Geological Journal最新文献

This study is based on stable isotope analysis of a rich ammonite assemblage from the Sogukcam Formation, which is widely exposed in Yesilbaglar (Olur-Erzurum, NE Türkiye). The presence of ammonid, planktic, and benthic foraminifers in the marine sediments suggests that they are from the early Cretaceous period. The late Valanginian-early Aptian-rich ammonite assemblage includes the following genera and species: Acrioceras sp., Barremites difficilis, Barremites sp., Crioceratites duvalii, Crioceratites sp., Deshayesites aff. dechyi, Deshayesites sp.1, Deshayesites sp.2, Deshayesites sp.3, Deshayesites sp., Dufrenoyia cf. dufrenoyi, Dufrenoyia cf. furcata, Dufrenoyia sp., Hemihoplites sp., Heteroceras sp., Neocomites sp., Phyllopachyceras infundibulum, Protetragonites cf. quadrisulcatus, Protetragonites sp., Ptychoceras sp., Turkmeniceras cf. geokerense, and Turkmeniceras sp. This assemblage suggests that the Sogukcam Formation's deeper facies formed in the late Valanginian to early Aptian period. Fossils and δ¹⁸O data show normal paleosalinity levels. During the late Valanginian-early Aptian period, δ¹⁸O values ranged from −3.67‰ to −2.24‰, with paleotemperatures ranging from 21.3°C to 27.9°C. δ¹³C positive values range from +0.65‰ to +2.86‰. δ¹³C isotope data show the oxygen minimum zone (OMZ) and changes in sea level and productivity. The presence of planktonic foraminifera and the ammonite assemblage indicates that the formation was deposited in warm subtropical waters ranging from the outer shelf to the open sea.

The increase in global waste generation is an important issue directly addressed in the Sustainable Development Goal (SDG)-12 and OECD countries produce large amounts of waste. In this context, the study examines the influence of waste generated and recycled on the load capacity factor (biocapacity/ecological footprint) in 28 OECD countries from 2000 to 2021 using novel panel data approaches. The study employs augmented mean group and novel half-panel jackknife estimation approaches within the Load Capacity Curve (LCC) hypothesis and confirms the LCC for OECD nations. In addition, the long-term prediction results illustrate that waste generation increases environmental destruction, while waste recycled supports the increase in the load capacity factor. The study recommends policymakers in OECD countries to support economic growth and increase investment in waste recycling technologies to achieve SDG-12.

The Northwest Himalayan region has a record of several phases of mafic magmatic activity spanning from Precambrian to Cenozoic in a dynamic tectonic setting. Here, we studied detailed petrography and new whole-rock geochemistry of mafic volcanic and dykes from the Nagrota–Kathindi Section (NKS), Himachal region of the NW Himalaya, to understand the petrogenesis and possible tectonic setting. Both rock types have comparable mineralogical compositions (clinopyroxene + plagioclase + actinolite-tremolite + chlorite + iron oxides ± hornblende ± epidote ± quartz ± carbonates) overprinted by greenschist to lower amphibolite facies metamorphism. The mafic volcanic and dykes of NKS exhibit subalkaline basalts to basaltic andesites and a typical tholeiite compositional character. The chondrite-normalized rare earth element pattern exhibits similar LREE-enrichment and strong HREE-fractionation, whereas primitive mantle-normalized multi-element patterns show pronounced LILE-enrichment of Rb, Ba, Th, LREE, and HFSE depletion of Nb, K, P, and Ti. The Zr–Y–Nb–Th relationships indicate that both rock types were derived from the plume source, whereas low Nb/La (< 1), similar high large-ion lithophile element concentrations, and pronounced negative Nb, Zr, P, and Ti anomalies suggest that components other than mantle plume must have been involved in the generation and evolution of both rock types, that is, most likely plume and subcontinental lithosphere mantle (SCLM) interaction. The genesis of parent magma for the NKS volcanic and dykes was derived by 4%–6% and 10%–20% partial melting from the spinel + garnet lherzolite stability field. The majority of the studied samples correspond to spinel + garnet peridotite melting on (Gd/Yb) _N versus CaO/Al₂O₃ diagram, thereby corroborating residual garnet in the mantle restite. All the basalts and dykes from the NK section did erupt/intrude in an intracontinental rift setting based on geochemical discrimination. The key petro-tectonic processes attributed to the formation of these rocks are as follows: (i) the melting of the ascending plume by adiabatic decompression; (ii) the partial melting of this plume–SCLM source in the melting regime, which produces basaltic magma with a tholeiitic composition; and (iii) the release of heat that provides the thermal condition for melting of SCLM and interaction between upwelling mantle plume and subduction metasomatized SCLM.

