Solid Earth Sciences最新文献

{"title":"The mineralization potential of the I-type granites from Misajé pluton (NW-Cameroon): AMS and geochemical constraints","authors":"E.M. Fozing ,&nbsp;M. Kwékam ,&nbsp;S. Tetsopgang ,&nbsp;T. Njanko ,&nbsp;B. Chako-Tchamabé ,&nbsp;J. Tcheumenak Kouémo ,&nbsp;M. Gountié Dedzo ,&nbsp;E.A. Asobo Nkengmatia ,&nbsp;C. Njiki Chatué","doi":"10.1016/j.sesci.2021.06.002","DOIUrl":"10.1016/j.sesci.2021.06.002","url":null,"abstract":"<div><p>The I-type Pan-African Misajé granites, situated in the Western domain of the Central African Fold Belt are among the late-to post tectonic granites that intruded the ante-Pan-African country rocks. In this study, magnetic susceptibility and geochemistry data are integrated to evaluate the productive and non-productive metal potential of these I-type plutonic granites, which comprise Leucocratic granite, Biotite granite, Biotite-hornblende granite, and granodiorites. The magnetic susceptibility of the representative rock samples of the Misajé pluton ranges from 0.001 × 10⁻³ SI to 33.2 × 10⁻³ SI. These values indicate the coexistence of both magnetite and ilmenite-series. The magnetite-series (&gt;3 × 10⁻³ SI; oxidized type) constitute about 32 vol.% while the ilmenite-series (&lt;3 × 10⁻³ SI; reduced type) represent 68 vol.%. These magnetite-series vary from small MD (Ms ≤ 1) to coarse PSD (Ms &gt; 1) grains sizes. The Misajé plutonics are high potentially productive in Zn, Th, ilmenite, and magnetite and low productive in Sn, W and Cu though their extension remains limited, probably due to the remobilization of the ancient Paleoproterozoic crust that would have contributed to the dispersing of pre-Pan-African metal deposits.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 3","pages":"Pages 283-296"},"PeriodicalIF":2.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.06.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44059927","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 and Geothermometry study on hot-water springs for understanding prospectivity of low enthalpy reservoirs of Dholera Geothermal field, Gujarat, India","authors":"Manan Shah ,&nbsp;Anirbid Sircar ,&nbsp;Vrutang Shah ,&nbsp;Yashraj Dholakia","doi":"10.1016/j.sesci.2021.04.004","DOIUrl":"10.1016/j.sesci.2021.04.004","url":null,"abstract":"<div><p>While performing various steps for exploration and exploitation of geothermal resources, the applications of geochemical methods are pivotal for reservoir characteristics evaluation. It is used concurrently with geological and hydro-geological appraisals to supplement available information regarding the prospectively of the region of investigation at the relatively low cost compared to geophysical methods or drilling. Temperature range of 40 °C to 47 °C is demonstrated by the study area comprising of several thermal water manifestations. Studies from existing wells and surveys have suggested the presence of a sizable low enthalpy geothermal resource in the field. One of the most prominent uses of geochemical sampling is the determination of subsurface temperatures using Geothermometry. In this study, commonly accepted concepts of cationic and Silica Geothermometry have been applied to understand conditions in the reservoir. Interpretation of the data has given us some input on the reservoir characteristics like reservoir temperature, mixing process and multiple fluid origins. In Dholera geothermal field for determination of variation in hydrochemical facies and understanding of the advancement of the hydrochemical forms, the current research additionally imagines the significance of graphical portrayals like Piper chart, Scholler and so forth individually. The seawater intrudes the composition of water shows the reservoir. The physio-chemical properties of the water also influence exploitation strategies.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 3","pages":"Pages 297-312"},"PeriodicalIF":2.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.04.