The Permian basalts in the Central Asian Orogenic Belt(CAOB)are crucial for constraining the closure of the Paleo-Asian Ocean.However,the origin of these basalts is still under discussion.Here,we present comprehensive...The Permian basalts in the Central Asian Orogenic Belt(CAOB)are crucial for constraining the closure of the Paleo-Asian Ocean.However,the origin of these basalts is still under discussion.Here,we present comprehensive bulk-rock geochemical,Sr-Nd-Pb-Hf isotopic,and zircon U-Pb-Lu-Hf isotopic data of the Liuyuan basalts and coexisting gabbros,which are located in the Beishan Orogen in the southern CAOB,to constrain their emplacement setting and tectonic implications.Our new gabbro ages of ca.288–294 Ma are interpreted to represent the formation time of the Liuyuan basaltic belt.The Liuyuan basalts show MORB-like rare earth element(REE)patterns and bulk-rockε_(Hf)(t)andε_(Nd)(t)values of 11.0–15.4 and 4.6–9.2,respectively,suggesting an origination mainly from a depleted mantle source.However,positive Pb anomalies,Nb-Ta depletions,and high Th/Yb ratios as well as evolved Sr-Nd-Pb-Hf isotopic compositions of some samples indicate variable continental crustal contribution.According to the covariation of Pb anomalies(Pb^(*)=2×Pb_(N)/(Ce_(N)+Pr_(N)))with Sr-Nd-Pb-Hf isotopic compositions,we speculate that parent magma of the Liuyuan basalt was contaminated by continental crustal materials during the eruption rather than having been generated from an enriched mantle source.As revealed by mixing modelling,the Liuyuan basaltic magmas would require a minor(<10%)upper continental crustal assimilation to explain the enriched trace elemental and radiogenic Sr-Nd-Pb-Hf isotopic signatures.Consequently,the Liuyuan basaltic belt is believed to have been generated in a continental extensional environment instead of an oceanic setting and does not constitute a Permian ophiolitic suture zone as previously suggested,since the Paleo-Asian Ocean was already closed in the southern Beishan Orogen in the Early Permian.展开更多
In this paper, we study the existence and multiplicity of solutions for the following fractional Schrodinger-Poisson system：（{ε2S（-△）Su＋V（x）u＋φu=｜u｜2＊s-2＋f（u）in R3ε2s（-△）sφ=u in R3（0.1）where 3/...In this paper, we study the existence and multiplicity of solutions for the following fractional Schrodinger-Poisson system：（{ε2S（-△）Su＋V（x）u＋φu=｜u｜2＊s-2＋f（u）in R3ε2s（-△）sφ=u in R3（0.1）where 3/4〈s〈1,2＊：＋6/3-2s）is the fractional critical exponent for 3-dimension, the potential V ： R3→ R is continuous and has global minima, and f is continuous and supercubic but subcritical at infinity. We prove the existence and multiplicity of solutions for System （0.1） via variational methods.展开更多
基金co-supported by the National Natural Science Foundation of China(No.41922021)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(No.MSFGPMR01-03)。
文摘The Permian basalts in the Central Asian Orogenic Belt(CAOB)are crucial for constraining the closure of the Paleo-Asian Ocean.However,the origin of these basalts is still under discussion.Here,we present comprehensive bulk-rock geochemical,Sr-Nd-Pb-Hf isotopic,and zircon U-Pb-Lu-Hf isotopic data of the Liuyuan basalts and coexisting gabbros,which are located in the Beishan Orogen in the southern CAOB,to constrain their emplacement setting and tectonic implications.Our new gabbro ages of ca.288–294 Ma are interpreted to represent the formation time of the Liuyuan basaltic belt.The Liuyuan basalts show MORB-like rare earth element(REE)patterns and bulk-rockε_(Hf)(t)andε_(Nd)(t)values of 11.0–15.4 and 4.6–9.2,respectively,suggesting an origination mainly from a depleted mantle source.However,positive Pb anomalies,Nb-Ta depletions,and high Th/Yb ratios as well as evolved Sr-Nd-Pb-Hf isotopic compositions of some samples indicate variable continental crustal contribution.According to the covariation of Pb anomalies(Pb^(*)=2×Pb_(N)/(Ce_(N)+Pr_(N)))with Sr-Nd-Pb-Hf isotopic compositions,we speculate that parent magma of the Liuyuan basalt was contaminated by continental crustal materials during the eruption rather than having been generated from an enriched mantle source.As revealed by mixing modelling,the Liuyuan basaltic magmas would require a minor(<10%)upper continental crustal assimilation to explain the enriched trace elemental and radiogenic Sr-Nd-Pb-Hf isotopic signatures.Consequently,the Liuyuan basaltic belt is believed to have been generated in a continental extensional environment instead of an oceanic setting and does not constitute a Permian ophiolitic suture zone as previously suggested,since the Paleo-Asian Ocean was already closed in the southern Beishan Orogen in the Early Permian.
基金supported by National Natural Science Foundation of China(Grant Nos.11361078 and 11661083)
文摘In this paper, we study the existence and multiplicity of solutions for the following fractional Schrodinger-Poisson system：（{ε2S（-△）Su＋V（x）u＋φu=｜u｜2＊s-2＋f（u）in R3ε2s（-△）sφ=u in R3（0.1）where 3/4〈s〈1,2＊：＋6/3-2s）is the fractional critical exponent for 3-dimension, the potential V ： R3→ R is continuous and has global minima, and f is continuous and supercubic but subcritical at infinity. We prove the existence and multiplicity of solutions for System （0.1） via variational methods.
