Acta Geochimica最新文献

{"title":"Petrography, geochemistry, and zircon U–Pb chronology of the Late Ordovician metavolcanic suites in the eastern North Qilian orogenic belt, NW China: constraints on their petrogenesis and tectonic implications","authors":"Irshad Hussain,&nbsp;Zuochen Li,&nbsp;Xianzhi Pei,&nbsp;Lei Pei,&nbsp;Feng Gao,&nbsp;Mao Wang,&nbsp;Xiao Wang,&nbsp;Hao Lin,&nbsp;Li Qin,&nbsp;Shang Ji","doi":"10.1007/s11631-025-00796-5","DOIUrl":"10.1007/s11631-025-00796-5","url":null,"abstract":"<div><p>The study area is situated in the Tianshan region, specifically within the eastern segment of the North Qilian Orogenic Belt (NQLOB). The NQLOB is a critical region for understanding oceanic closure and continental collision processes driven by the Shangdan Ocean subduction-exhumation, which was a segment of the Proto-Tethys Ocean during the Early Paleozoic. Despite significant research, the Early Paleozoic tectonic background and subduction-related orogenic processes, particularly in the eastern NQLOB, remain subjects of debate. This study presents significant petrographic, geochemical, and geochronologic insights into the metavolcanic rocks of the Chenjiahe Group in the eastern NQLOB. Petrographic analysis reveals that these metavolcanic rocks originated in a low-grade metamorphic setting. Zircon laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb dating yielded ages ranging between 449.7–443.4 Ma, indicating Late Ordovician formation. Geochemical signatures of felsic and intermediate rocks exhibit calc-alkaline to high-K calc-alkaline similarities, characterized by high light rare earth elements (LREEs), low heavy rare earth elements (HREEs), and moderate Eu anomalies, consistent with a continental arc setting. In contrast, basaltic rocks display tholeiitic features with elevated large-ion lithophile elements (LILEs), reduced high-field-strength elements (HFSEs), and weak Eu anomalies, suggesting an extensional environment. These findings imply that the metavolcanic rocks evolved in a continental arc-back-arc extension setting connected with the northward subduction and exhumation of the Huluhe back-arc oceanic basin. This process was likely triggered by the northward subduction and closure of the Shangdan Ocean, culminating in the Late Ordovician amalgamation of the Qilian Block and the southwestern North China Block. This study provides critical insight into the tectonic development of the NQLOB and the broader Proto-Tethys Ocean dynamics at the northern periphery of the Eastern Gondwana.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"759 - 783"},"PeriodicalIF":1.3,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170067","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":"Prolonged mantle metasomatism in the Neoproterozoic continental arc: Insights from mafic magmatism in the western Yangtze Block, South China","authors":"Zhe-hao Zhong,&nbsp;Shao-cong Lai,&nbsp;Yu Zhu,&nbsp;Jiang-feng Qin,&nbsp;Ren-zhi Zhu,&nbsp;Min Liu,&nbsp;Yu-hong Xia","doi":"10.1007/s11631-025-00791-w","DOIUrl":"10.1007/s11631-025-00791-w","url":null,"abstract":"<div><p>Mafic rocks generated from subduction settings have recorded valuable source information about the mantle source. In this study, we present a comprehensive analysis of zircon U–Pb dating, whole-rock major and trace elements, and Sr–Nd isotopic data for the mafic gabbro located in the Yumen area, on the western part of the Yangtze Block, South China, aiming to constrain the processes of mantle metasomatism within subduction settings. U–Pb dating results for zircon yield crystallization ages of 800 Ma for type 1 mafic gabbro and 753–734 Ma for type 2 mafic gabbro. Type 1 mafic gabbro exhibits higher SiO₂ (44.13%–48.93%) and Al₂O₃ content but lower total Fe₂O₃ and MgO content than type 2 gabbro (SiO₂: 41.02%–43.28%). These gabbros display a high-Mg^# signature (52.50–62.81 for type 