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43124744","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":"Hydrothermal origin of the Naojiao Fe deposit in Lingxiang district, Eastern China: Evidence from in-situ LA-ICP-MS magnetite trace element analysis","authors":"Haibo Yan ,&nbsp;Jing Tian ,&nbsp;Deshui Yu ,&nbsp;Jian Di ,&nbsp;Jiahao Li ,&nbsp;Zhuoyu Liu","doi":"10.1016/j.sesci.2021.06.004","DOIUrl":"10.1016/j.sesci.2021.06.004","url":null,"abstract":"<div><p>The Naojiao Fe deposit (Lingxiang district of Daye orefield) in Eastern China is closely associated with the Early Cretaceous Lingxiang diorite intrusion. However, the metallogenic origin of the Fe deposit and its possible magmatic link remains controversial. Here, we present microstructural and trace element features of magnetite grains from the ore-related diorite (type 1), orebodies (type 2), and the orebody-wallrock contact (type 3) at Naojiao. Type 1 magnetite grains have primary automorphic texture, and high P, V, Cr, Ni, and Ga contents but low Mg and Al contents. However, both type 2 and 3 magnetite grains display alteration zoning and oscillatory zoning, and have high Mg, Al, Zn, Zn/V, Co/Ni, Ti/V, and Ni/Cr, but low V, Cr, Ni, and Ga contents. Based the multi-element variation plots, and (Ca+Al+Mn) vs. (Ti+V), Ti vs. Ni/Cr, and (Ti+V) vs. (Al+Mn) discrimination plots, type 1 magnetite could be magmatic and underwent metasomatism, and was formed under relatively high temperature (&gt;500 °C). Type 2 and 3 magnetite grains may have been hydrothermal and closely associated with relatively oxidizing fluids, and formed under relatively low temperature (300–500 °C). Type 3 has wider range of trace element contents, and may have undergone late-stage alteration. Moreover, the Naojiao Fe deposit has similar magnetite microstructures and trace element contents, pyrite δ³⁴S values, and mineralization ages to other skarn deposits in the Daye orefield, and further suggests that it is a skarn deposit.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 3","pages":"Pages 268-282"},"PeriodicalIF":2.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.06.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45802281","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":"Temperature control on high-resolution SIMS oxygen isotopic compositions in Porites coral skeletons","authors":"Jieqiong Zou ,&nbsp;Wenfeng Deng ,&nbsp;Xuefei Chen ,&nbsp;Xi Liu ,&nbsp;Yangrui Guo ,&nbsp;Guanqiang Cai ,&nbsp;Xiaoping Xia ,&nbsp;Qing Yang ,&nbsp;Yanqiang Zhang ,&nbsp;Ti Zeng ,&nbsp;Gangjian Wei","doi":"10.1016/j.sesci.2021.02.002","DOIUrl":"10.1016/j.sesci.2021.02.002","url":null,"abstract":"<div><p>Oxygen isotope composition (δ¹⁸O) in <em>Porites</em> coral skeletons at the micrometer scale has been proposed to be uninfluenced by temperature in previous studies. Considering that temperature is the main controlling factor of coral δ¹⁸O at the macro scale, the effect of temperature on the δ¹⁸O variations at the micrometer scale should be evaluated carefully. To better understand the climatic and biological significance of high-resolution δ¹⁸O in coral skeletons, <em>in situ</em> δ¹⁸O values were analyzed in three modern <em>Porites</em> corals from the South China Sea and the Great Barrier Reef by a Cameca IMS 1280-HR secondary ion mass spectrometry (SIMS). A twice vacuum impregnation procedure for sample mount preparation and a subsection calibration method based on multiple controlling points for coral matrix effect correction were used for SIMS analysis. The derived SIMS coral δ¹⁸O time series exhibit consistent long-term variations with the monthly δ¹⁸O (measured by conventional gas isotope ratios mass spectrometry), monthly Sr/Ca, and daily sea surface temperature, first highlighting the dominant temperature control on micrometer-scale coral δ¹⁸O. The 1.5‰ fluctuation amplitude of SIMS coral δ¹⁸O at the scales of 400–800 μm can be explained by the combined SST effects of ~10-day variation and day–night fluctuation, whereas the effects of seawater δ¹⁸O and growth rate on SIMS coral δ¹⁸O seem not dominant. Some abnormally negative δ¹⁸O values possibly resulted from the primary ion bombardment on indistinguishable centers of calcification.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 129-141"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.02.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44710337","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":"Review of calculating the electrical conductivity of mineral aggregates from constituent conductivities","authors":"Kui Han ,&nbsp;Simon Martin Clark","doi":"10.1016/j.sesci.2021.02.003","DOIUrl":"10.1016/j.sesci.2021.02.003","url":null,"abstract":"<div><p>The electrical conductivity of mineral aggregates depends both on the properties of the constitutive minerals and the ways those minerals are assembled. Mixing, or average models combine the conductivity of single phases to give bulk conductivity of rocks, thereby linking experimental measurements to geophysical observations. In order to