Nitrogen isotope ratios (δ15N) are a well-established tool for investigating the dietary and trophic behavior of animals in terrestrial and marine food webs. To date, δ15N values in fossils have primarily been measured in collagen extracted from bone or dentin, which is susceptible to degradation and rarely preserved in deep time (>100,000 years). In contrast, tooth enamel organic matter is protected

Accessible surface areas (ASAs) of individual rock-forming minerals exert a fundamental control on the maximum mineral reactivity with formation fluids. Notably, ASA efficiency during fluid-rock reactions can vary by orders of magnitude, depending on the inflow fluid chemistry and the velocity field. Due to the lack of adequate quantification methods, determining the mineral-specific ASAs and their

The combination of authigenic chromium and cadmium stable isotopes in marine sedimentary archives enables reconstruction of the redox conditions and levels of primary productivity in past oceans and basins. The Ediacaran to Cambrian Nanhua Basin (Yangtze Platform, South China) and its sedimentary sequences have been studied intensively in the past with respect to investigating the effects of post-Snowball

The relative proportion of mid-chain to long chain n-alkane homologues and isotopic compositions of total organic carbon (Paq and δ13Corg) have been proposed as potential lake-level proxies since such features mainly come from submerged aquatic plants living within an optimum range of lake water depth. With limited dataset available, the applicability of both indices and their sensitivity to lake water

Development of an effective biotechnological method of reducing the continuous emission of CO2 has caused wide public concern. Research on serpentine bio-weathering coupled with carbonation is a current focus of interest. To investigate the molecular mechanisms, Bacillus subtilis was cultured in the Mg2+-free medium with the addition of serpentine. Based on the composition of organic matter and the

Chromium isotopes have emerged as powerful redox proxies for past ocean-atmosphere systems as shifts in Cr isotope ratios towards heavier isotope compositions are indicative of Cr redox cycling on Earth. Knowledge of the Cr cycle in the critical zone and the fate of Cr during serpentinization and other hydrothermal processes is therefore important to assess the geologic interpretation of Cr isotopes

Flowback/Produced fluid samples were collected from several wells from two Utica/Point Pleasant (UPP) sites (UPPW and UPPS) in Ohio, and one Marcellus (Marcellus Shale Energy and Environment Laboratory (MSEEL)) site in West Virginia over a period of approximately two years. Although these formations have different ages, depositional environments, diagenetic histories, and geochemical and mineralogical

Copper is of importance in geosciences, biosciences, and industry. Its isotopes can be used to study planetary processes, trace Cu biogeochemical cycling, identify the type of Cu-bearing ore minerals, investigate the formation of ore deposits, and explore concealed ore-bodies. However, Cu isotope fractionation parameters of the majority of copper minerals remain poorly known, impeding the application

Iron oxide concretions are found in sedimentary rocks on both Earth and Mars. On Earth, concretions are common in eolian formations, such as the Jurassic Navajo Sandstone in Utah, USA and those found in the Cretaceous Djadokhta Formation, Gobi Desert, Mongolia. Although it is known that the formation conditions of the iron oxide concretions were affected by the paleoclimate of these regions, quantitative

The present work uncovers the geochemical control on the nature (tunnel size) of the tectomanganates formed from layered precursors, and thus provides insights into the formation of Mn oxides in natural environments. Large tunnel sizes are favored under circum-neutral conditions, whereas low pH conditions favor the formation of tectomanganates with smaller tunnel sizes. Both the increased proportions

The remnant rear-arc segment of the early Izu-Bonin arc, known as the Kyushu-Palau Ridge (KPR), is a key location where magmatic outputs can be constrained during the lifetime of an island arc. We present new geochemical data for coarse-grained basaltic to andesitic volcaniclastic sandstones derived from the KPR and deposited in the Amami Sankaku Basin (IODP Site U1438, Unit III rocks) in the time

We measured germanium-silicon (Ge/Si) ratios in both fluid and solid phases using a series of highly constrained amorphous silica precipitation experiments at 20°C and neutral pH for a wide range of seed crystal surface areas. Silicon isotope data (δ30/28Si) on these experiments were previously reported by Fernandez et al. (2019). A distinct lag in the onset of Ge/Si partitioning relative to δ30Si