1, 50.89–57.04 for type 2), while they are enriched in significant large-ion lithophile elements (LILEs: Rb, Ba, Sr, K) and depleted in high-field-strength elements (HFSEs: Zr, Hf, Nd, Ta, Ti), which indicates an arc-like element signature. The positive whole-rock εNd(t) values (type 1: 3.5–4.4, type 2: 5.6–6.3) combined with a narrow range of (⁸⁷Sr/⁸⁶Sr)_i (type 1: 0.7035–0.7043, type 2: 0.7035–0.7036) of both gabbro types suggest a depleted lithospheric mantle origin. Therefore, these mafic rocks may derive from a metasomatized spinel lherzolite mantle source (with amphibole) due to the interactions of the deep mantle source and subduction fluid materials. We propose that the long-term metasomatism recorded by mafic gabbro in this study supports the fact that the subduction during the Neoproterozoic contributed to the formation of a metasomatized mantle source in the Yumen area, western Yangtze Block, South China.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"844 - 857"},"PeriodicalIF":1.3,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167985","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":"Petrogenesis of the dioritic rocks in the eastern North Qaidam: Implications for the tectonic evolution of the Paleo-Tethys Ocean","authors":"Panlong Wang,&nbsp;Yongjun Li,&nbsp;Yujun Zhuang,&nbsp;Pingyang Gu,&nbsp;Chao Shi,&nbsp;Jiaxin Yan,&nbsp;Gaoxue Yang,&nbsp;Wei Li,&nbsp;Hai Li,&nbsp;Jianye Zhang,&nbsp;Hao Fu","doi":"10.1007/s11631-025-00792-9","DOIUrl":"10.1007/s11631-025-00792-9","url":null,"abstract":"<div><p>Numerous Indosinian igneous rocks in the North Qaidam (NQ) provide crucial insights into the tectonic evolution of the Paleo-Tethys Ocean. This paper presents a comprehensive study of the petrography, mineralogy, geochemistry, zircon U–Pb geochronology, and Hf isotope composition of dioritic rocks from the eastern NQ. Zircon U–Pb dating results indicate that the dioritic rocks were formed during the Middle Triassic (244–240 Ma). The rocks exhibit high-K calc-alkaline characteristics with variable SiO₂ (55.25–65.39 wt%) and elevated K₂O + Na₂O (4.81–6.94 wt%) contents. They show enrichment in LILEs (Rb, Ba, K) and depletion in HFSEs (Nb, Ta, Ti), with slight negative Eu anomalies (Eu/Eu* = 0.89–0.97). Zircon ε_Hf(t) values (−20.93 to + 5.60) and T_DM2 ages (0.85–1.72 Ga) suggest mixed sources. Petrographic and mineralogical analysis reveals that the plagioclase phenocrysts exhibit disequilibrium textures (including reverse zoning), primarily composed of andesine and labradorite, with a small amount of oligoclase. The clinopyroxenes are all augites and have high crystallization temperatures (1111–1151 °C). These features, particularly the reverse zoning of plagioclase, support a petrogenetic model involving mantle-derived magma underplating that induced melting of ancient lower crust, followed by mixing of underplated basaltic magma with crust-derived felsic magma. Our results indicate formation in a back-arc extensional setting during subduction of the Zongwulong Paleo-Tethys Ocean.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"805 - 825"},"PeriodicalIF":1.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167393","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":"Paleoproterozoic trench–distal back-arc setting origin of the Mahakoshal Basin, Central Indian Tectonic Zone (CITZ): Evidence from the geochemistry of the metabasalts","authors":"Kamaal Parvez,&nbsp;M. E. A. Mondal,&nbsp;Iftikhar Ahmad,&nbsp;Wamiq Mohammed Khan","doi":"10.1007/s11631-025-00788-5","DOIUrl":"10.1007/s11631-025-00788-5","url":null,"abstract":"<div><p>The present study of metabasalts was carried out to understand the mantle source and geodynamic setting of the Mahakoshal Group in the Central Indian Tectonic Zone. In this study, we present detailed field, petrography, and whole rock geochemistry of the Mahakoshal metabasalts. The