•A comprehensive landscape evaluation system was constructed under the earthquake’s effects.•The indicators of natural landscape evaluation before and after earthquake were determined.•Evaluate the ...visual impact of geological hazard points on people.•Slope gradient, slope aspect, relative distance, and vegetation coverage are important factors in landscape visual evaluation.
The Jiuzhaigou earthquake caused severe damage to its natural landscape. The seismic-induced changes in landscapes represent a complex and diverse process. In order to creatively assess the extent of earthquake-induced landscape destruction and study the focal points of landscape restoration, this study proposes a comprehensive framework system that integrates multiple indicators and methods to evaluate the impact of earthquakes on the Jiuzhaigou scenic area. In comparison to previous single-method studies, our framework system offers a more holistic explanation and predictive capacity regarding the trends and characteristics of post-earthquake landscape changes. Within this approach, we amalgamate Grey Statistical Technique (GST), Fuzzy Analytic Hierarchy Process (FAHP), Delphi Technique, and Geographic Information System (GIS). By selecting 24 landscape evaluation indicators, we establish five levels of landscape assessment, ranging from broad to fine-grained. Areas with higher visibility sensitivity are categorized as high visual sensitivity regions, indicating the need for focused restoration efforts. Based on the degree of landscape visual sensitivity, we introduce four visual sensitivity evaluation factors: slope gradient, slope aspect, relative distance, and vegetation coverage. The result demonstrates that the overall landscape grade of Jiuzhaigou decreased by 15% after the earthquake; the aesthetic indicator of the landscape within geological hazard experienced the greatest decline, decreasing by 73.3%, while the landscape's resilience indicator showed relatively minor changes. Notably, regions with high visual sensitivity exhibit a distinctive “Y”-shaped distribution pattern, with 56.8% of environmental hazard points possessing the highest visual sensitivity. The study also underscores the concentrated presence of geological hazard points and high visual sensitivity between the Nuorilang Waterfall and the scenic area entrance, necessitating prioritized restoration efforts in this zone. This research innovatively provides a method for assessing the damage caused by earthquakes to natural landscapes, and it holds significant guiding implications for relevant national decision-making bodies in policy formulation and implementation.
•Carbon emissions from the power sector among provinces in China are analyzed.•Geographically and temporally weighted regression model was used.•Effects of driving factors show spatio-temporal ...heterogeneity.•Targeted measures for carbon emission reduction in power sector are proposed.
Carbon emissions from the power sector (CEPS11CEPS: Carbon emissions from the power sector.) contribute more than 40% of carbon emissions to both the world and China, which is the key link of carbon emission reduction. In the context of China’s “carbon peaking and carbon neutrality” goals, clarifying the regional differences and driving factors of CEPS is helpful to formulate carbon emission reduction policies. Based on the CEPS data of 30 provinces in China from 2004 to 2019, this study uses data statistics and spatial autocorrelation analysis to test the temporal and spatial differences of CEPS among provinces. Ten indicators are selected to construct a geographically and temporally weighted regression (GTWR) model for the regression analysis of driving factors of CEPS in the provinces. During 2004–2019, the CEPS in China’s 30 provinces show obvious differences. The CEPS in Shandong, Inner Mongolia and Shanxi maintain a high rise, while that in Sichuan and Yunnan shows a downward trend. The global Moran’s I of provincial CEPS in China shows significant positive spatial autocorrelation, high-high clustering area is concentrated in North and East China, and low-low clustering area is distributed in Southwest China. The effects of various driving factors on provincial CEPS show obvious temporal and spatial heterogeneity. The power structure (PS), the thermal power energy consumption rate (TE) and the per capita electricity consumption (PC) have positive effects on CEPS in most provinces, while the contribution of the power industry (IC) has a negative effect. The effects of other indicators on different provinces fluctuate in different periods. In order to realize the low-carbon sustainable development of power sector, relevant measures such as improving the efficiency of thermal power production, optimizing power structure by region, and support the major power producing provinces are proposed.
•We prefer to classify gold deposits in the western Qinling Orogen into orogenic, Carlin-type, and Carlin-like gold deposits.•We describe major characteristics of different types of gold deposits in ...the western Qinling Orogen.•We select several typical gold deposits for a detailed study.•We discuss the differences and links between different types of gold deposits and their ore-forming process.•We provide potential genetic models for the formation of different types of gold deposits.
