Editorial

3 pages, 172 KiB

Open AccessEditorial

Special Issue on New Advances and Illustrations in Applied Geochemistry in China

by Qingjie Gong and Zeming Shi

Appl. Sci. 2023, 13(14), 8220; https://doi.org/10.3390/app13148220 - 15 Jul 2023

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The 9th national conference on applied geochemistry in China will be held in Chengdu, Sichuan province, in October 2023, hosted by the committee of applied geochemistry, the Chinese Society for Mineralogy, Petrology and Geochemistry (CSMPG) [...] Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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22 pages, 11856 KiB

Open AccessArticle

Pore Fractal Characteristics of Lacustrine Shale of Upper Cretaceous Nenjiang Formation from the Songliao Basin, NE China

by Tian Dong, Lei Kang, Yifan Zhang and Yuan Gao

Appl. Sci. 2023, 13(7), 4295; https://doi.org/10.3390/app13074295 - 28 Mar 2023

Cited by 2 | Viewed by 1251

Abstract

The evaluation of pore characteristics in lacustrine shales is of significance for shale oil and gas exploration in terrestrial sedimentary basins. However, due to the complex depositional environments, there have been few reports on the quantitative evaluation of lacustrine pores. In this study, [...] Read more.

The evaluation of pore characteristics in lacustrine shales is of significance for shale oil and gas exploration in terrestrial sedimentary basins. However, due to the complex depositional environments, there have been few reports on the quantitative evaluation of lacustrine pores. In this study, we carry out experiments, e.g., scanning electron microscopy (SEM), nitrogen adsorption, X-ray diffraction (XRD), and rock pyrolysis, on sixteen lacustrine shale core samples of the Late Cretaceous Nenjiang Formation (K₂n¹⁺²) in the Songliao Basin. At the same time, we bring in the fractal dimensions to quantitatively characterize the pores of shale samples in K₂n¹⁺². The kerogen type of shales in the Nenjiang Formation is mainly type Ⅰ. The shales of K₂n¹⁺² develop a large number of mineral intergranular pores and a small number of organic pores and mineral intragranular pores. The primary minerals of the samples are clay minerals and quartz. The total organic carbon (TOC) has a correlation with the pore physical parameters, whereas the content of minerals does not correlate significantly with pore development. The average pore fractal dimensions obtained from the analysis of nitrogen adsorption data are D1 = 2.5308 and D2 = 2.6557. There is a significant negative correlation between the fractal dimensions (D1 and D2) and the TOC content: the lower the fractal dimensions, the higher the TOC, and the more the free oil. In low maturity shales with higher TOC content, due to hydrocarbon generation, larger pores with a regular shape (small fractal parameters) can be produced, which can store more free oil. The shale reservoir evaluation of K₂n¹⁺² in the Songliao Basin should be focused on shales with higher TOC and lower pore fractal parameters. Our work provides a reference for the shale oil evaluation of K₂n¹⁺² in the Songliao Basin and complements studies on lacustrine pore characteristics. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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20 pages, 4074 KiB

Open AccessArticle

A Helmholtz Free Energy Equation of State of CO₂-CH₄-N₂ Fluid Mixtures (ZMS EOS) and Its Applications

by Jia Zhang, Shide Mao and Zeming Shi

Appl. Sci. 2023, 13(6), 3659; https://doi.org/10.3390/app13063659 - 13 Mar 2023

Cited by 1 | Viewed by 1448

Abstract

An equation of state (EOS) of CH₄-N₂ fluid mixtures in terms of Helmholtz free energy has been developed by using four mixing parameters, which can reproduce the pressure-volume-temperature-composition (PVTx) and vapor-liquid equilibrium (VLE) properties of CH₄-N [...] Read more.