Many countries accelerate climate change by using fossil fuels like coal, gas, and petroleum to power their energy production systems and boost economic growth, which in turn releases large amounts of greenhouse gases (GHG). Recently, biofuels (BIO) have gained significant global attention for their potential to decarbonize the economy and reduce dependence on petroleum by replacing fossil fuels. This study examines the effect of biofuel consumption and innovation in non-fossil fuels on the load capacity factor (LCF) in the United States spanning from 1981 to 2020. The empirical outcomes verify the validity of the load capacity curve (LCC) theory. In addition, biofuel consumption has a favourable impact on LCF. The findings further demonstrate that innovation in non-fossil fuel technologies has no significant impact on the LCF. Based on these outcomes, the US government should increase the share of BIO as an energy component in the energy mix to replace fossil fuels. As a result, BIO have significant potential for the United States to meet its low-carbon goal by efficiently reducing GHG.

Subduction zones are the primary locations of material exchange between the crust and mantle, and thus, arc igneous rocks are extensively examined to explore crust–mantle interactions during oceanic subduction. In this study, the Sr-Nd-Hf isotopic compositions and elemental characteristics of the Yinwaxia mafic dykes from the Shibanshan–Huaniushan arc in the southern Beishan Orogen were investigated to determine their petrogenesis and explore crust–mantle interactions during the subduction of the Liuyuan Ocean. The dykes were subdivided into two groups based on their geochemical composition and spatial distribution. Group I dykes in the northern Yinwaxia area possess depleted light rare earth elements and slightly enriched large-ion lithophile elements, indicated by relatively high ratios of Rb/Nb (1.4–82), Ba/Nb (6–408), and Cs/Nb (0.13–2.74), and low ratios of Th/Yb (0.03–0.39), Th/Nb (0.10–0.83), and (La/Yb) _N (0.33–1.36). Further isotopic composition study revealed that low values of (⁸⁷Sr/⁸⁶Sr) _i (0.7028–0.7052), and high values of ε _Nd(t) (4.9–9.1) and ε _Hf(t) (13.2–24.0), which suggests that the mantle source of Group I dykes was metasomatized by aqueous fluids. In Group II dykes located in the southern Yinwaxia area, enrichment of light rare-earth elements and large-ion lithophile elements was observed, featuring lower ratios of Rb/Nb (0.5–16.7), Ba/Nb (13–51), and Cs/Nb (0.15–1.56), but higher ratios of Th/Yb (0.25–2.64), Th/Nb (0.19–1.49), and (La/Yb) _N (1.09–2.98) compared to Group I. Furthermore, Group II dykes exhibited higher values of (⁸⁷Sr/⁸⁶Sr) _i (0.7051–0.7077) and lower ε _Nd(t) (−1.7 to +3.8) and ε _Hf(t) (3.7–9.4) isotopic compositions, which suggests that the slab fluids involved in their mantle source were dominated by sediment-derived melts. The difference between the mafic dykes from Groups I and II suggests the addition of steadily increasing amounts of sediment-derived melt in their mantle source; moreover, the increased (La/Yb) _N ratio and decreased ε _Nd(t) with increasing distance from the Liuyuan mélange are records of the spatial evolution of the composition of the slab fluids during the oceanic subduction of Liuyuan Ocean in the early Permian.

