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Whole-rock geochemical and U-Pb-Hf isotopic data were used to investigate the age, petrogenesis, and tectonic setting of a suite of gabbro-diorite-monzonite-syenite rock exposed in Qinsai area, Hainan Island. Zircon U-Pb dating shows that the gabbro and monzonite, respectively, crystallized at 179.5 [+ or -] 2.7 and 179.0 [+ or -] 2.3 Ma. The suite consists of shoshonitic alkaline intrusive rocks with [SiO.sub.2] content ranging from 41.7 to 63.4 wt%, with high U, K, and Pb and low Nb, Ta, and Ti. The suite is enriched in light rare earth elements relative to heavy rare earth elements. The gabbro has no obvious Eu anomaly but a positive Eu anomaly is evident in intermediate rocks. Zircon [[epsilon].sub.Hf](t) values are positive and have a wide variation (gabbro [[epsilon].sub.Hf](t) = +5.2 [+ or -] 8.2, monzonite [[epsilon].sub.Hf](t) = +4.7 [+ or -] 7.1). Gabbro and syenite are both likely derived from an enriched lithospheric mantle that was metasomatized by subduction fluids. Syenite evolved from the differentiation of gabbro, monzonite, and diorite. Collectively these intrusive rocks formed in an extensional regime within an arc formed by subduction of the ancient Pacific plate beneath the Asian margin, which was accompanied by extensional thinning of the lithosphere. Key words: Hainan, Middle Jurassic, intrusive rocks, U-Pb age, geochemistry, petrogenesis, Introduction The South China plate is located to the south of the Chinese mainland. Since the Late Paleozoic, the southeastern margin of the South China plate has been affected by [...]

During the Late Paleozoic–Early Mesozoic Era, the sediment transport system and tectonic regime in the southeastern margin of the South China Block (SESCB) all changed, significantly affected by the Paleo-Pacific subduction. However, controversy exists about the Paleo-Pacific subduction's initiation time. This study uses detrital zircon U-Pb ages to discuss the Late Triassic source-to-sink system in the SESCB. It provides some references for the Paleo-Pacific subduction process based on crucial age information and zircons' trace elements. The paleogeography and similarity of detrital zircon age distribution indicate that three sinks were found in the SESCB during the Late Triassic: 1. the Yangchun-Kaiping-Gaoming area, comprising major age ranges of 260–220, 460–400, and 1 200–800 Ma, which might be sourced from the Yunkai terrane; 2. the Jiexi-Kanshi-Nanjing area, characterized by the significant age component of 2 000–1 800 Ma, which corresponded to the Wuyi terrane; 3. the Xinan area, consisting of significant age groups of 290–250 and 380–320 Ma, which might be sourced from the magmatic rocks formed by the Huinan Movement and Paleo-Pacific subduction. Note that 290–250 Ma zircons were widely distributed in the Upper Triassic strata, and their trace elements suggested the existence of a magmatic arc near the SESCB during the 290–250 Ma. Thus, we propose that the Paleo-Pacific subduction might have begun in the Early Permian. [ABSTRACT FROM AUTHOR]

