Acta Geochimica最新文献

{"title":"Trace element compositions of pyrite and stibnite: implications for the genesis of antimony mineralization in the Yangla Cu skarn deposit, Northwestern Yunnan, China","authors":"Ping Pan,&nbsp;Xinfu Wang,&nbsp;Bo Li,&nbsp;Guo Tang,&nbsp;Zuopeng Xiang","doi":"10.1007/s11631-024-00672-8","DOIUrl":"10.1007/s11631-024-00672-8","url":null,"abstract":"<div><p>The Yangla Cu skarn deposit is located in the central part of the Jinshajiang Suture Zone, southwest China, with a total reserve of 150 Mt Cu @ 1.03%. The newly discovered antimony orebodies at the depth of Yangla are strictly controlled by the stratum, structure, and lithology, which are lenticular and vein-like within the marble fracture zone, which can provide a window into multistage mineralization and ore genesis at Yangla. Mineralization can be divided into three types, Cu–Pb–Zn (skarn) pyrite, galena, and sphalerite, Cu (porphyry) chalcopyrite and pyrite, and Sb (hydrothermal) stibnite and pyrite. The mineral assemblages were stibnite + pyrite + calcite + quartz ± minor scheelite in antimony ores. This study presents quantitative measurements of the trace element compositions of pyrite and stibnite from the Yangla antimony ores. Analysis of pyrite with electron probe microanalysis (EPMA) showed enrichment in Co, Ni, Sb, As, and Mo, and deficit in its S and Fe contents when compared to the stoichiometric concentrations of S and Fe in pyrite. The Sb-related pyrite may belong to sedimentary-reworked genesis and may be modified by hydrothermal fluids, thereby presenting a certain difference (i.e., crystal morphology, texture, and chemical composition) compared to the skarn and porphyry Cu-related pyrite in the Yangla Cu skarn deposit. Analysis of stibnite with EPMA and inductively coupled plasma-mass spectrometry showed enrichment in As, Pb, Sn, Pb, Cu, and Zn, and presented much higher Sb contents and slightly lower S contents when compared to the stoichiometric concentrations of Sb and S in stibnite. Statistical analysis of the stibnite trace elements showed correlations for the elemental pairs Cu–Pb, As–Sb, and Sn–Pb, and the coupled substitution equations Sb³⁺ ↔ Cu⁺ + Pb²⁺, Sb³⁺ ↔ As³⁺, and Sn²⁺ ↔ Pb²⁺ may be the major factors governed the incorporating Cu, Pb, As and Sn within the stibnite. Moreover, this study preliminary shows that the antimony mineralization may belong to a carbonate replacement hydrothermal genesis at Yangla.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 3","pages":"535 - 554"},"PeriodicalIF":1.4,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140233594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogy and whole-rock geochemistry of the Oligocene Barail Group of rocks of Belt of Schuppen, Northeast India: Implications for tectono-provenance and paleo-weathering","authors":"Manash Pratim Gogoi,&nbsp;Yunpeng Dong,&nbsp;Pradip Borgohain,&nbsp;Devojit Bezbaruah,&nbsp;Arvind Pandey,&nbsp;Yadav Krishna Gogoi,&nbsp;Garima Konwar,&nbsp;Gautam Raj Bawri,&nbsp;Bubul Bharali","doi":"10.1007/s11631-024-00679-1","DOIUrl":"10.1007/s11631-024-00679-1","url":null,"abstract":"<div><p>The petrographic and geochemical attributes of the Oligocene Barail Group of rocks are used to decipher the likely source area(s) or tectonic domains, as this sequence of rocks was deposited in a foreland basin governed by orogenic domain, namely the North-east Arunachal Himalayas. The river system that gave rise to the Brahmaputra River (Yarlung-Tsangpo), which flowed through several tectonic domains of the Himalayan ranges, primarily from Bomi-Chayu, Gangadese Granitoid, Higher Himalayan Leucogranites, and Namche Barwa into the proto Bengal Basin now a part of Assam Arakan Basin and Naga Schuppen Belt, was the main source of the sandstone formation of the Barail Group. The purpose of sandstone petrography, which combines modal analysis with XRF (Major Oxides) and HR-ICP-MS (Trace &amp; Rare Earth Elements) research, is to identify the type of source rock(s), their weathering pattern, and its paleo-environmental circumstances. These sandstones were formed from recycled orogen and include lithic and sublithic arenite variants with advanced texture and chemical maturity. The sediments were felsic (Th/Co: 1.38, Cr/Th: 9.78, La/Lu: 11.58, Th/Sc: 0.99, Eu/Eu*: 0.66, La/Sc: 3.05, La/Co: 4.18), with contributions from intermediate source rocks and low-rank metamorphics deposited in an active continental margin to a continental island arc setting. Climatic conditions impacted the sediments of Barails, characterised by being warm and semi-humid to humid which resulted in moderate to a high degree of chemical weathering, as shown by weathering indices like CIA (79.14), PIA (85.47), CIW (86.9), WIP (32.50), ICV (0.71), and Th/U (6.03), which were further additionally supported by C-Value (1.01), PF (1.20), Sr/Cu (2.04), and Rb/Sr (0.97).