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Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane, Southern Tibet: Implications for the Evolution of the Sumdo Paleo-Tethys Ocean

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 955-968页

作者： MA Wang LIU Yingchao YANG Zhusen jan-marten huizenga LI Zhenqing YUE Longlong ZHAO Sibo School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Institute of Geology Sinoprobe LaboratoryChinese Academy of Geological SciencesBeijing 100037China MLR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life SciencesNO-1432ÅsNorway Economic Geology Research Centre(EGRU) College of Science and EngineeringJames Cook UniversityTownsvilleQueensland 4811Australia Department of Geology University of JohannesburgAuckland Park 2006South Africa

Basalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane, southern Tibet. Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo-Tethys Ocean and its dynamic mechanism. Basalt samples from the Luobadui Formation in the Leqingla area, NW of Linzhou City in the central Lhasa subterrane, southern Tibet exhibit arc-like geochemical signatures in a subduction-zone tectonic setting characterized by high Al_(2)O_(3) and low TiO_(2) contents, fractionated REE patterns with low Nb/La ratios and high LREE concentrations, and negative HFSE anomalies. Based on their higher Th/Ce, Nb/Zr, and lower Ba/Th, Pb/Nd ratios, slightly negative to positive ε_(Nd)(t) values, and the relatively high Sr-Pb isotopic compositions, these samples were probably derived from partial melting of a depleted mantle source of garnet + spinel lherzolite, metasomatized by subducted sediments around 297 Ma. Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine, clinopyroxene and minor plagioclase during magma ascent and eruption. It is proposed that these Late Carboniferous–Early Permian basalts are associated with the northward subduction of the Sumdo Paleo-Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane.

关键词： geochemistry northward subduction Sumdo Paleo-Tethys Ocean Lhasa terrane Tibet

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Fluid-rock interaction in retrograde granulites of the Southern Marginal Zone,Limpopo high grade terrain,South Africa

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Geoscience Frontiers 2014年第5期5卷 673-682页

作者： jan marten huizenga Dirk van Reenen Jacques L.R.Touret Unit of Environmental Sciences and Management North-West UniversityPrivate Bag X60012520South Africa Economic Geology Research Institute(EGRU) School of Earth and Environmental SciencesJames Cook UniversityTownsvilleQLD 4811Australia Department of Geology University of JohannesburgJohannesburgSouth Africa Institut de Mineralogie.de Physique des Materiaux et de Cosmochimie(IMPMC) Sorbonne Universites UPMC Univ Paris 06UMR CNRS 7590 Museum National d'Histoire Naturelle.IRD UMR 206.4 Place Jussieu.F-75005

Fluid infiltration into retrograde granulites of the Southern Marginal Zone （Limpopo high grade terrain） is exemplified by hydration reactions, shear zone hosted metasomatism, and lode gold mineralisation. Hydration reactions include the breakdown of cordierite and orthopyroxene to gedrite ＋ kyanite, and anthophyllite, respectively. Metamorphic petrology, fluid inclusions, and field data indicate that a low H2O-activity carbon-saturated CO2-rich and a saline aqueous fluid infiltrated the Southern Marginal Zone during exhumation. The formation of anthophyllite after orthopyroxene established a regional retrograde anthophyllite-in isograd and occurred at P-Tconditions of -6 kbar and 610 ℃, which fixes the minimum mole fraction of H20 in the CO2-rich fluid phase at ~ 0.1. The maximum H20 mole fraction is fixed by the lower temperature limit （~800 ℃） for partial melting at -0.3. C-O-H fluid calculations show that the CO2-rich fluid had an oxygen fugacity that was 0.6 log10 units higher than that of the fayalite-magnetite- quartz buffer and that the CO2/（CO2＋CH4） mole ratio of this fluid was 1. The presence of dominantly relatively low density CO2-rich fluid inclusions in the hydrated granulites indicates that the fluid pressure was less than the lithostatic pressure. This can be explained by strike slip faulting and/or an increase of the rock permeability caused by hydration reactions.

