Unique Carboniferous-Permian tectonic-metallogenic framework of Northern Xinjiang (NW China): Constraints for the tectonics of the southern Paleoasian Domain

The late Paleozoic tectonic-metallogenic framework of North Xinjiang of the southern Paleoasian Domain was characterized by a serious of Carboniferous-Permian events, including: (1) late Carboniferous-Permian Chinese Altay island arc and its metamorphism, granulite in the Chinese Altay, radiolarian chert and high-pressure/ultra-high-pressure metamorphism; (2) late Carboniferous-early Permian adakites, Alaskan-type mafic-ultramafic complexes, and calc-alkaline magmatism, together with porphyry copper deposits, which occurred in the North Xinjiang; and (3) late Carboniferous ophiolite and island arc volcanic rocks located in the Tian Shan. Combined with the facts that there was no typical foreland basin, no typical collisional-type granitoid, and there were large amount of strike-slip faulting, it is suggested that in the Carboniferous-early Permian North Xinjiang was characterized by the coexistence of compression-extension-strike-slip structures with active magmatism and metallogeny. These phenomena all indicate that there were active margins during the late Carboniferous-early Permian, leading to the notion that the complicated accretionary orogeny along the southern Paleoasian Domain may have lasted to the latest Carboniferous-Permian.新疆北部晚古生代独特的构造一成矿作用以发育大量石炭纪一二叠纪构造一成矿事件为特征, 其中包括: (l) 发育于晚石炭世一二叠世的阿尔泰岛弧及其变质事件、阿尔泰麻粒岩与基性杂岩、西南天山放射虫硅质岩和高压一超高压一低压麻拉岩相变质事件; (2 )北疆发育的石炭纪(一二叠世)埃达克岩一高镁安山岩一富N d 玄武质岩组合、阿拉斯加型基性一超基性杂岩和大量的与俯冲相关的钙碱性岩浆活动与斑岩型铜矿床成矿作用; (3) 天山晚石炭世晚期蛇绿岩与岛弧火山岩等。结合北疆地区相关的前陆盆地发育不明显、碰撞型花岗岩欠发育与大量发育平行造山带大型走滑构造等现象, 可以认为新疆北部在石炭纪一二叠纪挤压一伸展一走滑并存, 岩浆活动与成矿作用活跃。这些新进展表明新疆北部在晚石炭世一二叠纪可能仍存在活动陆缘, 因此, 古亚洲洋构造域南部复杂增生造山作用最后延至晚石炭世晚期一二叠纪。published_or_final_versio

Effect of surface oxygen concentration on activation of methane over supported metal catalysts

Activation of methane over supported metal catalysts was investigated using MS-pulse technique on-line. Oxygen-free CH4 pulsing reactions were carried out over both Rh/SiO2 and Ru/SiO2 at 700 degreesC. Large amounts of CO and CO2 were observed at the first pulse of CH4 over oxidized Rh(O)/SiO2 catalyst. However, no CO2 formation was observed at the second pulse and thereafter. Similar to the response of Rh(O) /SiO2 catalyst, the intensity of CO and CO2 was strong at the first pulse over reduced Rh/SiO2 catalyst, and CO2 appeared also only at the first pulse over Rh/SiO2 catalyst. No CO2 was detected at the second pulse and thereafter. CH4 pulsing over Ru(O)/SiO2 catalyst also produced CO and CO2. CO and CO2 were detected from the first pulse I and their intensity was much stronger than that of CO and CO2 produced over Rh/SiO2 catalyst. However, unlike Rh/SiO2 catalyst, CO2 was formed at every pulse over Ru(O)/SiO2 catalyst. Pulsing CH4 over Ru/SiO2 catalyst also produced both CO and CO2 at every pulse. This difference between Rh and Ru catalysts may be due to the difference in the bond strength of Ru-O (528.4 kJ/mol) and Rh-O (405.1 kJ/mol) and in their relative oxygen affinities, Ru-0 can be more easily oxidized by O-2 than Rh-0 owing to the greater oxygen affinity of Ru. Surface oxygen should play an important role in the activation of methane and the product distribution

Measurement of the matrix element for the decay η′→ηπ +π -

The Dalitz plot of η⊃′→ηπ⊃+π⊃- decay is studied using (225.2±2.8)×106 J/ψ events collected with the BESIII detector at the BEPCII e⊃+e⊃- collider. With the largest sample of η⊃′ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ψ→γη⊃′ is determined to be (4.84±0.03±0.24)×10⊃-3, where the first error is statistical and the second systematic. © 2011 American Physical Society.published_or_final_versio

Higher-order multipole amplitude measurement in ψ ′→γχ c2

Using 106×106 ψ ′ events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition ψ ′→γχ c2→γπ +π -/γK +K - are measured. A fit to the χ c2 production and decay angular distributions yields M2=0.046±0. 010±0.013 and E3=0.015±0.008±0.018, where the first errors are statistical and the second systematic. Here M2 denotes the normalized magnetic quadrupole amplitude and E3 the normalized electric octupole amplitude. This measurement shows evidence for the existence of the M2 signal with 4.4σ statistical significance and is consistent with the charm quark having no anomalous magnetic moment. © 2011 American Physical Society.published_or_final_versio

