Geochemistry Geophysics Geosystems最新文献

{"title":"Biomarkers Indicate Pliocene Uplift of the Maxian Mountains, Northeastern Tibetan Plateau","authors":"Bingyan Han,&nbsp;Tingjiang Peng,&nbsp;Churun Han,&nbsp;Zhichao Liu,&nbsp;Xiaomiao Li,&nbsp;Zhenhua Ma,&nbsp;Zhantao Feng,&nbsp;Meng Li,&nbsp;Aifeng Zhou,&nbsp;Chunhui Song","doi":"10.1029/2023GC011401","DOIUrl":"https://doi.org/10.1029/2023GC011401","url":null,"abstract":"<p>Knowledge of Late Miocene-Early Pliocene environmental change is critical for understanding the interactions among global cooling, regional tectonic activity and Asian climatic evolution. However, their relationships remain unclear, partly due to the scarcity of quantitative reconstructions of temperature and hydroclimatic conditions, which limits our understanding of the effect of topography on montane climatic evolution. Here, we quantitatively reconstructed the Late Miocene-Early Pliocene temperature, hydroclimate, and pH of the Xiaoshuizi peneplain, northeastern Tibetan Plateau (NETP), based on glycerol dialkyl glycerol tetraethers. Our results indicate that the Xiaoshuizi temperature was relatively high with large fluctuations during 6.2–4.6 Ma. The temperature then gradually decreased until 4.0 Ma, when this trend was interrupted by an intensive warming event. Additionally, the combined R_i/b and pH proxies revealed that the Xiaoshuizi region experienced a hydroclimatic transition from relatively wet to dry conditions after 4.0 Ma. Our integrated results show that the Xiaoshuizi climate became warm and dry during 4.0–3.6 Ma, in contrast to the global cooling trend and the occurrence of a humid climate on the eastern Chinese Loess Plateau and the North China Plain. We ascribe this anomalous change to a warm and dry climate during 4.0–3.6 Ma to a topographic Foehn effect triggered by surface uplift of the Maxian Mountains associated with extensive tectonic uplift of the NETP during the Middle Pliocene.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011401","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142174169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Late Cretaceous and Early Paleogene Fluid Circulation and Microbial Activity in Deep Fracture Networks of the Precambrian Basement of Western Greenland","authors":"H. Drake,&nbsp;W. R. M. Makahnouk,&nbsp;N. M. W. Roberts,&nbsp;M. Reinhardt,&nbsp;E. Henkemans,&nbsp;S. K. Frape,&nbsp;E.-L. Tullborg,&nbsp;C. Broman,&nbsp;M. J. Whitehouse,&nbsp;E. Kooijman","doi":"10.1029/2024GC011646","DOIUrl":"https://doi.org/10.1029/2024GC011646","url":null,"abstract":"<p>Deep fracture-hosted fluids of Precambrian bedrock cratons are relatively stagnant over long time spans compared to near-surface systems. However, episodic events, such as fracture reactivations, transgressions, and deglaciations, may introduce dilute water, replacing, and mixing with the deep continental brines, thereby sparking microbial activity. Secondary minerals that line bedrock fractures serve as important geochemical archives for such episodic events. Here we explore the fracture mineral record of Archean rocks of Western Greenland by analyzing samples from deep boreholes with the aim to trace and characterize episodic paleofluid flow and paleomicrobial activity. A sequence of hydrothermal to low temperature fluid flow events is demonstrated. For the youngest generation, microscale S-isotope analysis of pyrite reveals substantial ³⁴S-depletion (minimum δ³⁴S:−58‰V-CDT) compared to fracture-hosted barite (δ³⁴S:13‰ ± 2‰) and gypsum (δ³⁴S:2.6‰–10.6‰). This suggests the formation of pyrite following S isotope fractionation during microbial sulfate reduction. This metabolism is further indicated by several methyl-branched fatty acids preserved in calcite. A general discrepancy between calcite and groundwater δ¹⁸O-values suggests that calcite formed from water different from the presently residing glacial meltwater-influenced groundwater mix. High spatial resolution U-Pb carbonate geochronology of the youngest generation of calcite yielded ages for two samples: 64 ± 3, 75 ± 7 Ma (2<i>σ</i>). These ages overlap with tectonic events related to early stages, or prestages, of the opening of the Atlantic and Labrador Seas. This suggests that deep fracture networks in Western Greenland were colonized by microorganisms, such as sulfate reducers, in the course of this extensional event.