关键词： GranuliteFluidLimpopoRetrogradeSouthern Marginal Zone

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Charnockite microstructures:From magmatic to metamorphic

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Geoscience Frontiers 2012年第6期3卷 745-753页

作者： Jacques L.R.Touret jan marten huizenga Musee de Mineralogie MINES ParisTech75272 Paris Cedex 06France Department of Geology.School of Environmental Sciences and Development North-West UniversityPrivate Bag X6001Potchefstroom 2520South Africa

Charnockites sensu lato （charnockite-enderbite series） are lower crustal felsic rocks typically characterised by the presence of anhydrous minerals including orthopyroxene and garnet. They either represent dry （H2O-poor） felsic magmas that are emplaced in the lower crust or granitic intrusions that have been dehydrated during a subsequent granulite facies metamorphic event. In the first case, post- magmatic high-temperature recrystallisation may result in widespread metamorphic granulite microstruc- tures, superimposed or replacing the magmatic microstructures. Despite recrystallisation, magmatic remnants may still be found, notably in the form of melt-related microstructures such as melt inclusions. For both magmatic charnockites and dehydrated granites, subsequent fluid-mineral interaction at inter- grain boundaries during retrogradation are documented by microstructures including K-feldspar micro- veins and myrmekites. They indicate that a large quantity of low-H2O activity salt-rich brines, were present （together with CO2 under immiscible conditions） in the lower crust.

关键词： Charnockite Petrology Microstructure Melt inclusions

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The current performance of biodegradable magnesium-based implants in magnetic resonance imaging:A review

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Bioactive Materials 2021年第12期6卷 4360-4367页

作者： Jonathan Espiritu Martin Meier jan-marten Seitz Syntellix AG HannoverGermany Hannover Medical School HannoverGermany

Magnesium-based implants are re-emerging as a substantial amendment to standard orthopaedic implants.A brief introduction of magnesium(Mg)as a biodegradable material and basic magnetic resonance imaging(MRI)principles are *** review aims to highlight the current performance of these implants during examinations with *** also aim to summarise comparisons between Mg-based implants with current standards to emphasise the promotion of biodegradable implants in clinical practice.A comprehensive search of current literature on Mg-based implants and the utilisation of MRI in the studies was ***,recorded artefact behaviour of Mg-based implants during MRI was investigated.A total of nine studies were included in which MRI was employed to image Mg-based *** those studies,four of the nine discuss artefact production caused by the *** successfully imaged regions of interest over all and produced fewer artefacts than other materials used in the *** was employed in contrast angiography,bone growth observation,bone infection healing,and blood *** capabilities of an implant material are vital to translating products into clinical *** findings presented in this review suggest and support the use of Mg-based implants due to their successful visual compatibility with MRI techniques.

关键词： Magnetic resonance imaging Magnesium Biodegradable implants Medical imaging Patient safety

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Detailing the influence of PEO-coated biodegradable Mg-based implants on the lacuno-canalicular network in sheep bone:A pilot study

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Bioactive Materials 2023年第8期26卷 14-23页

作者： Jonathan Espiritu Sandra Sefa Hanna Cwieka Imke Greving Silja Flenner Regine Willumeit-Römer jan-marten Seitz Berit Zeller-Plumhoff Syntellix AG HannoverGermany Institute of Metallic Biomaterials Helmholtz-Zentrum HereonGeesthachtGermany Institute of Materials Physics Helmholtz-Zentrum HereonGeesthachtGermany

An increasing prevalence of bone-related injuries and aging geriatric populations continue to drive the orthopaedic implant market.A hierarchical analysis of bone remodelling after material implantation is necessary to better understand the relationship between implant and ***,which are housed and communicate through the lacuno-canalicular network(LCN),are integral to bone health and remodelling ***,it is essential to examine the framework of the LCN in response to implant materials or surface *** materials offer an alternative solution to permanent implants,which may require revision or removal *** alloys have resurfaced as promising materials due to their bone-like properties and safe degradation in *** further tailor their degradation capabilities,surface treatments such as plasma electrolytic oxidation(PEO)have demonstrated to slow *** the first time,the influence of a biodegradable material on the LCN is investigated by means of non-destructive 3D *** this pilot study,we hypothesize noticeable variations in the LCN caused by altered chemical stimuli introduced by the *** synchrotron-based transmission X-ray microscopy,we have characterised morphological LCN differences around uncoated and PEO-coated WE43 screws implanted into sheep *** specimens were explanted after 4,8,and 12 weeks and regions near the implant surface were prepared for *** from this investigation indicate that the slower degradation of PEO-coated WE43 induces healthier lacunar shapes within the ***,the stimuli perceived by the uncoated material with higher degradation rates induces a greater connected LCN better prepared for bone disturbance.