Mahakoshal metabasalts are sub-alkaline in nature and belong to the tholeiitic series of rocks. The variation in rare-earth element patterns of metabasalts indicates the different degrees of partial melting at shallow as well as deeper depths. Further, Eu/Eu* varies from 0.8 to 1.1 (except sample KP-144=0.3), Ce/Ce* varies from 0.97 to 1.05, showing no cerium anomaly, and Nb/Nb* ranges from 0.7 to 1.3 (except KP-144=0.1). The magnesium number (Mg#) varies from 0.2 to 0.3, which is quite low, indicating the evolved nature of the metabasalts. The studied metabasalts show E-MORB to OIB-type affinities, which are placed in the trench-distal back-arc setting. The opening of the Mahakoshal Basin is due to retreating orogen in the accretionary orogen setting and is contemporaneous with the assembly of the Columbia Supercontinent (~2.1–1.8 Ga). Hence, field, petrographic, and geochemical signatures indicate that the Mahakoshal basin opened as a back-arc rift basin on the Bundelkhand Craton, and that metabasalts are derived from the mantle that underwent variable degrees of partial melting at different depths.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"826 - 843"},"PeriodicalIF":1.3,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145166094","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":"Petrogenesis and tectonic implications of the Jiudaowan Pluton in Jinning, western margin of the Yangtze Block: Evidence from geochemistry and U–Pb geochronology","authors":"Jiaorong Hu,&nbsp;Yongfeng Yan,&nbsp;Xiaofei Xu,&nbsp;Guangshu Yang,&nbsp;Xiaojun Zheng,&nbsp;He Chang,&nbsp;Yunhua Ren,&nbsp;Guolong Zheng,&nbsp;Xiao Li","doi":"10.1007/s11631-025-00789-4","DOIUrl":"10.1007/s11631-025-00789-4","url":null,"abstract":"<div><p>The western margin of the Yangtze Block hosts diverse Neoproterozoic igneous rocks, with exposed S-type granites serving as key indicators for deciphering regional geological evolution. This study focuses on the Jiudaowan granite pluton, located on the western margin of the Yangtze Block, through systematic petrographic, whole-rock geochemical, zircon and monazite U–Pb geochronology, and whole-rock Nd isotopic analyses aiming to elucidate its petrogenesis and tectonic significance. The Jiudaowan granite pluton is a composite body, consisting of the Luotaijiu, Jiudaowan, and Daheishan units, characterized by biotite monzogranites, muscovite–plagioclase granites, and two-mica monzogranites, respectively. LA-ICP-MS zircon and monazite U–Pb dating reveals crystallization ages between 832 and 798 Ma. The three units are peraluminous, containing minerals such as muscovite, garnet, and tourmaline, and exhibiting high SiO₂ (72.99–77.83 wt%), Al₂O₃ (12.36–15.02 wt%), and A/CNK values (1.06–1.43), confirming their classification as peraluminous S-type granites. Compositional variations within the Jiudaowan granite pluton are primarily controlled by protolith composition and melting mechanisms. The pluton is distinguished by low CaO/Na₂O ratios (0.02–0.18), high Rb/Sr (0.83–113) and Rb/Ba (0.33–15.2) ratios, and negative <i>ε</i>_Nd(<i>t</i>) values (−13.6 to −9.1), indicating derivation from partial melting of heterogeneous metasedimentary sources. MgO, TiO₂, Rb/Sr, and whole-rock Zr saturation temperatures suggest that the Luotaijiu and Daheishan units formed via biotite dehydration melting, whereas the Jiudaowan unit resulted from muscovite dehydration melting. Additionally, the Jiudaowan granite pluton displays a clear negative correlation between Al₂O₃, CaO, Fe₂O₃T, MgO, TiO₂, and SiO₂, along with pronounced Eu negative anomalies and depletions in Sr and Ti, suggesting fractional crystallization of feldspar, mica, and Fe-Ti oxides during magma emplacement. Similarly, variable incompatible element ratios of Nb/U (1.07–18.97) and Nb/La (0.24–26.88) further indicate minor crustal assimilation and contamination during magma evolution. Integrating regional geological data, we propose that the Jiudaowan pluton formed during crustal thickening associated with post-collisional extension, likely related to the breakup of the Rodinia supercontinent.