Controversies exist regarding the mechanismofformationofbasins locatedonthe continental marginof South China as well as when they formed. It was ascertained based on clastic petrology, geochemical analysis, and zircon U--Pb dating that the sedimentary provenances in the eastern Guangdong Basin are mainly felsic igneous rocks from the late Early Jurassic to the Middle Jurassic. The late Early Jurassic Qiaoyuan Formation mainly shows major age peaks atapproximately 238 Ma, 259 Ma, and 1858 Ma, and the Middle Jurassic Tangxia Formation shows major age peaks at approximately 169 Ma and 172 Ma. From the late Early Jurassic to the Middle Jurassic in the eastern Guangdong Basin, the source region changes from southwestern South China and southern South China to the eastern Nanling Range. It was determined by comparing the detrital zircon ages of the Qiaoyuan Formation and the Tangxia Formation with thoseofthe late Paleozoictoearly Mesozoic basins, and analyzing both the geochemical data and sedimentation, that the eastern Guangdong Basin changed from the basin-arc foreland basin of the late Early Jurassic to the back-arc extension basin of the Middle Jurassic. The changes in early Mesozoic detrital zircon age peaks indicate that the tectonic regime of the eastern Guangdong Basin ended the transformation from the Tethyan tectonic domain to the paleo-Pacific tectonic domain in the early Middle Jurassic (approximately 172 Ma). Key words: eastern Guangdong Basin, late Early Jurassic to Middle Jurassic, provenances, tectonic regime transformation, zircon U--Pb dating. Des controverses persistent quant au mecanisme de formation de bassins situes sur la marge continentale de la Chine meridionale, ainsi qu'au moment de leur formation. Il a ete etabli, sur la base de la petrologie, l'analyse geochimique et la datation U--Pb sur zircons de depots clastiques que les sources de sediments dans le bassin de Guangdong oriental sont principalement des roches ignees felsiques d'age jurassique precoce tardif a jurassique moyen. La Formation de Qiaoyuan du Jurassique precoce tardif produit principalement de grands pics d'ages vers 238 Ma, 259 Ma et 1858 Ma, et la Formation de Tangxia du Jurassique moyen donne de grands pics d'ages vers 169 Ma et 172 Ma. Du Jurassique precoce tardif au Jurassique moyen dans le bassin de Guangdong oriental, la region source passe du sud-ouest et du sud de la Chine meridionale a la chaine de Nanling orientale. Il est determine, en comparant les ages de zircons detritiques des Formations de Qiaoyuan et de Tangxia a ceux des bassins d'age paleozoique tardif a mesozoique precoce et en analysant les donnees geochimiques et la sedimentation, que le bassin de Guangdong oriental est passe d'un bassin d'avant-pays d'un systeme arc-bassin au Jurassique precoce tardif a un bassin d'extension d'arriere-arc au Jurassique moyen. L'evolution des pics d'ages de zircons detritiques du Mesozoique precoce indique queleregime tectonique danslebassindeGuangdong orientalacloslatransformationdudomaine tectonique tethysien en un domaine tectonique paleopacifique au Jurassique moyen precoce (vers 172 Ma). [Traduit par la Redaction] Mots-cles : bassin de Guangdong oriental, Jurassique precoce tardif--Jurassique moyen, provenances, transformation du regime tectonique, datation U--Pb sur zircons., Introduction The main geotectonic outline of South China and even eastern China is controlled by the Indosinian and Yanshan movements (Wang and Zhou 2006; He et al. 2007; Z.H. Li [...]

During the existence of Proto-Tethys Ocean (550–430 Ma), microcontinents in northern East Gondwana merged with the northern margin of India-Australia, completing the assembly of Gondwana. Ongoing controversy surrounds the disappearance of the Proto-Tethys Ocean, the dynamic mechanisms of suturing and the palaeogeographic relationships among microcontinents in northern East Gondwana, contributing to the uncertainty about the tectonic evolution of the region. This paper concerns the lower Silurian Zusailing Formation in the Hainan Island and focuses on the affinity between Hainan Island and various microcontinents in northern East Gondwana during the early Silurian. We use detrital zircon geochronology to reconstruct the closure process of the Proto-Tethys Ocean and show that the detrital zircon U–Pb age groups of the lower Silurian Zusailing Formation are 2800–2200, 2100–1350, 1250–950, 600–480 and 480–430 Ma, with a significant age peak of ca. 449 Ma. Furthermore, the analysis of detrital zircon geochemistry and europium anomalies shows that the Hainan Island crust continued to thicken during 600–434 Ma. Comparing the age spectrum of early Palaeozoic detrital zircons from Hainan Island and various microcontinents in northern East Gondwana, as well as the affinity among them during the Silurian, we conclude that the closure of the eastern Proto-Tethys Ocean evolved from unidirectional subduction (600–480 Ma) to bidirectional subduction (480–430 Ma). [ABSTRACT FROM AUTHOR]