compare these mixing models and allow an informed choice, several popular approaches, including bounds and average models, have been used to estimate the conductivity of a typical dry upper mantle and transition zone with a pyrolite composition. All the estimations calculated using the various average models lie between the rigorous constraint that is given by the HS bounds. The average models in this study are found to give similar bulk conductivities with the difference of less than 0.5 orders of magnitude, except the geometric mean, implying that the choice of the average models is insignificant. The effective electrical conductivity of pyrolite mantle has been derived from the conductivity of dry mantle minerals using the effective medium theory, and was found consistent with observed conductivity values for some subsurface regions of the Earth which we expect to be relatively dry. This provides us with baseline conductivity for a dry mantle, which is helpful to understand the water distribution in the deep earth.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 111-128"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.02.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41941261","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":"Sedimentation and mineralization of the Late Paleozoic extensional basin in the western Kunlun Mountains, China","authors":"Zhengwei Zhang ,&nbsp;Xiaoyong Yang ,&nbsp;Lianchang Zhang ,&nbsp;Chengquan Wu ,&nbsp;Taiyi Luo ,&nbsp;Weiguang Zhu ,&nbsp;Jinhong Xu ,&nbsp;Pengcheng Hu ,&nbsp;Xiyao Li ,&nbsp;Ziru Jin","doi":"10.1016/j.sesci.2021.02.001","DOIUrl":"10.1016/j.sesci.2021.02.001","url":null,"abstract":"<div><p>In the western Kunlun Mountain region, due to the convergence of the Paleotethys Ocean in the Late Paleozoic, through northward subduction towards the West Kunlun Block, forming the Kangxiwa–Waqia arc magmatism and back-arc extensional basins, including the Tamu–Kalangu and Oytag–Kurliang basins. This study explores the relationship between basin evolution and mineralization. First, the Late Paleozoic back-arc and far-field continental back-arc basins were distinguished by analyzing sediment constructions in the basins. The former was continuously deposited in the Middle Devonian–Late Permian above the Precambrian basement due to the existence of the depressions. The latter were intermittently deposited in the Middle Devonian–Late Permian due to rifting above the Caledonian orogenic belt. Although the two settings were separated by the Tiekelike fault, their formations were subject to mantle upwelling caused by the subduction of the Kangxiwa oceanic crust. We also divided the Hercynian and Indosinian magmatic activities related to the basin; the former of which included the formation of bimodal magmatic rocks (339–291 Ma) as the basin expanded, which resulted in hydrothermal sediments and hydrothermal–magmatic mineralization, mainly including volcanic massive copper sulfide, Cu and Ni sulfide, and hydrothermal deposits. During the Indosinian orogeny, intermediate acidic magmatic rocks (265–206 Ma) associated with the closure of the basin was formed, leading to the development of hydrothermal Cu–polymetallic and porphyritic copper deposits. The relationship between basin evolution and mineralization was determined. Based on the findings, we concluded that the basin extended between the Middle Devonian and Early Permian. Syngenetic sedimentary deposits formed in the closed basins and anoxic environments of local depressions and mainly included sedimentary rock-hosted stratiform Cu deposits, exhalation-sedimentary Pb–Zn deposits, and sedimentary Mn deposits. Between the Middle Permian and Early Triassic, the basin began to close and the transformation from a basin to a mountain range finally occurred. The sedimentary basement was transformed by folding and faulting, thus forming tectonic deposits, including hydrothermal vein-type Pb–Zn deposits and Cu–Pb deposits within tectonically altered rocks. The results of this work show that the Late Paleozoic extensional tectonic environment formed both the back-arc basin and the far-field continental basin simultaneously. Periods of magmatism related to rifting and convergence could be distinguished by the corresponding mineralization. The metallogenic types related to the basin could also be divided into sedimentary, magmatic hydrothermal and tectonic hydrothermal deposits.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 142-177"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.02.