</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 5","pages":"904 - 932"},"PeriodicalIF":1.4,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140241900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Processes involving soil CO2 dynamic in a sector of Chaco-Pampean plain, Argentina: An isotope geochemical approach","authors":"Sanci Romina,&nbsp;Panarello Héctor","doi":"10.1007/s11631-024-00678-2","DOIUrl":"10.1007/s11631-024-00678-2","url":null,"abstract":"<div><p>The magnitude and spatial variability of CO₂ surface emissions and processes involving CO₂ released to the atmosphere from the soils are relevant issues in the context of climate change. This work evaluated CO₂ fluxes and ¹³C/¹²C ratio of vegetation, organic matter, and soil gases from no disturbed soils of Chaco Pampean Plain (Argentina) with different soil properties and environmental conditions (PL and PA units). Soil organic decomposition from individual layers was accompanied by δ¹³C of total organic carbon (δ¹³C-TOC) values more enriched to depth. δ¹³C-TOC values in the upper soil profile ~ <i>ca.</i> 0–15 cm were like the plant community of this area (~−33 to −29 ‰) while δ¹³C-TOC varied stronger bellow horizon A, till ~ −24‰. Both δ¹³C-TOC and soil δ¹³C-CO₂ were similar (~ −24 to 26 ‰) at deeper horizons (~ 50–60 cm). Toward the superficial layers, δ¹³C-TOC and δ¹³C-CO₂ showed more differences (till ~ 4 ‰), due influence of the diffusion process. Horizon A layer (~ 0–20 cm) from both PL and PA units contained the most enriched δ¹³C-CO₂ values (~ −15–17 ‰) because atmospheric CO₂ permeated the soil air. A simple two-component mixing model between sources (atmospheric δ¹³C-CO₂ and soil CO₂) confirmed that process. Isotopically, CO₂ fluxes reflected the biodegradation of C3 plants (source), diffusive transport, and CO₂ exchange (atmosphere/soil). Soil moisture content appeared as a determining factor in the diffusion process and the magnitude of CO₂ surface emissions (12–60 g·m⁻²·d⁻¹). That condition was confirmed by CO₂ diffusion coefficients estimated by air-filled porosity parameters and soil radon gradient model.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 5","pages":"947 - 958"},"PeriodicalIF":1.4,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Features of rare earth elements geochemistry in coals of Central Kazakhstan","authors":"Aiman Nygmetovna Kopobayeva,&nbsp;Altynay Amangeldikyzy,&nbsp;Gulim Galymzhanovna Blyalova,&nbsp;Nazym Srajadinkyzy Askarova","doi":"10.1007/s11631-024-00677-3","DOIUrl":"10.1007/s11631-024-00677-3","url":null,"abstract":"<div><p>This research presents the results of a comprehensive study of mineralogical and geochemical features of REE distribution in coals of Central Kazakhstan deposits—Karaganda coal basin and Shubarkol deposit, which have large hard coal reserves and are industrially important for the coal industry of Kazakhstan; the research is based on 205 samples of clayey interlayers and coal seams. It shows basic patterns of distribution and features of concentration for impurity elements, gives an estimate of the impurity elements concentration, including REE, defines conditions and factors of their accumulation, and studies features of their forms in coal and coal-bearing rocks, which allows estimating the mechanisms of their migration and conditions of accumulation. According to the results of geochemical indicators, the article establishes the factors of REE dislocation, reveals the composition of margin rocks that have influenced REE concentration in coal seams, and the presented latest data on mineralogy allowed to establish the ways of their transportation to the paleobasin during the syn- and epigenetic periods of formation of the coal deposits of Central Kazakhstan being researched. It was found that the coals are insignificantly enriched with heavy lanthanides from Ho to Lu. The distribution curves of UCC normalized REE values in the coals are similar and coincide, but they are less than the average value for world coal, and amount to only one-third of the UCC. It was found that the highest concentrations of all REE are characteristic of clayey interlayers and oxidized coals. The La/Yb ratio in this case increases upwards along the section, indicating mainly clastogenic mechanism of REE delivery to the coals. In coal and clay samples, the predominant mineral form of REE is light lanthanide phosphates. Identified particles of REE from minerals and their composition peculiarities suppose autigene nature of their formation. The formation of the bulk of autigene minerals occurred during the maturation of brown coals and their transformation into hard ones.