The western Qinling, belonging to the western part of the Qinling–Dabie–Sulu orogen between the North China Block and South China Block, is one of the most important gold regions in China. Isotopic dates suggest that the Mesozoic granitoids in the western Qinling region emplaced during the Middle-Late Triassic, and the deposits formed during the Late Triassic. Almost all gold deposits in the western Qinling region are classified as orogenic, Carlin-type, and Carlin-like gold deposits, and they are the products of Qinling Orogenesis caused by the final collision between the North China Block and the South China Block. The early subduction of the Mian-Lue oceanic crust and the latter collision between South Qinling Terrane and the South China Block along the Mian-Lue suture generated lithosphere-scale thermal anomalies to drive orogen-scale hydrothermal systems. The collision-related magmatism also provided heat source for regional ore-forming fluids in the Carlin-like gold deposits.
Orogenic gold deposits such as Huachanggou, Liziyuan, and Baguamiao lie between the Shang-Dan and Mian-Lue sutures and are confined to WNW-trending brittle-ductile shear zones in Devonian and Carboniferous greenschist-facies metasedimentary rocks that were highly-deformed and regionally-metamorphosed. These deposits are typical orogenic gold deposits and formed within a Late Triassic age. The deposits show a close relationship between Au and Ag. Ores contain mainly microscopic gold, and minor electrum and visible gold, along with pyrite. The ore-forming fluids were main metamorphic fluids. Intensive tectonic movements caused by orogenesis created fluid-migrating channels for precipitation locations. Although some orogenic gold deposits occur adjacent to granitoids, mineralization is not synchronous with magmatism; that is, the granitoids have no genetic relations to orogenic gold deposits. As ore-forming fluids converged into dilated fractures during the extension stage of orogenesis, changes of physico-chemical conditions resulted in fluid immiscibility that played a key role in gold and sulfide deposition.
The geochemical and mineralogical characteristics of the Carlin-type deposits in the western Qinling region are similar to those in the Carlin trend, Nevada, USA. Gold deposits such as La’erma and Jinlongshan occur mostly in the southeastern margin of the western Qinling regionic region whereas some deposits occur in its eastern part. These deposits are hosted in slightly metamorphosed Cambrian to Triassic sedimentary rocks, showing structurally- and stratigraphically-controlled features. The deposits mainly contain submicroscopic and microscopic gold in arsenian pyrite and arsenopyrite, with characteristic ore-forming elements of Au–As–Sb–Ba. The ore-forming fluids are early-stocked formation water and later-recharged meteoric water. Meteoric water apparently evolved in ore-forming fluids by circulation, indicating the extensional setting, and led to the deposition of Au and other elements in cool reactive permeable rocks at shallow levels, forming the disseminated ores.
Carlin-like gold deposits occur between the Shang-Dan suture and the Fengxian-Zhen’an fault. The host rocks are mainly sedimentary rocks that underwent reconstruction through reworking by structural metamorphism. These deposits are structurally controlled by brittle-ductile shear zone and occur adjacent to granitoid plutons. The most important characteristic that differ to the orogenic and Carlin-type gold deposits is the genetic relationship with the synchronous magmatism. Gold occurs mainly as microscopic gold. Pyrite and arsenian pyrite can be recognized as gold-bearing minerals. The ore-forming fluids are main magmatic water mixed with metamorphic and/or formation water. Similar to orogenic gold deposits, fluid immiscibility caused the deposition of gold Carlin-like gold deposits.
The aeolian loess-paleosol sections on the northeast Tibetan Plateau (NETP) are a valuable source of paleoclimatic information because of their geographical location. In this study, two late ...Pleistocene–Holocene aeolian loess-paleosol sections were identified based on detailed field investigations in the Maqu reach in the Yellow River source area on the NETP. A robust chronostratigraphic framework for these two sections was established using AMS 14C dating, optically stimulated luminescence (OSL) dating, Bacon age-depth modelling and stratigraphic correlation. Measurements of magnetic susceptibility, hygroscopic water, loss-on-ignition, grain-size, micromorphology, and chemical element analysis suggest that most stratigraphic units in these aeolian loess-paleosol sections are in weak weathering and pedogenesis, whereas the mid-Holocene paleosol approaches to the moderate weathering and pedogenesis, and the sediments are in initial weathering stage of Na+ and Ca2+ leaching is dominated by plagioclase weathering. The main pedogenesis in the mid-Holocene paleosol is calcification process. In terms of intensity of weathering and pedogenesis, the stratigraphic units can be ordered as follows: paleosol > modern soil > transitional loess > aeolian loess. Multi-index comparison shows that the local climatic evolution during the late Pleistocene–Holocene was closely related to the evolution of the East Asian summer monsoon (EASM) and the Westerlies. Overall, the results provide a foundation for further exploration of the pedogenic and paleoclimatic evolution on the NETP.
•Chronostratigraphic framework for two aeolian loess-paleosol sections is established.•Sediments are at initial stage of Na+ and Ca2+ leaching.•Pedogenesis in the mid-Holocene paleosol is calcification process.•Pedogenic intensity is paleosol > modern soil > transitional soil > aeolian loess.