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48483383","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":"First discovery of gold in kimberlite in Xuzhou, Northern Jiangsu Province","authors":"Qi Hou ,&nbsp;Xiaoyong Yang ,&nbsp;Jun Tang ,&nbsp;Jingya Cao ,&nbsp;Jianbin Shi ,&nbsp;Qizhong Zhou","doi":"10.1016/j.sesci.2020.08.001","DOIUrl":"10.1016/j.sesci.2020.08.001","url":null,"abstract":"<div><p>Several individual particle native golds were observed in two Mesozoic Group II kimberlites dikes in the southeastern margin of North China Craton (NCC). This discovery provides new information of the nature of the Mesozoic lithospheric mantle beneath the southeastern NCC, the metallogenic setting of gold deposits in the Jiaodong peninsula and the metallogenic theory of decratonic gold deposits.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 246-248"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2020.08.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45527700","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":"Geochronological and geochemical constraints on the origin of the Mesozoic granitoids in the Fanchang volcanic basin, the Middle-Lower Yangtze Metallogenic Belt","authors":"Songsong Zhang ,&nbsp;Xiaoyong Yang ,&nbsp;Keyou Wang ,&nbsp;Changsheng Han ,&nbsp;Yunlou Yang","doi":"10.1016/j.sesci.2020.12.002","DOIUrl":"10.1016/j.sesci.2020.12.002","url":null,"abstract":"<div><p>The Fanchang volcanic basin is located between the ore-cluster districts of Tongling and Ningwu，the Middle-Lower Yangtze Metallogenic Belt (MLYMB), regionally. This study extends a set of methods，i.e., petrographic observations, chemical compositions of intrusive rocks and LA-ICP-MS analysis of magmatic zircons, zircon LA-ICP-MS U-Pb geochronology and whole-rock Sr-Nd isotope analysis, on several intrusive rocks, such as Baimashan, Xiangxingdi, Zhuhouling, Chichong, Suishan, Puyingshan and Zishanling. In detail, in this area, monzonite, quartz diorite, granite and syenite are characterized by a series of high-K calc-alkaline and shoshonite, with a positive anomaly in Rb, Th, U, Ce, Pb, Nd, Sm, Gd and a negative anomaly in Ba, Nb, Ta, Sr, P, Ti, plus LREE enrichments and a flattened right-dip of HREE. Moreover, the diagenesis ages of these intrusions mainly overlap the 128–121 Ma time, all but two exceptions, including Baimashan quartz dioritic porphyrite (138.5 ± 4.9 Ma) and Puyingshan diorite (132.1 ± 3.8 Ma). Interestingly, the inherited zircon ages in the Baimashan intrusion are polyphased, primarily in three intervals, 2211.1–2675.9 Ma, 1862.0–2057.1 Ma and 661.1–990.7 Ma, respectively, indicating diachronic magmatic sources and possible existence of the late-Archean and Proterozoic basements. In addition, crystallization temperatures of these intrusive rocks in the Fanchang volcanic basin significantly increase from 802 °C to 931 °C, while the values of (Ce⁴⁺/Ce³⁺)_zircon decrease from 192.34 to 24.84, throughout the period from 132 Ma to 125 Ma, probably due to the enhanced magma assimilation process with the reductive carbonaceous wall rocks. Furthermore, A-type granites in this area, as defined in this paper, would have been derived from the partial melting of the residues of the early I-type granite source area. Values of (^S7Sr/⁸⁶Sr)_i array between 0.70718 and 0.72642 (a.v. 0.70970) and <em>ε</em>Nd(<em>t</em>) between −14.0 and 2.2 (a.v. −7.1). In brief, the intrusive rocks in Fanchang volcanic basin is considered to have characteristics of both enriched mantle and lower crust and a strong assimilation process had occurred.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 178-204"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2020.12.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41522076","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":"The deformation and mechanisms of the Zhangbaling tectonic belt during Indosinian to early Yanshanian: Implications for the relationship with the Tan-Lu Fault Zone","authors":"Qi Hou ,&nbsp;Xiaoyong Yang ,&nbsp;Mingjin Hou","doi":"10.1016/j.sesci.2020.08.004","DOIUrl":"10.1016/j.sesci.2020.08.004","url":null,"abstract":"<div><p>The Zhangbaling tectonic belt is located in the middle segment of Dabie-Sulu Orogenic Belt and in the eastern part of the main segment of the Tan-Lu Fault Zone (TLFZ). Based on detailed field work and comprehensive analysis, this study discussed the tectonic evolution mechanics of the Zhangbaling tectonic belt and the Tan-Lu Fault Zone as well as the relationship between them during