Determination of the number of J/ψ events with J/ψ → inclusive decays

postprin

Two-photon widths of the χ c0,2 states and helicity analysis for χ c2→γγ

Based on a data sample of 106×106 ψ ′ events collected with the BESIII detector, the decays ψ ′→γχ c0,2, χ c0,2→γγ are studied to determine the two-photon widths of the χ c0,2 states. The two-photon decay branching fractions are determined to be B(χ c0→γγ)=(2. 24±0.19±0.12±0.08)×10 -4 and B(χ c2→γγ)=(3.21±0.18±0. 17±0.13)×10 -4. From these, the two-photon widths are determined to be Γ γγ(χ c0)=(2. 33±0.20±0.13±0.17)keV, Γ γγ(χ c2)=(0.63±0.04±0. 04±0.04)keV, and R=Γ γγ(χ c2)/ Γ γγ(χ c0)=0.271±0. 029±0.013±0.027, where the uncertainties are statistical, systematic, and those from the PDG B(ψ ′→γχ c0,2) and Γ(χ c0,2) errors, respectively. The ratio of the two-photon widths for helicity λ=0 and helicity λ=2 components in the decay χ c2→γγ is measured for the first time to be f 0/2=Γγγλ= 0(χ c2)/Γγγλ=2(χ c2)=0. 00±0.02±0.02. © 2012 American Physical Society.published_or_final_versio

Observation of \chi_{cJ} decaying into the p\bar{p}K^{+}K^{-} final state

First measurements of the decays of the three $\chi_{cJ}$ states to $p\bar{p}K^{+}K^{-}$ final states are presented. Intermediate $\phi\to K^{+}K^{-}$ and $\Lambda(1520)\to pK^{-}$ resonance states are observed, and branching fractions for $\chi_{cJ}\to \bar{p}K^{+}\Lambda(1520)$, $\Lambda(1520) \bar{\Lambda}(1520)$, and $\phi p\bar{p}$ are reported. We also measure branching fractions for direct $\chi_{cJ}\to p\bar{p} K^{+}K^{-}$ decays. These are first observations of $\chi_{cJ}$ decays to unstable baryon resonances and provide useful information about the $\chi_{cJ}$ states. The experiment uses samples of $\chi_{cJ}$ mesons produced via radiative transitions from 106 million $\psi^{\prime}$ mesons collected in the BESIII detector at the BEPCII $e^+e^-$ collider.Comment: 16 pages, 5 figure

Search for a light exotic particle in J/psi radiative decays

Using a data sample containing 1.06x10^8 psi' events collected with the BESIII detector at the BEPCII electron-positron collider, we search for a light exotic particle X in the process psi' -> pi^+ pi^- J/psi, J/psi -> gamma X, X -> mu^+ mu^-. This light particle X could be a Higgs-like boson A^0, a spin-1 U boson, or a pseudoscalar sgoldstino particle. In this analysis, we find no evidence for any mu^+mu^- mass peak between the mass threshold and 3.0 GeV/c^2. We set 90%-confidence-level upper limits on the product-branching fractions for J/psi -> gamma A^0, A^0 -> mu^+ mu^- which range from 4x10^{-7} to 2.1x10^{-5}, depending on the mass of A^0, for M(A^0)<3.0 GeV/c^2. Only one event is seen in the mass region below 255 MeV/c^2 and this has a mu^+mu^- mass of 213.3 MeV/c^2 and the product branching fraction upper limit 5x10^{-7}.Comment: 7 pages, 3 figures, submitted to Physical Review

Re-Os isotopic analysis of the Kalatongke Cu-Ni sulfide deposit, northern Xinjiang, NW China, and its geological implication

喀拉通克銅鎳硫化物礦石的Re-Os同位素測年結果為305±15(2σ)Ma。該數據表明產于阿爾泰山南緣的銅鎳硫化物礦床形成于晚石炭世一早二疊世,與區內廣泛發育的造山型金礦和淺成低溫熱液型金礦基本為同一時期。其等時線~187Os/~188Os初始比值為0．35±0．04,γ_Os仉值平均為183,表明在成礦過程及巖漿侵位期間有少量地殼物質加入成礦系統中。The Kalatongke is a large Cu-Ni deposit in the southern part of the Altay orogenic belt, northwestern China. Rhenium and osmium isotopic analyses of Ni-and Cu-bearing sulfide minerals from the deposit have been used to determine the timing of mineralization, the source of osmium, and, by inference, the source of ore metals. Sulfide ore samples have osmium and rhenium concentrations varying in the ranges of 0.29 - 3.07 ppb, and 6.605 - 61.10ppb, respectively. Analyses of these data yield a six-point isochron with an age of 305 ± 15Ma. The age implies that the Cu-Ni sulfide deposit and other related magmatic deposits in the same area formed between the latest Carboniferous and Early Permian post-collisional extension in the Altay Shan. An initial 187Os/ 188Os ratio of 0.352 ± 0.044 (MSWD=2.1) and the δ 34S of -3.5‰ to + 3.0‰ for the ores, as well as initial 87Sr/ 86Sr ratios of metalliterous intrusions that vary from 0.70375 to 0.70504, suggest a magmatic source for the ores, with the melts being dominated by mantle contributions. The data also indicate that the Kalatongke Ni-Cu deposit, like many other copper, gold, and nickel deposits within central Asia, is related to post-collisional extensional processes.link_to_subscribed_fulltex