Based on research of the petrology, geochemistry, and zircon U-Pb dating of detrital rocks in the Late Triassic Wenbinshan Formationin southwestern Fujian, and comparing the detrital zircon ages of Wenbinshan Formation with those of Late Paleozoic--Early Mesozoic main basins in South China, the sedimentary provenance of the Late Triassic in southwestern Fujian and its implications for changes in basin properties are discussed. The research results demonstrate that there is a major age peak at 222 Ma, two subordinate age peaks at 275 Ma and 1851 Ma, and two minor age peaks at 413 Ma and 2447 Ma in the detrital zircon age spectra of the upper samples (YGP-6) of the Wenbinshan Formation, whereas there are two major age peaks at 229 Ma and 1817 Ma and other minor age peaks 265 Ma 309 Ma, 415 Ma, 1968 Ma, and 2435 Ma in the detrital zircon age spectra of the lower samples (YGP-26) of the Wenbinshan Formation. The upper samples contain fewer old detrital zircons than the lower samples, but the upper and lower samples of Wenbinshan Formation are similar in major age composition, which indicates the main provenances of the upper and lower sediments are very similar. The source rocks are mainly sedimentary rocks and their provenances are derived from a source area of recycled orogenic belt and volcanic arc orogenic belt (acidic island arc). The detrital zircon composition of the Wenbinshan Formation is mainly composed of Paleoproterozoic zircon and Late Paleozoic-Early Mesozoic zircon. In the Paleoproterozoic, sedimentary provenances were mainly derived from the Wuyi Massif and partly from northwestern Fujian-southwestern Zhejiang. As for the period of Late Paleozoic-Early Mesozoic, the provenances of the Wenbinshan Formation were derived from magmatic active belts of the Early Indosinian Epoch of northern South China, eastern South China, and the Indosinian Period of northern South China and coastal areas of eastern South China. The similarities and differences between detrital zircon age peaks of the Wenbinshan Formation in southwestern Fujian and that of the main basins in South China during the period of Late Paleozoic-Early Mesozoic indicate that from eastern coastal areas of South China to the north and interior of South China, the age composition of basin sediments has changed from simple to relatively complex, and from young sediments to older sediments. There are similarities and differences in the detrital zircon compositions of the different basins, which can indicate differences in the nature of the basins. Key words: Southwestern Fujian, Late Triassic, zircon U-Pb dating, provenances, Indosinian movement. A la lumiere de travaux sur la petrologie, la geochimie et la datation U-Pb sur zircons de roches detritiques de la Formation de Wenbinshan du Trias tardif dans le sud-ouest de la province du Fujian, et de la comparaison des ages de zircons detritiques de cette formation a ceux de principaux bassins d'age paleozoique tardif a mesozoique precoce en Chine meridionale, la provenance sedimentaire des sediments du Trias tardif dans le sud-ouest du Fujian et ses consequences pour la comprehension des variations des proprietes des bassins sont abordees. Les resultats de ces travaux demontrent une pointe d'ages majeure a 222 Ma, deux pointes subordonnees a 275 Ma et 1851 Ma et deux pointes mineures a 413 Ma et 2447 Ma dans les spectres d'ages de zircons detritiques de la partie superieure (YGP-6) de la Formation de Wenbinshan, alors qu'il y a deux pointes d'ages majeures a 229 Ma et 1817 Ma et d'autres pointes mineures a 265 Ma, 309 Ma, 415 Ma, 1968 Ma et 2435 Ma dans les spectres d'ages de zircons detritiques de la partie inferieure (YGP-26) de cette formation. Les echantillons superieurs contiennent moins de vieux zircons que les echantillons inferieurs, mais les echantillons superieurs et inferieurs presentent des pointes d'ages majeures semblables, ce qui indique que les principales provenances des sediments superieurs et inferieurs sont tres semblables. Les roches sources consistent principalement en des roches sedimentaires derivees de ceintures orogeniques recyclees et de ceintures d'arc volcanique (arc oceanique acide). Les zircons detritiques de la Formation de Wenbinshan comprennent principalement des zircons paleoproterozoiques et des zircons paleozoiques tardifs a mesozoiques precoces. Durant le Paleoproterozoique, les sediments provenaient principalement du massif de Wuyi et en partie du nord-ouest du Fujian et du sud-ouest du Zhejiang. En ce qui concerne la periode du Paleozoique tardif au Mesozoique precoce, les sediments de la Formation de Wenbinshan proviennent de ceintures magmatiques actives du debut de l'epoque indosinienne du nord et de l'est de la Chine meridionale, ainsi que de la periode indosinienne du nord et de zones cotieres de l'est de la Chine meridionale. Les similitudes et differences entre les pointes d'ages de zircons detritiques de la Formation de Wenbinshan dans le sud-ouest de la province du Fujian et des principaux bassins d'ages paleozoiques tardifs a mesozoiques precoces en Chine meridionale indiquent que, des zones cotieres orientales jusqu'au nord et a l'interieur de la Chine meridionale, la composition des ages des sediments de bassin est passee de simple a relativement complexe, et de sediments jeunes a des sediments plus vieux. La composition des zircons detritiques des differents bassins presente des similitudes et des differences, ce qui indique des variations de la nature des bassins. [Traduit par la Redaction] Mots-cles : sud-ouest de la province du Fujian, Trias tardif, datation U-Pb sur zircon, provenance, mouvement indosinien., 1. Introduction The Indosinian and Yanshan movements were two tectonic movements that formed the main tectonic framework during the formation of South China and East China (Lin et al. 2013; [...]