This article proposes a novel longitudinal vehicle speed estimator for snowy roads in extreme conditions (four-wheel slip) based on low-cost wheel speed encoders and a longitudinal acceleration ...sensor. The tire rotation factor, η, is introduced to reduce the deviation between the rotation tire radius and the manufacturer’s marked tire radius. The Local Vehicle Speed Estimator is defined to eliminate longitudinal vehicle speed estimation error. It improves the tire slip accuracy of four-wheel slip, even with a high slip rate. The final vehicle speed is estimated using two fuzzy control strategies that use vehicle speed estimates from speed encoders and a longitudinal acceleration sensor. Experimental and simulation results confirm the algorithm’s validity for estimating longitudinal vehicle speed for four-wheel slip in snowy road conditions.
The Shuangwang Au deposit (with a gold resource of approximately 70 t Au), is located in the Fenxian-Taibai fore-arc basin in the West Qinling Orogen of central China. Igneous intrusions in the ...region include the Xiba granitic pluton and granite porphyry and lamprophyre dykes. The Xiba pluton is composed of granodiorite and monzonite granite. The granodiorite is typical I-type granite, and it yields a crystallization age of 221.1 ± 1.2 Ma and a two-stage Hf model age of 1432–1634 Ma. The monzonite granite shows a transitional characteristic between I-type and A-type granite, and it yields a crystallization age of 214.8 ± 1.2 Ma and a two-stage Hf model age of 1443–1549 Ma. The granitoid was derived mainly from a crust–mantle mixed source. The ages indicate that the granodiorite and monzonite granite formed during two different stages. The REE distribution patterns of the Xiba granitoid exhibit significant fractionation between LREE and HREE, showing right-dipping curves, with an enrichment of LREE and a deficit of HREE. The granodiorite displays a light negative Eu anomaly, while the monzonite granite displays an obvious negative Eu anomaly. The granite porphyry dikes are distributed in the No. I breccia and Jiupinggou granite porphyry, and they yield crystallization ages of 219.9 ± 1.5 Ma and 213.1 ± 0.89 Ma, respectively, and two-stage Hf model ages of 1382–1501 Ma and 1373–1522 Ma, respectively. The lamprophyre dikes in the deposit yield a crystallization age of 214.4 ± 2.7 Ma. After the collision event between the Yangtze and the North China Plates along the Qinling orogenic belt, at approximately 220 Ma in the Late Triassic, the detachment of the slab produced the upwelling of the asthenosphere material. Under conditions of mantle heat and tectonic stress, widespread partial melting of the subducted continental crust and the upper lithosphere mantle occurred, forming granitoids with various degrees of adakite characteristics.
•Unravel uranium-organic matter interactions in Lanhe deposits.•Use advanced methods to detail uranium’s micro-scale mineral features.•Advocate green processing techniques and environmental ...management.•Identify fine-grained uranium in host minerals, requiring refined techniques.•Suggest sustainable mining practices and ecological restoration strategies.
The exploration of granite-type uranium deposits in regions with unique and complex geological features is crucial, given their significant potential for uranium reserves. However, the intricate mineral composition and diverse occurrence states of uranium within these deposits pose significant challenges for efficient processing. This study focuses on the Lanhe area in northern Guangdong’s Zhuguang Mountain, analyzing uranium ore samples to understand the geochemical behavior, mineral associations, and extraction feasibility. Advanced analytical methodologies, including petrographic thin-section analysis, photomicrography, backscattered electron imaging, and energy-dispersive spectroscopy, were employed to delineate the primary uranium-bearing minerals, such as Uraninite, Pitchblende, Uranophane, Torbernite, Autunite, and Uranothorite. The findings reveal a complex interplay between uranium and organic matter, emphasizing the fine dissemination of uranium within host minerals like pitchblende and uranophane. The study also highlights the environmental implications of uranium mining, advocating for green processing technologies and strategic environmental management practices. Innovative methods like bioleaching are proposed to minimize the environmental footprint while optimizing uranium recovery. The necessity of advanced hydrometallurgical processes for efficient uranium isolation is underscored, given the limitations of conventional physical beneficiation methods for fine-grained ore. This research provides critical insights into sustainable uranium resource management, promoting environmentally responsible mining practices and ecological restoration strategies. These findings offer substantial guidance for the global uranium mining industry, contributing to sustainable development and ecological stewardship in uranium geology.
