The Lantian biota at the Lantian Town of Xiuning County, Anhui Province, is preserved in black shales of the Ediacaran Lantian Formation. It yields some of the oldest known complex macroorganisms, including fan-shaped...The Lantian biota at the Lantian Town of Xiuning County, Anhui Province, is preserved in black shales of the Ediacaran Lantian Formation. It yields some of the oldest known complex macroorganisms, including fan-shaped seaweeds and possible animal fossils with tentacles and intestinal-like structures reminiscent of modern coelenterates and bilaterians. The Lantian Lagerst^itte sheds new light on the origin and early evolution of multicellular organisms in relatively quiet and deep environments soon after the Neoproterozoic Marinoan glaciation. The morphological complexity and diversity of early multicellular organisms may be closely related to sexual reproduction and alternation of generations. The fluctuation of oceanic redox conditions during this peri- od may have played a role in the ecology and preservation of the Lantian biota.展开更多
In recent years,explosion of research in the early Tertiary mammals of India has attracted widespread interest because of the importance of this fauna in understanding biogeographic origins,early evolution,and dispers...In recent years,explosion of research in the early Tertiary mammals of India has attracted widespread interest because of the importance of this fauna in understanding biogeographic origins,early evolution,and dispersal patterns of several modern mammal orders as well for its paleogeographic implications.Although Paleocene mammals are yet to be discovered in the Indian subcontinent,Indian Early Eocene mammal faunas are now becoming increasingly important in debates concerning the origins of several modern terrestrial orders.展开更多
The buildup of oxygen in the Earth＇s atmosphere and oceans has fundamentally reshaped the dynamics of nearly all major biogeochemical cycles and ultimately paved the way for the diversification of complex life on Ear...The buildup of oxygen in the Earth＇s atmosphere and oceans has fundamentally reshaped the dynamics of nearly all major biogeochemical cycles and ultimately paved the way for the diversification of complex life on Earth. Over the past decades there have been sustained efforts to develop a more comprehensive understanding of ocean-atmosphere redox evolution and its relationship to the evolution of early life （Fig. 1）. It is generally accepted that the development of oxygenic photosynthesis at ~2.7 Ga may have been responsible for the Great Oxidation Event （GOE） at the beginning of the Proterozoic Eon, whereas a second big O2 rise at the end of the Proterozoic Eon （the so-called Neoproterozoic Oxidation Event or NOE） was responsible for the diversification of metazoans （Lyons et al., 2014）.展开更多
Charnockite and granulite in Yishui area, Shandong Province are located in the middle part of the Tancheng Lujiang fault zone, eastern China. Field studies have shown that the charnockites, derived from the adjacent ...Charnockite and granulite in Yishui area, Shandong Province are located in the middle part of the Tancheng Lujiang fault zone, eastern China. Field studies have shown that the charnockites, derived from the adjacent granulites, are classified as three types: enderbite, garnet enderbite and hypersthene trondhjemite. In addition, two generations of minerals are present in the charnockites: the relic minerals such as garnet, hypersthene and clinopyroxene, and the neocrystallized minerals such as plagioclase and K feldspar. The relic minerals occurring in the granulite facies stage were affected by the later partial melting. The relic minerals, irregular and usually ragged in shape, occupy the interstitial positions in the neocrystalline minerals. The neocrystalline minerals are usually euhedral subhedral crystals. The study of petrology, mineralogy and geochemistry of charnokites concludes that the enderbite was formed by the anatexis of the two pyroxene plagioclase granulite, that the garnet enderbite was formed by the anatexis of sillimanite garnet gneiss, and that the hypersthene trondhjemite was formed by the anatexis of the leucocratic two pyroxene plagioclase granulite. The U Pb dating of the zircon indicates that the formation of the charnockite and granulite was related to the Archean Proterozoic upwelling of a mantle plume (hot spot) around 2 500 Ma, in Yishui area, Shandong Province.展开更多
1 Introduction The North Qinling orogenic belt is characterized by diverse rocks,multi-phase tectonic-magmatic events,which is composed of not only basement rocks of the Qinling Group,but also numerous magmatic rocks in