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 5","pages":"876 - 888"},"PeriodicalIF":1.4,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11631-024-00677-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140081386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-situ analysis and genetic investigation of Li-bearing minerals in McDermitt clay-type lithium deposit, Nevada, USA","authors":"Yi Cui,&nbsp;Hanjie Wen,&nbsp;Zhengbing Zhou,&nbsp;Kunyue Ling,&nbsp;Lin Xu,&nbsp;Shirong Liu,&nbsp;Fei Xu","doi":"10.1007/s11631-024-00675-5","DOIUrl":"10.1007/s11631-024-00675-5","url":null,"abstract":"<div><p>Clay-type Li deposits are poised to play a pivotal role in addressing the surging global demand for Li. The McDermitt clay-type Li deposit, located in Nevada, is the largest Li deposit in the United States, with Li hosted by a clay-rich sequence of smectite-dominated intervals and illite-dominated intervals, respectively. However, the occurrence of Li and the genesis of Li-bearing minerals within smectite-dominated intervals have not been thoroughly investigated in previous research. Here, we studied the mineralogy, the in-situ Li distribution, and the bonding environments of Li within the smectite intervals using a combination of instrumental techniques including scanning electron microscope, transmission electron microscope, time-of-flight secondary ion mass spectrometry, and nuclear magnetic resonance. Our results indicate that the smectite exhibits low crystallinity characteristics of lacustrine clay authigenesis and is commonly found to fill the interstices among volcanic minerals or envelop them; Li is mainly hosted by Mg-smectite rather than the volcanic minerals. Within the tuffaceous sediment samples, the volcanic glass has undergone a transformation, resulting in its complete disappearance and alteration into clay minerals. Owing to the octahedral sites of Mg-smectite bounded in Li, it is referred to be hectorite. We interpret that the hectorite’s precipitation occurs in a high saline-alkaline water environment, a result of McDermitt tuff dissolution. This conclusion can be supported by the coexistence of spherulitic calcite and hectorite. Overall, this study confirms hectorite as the main Li-bearing mineral and increases the understanding of the genetic model of hectorite formation in intracontinental caldera basins.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 3","pages":"478 - 488"},"PeriodicalIF":1.4,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140090749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry of island arc assemblage in the Eastern Desert of Egypt and the role of Pan-African magmatism in crustal growth of the Arabian–Nubian Shield: A review","authors":"Abdel-Aal M. Abdel-Karim,&nbsp;Mohamed M. Hamdy,&nbsp;Adel A. Surour","doi":"10.1007/s11631-024-00676-4","DOIUrl":"10.1007/s11631-024-00676-4","url":null,"abstract":"<div><p>Neoproterozoic island arc assemblage of the Arabian–Nubian Shield (ANS) in the Eastern Desert (ED) of Egypt comprises juvenile suites of metavolcanics (MV), large amounts of meta-sedimentary rocks (MS), and voluminous metagabbros-diorites (MGD) and syn-tectonic intrusions of older granitoids (OG). We report here the updates of these four rock units in terms of classification, distribution, chemical characteristics, geodynamic evolution, metamorphism, and ages. In addition, we discuss these integrated data to elucidate a reasonable and reliable model for crustal evolution in the ANS. The main features of these rock units indicate their relation to each other and the geodynamic environment dominated by early immature oceanic island arcs to primitive continental arcs. Integrated information of the island arc metavolcanic and plutonic rocks (gabbros, diorites, tonalites, and granodiorites) furnish evidence of the genetic relationships. These include proximity and a coeval nature in the field; all protolith magmas are subalkaline in nature following calc-alkaline series with minor tholeiitic affinities; common geochemical signature of the arc rocks and subduction-related magmatism; their similar enrichment in LREEs; and similar major element compositions with mafic melts derived from metasomatized mantle wedge. The volcano-sedimentary and the OG rocks underwent multiphase deformation events whereas the MGD complexes deformed slightly. Based on the magmatic, sedimentological, and metamorphic evolutions constrained by geochronological data as well as the progressive evolutionary trend from extensional to compressional regimes, a possible gradual decrease in the subducted slab dip angle is the most influential in any geodynamic model for arc assemblage in the ED of Egypt.