Geological Journal最新文献

Determining subduction-related processes is crucial for understanding lithological heterogeneity, as substantial quantities of slabs are recycled into the mantle. Molybdenum isotopes are valuable for distinguishing sources materials due to the significant isotope differences between the crust and the mantle. In this study, we systematically investigate Mo isotopes in a suite of well-characterized continental basalts from Keluo and Halaha-Chaoer, located in Northeast China. The δ⁹⁸Mo values of Keluo range from −0.41 to −0.23‰, with an average of −0.34‰, while Halaha-Chaoer samples ranged from −0.18 to −0.12‰, with an average of −0.15‰. The δ⁹⁸Mo values of Keluo basalts are lighter than the mean value of fresh oceanic basalts (−0.21‰), whereas those of Halaha-Chaoer basalts are similar to oceanic basalts. Combined with other geochemical indications (LOI, Ce/Pb, La/Yb and so on), the Mo isotopic variations cannot be attributed to chemical weathering, continental crust contamination or magmatic processes. Instead, the δ⁹⁸Mo variations in this study are explained by the incorporation of different oceanic crustal materials into the magma sources. Correlations of δ⁹⁸Mo with Ba/Th, Th/U, ¹⁴³Nd/¹⁴⁴Nd indicated that both sediment and altered oceanic crust have significantly influenced these variations. This study demonstrates the potential of Mo isotopes to distinguish different types of recycled oceanic crust materials.

This study investigates the dynamic effect of resource productivity and green technologies on renewable energy (RE) use in 28 middle-income countries from 2006 to 2022 using MMQR, QR and causality techniques. Results suggested that green technology innovation substantially influences RE use. Second, the significant positive coefficients show that resource productivity leads to higher RE consumption at the upper quantile due to decoupling Gross Domestic Product (GDP) growth from extracting natural resources, indicating a transition towards more sustainable and efficient practices. Based on the empirical findings, several policy implications are suggested for middle-income economies.

Differences in the pore and fracture systems of four marcolithotypes (bright，semi-bright, semi-dull and dull) in coal reservoirs affect the quality of coalbed methane (CBM) and constrain exploration and development of CBM. In this paper, vitrinite reflectance (R _O), maceral composition, proximate analysis, scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), low-field nuclear magnetic resonance (NMR) and high-pressure isothermal adsorption experiments and the mathematical method of fractal dimension were carried out on high-rank coal samples of different marcolithotypes from the Weizhou mining area in the western margin of Ordos Basin. The results show that from bright coal to dull coal, the R _O and vitrinite content gradually decrease, while the mineral content and A _ad gradually increase. SEM images show that the bright and semi-bright coals develop open fractures, whereas semi-dull and dull coals develop closed fractures. According to pore size distribution established by MIP and NMR, the proportion of seepage pores gradually increased from bright coal to dull coal, and MIP fractal dimension of seepage pores (D _M2; 2.3352, 2.3532, 2.3755 and 2.4727, respectively) and NMR fractal dimension of seepage pores (D _N2; 2.8767, 2.9142, 2.9297 and 2.9981, respectively) show that the structure of the seepage pore is progressively more complex from bright coal to dull coal. In addition, percentage of NMR adsorption pores progressively increases from bright coal to dull coal (64.96%, 76.64%, 82.04% and 89.67%, respectively), but total porosity of bright coal (6.74%) is much greater than that of dull coal (1.34%), which results in that bright coal also has the strongest CH₄ adsorption capability (Langmuir volume is 22.898 cm³/g).

The present study explores the impact of energy natural resource productivity and environmental tax on environmental sustainability in six major CO₂-emitting economies: the Euro Area, China, South Korea, Japan, the United Kingdom and the United States, from 1997 to 2019. This analysis aims to reveal novel findings and implications for different energy natural resource productivity types and environmental regulations. We employed data regarding leading national and regional CO₂ emitters from 1997 to 2020 to conduct an empirical analysis using the panel non-linear auto-regressive distributed lag (NARDL) and panel quantile ARDL (QARDL) methods. The results show that energy natural resource productivity and environmental tax are crucial components in reducing CO₂ emissions by controlling for innovation technology and renewable energy consumption. The main findings demonstrate that the impact is stronger in the presence of increased energy natural resource productivity and vice versa. These findings have novel implications for sustainable development and carbon neutrality.