Reversible charge transfer between lanthanide ions is identified as storage mechanism for the current workhorse persistent phosphors. Present evidence relies on sophisticated X‐ray absorption spectroscopy to detect the reversible charge transfer. Here, simple optical spectroscopy is used to study the charge transfer in one of the benchmark persistent phosphors CaAl2O4:Eu2+,Nd3+. Based on the observation that both the trapping and de‐trapping processes in CaAl2O4:Eu2+,Nd3+ are thermally activated, forward charge transfer from Eu2+ to Nd3+ and backward charge transfer from Nd2+ to Eu3+ are identified. The percentages of Eu2+ and Nd3+ involved in the charge transfer are >10%, which exceeds the previous estimates in other persistent phosphors. Furthermore, this strategy offers additional advantage of site selectivity, which enables the identification of the distinct contributions of different Nd3+ sites to the charge transfer. These findings underline the significance of reversible charge transfer in persistent phosphors and move towards a complete understanding of persistent luminescence mechanism. [ABSTRACT FROM AUTHOR]

Abstract: Cesium‐lead halide perovskites (e.g. CsPbBr3) have gained attention because of their rich physical properties, but their bulk ferroelectricity remains unexplored. Herein, by alloying flexible organic cations into the cubic CsPbBr3, we design the first cesium‐based two‐dimensional (2D) perovskite ferroelectric material with both inorganic alkali metal and organic cations, (C4H9NH3)2CsPb2Br7 (1). Strikingly, 1 shows a high Curie temperature (Tc=412 K) above that of BaTiO3 (ca. 393 K) and notable spontaneous polarization (ca. 4.2 μC cm−2), triggered by not only the ordering of organic cations but also atomic displacement of inorganic Cs+ ions. To our knowledge, such a 2D bilayered Cs+‐based metal–halide perovskite ferroelectric material with inorganic and organic cations is unprecedented. 1 also shows photoelectric semiconducting behavior with large “on/off” ratios of photoconductivity (>103). [ABSTRACT FROM AUTHOR]