To reconstruct the detailed location of proto-Japan around northeastern Gondwana during the early Palaeozoic, this article presents detrital zircon U–Pb age spectra for lower Palaeozoic metamorphic complexes and Silurian–Devonian strata from the western margin of the South Kitakami belt in northeast Japan. Psammitic and siliceous schists have youngest age peaks ranging from the Ordovician (479–458 Ma) to early Silurian (ca. 439 Ma). Sandstones have youngest age peaks varying from the early Silurian (ca. 435 Ma) to Late Devonian (370–360 Ma). The U–Pb age spectra exhibit major peaks at 510–500, 480–470, and 450–440 Ma. Excluding the Upper Devonian sandstones, significant age peaks occur at 650–550 and 1300–900 Ma. These data can be interpreted as a Pacific Gondwana signature, indicating a tectonic association with the Terra Australis Orogen that developed along the northeastern Gondwanan margin and Paleo-Pacific Ocean, extending from eastern Australia (i.e., the Thomson, Lachlan, and Delamerian orogens) to Antarctica (i.e., the Ross Orogen). In northeast Asia, the Pacific Gondwana detrital zircons and 480–470 Ma zircons occur in the Bainaimiao arc belt along the northern margin of the North China Craton and in the Jiangyu continental arc in the Jilin area. The magmatic arcs of proto-Japan and these regions were part of the Terra Australis Orogen during the Ordovician–early Silurian. A decrease in the proportion of Pacific Gondwana detrital zircons in Upper Devonian strata may be due to multistage trench retreat, such as that recognized in the Tasmanides in eastern Australia, which corresponds to the northern Terra Australis Orogen.

This study evaluates the factors contributing to carbon emissions in China between 2002 and 2021, considering the impact of GDP growth, shocks in oil prices, trade liberalization and energy use. Using the dynamic simulated ARDL (SARDL) model, we indicate a long-term link between trade liberalization, oil prices (WTI) shocks, GDP growth, energy use and CO₂. The novel SARDL revealed a direct relationship between trade liberalization and CO₂ in China in the long term. However, the results show a negative impact of WTI shocks on CO₂ emissions. The study suggests that renewable energy (RE) significantly and negatively affects China's CO₂ emissions. In addition, the findings conclude that, in the case of China, GDP has an insignificant long-run relationship with CO₂ emissions. The outcomes provide valuable insights for policymakers, researchers and industry stakeholders to enhance RE and promote sustainable energy practices.

U–Pb ages and Hf isotopic data from detrital zircon of the Silasia Formation in the Midyan Terrane record evidence for the provenance and tectonic evolution of the northern Arabian Shield. Given that the youngest acknowledged age of these detritus sediments is 735 ± 13 Ma, it is likely that the Silasia Formation was deposited during the closure of the Mozambique Ocean. The U–Pb ages define a major Mesoproterozoic peak, with two minor peaks of Neoproterozoic and Archean age. Combined with zircon Hf isotopic compositions, the sedimentary detritus of the Silasia Formation was mainly derived from source rocks formed during the Grenville Orogeny during the assembly of Rodinia, with a minor contribution from Archean and Paleoproterozoic crustal material, in addition to a limited arc-basement supply related to the early Mozambique Ocean. The youngest Concordia age of 735 ± 13 Ma with highly variable εHf_(t) values (11 to −35) indicates a complex mixture of sources from juvenile to extremely ancient. The Concordia ages at 1113 ± 11 and 1046 ± 10 Ma have positive hafnium isotope signatures (up to +10.45) that are consistent with juvenile source rocks formed during the Grenville Orogeny. Several detrital zircons with ages of 2622 ± 22 Ma and 2690 ± 7 Ma are similar to those reported in Yemen, whereas 1818 ± 19 Ma, 2071 ± 8 Ma and 2001 ± 19 Ma Paleoproterozoic ages are similar to dated outcrops in the Khida terrane in the eastern Arabian Shield.