A combination of magnetic polarity and rock magnetic analysis on the well-documented section of the Um Sohryngkew River (USR) in the south Shillong Plateau, NE India, produced a sharp reversal marking the C29r-C29n geomagnetic polarity transition at approximately 65.688 Ma. The rock magnetic studies indicate ferrimagnetic dominant mineralogy with abundance of SSD grains, with an anomalous peak in susceptibility coinciding with Ir-rich limonitic layer. The magnetic reversal occurs precisely 61 m above the Ir-rich distinct in situ limonitic layer, indicating that the C29r-C29n geomagnetic reversal post-dates the widely accepted Ir-anomaly based K-Pg boundary by approximately 355 Ka. Furthermore, the rock magnetic studies indicate its frequency dependence coinciding with the Ir-rich limonitic layer suggesting a possible dust/aerosol source, while akaganéite is reported from the interval approximately 1 m below peak susceptibility, indicating signature of Deccan volcanism. This study infers the completeness of the USR section with a high rate of sedimentation of approximately 17 cm/ka among the marine K-Pg boundary sections in the world.

The Shandong Peninsula is located in the eastern part of the North China Craton (NCC). Influenced by the collision between the North and South China blocks and the subduction of the Pacific Plate, the tectonic evolution process is highly complex. Previous studies have proposed that the thick cratonic root beneath the eastern NCC has been destructed. To better understand the relationship between the craton reactivation and the deep subduction, more constraints on the topography variations of the mantle transition zone (MTZ) discontinuities are required. In this study, we stacked 9073 P-to-S receiver functions calculated from 129 broadband seismic stations to image the depth variations of the MTZ discontinuities beneath the Shandong Peninsula and its adjacent area. To decrease the influence of velocity anomaly above the MTZ discontinuities, we converted the apparent depths into corrected depth using regional and global 3D velocity models. The apparent depth of the 410-km discontinuity exhibits a depression of approximately 6 km, which normalizes after velocity correction. This implies the existence of the low-velocity anomaly in the upper mantle, possibly caused by slab dehydration and water infiltration into the upper mantle. The significant depression of the 660-km discontinuity indicated the presence of the cold Pacific slab stagnating at the base of the MTZ. The gradual westward depression of the 660-km discontinuity by 50 km could provide evidence for the sinking of the western margin of the flat-lying subducting Pacific slab in the MTZ beneath the Shandong Peninsula.

The state parameter (ѱ) accounts for both relative density and effective stress, which influence the cyclic stress or liquefaction characteristic of the soil significantly. This study presents a ѱ-based probabilistic liquefaction evaluation method using six soft computing (SC) techniques. The liquefaction probability of failure (P_L) is calculated using the first-order second moment (FOSM) method based on the cone penetration test (CPT) database. Then, six SC techniques, such as Gaussian process regression (GPR), relevance vector machine (RVM), functional network (FN), genetic programming (GP), minimax probability machine regression (MPMR) and multivariate adaptive regression splines (MARS), are used to predict P_L. The performance of these models is examined using nine statistical indices. Additionally, plots such as regression plots, Taylor diagrams, error matrix and rank analysis are shown to assess the SC model's performance. Finally, sensitivity analysis is performed using the cosine amplitude method (CAM) to assess the influence of input parameters on output. The current study demonstrates that SC models based on state parameter predict P_L effectively. RVM and MPMR models closely follow the GPR model in terms of performance, which is superior to the other models. Notably, two equations are generated using GP and MARS models to predict P_L. The results of the sensitivity analysis reveal the magnitude of earthquake (M_w) as the most sensitive parameter. The outcomes of this research will offer risk evaluations for geotechnical engineering designs and expand the use of state parameter-based SC models in liquefaction analysis.

Global research on the geological particularities of coal-accumulating environments and the enrichment patterns of coalbed methane (CBM) is still relatively weak. This paper studies the geological characteristics and coal accumulation patterns of Carboniferous-Permian coal-bearing seams in the southern Qinshui Basin. The results show that the coal-bearing strata in the basin represent the offshore marine and continental intercalated coal seam sediments developed. The southern part of the basin is dominated by lacustrine facies, and the delta front sub-facies is locally developed. The characteristics of coal accumulation environment in the southern Qinshui Basin are characterized by basement properties, fault networks and coal-bearing sedimentary facies, which collectively control the spatial and temporal distribution characteristics of the coal-rich belt. The differences in coal accumulation environment in the southern basin affect the tectonic evolution, the thickness of the coal seam roof and floor and the hydrogeological conditions of the coal-rich area, which further control the CBM enrichment in the Taiyuan-Shanxi Formation. The aim of this study is to explore the factors of CBM enrichment and gas control mode, so as to enrich and improve the theory and method of CBM exploration, which will also help identify the appropriate underground geological structure environment for carbon sequestration (CCS), reduce greenhouse gas emissions and effectively respond to the challenge of global warming.