The Pilbara region of Western Australia is one of only two areas on Earth–the other being the Kaapvaal Craton of southern Africa–that contain well preserved,nearcontinuous geological records of crustal evolution fro...The Pilbara region of Western Australia is one of only two areas on Earth–the other being the Kaapvaal Craton of southern Africa–that contain well preserved,nearcontinuous geological records of crustal evolution from the Paleoarchean into the late Paleoproterozoic.The Pilbara is famous for hosting fossil evidence of early life(stromatolites and microfossils),and for containing a record of the early Archean atmosphere.The geological record extends from granite–greenstone terranes and overlying clastic basins of the 3.53–2.83 Ga Pilbara Craton,across a major unconformity,to a series of 2.78–1.79 Ga volcanic and sedimentary successions.Between 3.53–3.23 Ga,a succession of mantle plume events formed a thick volcanic plateau on older continental crust,remnants of which include enclaves of c.3.6 Ga granitic gneiss and abundant 3.8–3.6 Ga inherited and detrital zircons.During each of the plume events,the volcanic plateau was intruded by crustally-derived granitic rocks,leading to vertical deformation by partial convective overturn.By 3.23 Ga,these processes had established thick continental crust that was then rifted into three microplates separated by c.3.2 Ga basins of oceanic crust.Subsequent plate tectonic processes to 2.90 Ga included subduction,terrane accretion,and orogeny.From 2.78–2.63 Ga the northern Pilbara Craton was affected by minor rifting,followed by deposition of thick basaltic formations separated by felsic volcanic and sedimentary rocks(Fortescue Basin).Rifting in the southern Pilbara resulted in progressively deepening marginal basin sedimentation,including thick units of banded iron formation(Hamersley Basin:2.63–2.45 Ga).展开更多
The Anshan- Benxi area is one of the important places of the Precambrian in the North China craton, in which a lot of old geological bodies were found, including the Baijiafen mylontized granitic gneiss of 3.8 Ga ,the...The Anshan- Benxi area is one of the important places of the Precambrian in the North China craton, in which a lot of old geological bodies were found, including the Baijiafen mylontized granitic gneiss of 3.8 Ga ,the Chentaigou gneissic granite of 33 Ga and the supracrustal rocks and associated granites of relatively younger ages .Based on the age data and other geological information obtained in recent yeais, mis paper establishes fourfold-divison scheme of the Archaean in the Anshan-Benxi area .The time boundaries are 2.5,2.8,3.2 and 3.6 Ga, corresponding to those recommended by the International Sub-commission on Precambrian Stratigraphy . This paper also discusses some questions related to the crustal evolution of the early history, and indicates that it is possible to find out more residual crustal materials of older than 2.8 Ga.展开更多
With the support of the National Natural Science Foundation of China,the Ministry of Science and Technology of China,and the Chinese Academy of Sciences(CAS),the research team led by Prof.Zhu Min(朱敏)at the CAS Key L...With the support of the National Natural Science Foundation of China,the Ministry of Science and Technology of China,and the Chinese Academy of Sciences(CAS),the research team led by Prof.Zhu Min(朱敏)at the CAS Key Laboratory of Vertebrate Evolution and Human Origins,Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Acadedy of Sciences,discovered a展开更多
The spatiotemporal evolution of lunar impact craters is crucial for investigating lunar interior structure,internal and external dynamic processes,and interplanetary impact history.Advances in lunar crater identificat...The spatiotemporal evolution of lunar impact craters is crucial for investigating lunar interior structure,internal and external dynamic processes,and interplanetary impact history.Advances in lunar crater identification are reviewed based on topography and gravity data,and the features and mechanisms of topographic or buried craters are analyzed regarding morphology,gravity anomalies,gravity gradients,and the underlying crust-mantle interface relief.Based on the compiled crater catalog,the early lunar impact flux and thermal evolution are further discussed according to the basin ages and their interior structures.For some ancient impact basins,the crater size-frequency distribution measurements revealed age discrepancies from previous studies,suggesting that the lunar late heavy bombardment event started at~3.95 Ga.The degraded bulge structures of the crust-mantle interface beneath mare basins reveal that these basins formed on the lunar crust surface under high-temperature conditions and underwent prolonged relaxation compared to highland basins.Finally,we reveal that the up-to-date identification of lunar buried craters remains inaccurate and incomplete,preventing us from accurately reconstructing lunar and interplanetary impact histories.Therefore,we propose that a gravity model constructed using localized orthogonal basis functions can be useful for identifying lunar craters.展开更多