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 3","pages":"588 - 622"},"PeriodicalIF":1.4,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140417280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thorium anomaly on the lunar surface and its indicative meaning","authors":"Jingyi Zhang,&nbsp;Jianzhong Liu","doi":"10.1007/s11631-023-00670-2","DOIUrl":"10.1007/s11631-023-00670-2","url":null,"abstract":"<div><p>The Moon has been divided into three terranes: Procellarum KREEP Terrane (PKT), Feldspathic Highland Terrane (FHT), and South Pole-Aitken Terrane (SPAT), using globally measured Th and FeO. Many lunar evolution models have predicted that a lunar magma ocean will produce a residual layer enriched in incompatible elements such as K, REE, and P (i.e., KREEP) in the late age of crystallization; and that the distribution of thorium can be used as a proxy for determining the global distribution of KREEP. The thorium distribution in these three terranes is inhomogeneous. The highest concentration of thorium is in PKT, the medium concentration of thorium is in SPAT, and almost none in FHT. Then what is the specific distribution in each of the terrane and what enlightenment can it tell us? Here we present and describe the detailed thorium distribution in PKT, SPAT, and FHT and provide some information for the origin of asymmetries on the lunar surface.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 3","pages":"507 - 519"},"PeriodicalIF":1.4,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11631-023-00670-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140425661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrology, geochemistry, and crystal size distribution of the basaltic andesite–dacite association at Mt. Sumbing, Central Java, Indonesia: Insights to magma reservoir dynamics and petrogenesis","authors":"Indranova Suhendro,&nbsp;Endra Yuliawan,&nbsp;Revina Fitri Zen,&nbsp;Zulfa Yogi Rahmawati,&nbsp;Pandu Eka Priyana,&nbsp;Sonna Diwijaya,&nbsp;Muhammad Alsamtu Tita Sabila Pratama Suhartono,&nbsp;Andre Jonathan,&nbsp;Gammanda Adhny El Zamzamy Latief","doi":"10.1007/s11631-024-00673-7","DOIUrl":"10.1007/s11631-024-00673-7","url":null,"abstract":"<div><p>Ten rock samples consisting of one pyroclastic density current (PDC1) deposit, seven lava flows (LF1–7), and two summit lava domes (LD1, 2) were studied to understand the petrogenesis and magma dynamics at Mt. Sumbing. The stratigraphy is arranged as LF1, PDC1, LF2, LF3, LF4, LF5, LF6, LF7, LD1, and LD2; furthermore, these rocks were divided into two types. Type I, observed in the oldest (LF1) sample, has poor MgO and high Ba/Nb, Th/Yb and Sr. The remaining samples (PDC1–LD2) represent type II, characterized by high MgO and low Ba/Nb, Th/Yb and Sr values. We suggest that type I is derived from AOC (altered oceanic crust)-rich melts that underwent significant crustal assimilation, while type II originates from mantle-rich melts with less significant crustal assimilation. The early stage of type II magma (PDC1–LF3) was considered a closed system, evolving basaltic andesite into andesite (55.0–60.2 wt% SiO₂) with a progressively increasing phenocryst (0.30–0.48 <span>(upphi_{PC})</span>) and decreasing crystal size distribution (CSD) slope (from − 3.9 to − 2.9). The evidence of fluctuating silica and phenocryst contents (between 55.9–59.7 wt% and 0.25–0.41 <span>(upphi_{PC})</span>, respectively), coupled with the kinked and steep (from − 5.0 to − 3.3) CSD curves imply the interchanging condition between open (i.e., magma mixing) and closed magmatic systems during the middle stage (LF4–LF6). Finally, it underwent to closed system again during the final stage (LF7–LD2) because the magma reached dacitic composition (at most 68.9 wt% SiO₂) with abundant phenocryst (0.38–0.45 <span>(upphi_{PC})</span>) and gentle CSD slope (from − 4.1 to − 1.2).