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"858 - 879"},"PeriodicalIF":1.3,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145166034","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":"Petrographic and geochemical perspectives on sandstones of the extra-peninsular Gondwana Group from the Arunachal Himalayas, NE India: Probing provenance, tectonic context and paleoenvironmental conditions","authors":"Yadav Krishna Gogoi,&nbsp;Pradip Borgohain,&nbsp;Diganta Bhuyan,&nbsp;Devojit Bezbaruah,&nbsp;Garima Konwar,&nbsp;Manash Pratim Gogoi,&nbsp;Bubul Bharali","doi":"10.1007/s11631-025-00771-0","DOIUrl":"10.1007/s11631-025-00771-0","url":null,"abstract":"<div><p>The extra-peninsular Gondwana Group rocks are exposed in narrow patches within the Lesser Himalayan sequence of the NE-Arunachal Himalayas, India. The bulk of sediments for the sandstones of the Gondwana Group were derived from felsic/acidic to intermediate igneous rocks, with minor mafic input from the upper continental crust (UCC), as supported by various discrimination diagrams based on quantification of detrital minerals coupled with sandstone geochemistry. The inputs from metamorphic sources in subordinate amounts cannot be ruled out, as indicated by quantification of the quartz varieties. These sediments were found to be sourced from the interior part of a craton or shield and recycled platformal sediments which were derived from both passive and active margin settings. The sediments experienced a wide variance in climatic conditions, from arid to humid, suffering low–moderate-intensity weathering (CIA: 63.43; CIW: 86.18; WIP: 44.84; PIA: 75.37; ICV: 2.39; <i>C</i>-value: 0.42; PF: 0.49; Sr/Cu: 9.23 and Rb/Sr: 1.68) within the vicinity of the low plains to moderate hills. Additionally, redox-sensitive elements indicate the deposition of sediments under oxygenated or oxygen-rich conditions (U_au: −2.91; Th/U: 7.37; U/Th: 0.18; V/Cr: 1.71; δU: 0.67 and Ce/Ce*: 0.93).</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"880 - 911"},"PeriodicalIF":1.3,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145160471","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":"Petrogenesis and geodynamic setting of the Wutang granites in the Tong’an-Baishuidong lithium mining district, South China: Evidence from monazite U–Pb chronology, geochemistry, and Nd–Pb isotope","authors":"Fushen Zhang,&nbsp;Xiaotian Zhang,&nbsp;Fangrong Zhang,&nbsp;Yong Zhang,&nbsp;Zhe Xu,&nbsp;Xinyu Xu,&nbsp;Jiayong Pan,&nbsp;Fei Xia,&nbsp;Guoqi Liu,&nbsp;Yu Zhou,&nbsp;Ying Liu,&nbsp;Longmin Nie,&nbsp;Fujun Zhong","doi":"10.1007/s11631-025-00772-z","DOIUrl":"10.1007/s11631-025-00772-z","url":null,"abstract":"<div><p>The Tong’an-Baishuidong mining district (TBMD), located in the eastern section of the Jiangnan Orogen, is a newly discovered granite-type lithium mining district. Thisstudy presents new monazite U–Pb chronological, whole-rock geochemical, and Nd–Pb isotopic data to reveal the petrogenesis and geodynamic setting of the Wutang granites in the TBMD. The monazite U–Pb age of 145.8 ± 1.0 Ma indicates that the granites were emplaced at the end of the Late Jurassic. Whole-rock geochemical results demonstrate that the Wutang granites are enriched in SiO₂ (72.80–73.40 wt%) but depleted in CaO (0.44–0.90 wt%) and MgO+TiO₂+TFeO (1.79–2.05 wt%). These granites exhibit negative Eu anomalies (<i>δ</i>Eu = 0.3−0.4) and high aluminum saturation indexes (A/CNK = 1.2−1.6), differentiation indexes (DI = 90–92), and Rb/Sr ratios (4.7–8.1). They also have moderate Ba contents (239–278 ppm) and low Sr contents (52.7–82.0 ppm) as well as low Nb/Ta (2.2–5.3) and Zr/Hf (21.3–31.5) ratios. All