Island Arc最新文献

{"title":"Geological and Geomorphological Causes of Two Historical Deep-Seated Catastrophic Landslides Induced by the 1892 Heavy Rainfall Event in the Shimanto Accretionary Complex, Tokushima, Japan","authors":"Noriyuki Arai","doi":"10.1111/iar.70000","DOIUrl":"https://doi.org/10.1111/iar.70000","url":null,"abstract":"<div>\u0000 \u0000 <p>The catastrophic Hose and Ogawatuetui landslides occurred coincidentally in 1892 following heavy rainfall in the upper reaches of the Kaifu River, Tokushima, Japan. The area is underlain by a steeply dipping coherent formation with many faults, and lies in the Shimanto Belt where deep-seated catastrophic landslides are known to occur following heavy rainfall and large subduction zone earthquakes. The main geological and geomorphological causes of the landslides were found to include local relief ≥ 350 m (1200-m-diameter analysis windows); knickpoints and slope breaks at 90–150 m above sea level, competent massive and thick-bedded sandstone with open fractures on the upper slope, and alternating thin beds of incompetent fine sandstone and shale beds of high deformability and low permeability on the lower slope.</p>\u0000 </div>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724235","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":"Distribution of Stable and Radioactive Iodine Dissolved in Interstitial Waters Within the Subduction Input Sediment Offshore Sumatra Subduction Zone","authors":"Satoko Owari,&nbsp;Hitoshi Tomaru,&nbsp;Hiroyuki Matsuzaki","doi":"10.1111/iar.12542","DOIUrl":"https://doi.org/10.1111/iar.12542","url":null,"abstract":"<p>Subduction input (sediment before subduction)-located seaward of the trench is one of the largest iodine budgets on the earth's surface. It is responsible for the deep iodine source in the landward of the trench where the iodine flux is significantly high. However, the distribution in the subduction input is poorly understood, contrary to the subducted sediment (sediment after subduction) landward of the trench. We determined iodine concentration and ¹²⁹I/¹²⁷I ratio of the interstitial water from the seafloor to the basement continuously at a subduction input site ~250 km southwest of the Sunda Trench for the first time to understand the iodine distribution. In the study site, the iodine concentration increased with depth linearly to ~100 μM at 1400 mbsf. Iodine isotope ratios (¹²⁹I/¹²⁷I) remained constant as low as ~400 × 10⁻¹⁵ from 400 to 1400 mbsf, suggesting that the iodine distribution was mainly controlled by old iodine-rich fluid (low ¹²⁹I/¹²⁷I ratio and high iodine concentration) supplied along the basement and by mixing with seawater (high ¹²⁹I/¹²⁷I ratio and low iodine concentration). The linear iodine gradient was changed at ~200 and ~1200 mbsf, where the methane concentration rapidly increased and total organic carbon decreased. This indicates that young iodine (low ¹²⁹I/¹²⁷I ratio) was released from the organic materials in the sediment into the interstitial water at these depths. This is the first observation of in situ iodine/methane addition to the interstitial water associated with the organic decomposition. The iodine concentration and ¹²⁹I/¹²⁷I ratio indicated that iodine in the subduction input was either derived from the in situ sediment or allochthonous fluid transported from subducted sediment due to differences in physical properties and permeability. This allochthonous iodine transportation to the subduction input may broaden the concept of the iodine cycling in the subduction system, including the sediments after and before subduction.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.12542","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724259","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":"Preface for the Thematic Issue: Tectono-Magmatic-Metallogenesis in Eastern China","authors":"Xilin Zhao,&nbsp;Shengyao Yu,&nbsp;Guangfu Xing,&nbsp;Tatsuki Tsujimori","doi":"10.1111/iar.12540","DOIUrl":"https://doi.org/10.1111/iar.12540","url":null,"abstract":"","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142641812","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":"Spatial and Temporal Exhumation of the Northeastern China: Insights From Low Temperature Thermochronology","authors":"Yannan Wang,&nbsp;Lian Chen,&nbsp;Jin Zhang,&nbsp;Cunliang Zhao,&nbsp;Heng Zhao,&nbsp;Wenmu Guo,&nbsp;Junfeng Qu,&nbsp;Yingjie