Indosinian to early Yanshanian period. Three stages of tectonic deformation have been determined in the period from Indosinian to early Yanshanian in Zhangbaling area, i.e., a series of WNW and nearly EW trending tight congruous nearly recumbent folds formed in the early stage; a flatly ductile shearing zone formed mainly between Beijiangjun lithofm. and Xileng lithofm. in the middle stage and the demonstrate NNE trending wide flat folds and strong thrusting or napping from NW to SE formed in the last stage. The superimposition of these three deformation stages formed the basic tectonic framework of this area. The folding and thrusting (sliding in the front margin) was developed in the mid-upper crust (include sedimentary cover) during the period of subduction and collision processes between South China Block and North China Block, shows a progress deformation of the three stages during the period of Indosinian and early Yanshannian due to the conversion of the Tethyan to the Circle Pacific Ocean tectonic regimes. The Tan-Lu Fault Zone can be divided into two big development phases since Hercynian. The first phase is a fault zone sensu lato, as a boundary of a rifted cratonic margin (or basin) that shows a wide arc-shaped along the northeastern margin of the South China Block during Indosinian. The TLFZ of this period is a collision suture between South China Block and North China Block during Indosinian period, a thrust-napping fault zone belong to the Tethyan regimes sensu lato, as well as the southeast margin of the Zhangbaling tectonic belt. This big phase corresponds to the three stages deformation activities in Zhangbaling area. The second phase is a wrench fault system usually mentioned by most researchers, which belongs to the Pacific Ocean Cycle Regime sensu stricto since early Yanshanian to Himalayan periods.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 205-227"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2020.08.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48946289","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":"Model of layered pattern formation in binary igneous systems","authors":"Jade Ghaoui ,&nbsp;Ivan L'Heureux","doi":"10.1016/j.sesci.2021.04.001","DOIUrl":"10.1016/j.sesci.2021.04.001","url":null,"abstract":"<div><p>Centimeter to meter-scale repetitive patterns in composition and texture are sometimes observed in igneous systems. Examples are found in layered intrusions and multi-shelled orbicular granites. These patterns may result from the action of nonlinear self-organization processes in which the interplay between crystallization dynamics, diffusion and thermal conduction causes mineral and crystal size segregations. These mechanisms are analogous to the ones underlying the formation of Liesegang bands and lead to comparable features, such as a geometric progression of the band positions and the presence of doublets. We present here a comprehensive one-dimensional numerical model of Liesegang pattern formation process from binary eutectic melts in igneous systems. The model incorporates nucleation, growth and Ostwald ripening and is applied to both the layered intrusion and the orbicular granite configuration with appropriate simple geometries and cooling boundary conditions. The emergence of cyclic layering is described in terms of two key parameters that control the pattern formation: the scaled latent heat of crystallization (Stefan number) and the ratio of the thermal diffusivity to a characteristic diffusion coefficient (Lewis number). It is found that, in intrusions, a banding pattern compatible with the Liesegang spacing law is generated when the Stefan number is large and the Lewis number small, in agreement with previous studies. For orbicular granites with low Lewis number, we show that the band thickness and the crystal size increase with distance from the rim to the core, in agreement with the observations of Zhang and Lee (2020). This suggests that the pattern progresses inwards from the outer boundary, rather than from a colder core, thus supporting the conceptual model reported in Zhang and Lee (2020). Moreover, the results for both geometries indicate that ripening plays an important role in the formation of realistic patterns.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"6 2","pages":"Pages 80-94"},"PeriodicalIF":2.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.sesci.2021.04.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47437458","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}