An equation of state (EOS) of CH₄-N₂ fluid mixtures in terms of Helmholtz free energy has been developed by using four mixing parameters, which can reproduce the pressure-volume-temperature-composition (PVTx) and vapor-liquid equilibrium (VLE) properties of CH₄-N₂ fluid mixtures. The average absolute deviation of all the PVTx data available up to 673.15 K and 1380 bar from this EOS is 0.38%. Combining this EOS of CH₄-N₂ fluid mixtures and the EOS of CH₄-CO₂ and CO₂-N₂ fluid mixtures in our previous work, an EOS of CO₂-CH₄-N₂ fluid mixtures has been developed, which is named ZMS EOS. The ZMS EOS can calculate all thermodynamic properties of ternary CO₂-CH₄-N₂ fluid mixtures and the average absolute deviation of the PVTx data from the ZMS EOS is 0.40% for the CO₂-CH₄-N₂ system. The ZMS EOS can be applied to calculate excess enthalpies of CO₂-CH₄-N₂ fluid mixtures, predict the solubility of CO₂-CH₄-N₂ fluid mixtures in brine and water, and quantitatively estimate the impact of the impurities (CH₄ and N₂) on the CO₂ storage capacity in the CO₂ capture and storage (CCS) processes. The ZMS EOS can also be applied to calculate the isochores of CO₂-CH₄-N₂ system in the studies of fluid inclusions. All Fortran computer codes and Origin drawing projects in this paper can be obtained freely from the corresponding author. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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22 pages, 3715 KiB

Open AccessArticle

The Quality of Scutellaria baicalensis Georgi Is Effectively Affected by Lithology and Soil’s Rare Earth Elements (REEs) Concentration

by Zijian Sun, Wei Shen, Weixuan Fang, Huiqiong Zhang, Ziran Chen, Lianghui Xiong and Tianhao An

Appl. Sci. 2023, 13(5), 3086; https://doi.org/10.3390/app13053086 - 27 Feb 2023

Cited by 2 | Viewed by 930

Abstract

The top-geoherb “Rehe Scutellaria baicalensis” was naturally distributed on Yanshan Mountain in Chengde city, Hebei Province, China. Exploring the influences of parent materials on the quality of the top-geoherbs in terms of micronutrient elements is of great significance for the protection of [...] Read more.

The top-geoherb “Rehe Scutellaria baicalensis” was naturally distributed on Yanshan Mountain in Chengde city, Hebei Province, China. Exploring the influences of parent materials on the quality of the top-geoherbs in terms of micronutrient elements is of great significance for the protection of origin and for optimizing replanting patterns of Scutellaria baicalensis. In this study, three habitats of Scutellaria baicalensis with contrasting geopedological conditions, i.e., naturally grown habitats (NGHs), artificial planting habitats (APHs), and biomimetic cultivation habitats (BCHs), are taken as objects to probe the influences of parent materials on the quality of Scutellaria baicalensis in terms of rare earth elements (REEs) by testing on REEs concentrations in the weathering profiles, rhizosphere soil and growing Scutellaria baicalensis, as well as their flavonoid compound contents. Hornblende-gneiss was the parent rock in NGHs, whose protolith was femic volcanic rock. Loess was the parent rock in APHs and BCHs. REEs were more abundant in hornblende-gneiss than loess, and therefore, soils developed in NGHs contained higher REE concentrations than those in APHs, which was lower than BCHs after REE-rich micro-fertilizers application. The coefficient of variation (CV) of REEs concentrations in the rhizosphere soils of hornblende-gneiss was higher than that in loess. It possibly was attributed to the complicated minerals compositions and various minerals’ grain sizes of hornblende-gneiss, resulting in the variety of weathering intensity involving eluviation, leaching, adsorption, etc., as well as weathering productions, dominated by clay minerals and Fe-(hydro)oxide, and ultimately the remarkable differences in the migrations, enrichments and fractionations within REEs. The biological absorption coefficients (BACs) of REEs for Scutellaria baicalensis decreased in the order of NGHs > APHs > BCHs. Roots of Scutellaria baicalensis contained similar