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC011646","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142174170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Incorporation of Dissolved Heavy Metals Into the Skeleton of Porites Corals Based on Multi-Element Culturing Experiments","authors":"Sarina Schmidt,&nbsp;Ed C. Hathorne,&nbsp;Joachim Schönfeld,&nbsp;Kathleen J. Gosnell,&nbsp;Dieter Garbe-Schönberg","doi":"10.1029/2022GC010726","DOIUrl":"https://doi.org/10.1029/2022GC010726","url":null,"abstract":"<p>Anthropogenic activities increase the level of dissolved heavy metals in some tropical near-shore environments threatening reef ecosystems. The skeleton of stony corals like <i>Porites</i> species potentially provides a high-resolution geochemical archive for past heavy metal concentrations, with potentially century long records revealing baseline values before large-scale human disturbance. However, few data exist for heavy metal partitioning into coral skeleton aragonite. To address this, culturing experiments exposing <i>Porites lobata</i> and <i>Porites lichen</i> to a mixture of dissolved Cr, Mn, Ni, Cu, Zn, Ag, Cd, Sn, Hg, and Pb over a wide concentration range have been performed. Water samples were taken frequently to monitor changes in the heavy metal concentration. Laser ablation ICP-MS measurements of the coral aragonite revealed metal concentrations that were positively correlated with Cr, Mn, Ni, Zn, Ag, Cd, and Pb concentrations in seawater. The D_TE values for most metals appear dependent on the seawater metal content, approximating a power law, and therefore stabilize at higher seawater metal/Ca ratios. The partitioning of Pb into the coral skeleton is a notable exception, with D_Pb being stable around 2 to 1 across a large range of “natural” to highly polluted seawater Pb concentrations. This and the general agreement with partition coefficients estimated by previous work suggests that the reconstruction of the heavy metal concentration in seawater for ecosystem monitoring is possible. However, the high variability within and between coral colonies requires further study and suggests that multiple records from multiple coral colonies should be combined to obtain robust reconstructions.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2022GC010726","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142174168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Tracking Agulhas Leakage in the South Atlantic Using Modern Planktic Foraminifera Nitrogen Isotopes","authors":"R. Granger,&nbsp;S. M. Smart,&nbsp;A. Foreman,&nbsp;A. Auderset,&nbsp;E. C. Campbell,&nbsp;T. A. Marshall,&nbsp;G. H. Haug,&nbsp;D. M. Sigman,&nbsp;A. Martínez-García,&nbsp;S. E. Fawcett","doi":"10.1029/2023GC011190","DOIUrl":"https://doi.org/10.1029/2023GC011190","url":null,"abstract":"<p>Seawater transported into the South Atlantic from the Indian Ocean via “Agulhas leakage” modulates global ocean circulation and has been linked to glacial-interglacial climate cycles. However, constraining past Agulhas leakage has been a challenge. We sampled a transect of the Cape Basin in winter 2017 that intersected a mature Agulhas eddy and found that the ¹⁵N/¹⁴N ratio (δ¹⁵N) of mixed-layer nitrate, zooplankton, and foraminifera (tissue and shells) was 2‰–3‰ lower in the eddy than in the background Atlantic even though the δ¹⁵N of the underlying thermocline nitrate was indistinguishable between the two settings. We suggest that the δ¹⁵N of foraminifera and other zooplankton in the eddy reflects the original Agulhas Current thermocline nitrate, which is ∼2‰ lower than that of the South Atlantic due to N₂ fixation that occurs in the Indian Ocean. Foraminifera δ¹⁵N may have been lowered further during eddy migration by in situ N₂ fixation and/or recycling of low-δ¹⁵N ammonium. The absence of low-δ¹⁵N Agulhas nitrate in the eddy thermocline can be explained by partial assimilation of the nitrate as it was mixed into the euphotic zone during and after eddy formation, raising its δ¹⁵N. The low δ¹⁵N of eddy foraminifera, apparent even after several months of eddy migration across the Cape Basin, suggests that fossil foraminifer-bound δ¹⁵N from the region could record variations in past Agulhas leakage.