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| 1 | Solenites (Czekanowskiales) from the Late Mesozoic Jehol Biota of Southeastern Jilin,China and its Paleoclimatic Implications显示文摘Situated at the easternmost area of the Late Mesozoic Jehol Biota, China, abundant fossils, including invertebrates, vertebrates and plants, were collected from the Early Cretaceous Yingzuilazi Formation of the Baishan Basin, southeastern Jilin. The faunal remains from this formation distinctly belong to the Early Cretaceous Lycoptera–Ephemeropsis–Eosestheria assemblage of the Jehol Biota. Based on the gross leaf morphology and epidermal structures, two new species and one indeterminate species of genus Solenites(Czekanowskiales), S. baishanensis sp. nov., S. gracilis sp. nov. and S. sp. are described in this paper. This is the first fossil plant of Czekanowskiales reported from this new fossil locality of the easternmost area of the Late Mesozoic Jehol Biota, China. The new discovery contributes to improve our knowledge for understanding of leaf morphology, epidermal characters and diversity of this genus during the Early Cretaceous time, and extends geologic and geographic distribution of Solenites in northern China and Eurasia. Along with consideration of associated plant and faunal assemblages and sedimentology, we suggest that the regional climate was warm and moderately humid with seasonal temperature and precipitation variations in warm–temperate zone during the Early Cretaceous. | LI Yunfeng SUN Chunlin LI Tao NA Yuling CHEN Yuejun XING Dehe | 2015 | Acta Geologica Sinica(English Edition)2015，89，4： | 5 |
| 2 | Generation of Nb-enriched mafic rocks and associated adakitic rocks from the southeastern Central Asian Orogenic Belt:Evidence of crust-mantle interaction显示文摘Melting of subducting oceanic lithosphere and associated melt-mantle interactions in convergent plate margins require specific geodynamic environment that allows the oceanic slab to be abnormally heated.Here we focus on the Early Mesozoic mafic rocks and granite porphyry,which provide insights into slab melting processes associated with final closure of the Paleo-Asian Ocean.The granite porphyry samples are calc-alkaline and distinguished by high Sr contents,strong depletion of heavy rare earth elements,resulting in high(La/Yb);and Sr/Y ratios,and negligible Eu anomalies.Based on their high Na_(2)O and Mg O,low K_(2)O contents,positiveε_(Hf)(t)andε_(Nd)(t)and low(^(87)Sr/^(86)Sr)ivalues,we propose that the granite porphyry was likely derived from partial melting of subducting Paleo-Asian oceanic crust.The Nb-enriched mafic rocks are enriched in Rb,Th,U,Pb and K,and depleted in Nb,Ta,Ba,P and Ti,corroborating a subduction-related origin.Their heterogeneous Sr-Nd-Hf-O isotopic compositions and other geochemical features suggest that they were likely derived from partial melting of peridotitic mantle wedge interacted with oceanic slab-derived adakitic melts.Trace element and isotope modeling results and elevated zirconδ^(18)O values suggest variable subducting sediments input into the mantle wedge,dominated by terrigenous sediments.Synthesizing the widely-developed bimodal rock associations,conjugated dikes,thermal metamorphism,tectonic characteristics,paleomagnetic constraints,and paleogeographical evidence along the Solonke-Changchun suture zone,we identify a slab window triggered by slab break-off,which accounts for slab melting and formation of the Nb-enriched mafic rocks and associated adakitic granite porphyry in southeastern Central Asian Orogenic Belt. | Yan Jing Wenchun Ge M.Santosh Yu Dong Hao Yang Zheng Ji Junhui Bi Hongying Zhou Dehe Xing | 2022 | Geoscience Frontiers2022，13，2： | 2 |
| 3 | Geochronological Framework of Paleoproterozoic Intrusive Rocks and Its Constraints on Tectonic Evolution of the Liao-Ji Belt,Sino-Korean Craton显示文摘The Liao-Ji belt(LJB)is one of the Paleoproterozoic tectonic belts located in the North China Craton.A large number of Paleoproterozoic meta-volcanic-sedimentary rock and intrusive rocks are preserved in the LJB,which provide reliable carriers for the study of the Paleoproterozoic tectonic evolution of the North China Craton.The Paleoproterozoic intrusive rock in the LJB can be divided into the following seven types:syenogranite,quartz diorite,porphyry granite,migmatitic granite,sye-nite,metamorphic plutonic rock,and granitic pegmatite and metagabbro(metamorphic diabase).Zir-con U-Pb dating of 15 samples from intrusive rocks was carried out in this study.The chronology framework of the Paleoproterozoic intrusive rock in the LJB was established,and the magmatism of intrusive rocks can be divided into three stages:2200 to 2110,2010 to 1937,1900 to 1820 Ma.The chronological framework