Σ

REE in NGHs (2.02 mg·kg

^{- 1}

) and BCHs (2.04 mg·kg

^{- 1}

), which were higher than that in APHs (1.78 mg·kg

^{- 1}

). Soils developed in hornblende-gneiss were characterized by lower clay fraction content and overall alkalinity with a pH value of 8.06. The absorption and utilization efficiency of REEs for Scutellaria baicalensis in NGHs was higher than in APHs and BCHs. Flavonoid compounds, effective constituents of Scutelleria baicalensis, showed more accumulations in NGHs than APHs and BCHs, implying their optimal quality of Scutellaria baicalensis in NGHs. Flavonoid compounds were remarkably correlated with REEs in the roots, suggesting the influence of REEs concentrations on the quality of Scutellaria baicalensis. It can be concluded that high REEs and micronutrient element concentrations of hornblende-gneiss favored the synthesis and accumulation of flavonoid compounds in Scutellaria baicalensis after the activation of endocytosis induced by REEs. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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11 pages, 1188 KiB

Open AccessArticle

The Improvement and Application of the Geoelectrochemical Exploration Method

by Ming Kang, Huanzhao Guo, Wende Zhu, Xianrong Luo and Jianwen Yang

Appl. Sci. 2023, 13(4), 2735; https://doi.org/10.3390/app13042735 - 20 Feb 2023

Cited by 1 | Viewed by 1074

Abstract

The anionic and cationic species of elements from deeply buried deposits migrate to the near surface driven by various geological forces. The geoelectrochemical exploration method (GEM), derived from CHIM, consists of the application of an electric field to collect these active ions at [...] Read more.

The anionic and cationic species of elements from deeply buried deposits migrate to the near surface driven by various geological forces. The geoelectrochemical exploration method (GEM), derived from CHIM, consists of the application of an electric field to collect these active ions at the designated electrode. Prospecting effects have been investigated by researchers since the coming up of CHIM. However, the cumbersome technical equipment, complex techniques and low production efficiency have restricted its potential application in field geological survey. This paper presents the newly developed CHIM that is electrified by a low voltage dipole. The improved technique allows both anionic and cationic species of elements to be extracted simultaneously in an anode and in a cathode. Compared with the conventional CHIM method, the innovative techniques called dipole geoelectrochemical method are characterized by simple instrumentation, low cost and easy operation in field, and in particular enables simultaneous extraction of anionic and cationic species of elements, from which more information can be derived with higher extraction efficiency. The dipole geoelectrochemical method was proposed and applied in the experiments of the Yingezhuang gold ore from Zhaoyuan, Shandong Province, the 210 gold ore from Jinwozi, Xinjiang Province, and the Daiyinzhang gold polymetallic deposit from Wutaishan, Shanxi Province. There are clearly anomalies above the gold ore body, indicating the effectiveness and feasibility of the improved dipole geoelectrochemical method in both scientific research and mineral exploration. The results of anode extraction in several mining areas have shown good results, indicating that gold may be mainly negatively charged. In fact, many metal nanoparticles, clay minerals, or complexes of metal ions are negatively charged, so they migrate to the anode electrode and enrich. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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11 pages, 2143 KiB

Open AccessArticle

Microscopic Morphology and Indicative Significance of Nanoscale Au Particles in Soils and Fault Muds: A Case Study of Jiaojia, Shandong Province

by Jie Li, Bimin Zhang, Qingjie Gong, Hanliang Liu and Ningqiang Liu

Appl. Sci. 2023, 13(4), 2126; https://doi.org/10.3390/app13042126 - 07 Feb 2023

Cited by 2 | Viewed by 957

Abstract

In recent decades, the human demand for mineral resources has increased dramatically, and the mining of shallow deposits has basically been completed. The prospecting direction has turned to concealed deposits. For this reason, various penetrating geochemical methods have been developed to find concealed [...] Read more.