For the first time, a new ordered double carbonate, BaFe(CO3)2, was synthesized by a solid-state reaction between BaCO3 and FeCO3 at high pressure-temperature conditions (PT; 3 GPa and 700 °C). This finding adds a new so-far unknown member to the group of norsethite-structured carbonates, which is often used as a geochemical analogue for dolomite. Thermogravimetric (TG) analysis and differential scanning

The Wulasigou polymetallic (zinc–copper–iron–gold) deposit is located in the volcano–sedimentary Kelan Basin of the Chinese Altay. The orebodies of the Wulasigou polymetallic deposit are hosted in the second unit of the upper member of the Lower Devonian Kangbutiebao Formation and exhibit the characteristics of a stratabound deposit. Three mineralization periods are identified: an exhalative–sedimentary

Stalagmites are the product of the combined effects of the surface environment and the cave environment, and their stable carbon and oxygen isotope ratios (δ18O and δ13C) have been widely used as proxies for palaeoclimatic and palaeoenvironmental reconstructions. Modern cave monitoring is essential for the accurate interpretation of multiple-proxies in stalagmites. However, the interpretation of the

This study proposed an advection-diffusion-mechanical deformation integral model to predict coal matrix methane permeability combining digital rock physics with laboratory measurements. The coal matrix pore network was first extracted from the segmented 3D digital coal image. Organic pore-controlled methane transport pathways and mineral-associated pore methane transport pathways were identified from

Mixed siliciclastic-carbonate sediments have been widely studied, especially those of marine origins. However, it is rarely investigated in continental settings. Boreholes from the Qinhuangdao-A (QHD-A) block in central Bohai Bay Basin sampled lacustrine mixed sediments during the Eocene Es1-2s period (32-38Ma), providing an opportunity to facilitate this aspect of research. Here, an integrated study

The continental margins of the South China Sea (SCS) have undergone episodic rifting since the Cenozoic, and there are ongoing debates surrounding the processes of crustal deformation and seafloor opening. In this work, we present a P‐wave velocity model extending from the north of Xisha Trough to the Zhongshanan Basin in the northwestern SCS margin, using ocean bottom seismometer data of the wide‐angle

Cosmogenic exposure data can be used to calculate time‐varying fault slip rates on normal faults with exposed bedrock scarps. The method relies on assumptions related to how the scarp is preserved, which should be consistent at multiple locations along the same fault. Previous work commonly relied on cosmogenic data from a single sample locality to determine the slip rate of a fault. Here we show that

The Bangong–Nujiang Suture Zone (BNSZ) in central Tibet represents relics of the Meso‐Tethys Ocean that once separated the Lhasa and Qiangtang terranes. When and how this ocean closed has been a matter of debate, and the cause of the uncertainty stems primarily from a lack of consensus as to whether Early Cretaceous ophiolite exists within the BNSZ. New geochronological and geochemical data presented

Recent Juno observations have greatly extended the temporal and spatial coverage of lightning detection on Jupiter. We use these data to constrain a model of moist convection and lightning generation in Jupiter's atmosphere, and derive a roughly solar abundance of water at the base of the water cloud. Shallow lightning, observed by Juno (Becker et al., 2020, Nature, 584, 55‐58) and defined as flashes

We catalogue the global inventory of Europa's cycloids, arcuate fractures whose paths have been linked to diurnal tidal stress, and use the locations and orientations of their cusps to further test the formation mechanism of cycloids and constrain Europa's rotation state. We find that the global distribution of cycloids is better explained by a precessing spin pole than longitude translation due to

Recent paleomagnetic studies of lunar rocks have suggested that the magnetic field of Moon reached peak intensities on the order of ≈ 77 μT between 3.85 billion and 3.56 billion years ago (Ga) and subsequently declined to surface intensities of ≈ 4 μT by 3.19 Ga. However, this decline in the intensity of the lunar field has only been shown in a small number of samples, presenting challenges for constraint

Migration of multi‐component elastic data in anisotropic models is difficult and has not been reasonably addressed. Thus we test three‐dimensional ray‐based Kirchhoff pre‐stack depth scalar migration and calculate migrated sections in a simple anisotropic velocity model. We generate ray‐theory seismograms for separate phases of reflected P, S1, S2 and converted waves. The velocity model is composed