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011190","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142170202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Metals, Volatiles, and Lithostratigraphy of Brothers Submarine Volcano","authors":"Ariadni A. Georgatou,&nbsp;Cornel E. J. de Ronde,&nbsp;Kalin Kouzmanov,&nbsp;Bruce L. A. Charlier,&nbsp;David Adams","doi":"10.1029/2024GC011716","DOIUrl":"https://doi.org/10.1029/2024GC011716","url":null,"abstract":"<p>Relatively fresh volcanic rocks have been sampled by a remotely operated vehicle in situ from the NE caldera wall of Brothers submarine volcano, associated with Seafloor Massive Sulfide-SMS deposits. Here, we present the first complete stratigraphic column of the NE caldera wall, comprising at least 12 massive dacitic lava flows, up to 80 m-thick intercalated with multiple volcaniclastic layers associated with tuffaceous sediment layers. Detailed petrographic and geochemical analyses from hand specimen to crystal to silicate melt scale show chemical variability with depth, correlating partly with an increase in pervasive alteration due to volatile degassing. Moreover, while sulfide saturation occurred prior to volatile exsolution—which sequestrated most chalcophile elements as confirmed by the low metal contents of melt inclusions (e.g., Cu ≤ 1.3 μg/g and Au ≤ 7.0 μg/g)—silicate glass records a Cu enrichment and Au loss with differentiation, with interstitial glass accounting for Cu = 4.2 μg/g and Au = 6.6 μg/g and matrix glass for Cu = 6.0 μg/g and Au = 2.8 μg/g, respectively. Our findings suggest multiple sources for metals compensating for the low initial metal contents: (a) from hydrothermal fluids and volatile percolation ensuing interaction with the host rock and thus also replacement and/or dissolution of pre-existing magmatic sulfides, (b) directly from the magma, consistent with metal release during magma degassing of metal- and Cl-, and S- rich volatiles, and (c) from fluid circulation within unusually metal-rich andesitic volcaniclastic layers (Cu = 40 μg/g, Au = 1.5 ng/g, and Pt = 0.99 ng/g). Our results elucidate the capacity of such hybrid mineralizing submarine volcanic systems to effectively scavenge, transport, and concentrate metals.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC011716","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142170203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Quantitative and Nuanced Approaches Elucidate Carbon Isotope Records","authors":"Cedric J. Hagen","doi":"10.1029/2024GC011718","DOIUrl":"https://doi.org/10.1029/2024GC011718","url":null,"abstract":"<p>Earth scientists have leveraged carbon isotope records to interpret Earth history and establish chronostratigraphic frameworks for decades (e.g., Halverson et al., 2005, https://doi.org/10.1130/b25630.1; Kaufman &amp; Knoll, 1995, https://doi.org/10.1016/0301-9268(94)00070-8; Knoll et al., 1986, https://doi.org/10.1038/321832a0; Saltzman &amp; Thomas, 2012, https://doi.org/10.1016/b978-0-444-59425-9.00011-1; Scholle &amp; Arthur, 1980, https://doi.org/10.1306/2f91892d-16ce-11d7-8645000102c1865d). Increasingly detailed and nuanced approaches have been applied to understanding carbon isotope records in light of local- and regional-scale processes that complicate interpretations. The recent work of Gazdewich et al. (2024, https://doi.org/10.1029/2023gc011376) is a prescient example, in which they conduct a series of analyses to constrain the influence of authigenic carbonate burial on the global carbon isotope mass balance during the Late Devonian. Here, I briefly review some recent developments in quantitative approaches to understanding carbon isotope values measured from carbonate rocks (δ¹³C_carb), with a focus on comparisons of measured δ¹³C_carb values, models for understanding what controls δ¹³C_carb values, and correlation tools for aligning δ¹³C_carb stratigraphies. These new approaches are elucidating carbon isotope records across Earth history and may prove to be transformative for our understanding of the global carbon cycle.