate that this forearc subsurface biosphere could sequester 1.4 × 109 to 1.4 × 1010 mol of carbon per year, which would decrease estimates of the total carbon delivered to the mantle by 2 to 22%. Based on the observed correlations, we suggest that distribution and composition of the subsurface bacterial community are probably affected by deep tectonic processes across the Costa Rican convergent margin and that, by sequestering carbon volatilized during subduction, these chemolithoautotrophic communities could in turn impact the geosphere. The subsurface biosphere across a convergent margin may reflect tectonic processes and reduce carbon transfer to the mantle, according to bacterial and geochemical correlations from hot springs across the Costa Rican margin.

Understanding the local stratigraphy and geometry of sediment units is necessary for successful 3D modelling and the prediction of ground behaviour and engineering-geological properties for urban land use and construction. A detailed 3D model of the main sediment units for the Rastaala basin in southern coastal Finland was constructed, combining a conceptual geological model and information from local drill-hole logs and geotechnical drilling. The 3D modelling was based on a cross-section approach, where sediment units were defined on the basis of lithological boundaries that are of major geotechnical importance for land use and construction. The conceptual geological model was based on a sequence of events that characterize the late- and postglacial evolution of the Rastaala basin. The present study combines the allostratigraphy and lithostratigraphy of unconsolidated glacial, late-and postglacial sediment units in southern coastal Finland. It also investigates the appearance and distribution of sediment units in the Rastaala basin and compares modelling and visualization results for unit surfaces and solids using two independent modelling software packages. Finally, information on the geotechnical properties of different sediment units in the Rastaala basin is provided so that they can be applied to other onshore regions with similar geological settings in the coastal Baltic Sea Basin.

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.

Loess sequences provide some of the most important continental records of climatic change, and various pedogenesis proxies from Chinese loess deposits have provided humidity records for the Miocene through Holocene. Amongst these proxies, magnetic properties have often been used to reconstruct paleoprecipitation; however, an increasing number of studies have recognized that magnetic records from loess deposits are also influenced by temperature and hence they can be used to reconstruct paleotemperatures. In the present study, the magnetic characteristics of modern loessic soils and loessic paleosols from five regions spanning a broad climatic gradient were studied to investigate the temperature dependence of the pedogenic production of magnetic minerals. The results indicate that the magnetic characteristics are dependent on the temperature of particularly season, rather than mean annual temperature in temperate region. The findings can potentially provide insights into changes in climatic seasonality on geological timescales.

Paleoclimatic reconstruction is critical for understanding present-day climate and for testing models that are currently used to predict future climatic changes. Different climatic conditions produce different clay minerals that can be recorded in geological archives providing insights into past weathering scenarios. However, in southern South America, scarce information is available from clay mineral assemblages found in aeolian sediments, such as loess deposits. Moreover, there is a lack of studies employing clay minerals for paleoclimatic reconstruction at dust sources and loess deposits. Therefore, this work explores clay mineral composition of modern dust source areas in southern South America and in the pampean loess records to gain insight into paleoenvironmental conditions prevailing during the late Pleistocene-early Holocene in the region. Clay minerals recovered from the loess deposits are of an allochthonous origin, implying their formation at the ‘arid diagonal’, then blown away, and deposited downwind in the Pampas without post-depositional changes. Clay mineral assemblages indicate that these minerals and rare earth elements (REE) analyzed in two loess sections of the Pampean Plain helped to reconstruct past climatic scenarios in the dust source areas during the transition from the last glacial to the current interglacial period. Furthermore, our work contributes to the assessment of the strengthening/weakening of the different South American dust sources in light of recent published geochemical and textural evidence.