In recent decades, the human demand for mineral resources has increased dramatically, and the mining of shallow deposits has basically been completed. The prospecting direction has turned to concealed deposits. For this reason, various penetrating geochemical methods have been developed to find concealed minerals and a series of geochemical exploration techniques have been proposed. At the same time, the use of the geochemical gene as a new technique presented in recent years is feasible in discussing component classification and provenance tracing. In this study, we applied these methods for mineral exploration in the Jiaojia gold deposit in Shandong Province, China. The results show that a large number of ore-forming element particles can be observed in ores, fault muds, and soils; compared with Chinese soil, Au has higher enrichment coefficients; according to the LG03 lithogene, the ores belong to a neutral composition, and the fault muds and soils belong to an acidic composition. Based on the above results, it can be found that the ore-forming elements in the Jiaojia gold deposit have migrated. Although this migration cannot change the original lithology, it can provide theoretical support for the fine-grained soil-prospecting method. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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10 pages, 2533 KiB

Open AccessCommunication

Dynamic Mechanism of Dendrite Formation in Zhoukoudian, China

by Ningqiang Liu, Yinfeng He, Shengchao Xu, Lei Xiong, Yushuai Wei, Jie Li, Peiyu Li and Qingjie Gong

Appl. Sci. 2023, 13(4), 2049; https://doi.org/10.3390/app13042049 - 04 Feb 2023

Cited by 1 | Viewed by 1064

Abstract

Dendrite, a typical geological pattern, is developed along the bedding plane in limestone and dolomite strata in Jinzigou area, Zhoukoudian, Beijing, China, with a self-similar dendritic morphology. In order to reveal the dynamic mechanism of its formation, the diffusion-limited aggregation method, a model [...] Read more.

Dendrite, a typical geological pattern, is developed along the bedding plane in limestone and dolomite strata in Jinzigou area, Zhoukoudian, Beijing, China, with a self-similar dendritic morphology. In order to reveal the dynamic mechanism of its formation, the diffusion-limited aggregation method, a model of fractal growth, was selected to simulate the microscopic dynamic mechanism of its formation. Take an L × L square lattice, with L = 200 lattices, 20,000 particles, and L = 250 lattices, 30,000 particles, for simulation. Obtain the simulation results of the dendritic pattern and the intermediate results with 8057 and 10,827 random particles released in the simulation process with 20,000 particles. The results show that the pattern is a typical fractal pattern formed in the process of fractal growth, with a fractal dimension of about 1.6. Its morphology is characterized by fractal geometry, and the dynamic mechanism of its formation is the fractal growth phenomenon generated by self-organizing criticality. The growth process is a nonlinear and non-equilibrium evolutionary process, which is dynamic and far from equilibrium. It is consistent with the fractal dimension of Zhoukoudian dendrite (1.52–1.78). Diffusion-limited aggregation (DLA) is a typical growth process in fractal growth. It leads to the growth of randomly branching structures that closely resemble various important systems in the earth sciences, providing a theoretical basis for revealing the nature of complex geological processes. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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12 pages, 43013 KiB

Open AccessFeature PaperArticle

Classification and Provenance on Geochemical Lithogenes: A Case Study on Rock–Soil–Sediment System in Wanquan Area of Zhangjiakou, North China

by Yonglong An, Xiulan Yin, Qingjie Gong, Xiaolei Li and Ningqiang Liu

Appl. Sci. 2023, 13(2), 1008; https://doi.org/10.3390/app13021008 - 11 Jan 2023

Cited by 4 | Viewed by 1017

Abstract

Geochemical lithogenes have been successfully applied as an innovative concept in the field of composition classification and source traceability of geological materials recently. This paper introduces the background of the development of geochemical genes and the construction and application of LG01 and LG03 [...] Read more.

Geochemical lithogenes have been successfully applied as an innovative concept in the field of composition classification and source traceability of geological materials recently. This paper introduces the background of the development of geochemical genes and the construction and application of LG01 and LG03 lithogenes. Based on LG01 and LG03, the LG_CR classification and provenance are applied and verified on a weathering profile, ten gully sedimentary profiles and regional stream sediments in the Wanquan area of Zhangjiakou city, Hebei province, China. The geochemical lithology of the weathering profile shows a gradual variation from basic-like in the bottom rock to acidic-like at the upper soils compositionally with heterogeneity. The classification results on 10 sedimentary gully profiles (each with five samples) indicate that soils at the bottom of the gully system are dominated with 11 types of LG_CR materials, while the top materials are made up of 21 types, reflecting the mixing of the upstream soils. The results of stream sediments from a regional geochemical survey with a scale of 1:200,000 in this area illustrate that the classification results of LG_CR on stream sediments are basically consistent with the petrological results derived from regional geological mapping. Therefore, LG_CR can be used not only as an effective tool for classification and traceability of geological materials but also has great potential in lithological mapping in petrological-overburdened areas. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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12 pages, 2015 KiB