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC011718","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142165678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Recycled Oceanic Crust in the Source of the Intraplate Changbaishan-Tianchi Volcano, China/North Korea","authors":"Yujie Liu,&nbsp;Chao Zhang,&nbsp;Hang Xu,&nbsp;Li-Hui Chen,&nbsp;Bo Pan","doi":"10.1029/2024GC011764","DOIUrl":"https://doi.org/10.1029/2024GC011764","url":null,"abstract":"<p>Continental intraplate volcano is an ideal probe to unravel the composition and structure of the deep Earth. The intraplate Changbaishan-Tianchi volcano was one of the most hazardous eruptions on the Earth's planet. The long-term activity of this volcano from the Pleistocene to 946 CE has erupted materials with a broad compositional range from basalt to rhyolite, which are expected to be associated with the continuous northeastward subduction of the Pacific plate, but the magma source remains controversial. In this paper, we present a comprehensive data set of in situ zircon Hf and O isotope data, combined with whole-rock element and Sr-Nd-Pb isotope compositions, for selected eruptions of the Changbaishan-Tianchi volcano, aiming to provide new insights into their magma source and the associated geodynamics. Radiogenic isotopic ratios and incompatible trace element compositions indicate that the erupted volcanic rocks at different stages, although with a varied differentiation degree, were derived from a common magma source characterized by a mixture of DM and EM1 end-members. Zircon Hf and O isotopes are both relatively homogeneous for different lithologies and eruption stages, with the <i>ε</i>_Hf(t) values varying between −5 and +5, and δ¹⁸O values between 3.58‰ and 5.97‰. Modeling of source mixing indicates that high-temperature altered oceanic crust materials are an important component in the source of Changbaishan-Tianchi volcano, likely derived from an ancient stagnant slab that has been reactivated by the subduction of the Pacific plate. This study demonstrates that the recycling of deeply subducted oceanic crust is potentially an important source and trigger for continental intraplate volcanism.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC011764","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"(De)hydration Front Propagation Into Zero-Permeability Rock","authors":"Stefan M. Schmalholz,&nbsp;Lyudmila Khakimova,&nbsp;Yury Podladchikov,&nbsp;Erwan Bras,&nbsp;Philippe Yamato,&nbsp;Timm John","doi":"10.1029/2023GC011422","DOIUrl":"https://doi.org/10.1029/2023GC011422","url":null,"abstract":"<p>Hydration and dehydration reactions play pivotal roles in plate tectonics and the deep water cycle, yet many facets of (de)hydration reactions remain unclear. Here, we study (de)hydration reactions where associated solid density changes are predominantly balanced by porosity changes, with solid rock deformation playing a minor role. We propose a hypothesis for three scenarios of (de)hydration front propagation and test it using one-dimensional hydro-mechanical-chemical models. Our models couple porous fluid flow, solid rock volumetric deformation, and (de)hydration reactions described by equilibrium thermodynamics. We couple our transport model with reactions through fluid pressure: the fluid pressure gradient governs porous flow and the fluid pressure magnitude controls the reaction boundary. Our model validates the hypothesized scenarios and shows that the change in solid density across the reaction boundary, from lower to higher pressure, dictates whether hydration or dehydration fronts propagate: decreasing solid density causes dehydration front propagation in the direction opposite to fluid flow while increasing solid density enables both hydration and dehydration front propagation in the same direction as fluid flow. Our models demonstrate that reactions can drive the propagation of (de)hydration fronts, characterized by sharp porosity fronts, into a viscous medium with zero porosity and permeability; such propagation is impossible without reactions, as porosity fronts become trapped. We apply our model to serpentinite dehydration reactions with positive and negative Clapeyron slopes and granulite hydration (eclogitization). We use the results of systematic numerical simulations to derive a new equation that allows estimating the transient, reaction-induced permeability of natural (de)hydration zones.