The Haoyaoerhudong gold deposit in the northern margin of the North China Craton (NCC) is a large tonnage lower-grade deposit with a reserve of about 148 tons of gold. Gold mineralization is ...characterized by pyrite and pyrrhotite films and thin veins on the schistosity plane of the Proterozoic black shales. The orebodies, strictly controlled by a near EW-trending shear zone, are stratabound within carbonaceous phyllite and andalusite-garnet schist of the Bilute Formation. Hydrogen and oxygen isotopic data show that the ore-forming fluid was derived from a magmatic source and mixed with meteoric water. Sulfur and carbon isotope data indicate that most of the sulfur and carbon came from the black shale strata. Well-defined biotite Ar-Ar plateau age and inverse isochron age show that the deposit formed at ca. 270Ma, which suggests a probable link between Hercynian magmatism and gold mineralization. Studies on regional geology, ore geology, isotope geochemistry, and ore-forming age substantiate a complex evolutionary history of the deposit. The Proterozoic black shales rich in gold, sulfur, and organic matter, which were deposited in the Proterozoic continental margin rifts, comprised the source bed for gold mineralization. EW-ENE-structures, products of Palaeozoic orogenic process, provided pathways and mineralization space for ore-forming fluids. Hercynian tectono-magmatism and subsequent hydrothermal events remobilized gold and drove the ore-forming fluids to dilatational fracture zones. Related to postcollisional magmatic hydrothermal events, the Haoyaoerhudong gold deposit is considered as a special type of orogenic gold deposit formed in the compression–extension transition stage.
•The breccia ores of the Shuangwang gold deposit are of hydrothermal origin.•Fluid boiling induced by hydrothermal explosion is critical to gold deposition.•The gold deposit is explained to be ...related to post orogenic magmatism.
The Shuangwang gold deposit (with a gold resource of approximately 70t Au), hosted in a NW-trending breccia belt, is located in the Fenxian-Taibai fore-arc basin in the West Qinling Orogen of central China. Four stages of ore paragenesis are identified, demonstrating mineral assemblages of ankerite–quartz–albite, quartz–albite–pyrite–ankerite, pyrite–calcite–quartz, and fluorite–dickite–gypsum, respectively. Fluid inclusions hosted in stages I, II, and III hydrothermal minerals yield homogeneous temperatures of 300–463°C, 220–340°C and 100–279°C, with salinities lower than 22.7wt% NaCl equiv. Trapping pressures estimated from CO2–H2O fluid inclusions show a gradual decrease from 100–170MPa (KT8 ore body) to 17–55MPa (KT2 ore body), corresponding to mineralization depths from 3.8–6.4km (KT8) to 0.6–2.1km (KT2). Hydrogen and oxygen isotopic data suggest that the ore-forming fluids evolved from metamorphic water to magmatic water, and lately meteoric water. Sulfur and carbon isotope compositions show that these fluids might have originated from interaction with the host rocks with minor additional magmatic source. Based on geochemical investigations, with combination of regional and ore deposit geology, a possible genetic model with a three-step ore-forming process is proposed. The Devonian Xinghongpu sedimentary rocks are characterized by a relatively high gold content, which might provide the initial gold source. Linear folds and faults formed during Triassic orogenic processes provided the subsequent pathways for ore-forming fluids and suitable space for gold mineralization. Postorogenic magmatic activity induced voluminous hydrothermal fluids that mixed with the basinal fluids and may have started the ore formation process. Over pressure led to hydrofracturing and the subsequent pressure drop promoted fluid boiling, which in turn resulted in abundant gold deposition. Induced by postorogenic magmatic hydrothermal activity, the Shuangwang gold deposit is considered a special type of orogenic gold deposit formed in a compression–extension transition.
The Shuangwang gold deposit, located in the Fengxian-Taibai fore-arc basin in the western Qinling Orogen of Central China, has yielded over 70 tons of gold. It is an orogenic gold deposit occurring ...in an NW-trending breccia belt. Most of the ores are hydrothermal breccia type containing fragments of adjacent strata cemented by ankerite and pyrite. Pyrite is the most abundant metallic mineral and the major gold-bearing mineral in the ores. A total of 58 pyrite samples from main ore bodies of the Shuangwang gold deposit have been analysed for 44 trace elements by HR-ICP-MS. Sb, Ba, Cu, Pb, Zn, Bi, Mo, Co are selected as indicator elements to investigate the potential usefulness of trace elements in pyrite as an indicator in gold exploration. The results show that the supra-ore halo elements Sb and Ba, which may have been more active than other near-ore halo elements and sub-ore halo elements, are best to characterize the shape of ore bodies. Five target areas are pointed out for deep ore exploration based on a comprehensive study of supra-ore, near-ore and sub-ore halos. This study provides evidence that trace elements in pyrite can be used to depict the deep extension of ore bodies and to vector towards undiscovered ore bodies.
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