关键词： Nanotomography Lacuno-canalicular network Bone Magnesium Biodegradable implants

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Evaluating metallic artefact of biodegradable magnesium-based implants in magnetic resonance imaging

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Bioactive Materials 2022年第9期7卷 382-391页

作者： Jonathan Espiritu Mostafa Berangi Christina Yiannakou Eduarda Silva Roberto Francischello Andre Kuehne Thoralf Niendorf Soren Konneker Regine Willumeit-Romer jan-marten Seitz Syntellix AG HannoverGermany MRI.TOOLS GmbH BerlinGermany Charit´e-Universitatsmedizin Berlin Corporate Member of Freie Universitat Berlin and Humboldt Universitat zu BerlinBerlinGermany Berlin Ultrahigh Field Facility(B.U.F.F.) Max-Delbrueck Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany Hannover Medical School HannoverGermany Institute of Clinical Physiology National Research CouncilPisaItaly Chemistry and Industrial Chemistry Department Universita di PisaVia Moruzzi 13PisaItaly Fondazione Toscana Gabriele Monasterio Via Moruzzi 1PisaItaly Institute for Materials Research Helmholtz Zentrum HereonGeesthachtGermany

Magnesium(Mg)implants have shown to cause image artefacts or distortions in magnetic resonance imaging(MRI).Yet,there is a lack of information on how the degradation of Mg-based implants influences the image quality of MRI *** this study,Mg-based implants are analysed in vitro,ex vivo,and in the clinical setting for various magnetic field strengths with the aim to quantify metallic artefact *** vitro corroded Mg-based screws and a titanium(Ti)equivalent were imaged according to the ASTM ***-based and Ti pins were also implanted into rat femurs for different time points and scanned to provide insights on the influence of soft and hard tissue on metallic ***,MRI data of patients with scaphoid fractures treated with CE-approved Mg-based compression screws(MAGNEZIX®)were analysed at various time points *** artefact production of the Mg-based material decreased as implant material degraded in all *** worst-case imaging scenario was determined to be when the imaging plane was selected to be perpendicular to the implant ***,the Mg-based implant outperformed the Ti equivalent in all experiments by producing lower metallic artefact(p<0.05).This investigation demonstrates that Mg-based implants generate significantly lower metallic distortion in MRI when compared to *** positive findings suggest and support further research into the application of Mg-based implants including post-operative care facilitated by MRI monitoring of degradation kinetics and bone/tissue healing processes.

关键词： Magnetic resonance imaging Magnesium Biodegradable implants Medical imaging Translational medicine

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Radiofrequency induced heating of biodegradable orthopaedic screw implants during magnetic resonance imaging

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Bioactive Materials 2023年第7期25卷 86-94页

作者： Jonathan Espiritu Mostafa Berangi Hanna Cwieka Kamila Iskhakova Andre Kuehne D.C.Florian Wieland Berit Zeller-Plumhoff Thoralf Niendorf Regine Willumeit-Römer jan-marten Seitz Syntellix AG HannoverGermany MRI.TOOLS GmbH BerlinGermany Charité-Universitätsmedizin Berlin Corporate Member of Freie Universität Berlin and Humboldt Universität zu BerlinBerlinGermany Berlin Ultrahigh Field Facility(B.U.F.F.) Max-Delbrueck Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany Institute of Metallic Biomaterials Helmholtz Zentrum HereonGeesthachtGermany

Magnesium(Mg)-based implants have re-emerged in orthopaedic surgery as an alternative to permanent *** reveals little information on how the degradation of biodegradable implants may introduce safety implications for patient follow-up using medical *** resonance imaging(MRI)benefits post-surgery monitoring of bone healing and implantation *** studies demonstrated radiofrequency(RF)heating of permanent implants caused by electromagnetic fields used in *** investigation is the first to report the effect of the degradation layer on RF-induced heating of biodegradable orthopaedic ***43 orthopaedic compression screws underwent in vitro *** techniques were applied to assess the corrosion process and the material composition of the degraded *** measurements were performed to quantify implant heating with respect to the degradation *** comparison,a commercial titanium implant screw was *** RF induced heating was observed for non-degraded WE43 screw *** heating had shown to decrease with the formation of the degradation *** statistical differences were observed for heating of the non-degraded WE43 material and the titanium *** highest risk of implant RF heating is most pronounced for Mg-based screws prior to *** to industry standards for MRI safety assessment is warranted to include biodegradable materials.

关键词： Biodegradable implants Magnesium Medical imaging Magnetic resonance imaging Patient safety

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