these indicate that they are highly fractionated granites. Additionally, these granites contain 5–10 wt% muscovite but no hornblende, with calculated corundum contents of 2.3–5.5 wt%. They have low high-field strength element (HFSE) contents (Zr + Nb + Ce + Y = 182–202 ppm) and zircon saturation temperatures (700–770 °C), with Th and Y negatively linked with Rb. These petrographic and geochemical features further reveal that the Wutang granites belong to highly fractionated S-type granites. The ε_Nd(t) values of these granites range from −9.03 to −8.23, corresponding to two-stage model ages (T_DM2) of 1488–1553 Ma. The initial Pb isotope ratios are: (²⁰⁶Pb/²⁰⁴Pb)_i = 18.38–18.55, (²⁰⁷Pb/²⁰⁴Pb)_i = 15.67–15.68, and (²⁰⁸Pb/²⁰⁴Pb)_i = 38.62–38.67. These Nd–Pb isotopic results demonstrate that the parental magma originated from the partial melting of ancient crustal materials. In the meantime, the TBMD in the eastern section of the Jiangnan Orogen was in a compression-extension transitional setting associated with the episodic subduction of the Paleo-Pacific Plate.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"912 - 930"},"PeriodicalIF":1.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170348","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":"Geochemical characteristics and source analysis of rare earth elements in Qinghai Lake sediments","authors":"Guangying Li,&nbsp;Yingyi Meng,&nbsp;Jinhan Zhou,&nbsp;Di Ming,&nbsp;Lijun Dai,&nbsp;Lingqing Wang","doi":"10.1007/s11631-025-00763-0","DOIUrl":"10.1007/s11631-025-00763-0","url":null,"abstract":"<div><p>This study investigates the distribution, geochemical behavior, and potential anthropogenic influences of rare earth elements (REEs) in the surface sediments of Qinghai Lake, the largest saline lake in China. A total of 36 surface sediment samples were analyzed for REE concentrations with a combination of self-organizing maps (SOM) and positive matrix factorization (PMF). Results indicate distinct enrichment patterns, with light REEs (LREEs) exhibiting higher concentrations than heavy REEs (HREEs), reflecting natural abundances and geochemical behaviors. The minimum value was found in Lu as low as 0.091 mg/kg, and the maximum concentration was exhibited in Ce at 78.877 mg/kg. Geoaccumulation index (<i>I</i>_geo) analysis reveals minor to moderate enrichment of specific REEs of Sm and Nd, suggesting possible localized anthropogenic inputs, particularly near river mouths. Spatial analysis using inverse distance weighting (IDW) and self-organizing maps (SOM) highlights significant correlations between REE distributions and riverine inputs, underscoring fluvial transport's role in sedimentary REE dynamics. PMF identifies mixed natural and anthropogenic sources, with agricultural and industrial activities contributing to elevated REE levels in sediment. These findings provide critical insights into the geochemical behavior of REEs in saline lake systems and offer a foundation for pollution control and sustainable resource management in sensitive environments like Qinghai Lake.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 2","pages":"231 - 246"},"PeriodicalIF":1.4,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749054","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":"Markov chains as a conceptual probabilistic model according to Vistelius","authors":"Hannes Thiergärtner","doi":"10.1007/s11631-025-00760-3","DOIUrl":"10.1007/s11631-025-00760-3","url":null,"abstract":"<div><p>This geo-historical case study analyses Vistelius’ ingenious idea of conceptual stochastic models and their application as Markov chain analysis in the geosciences. Vistelius (1915–1995) is regarded as one of the founders of mathematical geology. He was the first to define mathematical geology as “a scientific discipline concerned with the construction, analysis and use of conceptual mathematical