Open AccessArticle

Speciation Analysis and Pollution Assessment of Heavy Metals in Farmland Soil of a Typical Mining Area: A Case Study of Dachang Tin Polymetallic Ore, Guangxi

by Jiali Zhang, Yinghong Liu, Songtao Hong, Meilan Wen, Chaojie Zheng and Panfeng Liu

Appl. Sci. 2023, 13(2), 708; https://doi.org/10.3390/app13020708 - 04 Jan 2023

Cited by 5 | Viewed by 1607

Abstract

To explore the distribution characteristics and degree of pollution of heavy metals in the farmland soil around the Dachang tin polymetallic mining area in Guangxi, a total of 140 soil samples were collected around the mining area in this study. The total amount [...] Read more.

To explore the distribution characteristics and degree of pollution of heavy metals in the farmland soil around the Dachang tin polymetallic mining area in Guangxi, a total of 140 soil samples were collected around the mining area in this study. The total amount and various forms of seven heavy metals (Cu, Pb, Cd, Cr, Zn, As, and Ni) were analyzed by inductively coupled plasma mass spectrometry, and the improved continuous extraction method of heavy metal speciation analysis in the soil, the potential ecological risk index (RI), the and Nemerow evaluation index (P_N) were used to evaluate pollution characteristics of the soil and the bioavailability of heavy metals. Corresponding remediation suggestions were given according to the pollution degree. The results show that the whole soil in the study area is acidic, reducing, and the content of organic matter is low. The average content of heavy metal elements is higher than the background value of Guangxi, among which Cd, Pb, and As exceed the control value and are the main elements of pollution. The speciation analysis of heavy metals in soil shows that Cd is dominated by the ion exchange form; Cu is mainly residual and in a humic acid combined form; and the rest of the elements are mainly in residual form. Among the seven heavy metals, Cd has the strongest mobility, biological toxicity, and ecological risk, followed by As, Ni, and Zn. The overall pollution level of the soil in the study area is heavily polluted (P_N = 39.6), which is a very strong ecological risk level (RI = 2196.9), and the main pollutants are Pb, As, and Cd; Cd pollution is the most serious. Correlation (CA) and principal component analysis (PCA) indicate that the pollution sources of Pb, Cu, Zn, Cd, and As among the seven elements were mainly controlled by tailings accumulation, mining, and transportation, and the sources of Cr and Ni were controlled by soil-forming parent materials. Furthermore, according to the actual situation of the farmland around the mining area, two remediation suggestions are put forward: (1) use stabilization remediation technology to clean up the pollution source, such as calcium dihydrogen phosphate to reduce the bioavailability of the most polluted elements, Cd and Pb, in the soil; (2) under the concept of green environmental protection, use Typha orientalis Presl to repair the industrial and mining wasteland and some unused land. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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12 pages, 2243 KiB

Open AccessFeature PaperArticle

Construction, Test and Application of a Tungsten Metallogene Named MGW11: Case Studies in China

by Jie Li, Qingjie Gong, Bimin Zhang, Ningqiang Liu, Xuan Wu, Taotao Yan, Xiaolei Li and Yuan Wu

Appl. Sci. 2023, 13(1), 606; https://doi.org/10.3390/app13010606 - 02 Jan 2023

Cited by 6 | Viewed by 1155

Abstract

Geochemical gene is a new promising concept proposed recently in the discrimination and traceability of geological materials and is also a useful tool to recognize geochemical anomalies in mineral exploration. Based on the lithogenes of LG01 and LG03, geological materials can be classified [...] Read more.