Li","doi":"10.1111/iar.12541","DOIUrl":"https://doi.org/10.1111/iar.12541","url":null,"abstract":"<div>\u0000 \u0000 <p>The northeastern (NE) China has undergone a long-term tectonic history involving subduction–accretion of the Siberian Craton, North China Craton, and Western Pacific Plate, providing an ideal target for understanding the interactions between cratons and the Pacific oceanic lithosphere. However, the Mesozoic-Cenozoic geological and topographic evolutions of the NE China remain unclear. Here, we present new apatite fission track data from Precambrian metamorphic rocks in the Lesser Hinggan Mountains. Apatite fission track dating yielded a group of central ages ranging from 130 ± 18 to 151 ± 11 Ma with mean track lengths varying between 13.67 ± 0.13 and 14.49 ± 0.08 μm. Thermal modeling results revealed a rapid cooling event at ca. 165–140 Ma, which was related to compressional deformations driven by shallow subduction of the Paleo-Pacific Ocean Plate beneath the northeastern China. Furthermore, regional low temperature thermochronological datasets in NE China show additional three rapid exhumation stages, including the Early Jurassic (ca. 200–180 Ma), Early Cretaceous (ca. 120–100 Ma), and Late Cretaceous (ca. 80–60 Ma). They were associated with closure of the Mudanjiang Ocean, slab rollback of the Paleo-Pacific Plate, and collision between the Okhotomorsk Block and southeastern Asia. As the Cenozoic, slow exhumation has emerged throughout the northeastern China.</p>\u0000 </div>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142641811","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":"Zircon Trace-Element Compositions in Cenozoic Granitoids in Japan: Revised Discrimination Diagrams for Zircons in I-Type, S-Type, and A-Type Granites","authors":"Yusuke Sawaki,&nbsp;Hisashi Asanuma,&nbsp;Shuhei Sakata,&nbsp;Mariko Abe,&nbsp;Hisahiro Ueda,&nbsp;Wataru Fujisaki,&nbsp;Takeshi Ohno","doi":"10.1111/iar.12539","DOIUrl":"https://doi.org/10.1111/iar.12539","url":null,"abstract":"<p>Owing to high resistance to alteration, detrital zircons retain information about their formation ages and parental magmas for a long period of time. Many geochemical researchers have proposed various indicators for zircon to constrain tectonic settings and to identify source rock. Because most detrital zircons analyzed by geochronologic studies are derived primarily from granitoids, we focus on the classification of zircon within granitoids. In the style of alphabetical classification scheme (Igneous, I; Sedimentary, S; and Alkaline, A types), some discrimination diagrams have been proposed. To improve the database and enhance discriminating studies, we examined trace-element compositions of zircons extracted from some Cenozoic granitoids exposed in the Japan Islands. The zircons showed systematic differences in Nb, Ta, Ce, and P contents. Zircons in Oceanic Arc I-type granite are poor in Nb and Ta, and these signatures clearly reflect those elements in their parental bodies. Despite their low abundance at the whole-rock level, zircons in Oceanic Arc I-type granite are characterized by high Ce content. This is attributable to the relatively oxidizing conditions of Oceanic Arc I-type magma. Zircons in S-type granite are characterized by high P and low Ce contents. The former can be explained by high apatite solubility in Al-rich magma, whereas the reducing environment of S-type magma is accountable for the latter. The zircon crystallized at the later stage during S-type granite solidification is slightly depleted in Nb and Ta. This is attributable to the depletion of these elements in the magma by Ti-bearing minerals such as ilmenite prior to zircon crystallization. In analogy with whole-rock composition, zircons in transitional I-A-type granite have intermediate composition between I-type and A-type zircons. On the basis of the updated database, we demonstrated that the Nb/P–Ce/P or Ta/P–Ce/P crossplots are the most useful for discriminating zircons in Oceanic Arc I-type, I-type, S-type, and A-type granites.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.12539","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579657","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":"Correction to “Bringing the Submarine Mariana Arc and Backarc Basin to Life for Undergraduates and the Public”","authors":"","doi":"10.1111/iar.12538","DOIUrl":"https://doi.org/10.1111/iar.12538","url":null,"abstract":"<p>Stern, R. J. 2024. “Bringing the Submarine Mariana Arc and Backarc Basin to Life for Undergraduates and the Public.” <i>Island Arc</i> 33, no. 1: e12533. https://doi.org/10.1111/iar.12533.