supported the evolution model of subduction accretionary arc-continent colli-sion in the LJB effectively.Combined with previous geochemical work,it was a passive continental margin environment at approximately 2200 Ma,and then transformed into and active continental margin.The bimodal intrusive rocks between 2180 and 2150 Ma indicated a back-arc tension envi-ronment which lasted until approximately 2110 Ma with a large number of basic intrusive rocks.And then the back-arc basin began to contract and the magmatic activities were reduced,with only a small number of intrusive rock activities occurring at approximately 2040,2010 and 1937 Ma.After the orogenic activities,there was a post-orogenic extension stage from 1900 to 1820 Ma.Magmatic activi-ties caused by the environmental extension started to occur more frequently and subsequently resulted in the large-scale intrusive rocks in eastern Liaoning. | Jingsheng Chen Zhongzhu Yang Dexin Tian Dehe Xing Lidong Zhang Fan Yang Bin Li Miao Liu Yi Shi Chao Zhang | 2021 | Journal of Earth Science2021，32，1： | 1 |
| 4 | Final-stage Southward Subduction of the Eastern Paleo-Asian Ocean:Evidence from the Middle Permian Mafic Intrusions in the Northern Margin of the North China Craton显示文摘The northern margin of the North China Craton(NCC)contains widespread Permian magmatic rocks,but the origin of these rocks remains controversial.This uncertainty hampers us from better understanding of tectonic framework and evolution of the eastern Paleo-Asian Ocean,particularly with respect to its final-stage subduction and closure time.To address these questions,this study presents petrological,zircon U-Pb geochronological,whole-rock geochemical and in situ zircon Hf isotopic data for these Permian mafic intrusions in the northern margin of the NCC.Precise zircon U-Pb dating results indicate that these mafic intrusions were emplaced in the Middle Permian(ca.260 Ma).Geochemically,the studied mafic intrusions have high MgO and transition metals element contents,with high Mg^(#) values,indicating a mantle origin.These mafic intrusions are characterized by enrichments in large ion lithophile elements(LILEs;e.g.,Rb,Ba,and K)and light rare earth elements(LREEs),and depletions in high field strength elements(HFSEs;e.g.,Nb,Ta,and Ti)and heavy rare earth elements(HREEs),indicating that they were formed in a subduction-related setting.These geochemical features,together with zircon ε_(Hf)(t)values(-1.1 to+11.2),indicate that their parental magmas were derived from partial melting of heterogeneous mantle wedge metasomatized by subduction-related fluids,with the contributions of slab sediments.The studied mafic intrusions also show wide range of major and trace elements contents,and variable Mg^(#) values,Eu and Sr anomalies,suggesting that their parental magmas had undergone variable degrees of fractional crystallization.Together with the E-W trending Permian continental arc along the northern margin of the NCC,we confirm that the generation of the Middle Permian mafic intrusions was related to southward subduction of the Paleo-Asian oceanic lithosphere beneath the NCC and the Paleo-Asian Ocean had not closed prior to the Middle Permian. | JING Yan GE Wenchun DONG Yu YANG Hao JI Zheng BI Junhui ZHOU Hongying XING Dehe | 2022 | Acta Geologica Sinica(English Edition)2022，96，1： | 1 |
| 5 | Division and correlation of Yixian Formation in western Liaoning,China显示文摘The Yixian Formation is a series of volcanic-sedimentary rocks in Biepiao area of Liaoning Province. It is mainly composed of basic and intermediate-basic volcanic lava,pyroclasts and terrestrial sedimentary rocks. Based on the regularity of volcanic activity,the Yixian Formation was divided by the present authors into four members in ascending order:the first member is of basal conglomerate,basic and intermediate-basic volcanic rocks; the second member is of lake phrase sedimentary rocks,or in another word,precious fossil-rich sedimentary beds; the third is of basic volcanic rocks; and the fourth is of upper conglomerate. Field mapping and comprehensive study also indicate that there are abundant vertebrate fossils (mainly of Psittacosaurus) in the first member of the Yixian Formation,and the Jehol Biota (including Sinosauropterxy,Confuciusorns sanctus,Archaefructus,etc.) is yielded in the second member of Yixian Formation. From west to east,the volcanic activity of Yixian Formation changed regularly from early to late,and from basic and intermediate-basic to acid (alkali). | ZHAO Liang XING Dehe' SUN Chulin SUN Yuewu ZHANG Lidong GUO Shengzhe ZHANG Changjie PENG Yandong JIA Bin CHEN Shuwang DING Qiuhong ZHENG Yuejuan | 2010 | Global Geology2010，13，3： | 0 |
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