Geochemical gene is a new promising concept proposed recently in the discrimination and traceability of geological materials and is also a useful tool to recognize geochemical anomalies in mineral exploration. Based on the lithogenes of LG01 and LG03, geological materials can be classified into nine types of LG_CR compositionally. With respect to geological materials with 11 types of LG_CR, in order to eliminate the lithological influence and to further narrow the prospecting target area, a tungsten metallogene named MGW11 is proposed for geochemical tungsten exploration after the tungsten metallogene MGW. Six weathering profiles of 11 types of LG_CR developed on granitic intrusions in different areas in China are selected to test the stable properties such as heredity and inheritance of MGW11 and MGW. The results indicate that MGW11 and MGW metallogenes illustrate stable properties during rock weathering regardless of weathering degrees, although gene variations of MGW11 and MGW are also observed during extreme weathering. Based on the regional geochemistry survey data in the Lianyang area in south China, where stream sediments are mostly 11 types of LG_CR compositionally, geochemical maps of mineralization similarities of MGW11 and MGW are contoured, and the anomaly areas are determined on the mineralization similarity value of ≥40%. Comparing the tungsten deposits and anomaly areas determined on MGW11 and MGW metallogenes spatially, a total of six polymetallic W deposits recognized in the study area are all located in the anomaly areas. Therefore, mineralization similarities of MGW11 and MGW can be viewed as useful integrated indices on geochemical tungsten exploration. In areas with 11 types of LG_CR compositionally, anomaly areas determined on the MGW11 are smaller than those on the MGW, which indicates that MGW11 is more efficient than MGW in targeting W deposits during tungsten prospecting because of the elimination of the lithological influence. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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12 pages, 2516 KiB

Open AccessFeature PaperArticle

Elemental Abundances of Moon Samples Based on Statistical Distributions of Analytical Data

by Zhiguan Hou, Qingjie Gong, Ningqiang Liu, Biao Jiang, Jie Li, Yuan Wu, Jiaxin Huang and Weixuan Gu

Appl. Sci. 2023, 13(1), 360; https://doi.org/10.3390/app13010360 - 27 Dec 2022

Cited by 4 | Viewed by 1962

Abstract

The successful return of Chang’E-5 (CE5) samples urges the hot topic of the study of the Moon in geochemistry. The elemental data of the analyzed moon samples reported in the literature were collected to determine the elemental abundances in moon samples. Based on [...] Read more.

The successful return of Chang’E-5 (CE5) samples urges the hot topic of the study of the Moon in geochemistry. The elemental data of the analyzed moon samples reported in the literature were collected to determine the elemental abundances in moon samples. Based on 2365 analytical records of moon samples from ten missions of Apollo, Luna, and CE5, elemental abundances of 11 major oxides including Cr₂O₃, 50 trace elements including Ti, P, Mn, Cr, and 15 rare earth elements (REEs) including Y are derived based on statistical distributions of normal, log-normal, and additive log-ratio transformation, respectively. According to the value of 13.5% CaO content, moon samples are classified into two types, as low-Ca and high-Ca samples, whose elemental abundances are also calculated respectively based on the methods used in the total moon samples. With respect to the mid-ocean ridge basalt (MORB) of the Earth, moon samples (including the Moon, low-Ca, and high-Ca samples) are rich in Cr, REEs, Th, U, Pb, Zr, Hf, Cs, Ba, W, and Be and poor in Na, V, Cu, and Zn in terms of their concentrations, and are enriched in Cr and depleted in Na, K, Rb, P, V, Cu, Zn in spider diagrams. The CE5 sample is a low-Ca type of moon sample and is clearly rich in Ti, Fe, Mn, P, Sc, REEs, Th, U, Nb, Ta, Zr, Hf, Sr, Ba, W, and Be and poor in Mg, Al, Cr, and Ni in terms of their concentrations relative to the moon or the low-Ca samples. If compared with the moon sample, the CE5 sample is also clearly rich in K, REE, and P. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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20 pages, 4564 KiB

Open AccessArticle

Detrital Mica Composition Quantitatively Indicates the Sediment Provenance along the Subei Coast to the Yangtze Estuary

by Zhicheng Dong, Lina Zhang and Bingfu Jin

Appl. Sci. 2022, 12(24), 12653; https://doi.org/10.3390/app122412653 - 09 Dec 2022

Cited by 1 | Viewed by 1088

Abstract

The influence of large rivers on the Subei littoral plain area requires more research than the results that have been available up to now. Thus, specific diagnostic indices of detrital mica are successfully applied for the first time to identify the detritus of [...] Read more.