</p><p>Figures 3 and 4 captions should have been switched as shown below.</p><p>FIGURE 3(A) Front of a typical remotely operated vehicle (ROV). Note locations of key features: Lights, cameras (both still and video), manipulator arms, and sample baskets. Modified from NOAA ROV factsheet https://oceanexplorer.noaa.gov/edu/materials/rov-fact-sheet.pdf. (B) A typical ROV control room, from https://schmidtocean.org/cruise-log-post/technology-at-the-seafloor/.</p><p>FIGURE 4Schematic section through the upper 140 km of the Mariana convergent margen and subduction zone, showing the principal crustal and upper mantle components and their interactions. Note that the location of the “mantle wedge” (unlabeled) is that part of the mantle beneath the overriding plate and between the trench and the most distal part of the arc where subduction-related igneous or fluid activity is found. Modified after Stern (2002). MF, magmatic front.</p><p>We apologize for this error.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.12538","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447708","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":"Recent Efforts to Improve the Accuracy and Precision of Carbonate Clumped-Isotope Analysis","authors":"Kazuma Oikawa,&nbsp;Osamu Abe,&nbsp;Yasufumi Iryu","doi":"10.1111/iar.12537","DOIUrl":"https://doi.org/10.1111/iar.12537","url":null,"abstract":"<p>The carbonate clumped-isotope thermometer, a relatively recent innovation, is based on the strong relationship between ¹³C-¹⁸O bond abundance in carbonates and their formation temperature. It can measure temperatures solely based on the CO₂ extracted from carbonates and has attracted attention as it accurately reconstructs surface water temperatures on a geological timescale. However, at the time of development, there were many limitations in its application to paleoenvironmental reconstruction such as the large sample size (10 mg), the complicated organic contaminant removal process, and the lack of internationally recognized carbonate standards, and improvements in the measurement method were required. Here, we review the studies conducted since the thermometer development to improve the accuracy and precision of carbonate clumped-isotope analysis. Finally, we discuss advanced carbonate clumped-isotope analysis methods, including laser spectroscopy.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.12537","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142435384","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":"U–Pb Geochronology of the Baguio Area, a Major Mining District in Northern Luzon (Philippines)","authors":"Monika Walia,&nbsp;Rolando Pena,&nbsp;Ulrich Knittel","doi":"10.1111/iar.12535","DOIUrl":"https://doi.org/10.1111/iar.12535","url":null,"abstract":"<p>The Baguio District, located in northern Luzon (the Philippines), is one of the major gold and copper mining districts in the Philippines and SE Asia. U–Pb zircon ages for igneous rocks and for detrital zircons extracted from sediment samples of the principal formations of the Baguio District reveal major magmatic pulses at ca. 1, 3, 16, and 20 Ma. The oldest zircon dated in this study has an age of 27.3 ± 1.6 (2σ) indicating earlier activity which has, however, left only a small imprint on the zircon inventory of the sediments. The absence of older zircons suggests that northern Luzon formed as an intra-oceanic arc. Zircon Hf isotope data suggests that the magmas, from which the zircons crystallized, were derived from time-integrated highly depleted mantle sources, compatible with an intra-oceanic origin of the island. The results of the U–Pb dating of zircons mostly confirm previous estimates of the ages of the rock units. Mid-Miocene ages obtained for samples thought to represent the Pugo Formation, the lowermost unit, which is thought to be Cretaceous-Eocene in age, most likely date magmatic rocks that intruded the Pugo Formation.