</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 5","pages":"838 - 855"},"PeriodicalIF":1.4,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140437478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Source of metals related to gold occurrences in Cameroon, Central African Belt","authors":"Kevin Igor Azeuda Ndonfack,&nbsp;Jinlin Zhang,&nbsp;Yuling Xie,&nbsp;N. Samiratou Yaya,&nbsp;Emmanuel Archelaus Afanga Basua","doi":"10.1007/s11631-023-00669-9","DOIUrl":"10.1007/s11631-023-00669-9","url":null,"abstract":"<div><p>Suites of granitic and metamorphic rocks form a perfect geological environment in which to investigate the source of metals related to gold deposits. In the East Province of Cameroon, the source of metals-related gold (grade ~ 4.6 g/t) that occurs within metamorphic and granitic rocks remains ambiguous. The host rocks were subjected to XRF and ICP-MS whole-rock geochemistry and BSE/EDS mineral analyses to investigate the source(s) of metals related to gold in the Province. Petrographically, chalcopyrite-pyrite and magnetite-ilmenite are the main sulfides and oxides of granites, respectively. The low-grade metamorphic rocks are sulfide-rich consisting of arsenopyrite, chalcopyrite, pyrite, and sphalerite, and oxides include magnetite, ilmenite, hematite, and rutile. Cu, Ni, Co, Sb, Sc, and Zn concentrations depleted in high-grade metamorphic rocks and granites compared to low-grade metamorphic rocks. As well, Bi, Cd, Co, Cu, Ni, Sb, V, W, and Zn concentrations decrease with increasing temperatures from low-grade rocks to high-grade rocks and granites. The suite of depleted elements in high-grade rocks and granites is almost identical to those enriched in gold occurrences. We conclude that metals (Bi, Cd, Co, Cu, Ni, Sb, and Zn) related to gold mineralization in the East Province of Cameroon likely originated from metal-rich low-grade metamorphic rocks during prograde metamorphic processes prior to partial melting.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 2","pages":"308 - 324"},"PeriodicalIF":1.4,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140442376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative geochemical reconstruction of Eocene paleoenvironment in Fushun Basin, northeast China","authors":"Yuanji Li,&nbsp;Pingchang Sun,&nbsp;Qiang Zhang,&nbsp;Junxian Wang","doi":"10.1007/s11631-024-00674-6","DOIUrl":"10.1007/s11631-024-00674-6","url":null,"abstract":"<div><p>The quantitative estimation of key parameters of paleotemperature and paleoprecipitation is crucial for paleoclimate reconstruction. Geochemical data from modern sediments are highly consistent with climate data, and their relationship can provide an important reference for the quantitative reconstruction of the paleoclimate. In this study, detailed inorganic geochemical analysis was carried out using high-precision sampling of the Paleogene (LFD-1 well) Guchengzi, Jijuntun and Xiloutian Formations in the Fushun Basin located in the mid-latitudes of the Northern Hemisphere. The Eocene Guchengzi Formation (54.51–47.8 Ma) and Jijuntun Formation (47.8–41.2 Ma) in the Fushun Basin were found to have been deposited under a humid climate. The lower (41.2–40.1 Ma) and upper (40.1–37.8 Ma) parts of the Xiloutian Formation were characterized by semiarid and semihumid–semiarid climates, respectively, which is very similar to the paleoclimatic information reflected by organic carbon isotopes. The Eocene Thermal Maximum 2 (ETM2, ~ 53.7 Ma), Early Eocene Climatic Optimum (EECO, ~ 53.1–46.5 Ma, Eocene Thermal Maximum 3 (ETM 3, ~ 52.8 Ma), and Middle Eocene Climatic Optimum (MECO, ~ 40.7–40.1 Ma) events significantly enhanced chemical weathering during these periods. The rapid increase in <i>p</i>CO₂ concentration leads to an increase in temperature, precipitation, and surface runoff, exhibiting strong chemical weathering. The mean annual temperature (MAT<i>a</i>) and mean annual precipitation (MAP<i>a</i>, MAP<i>b,</i> and MAP<i>c</i>) were estimated using parameters, such as the corrosion index without potassium (CIA-K), CaO/Al₂O₃, and (Na₂O + K₂O)/Al₂O₃. Comparing MAP<i>a</i>, MAP<i>b</i>, and MAP<i>c</i> with the MAP estimated using pollen data, MAP<i>a</i> and MAP<i>b</i> were found to be more sensitive to the climate during high precipitation periods (precipitation &gt; 1000 mm, Guchengzi Formation), and the recovered average precipitation was similar to MAP. In contrast, MAP<i>c</i> was more sensitive to the climate during low precipitation periods (precipitation &lt; 1000 mm, Jijuntun, and Xiloutian Formations), with higher accuracy. To fully consider the influence of soluble inorganic salts Ca²⁺ and Na⁺, multivariate linear equations of CIA-K and CaO/Al₂O₃ with CIA, and CIA-K and CaO/Al₂O₃ with MAP were constructed, namely MAP<i>d</i> and MAP<i>e</i>. The results show that MAP<i>e</i> has the highest performance and can be effectively used to estimate the change of paleoprecipitation in Northeast Asia.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 3","pages":"571 - 587"},"PeriodicalIF":1.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139817895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}