The influence of large rivers on the Subei littoral plain area requires more research than the results that have been available up to now. Thus, specific diagnostic indices of detrital mica are successfully applied for the first time to identify the detritus of the Yangtze River and the ancient Yellow River and to analyze their influence on the coast in the Subei littoral plain area. Based on field investigation and sample collection, detrital mica minerals within the 0.063–0.125 mm grain size fraction were selected and identified. Their content/ratio differentiations and possible origins were analyzed. Moreover, specific diagnostic indices were evaluated for detritus identification considering these two large rivers in addition to their provenance influences on the Subei littoral plain area. The results indicate that the detrital mica contents in the Yangtze River Estuary differed from those in the ancient Yellow River Estuary. The mass percentage in the former (average value of 32.2%) was much higher than that in the latter (average value of 13.1%). The former contained abundant weathered mica, with a particle percentage of approximately 50.6%, while the latter contained abundant biotite (with a particle percentage of approximately 40.9%). Differences, including but not limited to those above, could be attributed to basic geological, climatic and hydrodynamic conditions. In particular, the mica indices were clearly distinguished between these two river estuaries. These indices constitute specific diagnostic indices for differentiating river detritus and quantitative contribution analysis of detritus provenance in the Subei littoral plain area. Finally, the changes and quantitative contributions of four diagnostic indices demonstrated that in the Subei littoral plain area, northward from the Yangtze River Estuary to sample site SBY11 located in Yangkou town, Rudong County, detrital micas were mainly affected by the Yangtze River, and southward from the ancient Yellow River Estuary to sample site SBY12 located in Bengcha town, Rudong County, detrital micas were largely affected by the ancient Yellow River. The main mixing area should be located between these two towns. This study provides both a good example and an efficient approach to the application of detrital mica in detritus identification, mixed zone determination, sediment provenance analysis and transport tracing. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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13 pages, 2241 KiB

Open AccessArticle

Evaluation of Soil Nutrient Status Based on LightGBM Model: An Example of Tobacco Planting Soil in Debao County, Guangxi

by Zhipeng Liang, Tianxiang Zou, Jialin Gong, Meng Zhou, Wenjie Shen, Jietang Zhang, Dongsheng Fan and Yanhui Lu

Appl. Sci. 2022, 12(23), 12354; https://doi.org/10.3390/app122312354 - 02 Dec 2022

Cited by 1 | Viewed by 1133

Abstract

Soil nutrient status is the foundation of agricultural development. Exploring the features of soil nutrients and status evaluation can provide a reference for the development of modern agriculture. LightGBM is an optimization algorithm based on the boosting framework, which uses histograms to improve [...] Read more.

Soil nutrient status is the foundation of agricultural development. Exploring the features of soil nutrients and status evaluation can provide a reference for the development of modern agriculture. LightGBM is an optimization algorithm based on the boosting framework, which uses histograms to improve the accuracy of the model. Based on the construction of the LightGBM model, the main nutrient features and status of tobacco planting soil were analyzed in seven towns in Debao County, Guangxi Province, namely Yantong Town, Longguang Town, Najia Town, Zurong Town, Du’an Town, Dongling Town and Jingde Town. The confusion matrix results show the accuracy of the LightGBM model is 94.2%, and the eigenvalue analysis shows that the available potassium (K) contributes the most to the nutrient status. The pH value of soil ranging from 6.1 to 7.8 is favorable for tobacco growth, and the contents of soil organic matter, total nitrogen (N), available phosphorus (P), exchangeable calcium (Ca) and exchangeable magnesium (Mg) are at the appropriate level. Available potassium (K) and available zinc (Zn) are at a high level, but available boron (B) is slightly insufficient. The nutrient status of 10% of soil is at an extremely high level, and about 81.03% of soil is medium level or above. The LightGBM model has high reliability in the automatic evaluation of soil nutrient status, which not only can accurately monitor the soil nutrient status but also reflects the correlation and importance of nutrient factors. Therefore, the LightGBM model is significant for guiding soil cultivation and agricultural production. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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25 pages, 6738 KiB