We propose an algorithm for seismic trace interpolation using generative adversarial networks, a type of deep neural network. The method extracts feature vectors from the training data using self‐learning and does not require any pre‐processing to create the training labels. The algorithm also does not make any prior explicit assumptions about linearity of seismic events or sparsity of the data, which

Migration, velocity and amplitude analysis are the employed processing steps to find the desired subsurface information from seismic reflection data. The presence of free‐surface and internal multiples can mask the primary reflections for which many processing methods are built. The ability to separate primary from multiple reflections is desirable. Connecting Marchenko theory with classical one‐dimensional

Wave‐mode separation is a critical step in anisotropic elastic‐wave imaging. To avoid high computational costs and additional corrections, we apply a separation formula in the space domain that projects Cartesian components of the elastic wavefield onto the polarization vectors in the orthogonal direction. By solving the Christoffel equation, we implement the conversion from the phase velocity direction

Manual fracture identification methods based on cores and image logging pseudo‐pictures are limited by the expense and the amount of data. In this paper, we propose an integrated workflow, which takes the fracture identification as an end‐to‐end project, to combine the boundary detection and the deep learning classification to recognize fractured zones with accurate locations and reasonable thickness

The Xiaorequanzi copper–zinc deposit, located in the eastern Tianshan, is considered as a medium‐sized polymetallic deposit in Xinjiang, NW China. Understanding the structural framework and delineating the location of intrusions as well as the distribution of ore‐controlling strata in this mining area are vital for identifying new potential exploration areas. This paper aims to provide new information

Magnetotelluric is one of the mainstream exploration geophysical methods, which plays a vital role in studying deep geological structures and finding deep hidden blind ore bodies. The seriousness of human electromagnetic noise causes a large number of abnormal waveforms in the time series of measured magnetotelluric data, and the data can no longer objectively reflect the underground electrical distribution

Although most electromagnetic data can be inverted to actual resistivity, ways of quickly getting a real‐time interpretation of a data set are still valuable. Such methods are useful when we are testing instrumentation or assessing data quality during a survey, or when we need to get a general understanding of the geological structure during a field survey. Apparent resistivity is a good way to satisfy

The perhumid coastal temperate rainforest (PCTR) of northwestern North America is projected to become warmer and wetter in coming decades, with largely unquantified implications for the magnitude and speciation of riverine nitrogen (N) and phosphorus (P) export from PCTR ecosystems. We collected streamwater at weekly to monthly intervals for a year and intensively during two multi-day storms (one each

Much of the crust of Iran and Anatolia, including their oldest exposed rocks, formed during an episode of intense convergent margin (arc) magmatism as a result of subduction of oceanic lithosphere beneath northern Gondwana from ca 620 Ma to ca 500 Ma, the Cadomian crust-forming event. Most igneous rocks formed between ca 570 and 525 Ma. Cadomian crust is well-known from western and southern Europe

This paper reports petrology, major and trace element abundances in bulk-rocks and minerals, and clinopyroxene Sr-Nd-Hf compositions from a suite of mantle xenoliths entrained in Cenozoic Sanyitang alkali basalts, Jining County in the Inner Mongolia Suture Zone. The aim is to constrain the nature and evolution of the lithospheric mantle beneath the western North China Craton. The Sanyitang mantle xenoliths

The Late-Permian Emeishan mantle plume event caused large-scale flood basalts and related mafic-ultramafic layered mafic intrusions in the inner zone of the Emeishan large igneous province (ELIP). However, the related crustal magma response of this mantle plume event in the inner zone of the ELIP remains poorly understood. In this contribution, we report contemporaneous (~259 Ma) ferrosyenite and A-type

Leucogranite, typically as an important signature of continent-continent collision, records valuable information on evolution of continental crust and provides an insight into the geodynamic processes during continental collision. Here, we present zircon U-Pb and muscovite Ar-Ar dating, major and trace elements, and Sr-Nd isotope data for the Yuanbaoshan leucogranites in southeast Inner Mongolia, with