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011422","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Cenozoic Volcanic Provinces and Shallow Asthenospheric Volumes in the Circum-Mediterranean: Evidence From Magmatic Geochemistry, Seismic Tomography, and Integrated Geophysical-Petrological Thermochemical Inversion","authors":"A. El-Sharkawy,&nbsp;T. H. Hansteen,&nbsp;C. Clemente-Gomez,&nbsp;J. Fullea,&nbsp;S. Lebedev,&nbsp;T. Meier","doi":"10.1029/2023GC011017","DOIUrl":"https://doi.org/10.1029/2023GC011017","url":null,"abstract":"<p>We compile an extensive catalog comprising geochemistry and ages of Cenozoic volcanic provinces in the Mediterranean region, distinguishing between three groups according to the geochemistry of magmatic rocks: intraplate (IVP), subduction-related (SRVP), and mixed-origin volcanic provinces (MVP; intraplate with subduction imprint). In order to relate their spatial distribution to properties of the lithosphere-asthenosphere system, we determine temperature-depth profiles by integrated geophysical-petrological inversion at representative locations, using Rayleigh and Love wave phase velocities, heat flow, rock densities, and accounting for thermochemical conditions. The results confirm the occurrence of thin lithosphere (&lt;100 km) above warm asthenosphere (&gt;1,300°C) in areas of low shear-wave velocities in the shallow upper mantle. Nine shallow asthenospheric volumes (SAVs) between 70 and 300 km depths are identified, forming a partly interconnected belt across the Circum-Mediterranean. A remarkable colocation exists between the SAVs and the intraplate and mixed-origin volcanic provinces (IMVPs). Whereas dense networks of IMVPs have formed above the SAVs, IMVPs are absent in areas of thick mantle lithosphere. Magmatic activity in IMVPs at 60–70 Ma indicates that several SAVs existed already in the Paleogene (Central European, Adriatic, Western Mediterranean, and Moesian SAVs). The formation of SAVs is related either to asthenospheric upwelling caused by slab rollback and back-arc extension (Aegean-Anatolian, Moesian, Pannonian, Western Mediterranean SAVs), or to thermal upwelling (Adriatic, Central European, Middle East [MEA], North African, Rhine-Rhone SAVs), with some of the latter coupled partly with continental rifting (Central European, MEA, North African, Rhine Rhone SAVs).</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Anatomy of the Emeishan Mantle Plume Head: Insights From New Geochronologic, Geochemical, and Geologic Data","authors":"Hongbo Li,&nbsp;Zhaochong Zhang,&nbsp;Ran Liu,&nbsp;Marc K. Reichow,&nbsp;Jiang Zhu,&nbsp;Richard Ernst,&nbsp;M. Santosh,&nbsp;Wei Wang,&nbsp;Changquan Li,&nbsp;Botong Li","doi":"10.1029/2024GC011635","DOIUrl":"https://doi.org/10.1029/2024GC011635","url":null,"abstract":"<p>The link between mantle plumes and the formation of large igneous provinces (LIPs) is well established although the anatomy of these remains equivocal. Recent experimental studies and geophysical data suggest that the mantle plume head is more likely to be irregular and asymmetric, rather than an axisymmetric flattened disk. The Emeishan large igneous province (ELIP) provides a unique opportunity to test this hypothesis. According to robust petrographic, geochronologic, and geochemical evidence from the late Permian basalts in the Sichuan Basin, and in conjunction with a comprehensive compilation of geologic maps and published geochemical data from the ELIP, we identified several giant radial “fingering” structures. Based on the shallow mantle source from the center to margin in the ELIP and relief of the lithosphere-asthenosphere boundary, we propose a new mantle plume model to explain the evolution of the Emeishan plume periphery, where narrow finger-like protrusions and plumelets developed outwards from the main body of the plume to the edges of the flattened plume head. Dragged fingers might have been torn apart into some plumelets, which dispersed and were trapped beneath the thinnest lithosphere relief, and eventually erupted to form small-scale flood basalt in the Outer Zone of the ELIP.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC011635","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}