Open AccessArticle

Geochemistry, Geochronology, and Prospecting Potential of the Dahongliutan Pluton, Western Kunlun Orogen

by Bing Zhou, Zhixue Zhang, Zeming Shi, Hao Song and Linsong Yu

Appl. Sci. 2022, 12(22), 11591; https://doi.org/10.3390/app122211591 - 15 Nov 2022

Cited by 2 | Viewed by 1188

Abstract

Triassic granitoids are abundant on the northwestern margin of the Tibetan Plateau. The Dahongliutan pluton, located in the eastern Western Kunlun orogen, formed in the Late Triassic.Previous field studies have identified potential mixing of crustal and mantle magmas. In this study, we used [...] Read more.

Triassic granitoids are abundant on the northwestern margin of the Tibetan Plateau. The Dahongliutan pluton, located in the eastern Western Kunlun orogen, formed in the Late Triassic.Previous field studies have identified potential mixing of crustal and mantle magmas. In this study, we used zircon U–Pb ages and major and trace elemental analyses to investigate the tectonic evolution of the pluton, and to determine whether any exchange of mantle-derived material occurred between the pluton and the source area. We found that the pluton has relatively high SiO₂ contents, and the aluminum saturation index is consistent with peraluminous high-K calc-alkaline granite. The pluton is enriched in light rare earth elements; both light and heavy rare earth elements are highly fractionated. The magma that formed the pluton was predominantly derived from the crust; however, a small amount of upper mantle material was involved in the early stages of magma formation. The pluton underwent composite emplacement as a result of tectonic extension and magmatic emplacement, which may have occurred in the late Triassic post-collisional orogenic stage. Late Triassic magmatism provided heat and ore-forming material for Pb–Zn, Cu, Fe, and rare metal mineralization, which is of considerable importance for geological prospecting. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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Open AccessArticle

Delineation and Analysis of Regional Geochemical Anomaly Using the Object-Oriented Paradigm and Deep Graph Learning—A Case Study in Southeastern Inner Mongolia, North China

by Bo Zhao, Dehui Zhang, Rongzhen Zhang, Zhu Li, Panpan Tang and Haoming Wan

Appl. Sci. 2022, 12(19), 10029; https://doi.org/10.3390/app121910029 - 06 Oct 2022

Cited by 4 | Viewed by 1563

Abstract

This research describes an advanced workflow of an object-based geochemical graph learning approach, termed OGE, which includes five key steps: (1) conduct the mean removal operation on the multi-elemental geochemical data and then normalize them; (2) data gridding and multiresolution segmentation; (3) calculate [...] Read more.

This research describes an advanced workflow of an object-based geochemical graph learning approach, termed OGE, which includes five key steps: (1) conduct the mean removal operation on the multi-elemental geochemical data and then normalize them; (2) data gridding and multiresolution segmentation; (3) calculate the Moran’s I value and construct the geochemical topology graph; (4) unsupervised deep graph learning; (5) the within-object statistical analysis. The final product of OGE is an object-based anomaly score map. The performance of OGE was demonstrated by a case study involving eighteen ore-forming elements (Cu, Pb, Zn, W, Sn, Mo, F, Au, Fe₂O₃, etc.) in stream sediment samples in the Bayantala-Mingantu district, North China. The results showed that the OGE analysis performed at lower levels of scale greatly improved the quality of anomaly recognition: more than 80% of the known ore spots, no matter what their scales and mineral species, were predicted in less than 45% of the study area, and most of the ore spots falling outside the delineated anomalous regions occur nearby them. OGE can extract both the spatial features and compositional relationships of geochemical variables collected at irregularly distributed centroids in irregularly shaped image objects, and it outperforms other convolutional autoencoder models such as GAUGE in anomaly detection. Full article

(This article belongs to the Special Issue New Advances and Illustrations in Applied Geochemistry)

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