Global Navigation Satellite System (GNSS) signals have become a useful tool to analyse signal‐in‐space performance in the presence of ionospheric perturbations with a view to improving the performance of satellite‐based systems and services. For this purpose, continuous monitoring of the signal tracking capabilities of commercial GNSS receivers is a priority, particularly from regions around the crests

A new discovery was made using the Radio Receiver Instrument (RRI) on the Canadian Enhanced Polar Outflow Probe (e‐POP) showing that Strong Plasma Wave Emissions (SPWE) are seen near 17 kHz and 300 Hz. The frequency of these emissions are affected by small injections of neutral gas from the Cygnus spacecraft. The technique of using a 150 g/s thruster to change frequencies and intensities of plasma

We modified and justified the radar equation for ground penetration by including the backscattering effect. We propose a strawman system on an orbiter 50 km above the surface based on lunar conditions. The Tightly‐coupled dipole arrays antenna substantially reduces the size and mass and consists of an array with 8x8 cells on a light weight plate that is 1.62m2 wide with cells 0.25m high providing increased

High‐speed data transfer and high‐performance imaging can be realized by using radio‐waves in high‐frequency bands, such as millimeter‐waves and THz‐waves, where wide frequency bands are available. However, the cell size would be smaller than a few hundred meters, due to large free space propagation loss and large atmospheric attenuation. Thus, many base stations, which are connected by networks, are

Several countries around the world are confronted solid waste management most especially from aluminum beverage containers. The recycling process is seen as an effective approach since it is energy saving, cost effective and reduced emission. In this study, the Sol-gel method was used to process the aluminum wastes and to consequently synthesize them into aluminum oxide (α-Al2O3) and presented in several

AbstractOne of the typical anisotropic media is the monoclinic anisotropy (MA) medium, which is formed by embedding two sets of non-orthogonal fracture sets into an isotropic or vertical transverse isotropic (VTI) background medium. Weak anisotropy (WA) parameters and fracture density provide important in situ stress and high-porosity zone information. Estimation of WA parameters and fracture density

Timor-Leste and Oecusse in particular have very little geological data coverage due to the many conflicts generated mainly by Portuguese colonization and Indonesian occupation. The main work that has been done was aimed at oil prospecting on the south coast. A regional stream sediment campaign was started from the Maquelab area in the Oecusse enclave, west of Timor-Leste, where no mineralization had

Rock stress sensitivity is typically investigated macroscopically. In contrast, a new method combining in situ Scanning Electronic Microscope (SEM) study and digital core deformation simulation is developed in this paper, providing an effective way to investigate the relationship between microstructural deformation and decreasing permeability. The simulation method might replace in situ SEM study under

Permeation grouting estimation is important for the design of grouting engineering. Filtration effects and rheological behavior play a key role in permeation grouting diffusion of cement-based grouts. To better understand the effect of filtration and grout rheological behavior on the grouting diffusion mechanism, one-dimensional permeation grout injections in sand columns under constant flow rate were

The present study takes the ratio of the matric suction to the net vertical stress and the ratio of the matric suction to the net mean stress as new unsaturated stress levels and , respectively. Based on the laboratory tests and theoretical derivation, the modified one-dimensional Mesri creep model and three-dimensional creep model were established, which takes the unsaturated stress level into account

Multicomponent thermal fluid huff and puff is an innovative heavy oil development technology for heavy oil reservoirs, which has been widely used in offshore oilfields in China and has proved to be a promising method for enhancing oil recovery. Components of multicomponent thermal fluids contain many components, including carbon dioxide, nitrogen, and steam. Under high temperature and high pressure

The settlement calculation model for soft clay foundation is established based on Hooke’s law and the Duncan-Chang model. By introducing the concept of damage ratio, the method for determining the deformation modulus of soil before and after damage under load is presented, and a nonlinear settlement calculation method which considers the structural characteristics of soft clay is proposed. In the end

This study gives two new analytical solutions to the tunnel by high-pressure water in the cavern. Firstly, it deals with the analytical solution for the seepage inflow in unsupported karst aquifer tunnels considering the boundary condition. Secondly, it focuses on the study of the seepage force and gives the reduction coefficient of lining water pressure. A comparison of the analytical solution and