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.12535","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142435526","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 Signatures of Igneous Zircon and Apatite: Generation of Archean TTGs in the Barberton Granitoid-Greenstone Terrain, South Africa","authors":"Shiho Miyake,&nbsp;Kazumasa Aoki,&nbsp;Tsuyoshi Komiya,&nbsp;Shogo Aoki,&nbsp;Mayuko Fukuyama,&nbsp;Masatsugu Ogasawara","doi":"10.1111/iar.12536","DOIUrl":"https://doi.org/10.1111/iar.12536","url":null,"abstract":"<div>\u0000 \u0000 <p>We performed isotopic and trace element analyses of zircons and apatites from the Inyoni, Batavia, and Badplaas tonalites, trondhjemites and granodiorites series (TTG) in the Barberton Granitoid-Greenstone Terrain (BGGT), South Africa using laser-ablation inductively-coupled plasma-mass spectrometry to investigate Archean tectono-magmatism. The U–Pb ages obtained from these minerals are consistent with previously reported ages ranging from ca. 3.28 to 3.23 Ga. The chondrite-normalized REE patterns of zircons and apatites enabled us to identify grains with primary information on TTG magmatism. Trace element characteristics, such as Sr/Y and Ti concentrations from primary grains, indicated that Inyoni TTG magmas coexisted with eclogite residue, whereas Badplaas and Batavia TTG magmas coexisted with garnet-amphibolite residue during the early formation stages. Furthermore, Lu–Hf isotope data, combined with the U/Yb-Nb/Yb data from zircons, suggested that the tectonic settings for TTG generation involved a subduction-type environment accompanied by crustal reworking. This implies that horizontal plate movement played a significant role in the TTG tectono-magmatism, and the subduction of old and cold plates facilitated slab melting under eclogite facies conditions, leading to TTG generation on the Archean Earth.</p>\u0000 </div>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429020","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":"Petrological and Geochemical Constraints on the Pelitic Hornfels of the Champaner Group, Western India: Implications for Its Origin and Evolution","authors":"Parita K. Gorania,&nbsp;Gayatri N. Akolkar,&nbsp;Aditya U. Joshi,&nbsp;Manoj A. Limaye,&nbsp;Mahendra K. Singh","doi":"10.1111/iar.12532","DOIUrl":"https://doi.org/10.1111/iar.12532","url":null,"abstract":"<p>The granitic intrusions emplaced into a terrane causes several textural, chemical and compositional changes in the host rock by wall-rock alteration and forms contact metamorphic rocks that is, hornfels. The low-grade metasedimentary rocks of the Champaner Group exposed as horse-shoe-shaped map pattern have envisaged several pulses of granitic intrusion with granitoid ages ranging from 2.5 to 0.95–0.93 Ga enclosing its most peripheries. However, it has been observed that the contact metamorphic signatures are most prominent on the eastern periphery of Champaner fading away towards the west slicing up the Champaner Group into outer, middle, and inner zone rocks. The present work is focused on the detailed study of inner zone pelitic hornfels by providing new constraints on field characteristics, reaction textures, mineral chemical compositional analyses, geochemical signatures, and P–T conditions. Three distinguished varieties of pelitic hornfels that is, biotite hornfels, andalusite-cordierite hornfels, and andalusite-sillimanite hornfels with increasing proximity to granitic intrusion respectively were identified. Based on the mesoscopic features, textural and phase relations, and mineral compositions, biotite, andalusite, cordierite, and sillimanite isograds were demarcated. The development of distinct mineral assemblages in different pelitic hornfels is correlated to the varying Al₂O₃, FeO, and MgO content in the bulk rock composition of the rocks and the geometry of the intruding felsic pluton (Godhra granite) beneath the Champaner supracrustals. The geochemical constraints suggest K-rich clay dominant shale protolith of post archean age comparable to Post-Archean Australian Shales (PAAS) deposited in an active continental margin tectonic setting. The increase in temperature gradient rather than pressure induced by 0.95–0.93 Ga “Godhra granitic” intrusion is considered to be a significant factor controlling the development of the observed progressive mineral assemblages. The P–T conditions constrained through P–T pseudosections built in a KFMASHTi model system suggest LP/HT metamorphism with P–T range from 200 to 350 MPa and 530°C–600°C respectively.</p>","PeriodicalId":14791,"journal":{"name":"Island Arc","volume":"33 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/iar.12532","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430316","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}