models of geological events to solve concrete problems” (Vistelius in Principles of mathematical geology, Nauka, Leningrad, 1980; Principles of mathematical geology, Kluwer Academic Publishers, Dordrecht, 1992). Mathematical models in this context should be primarily probabilistic because of the large number of influencing natural factors. They must be conceptual to avoid fundamental errors in application. Vistelius devoted his seminal book to geological random sequences and their description and analysis using Markov models as stochastic tools. He applied this approach to grain sequences in granitic intrusive rocks and to sedimentary rock layers. Among other things, Vistelius has used Markov chain analysis in mineral resource exploration to distinguish between “ideal” granites, which are not subsequently mineralized, and mainly hydrothermally mineralized, sometimes ore-bearing granites which contain at least two generations of main minerals. The application of this special conceptual stochastic model is demonstrated on Lusatian granite (Saxony, Germany).</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 3","pages":"663 - 672"},"PeriodicalIF":1.3,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11631-025-00760-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143183","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":"Geochemical behaviors of metal elements during a single flood event in the natural Chishui River, Southwest China","authors":"Zhongxuan Liang,&nbsp;Keyi Wang,&nbsp;Hongming Cai,&nbsp;Zhongwei Wang,&nbsp;Wei Yuan,&nbsp;Jiubin Chen","doi":"10.1007/s11631-025-00762-1","DOIUrl":"10.1007/s11631-025-00762-1","url":null,"abstract":"<div><p>The majority (up to 90%) of riverine materials is transported from the continent to the ocean mainly in flood events. It is thus crucial to characterize the geochemistry of elements and their flux in river system in order to better constrain their global biogeochemical cycling and impact on the oceanic ecosystem. However, the geochemical behavior including the distribution, migration and partitioning of typical metal elements amongst different phases, during hydrodynamic flood event remains still to be well explored. Here, we investigated the geochemical behaviors of typical metal elements in dissolved phase and suspended particulate matter collected from a single flood event in the natural Chishui River, Southwest China. The results showed clearly that the geochemistry of metal elements was largely controlled by the hydrodynamic effect, of which the different flowrates introduce a natural sorting of different mineral particles transported at different flood stages, depending on their shape, size and density. The maximum concentrations of alkaline and alkaline earth metals (Li, Mg, K, Rb and Sr) in SPM appeared before the flood peak, which was largely controlled by aluminosilicate minerals. However, transition metals (Cr, Mn, Fe, Ni and Cu) showed their abundance peaks lagging behind the flowrate summit, as a result of the late arrival of coarse particles or heavy minerals, evidenced by the mineralogical phase analysis. In addition, the distribution coefficient (<i>K</i>_<i>d</i>) between particulate and dissolved loads were lower and stable for soluble alkali/alkaline earth metals which could be affected by pH, while higher and fluctuant for transition metals that were largely influenced by SPM content. Overall, the present study reveals clear effects of hydrodynamic sorting on the geochemistry of metal elements during the flood event of the natural Chishui River, which should be taken into account when characterizing the riverine flux and their impact on marine ecosystem.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 2","pages":"373 - 386"},"PeriodicalIF":1.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749261","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}