Persistent luminescence nanoparticles (PLNPs) have shown great promise in the field of biomedicine, but are currently limited by the challenge in the synthesis of high-quality PLNPs with bright persistent luminescence and a long afterglow time. Herein, we report a facile strategy for the synthesis of monodisperse, rechargeable and LED-activated ZnGa 2 O 4  : Cr 3+ near-infrared (NIR) PLNPs based on a modified solvothermal liquid-solid-solution method. The as-synthesized PLNPs are not only flexible for bioconjugation, but could also circumvent the limitation of the weak persistent luminescence and short afterglow time that most PLNPs confronted owing to their rechargeable capability. It was unraveled that both thermal activation and quantum tunneling mechanisms contributed to the afterglow decay of the PLNPs, and the quantum tunneling was found to dictate the LED-activated afterglow intensity and lasting time. Furthermore, by utilizing the superior excitation-free persistent luminescence, we demonstrated for the first time the application of biotinylated ZnGa 2 O 4  : Cr 3+ PLNPs as background-free luminescent nano-bioprobes for sensitive and specific detection of avidin in a heterogeneous assay with a limit of detection down to ∼150 pM, thus revealing the great potential of these NIR PLNPs in ultrasensitive biodetection and bioimaging.

Modular optimization of metal-organic frameworks (MOFs) was realized by incorporation of coordinatively unsaturated single atoms in a MOF matrix. The newly developed MOF can selectively capture and photoreduce CO 2 with high efficiency under visible-light irradiation. Mechanistic investigation reveals that the presence of single Co atoms in the MOF can greatly boost the electron-hole separation efficiency in porphyrin units. Directional migration of photogenerated excitons from porphyrin to catalytic Co centers was witnessed, thereby achieving supply of long-lived electrons for the reduction of CO 2 molecules adsorbed on Co centers. As a direct result, porphyrin MOF comprising atomically dispersed catalytic centers exhibits significantly enhanced photocatalytic conversion of CO 2 , which is equivalent to a 3.13-fold improvement in CO evolution rate (200.6 μmol g -1  h -1 ) and a 5.93-fold enhancement in CH 4 generation rate (36.67 μmol g -1  h -1 ) compared to the parent MOF., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Persistent luminescence phosphors, which are capable of emitting light for a long time after ceasing excitation, have shown great promise in diverse areas as bioprobes, lighting and displays. Exploring new materials to realize efficient persistent luminescence is a goal of general concern. Herein, we report a novel persistent luminescence phosphor based on Eu(3+)-doped SnO2 nanoparticles (NPs). The afterglow decay behaviour, the trap depth distribution as well as the underlying mechanism for persistent luminescence of the NPs were comprehensively surveyed by means of thermoluminescence and temperature-dependent afterglow decay measurements. It was found that the thermal activation mechanism is responsible for the afterglow decay of the NPs with an inverse power-law exponent of 1.0 (or 1.7) in the temperature region below (or above) 220 K. In particular, the co-existence of uniform and exponential distributions in trap depths may result in such a unique afterglow decay behaviour. These results reveal the great potential of SnO2 NPs as an excellent host material for Eu(3+) doping for the generation of efficient persistent luminescence.

We report the successful incorporation of Er(3+) ions into SnO(2) nanocrystals via a solvothermal method, with a resulting Er(3+) concentration of the order of 10(19) cm(-3). Upon excitation above the SnO(2) bandgap at 300 nm, intense and well-resolved Er(3+)-related photoluminescence (PL) at 1.55 microm was observed at room temperature. The results of PL excitation and ultraviolet/visible diffuse reflectance spectra indicate that the excitation is a carrier-mediated process with an energy transfer from the SnO(2) host to Er(3+). For the above-gap excitation, only a single type of Er(3+) luminescence center located at a centrosymmetric site was identified. The near-infrared luminescence dynamics and the weak PL thermal quenching of Er(3+) were also revealed.