The fluvio-lacustrine sedimentary sequences in the Nihewan Basin, northern China, are important for studying Quaternary land mammal evolution and Paleolithic settlements in the high-latitude temperate East Asia. Here ...The fluvio-lacustrine sedimentary sequences in the Nihewan Basin, northern China, are important for studying Quaternary land mammal evolution and Paleolithic settlements in the high-latitude temperate East Asia. Here we report new magnetostrati- graphic results that constrain age of the Hougou Paleolithic site in this basin. Magnetite and hematite were identified as carriers of the characteristic remanent magnetizations, with the former being dominant. Magnetic polarity stratigraphy shows that the Hougou sequence recorded the very late Matuyama reverse chron and the Brunhes normal chron. The age of the Hougou Paleolithic site was estimated to be 395 ka based on an averaged rate of sediment accumulation. The combination of our mag- netostratigraphy and previously published chronological data for early Paleolithic or human sites in the high-latitude northern China may document a persistent colonization of the hostile high-latitude areas of the eastern Old World during the mid- die-early Pleistocene.展开更多
基金supported by the National Natural Science Foundation of China(41030209,41130209and40625006)the Chinese Academy of Sciences(KZZD-EW02,KZCX2-YW-153and KZCX2-EW-119)
文摘The Lantian biota at the Lantian Town of Xiuning County, Anhui Province, is preserved in black shales of the Ediacaran Lantian Formation. It yields some of the oldest known complex macroorganisms, including fan-shaped seaweeds and possible animal fossils with tentacles and intestinal-like structures reminiscent of modern coelenterates and bilaterians. The Lantian Lagerst^itte sheds new light on the origin and early evolution of multicellular organisms in relatively quiet and deep environments soon after the Neoproterozoic Marinoan glaciation. The morphological complexity and diversity of early multicellular organisms may be closely related to sexual reproduction and alternation of generations. The fluctuation of oceanic redox conditions during this peri- od may have played a role in the ecology and preservation of the Lantian biota.
基金funded by the Department of Science and Technology(DST),Government of Indiafunding support by the Science and Engineering Research Board(SERB),New Delhi(No.SR/FTP/ES-49/2012).
文摘In recent years,explosion of research in the early Tertiary mammals of India has attracted widespread interest because of the importance of this fauna in understanding biogeographic origins,early evolution,and dispersal patterns of several modern mammal orders as well for its paleogeographic implications.Although Paleocene mammals are yet to be discovered in the Indian subcontinent,Indian Early Eocene mammal faunas are now becoming increasingly important in debates concerning the origins of several modern terrestrial orders.
文摘The buildup of oxygen in the Earth＇s atmosphere and oceans has fundamentally reshaped the dynamics of nearly all major biogeochemical cycles and ultimately paved the way for the diversification of complex life on Earth. Over the past decades there have been sustained efforts to develop a more comprehensive understanding of ocean-atmosphere redox evolution and its relationship to the evolution of early life （Fig. 1）. It is generally accepted that the development of oxygenic photosynthesis at ~2.7 Ga may have been responsible for the Great Oxidation Event （GOE） at the beginning of the Proterozoic Eon, whereas a second big O2 rise at the end of the Proterozoic Eon （the so-called Neoproterozoic Oxidation Event or NOE） was responsible for the diversification of metazoans （Lyons et al., 2014）.
基金This study is supported by the Research Fund forthe Doctoral Pro- gram of Higher Education( No.970 4910 4)
文摘Charnockite and granulite in Yishui area, Shandong Province are located in the middle part of the Tancheng Lujiang fault zone, eastern China. Field studies have shown that the charnockites, derived from the adjacent granulites, are classified as three types: enderbite, garnet enderbite and hypersthene trondhjemite. In addition, two generations of minerals are present in the charnockites: the relic minerals such as garnet, hypersthene and clinopyroxene, and the neocrystallized minerals such as plagioclase and K feldspar. The relic minerals occurring in the granulite facies stage were affected by the later partial melting. The relic minerals, irregular and usually ragged in shape, occupy the interstitial positions in the neocrystalline minerals. The neocrystalline minerals are usually euhedral subhedral crystals. The study of petrology, mineralogy and geochemistry of charnokites concludes that the enderbite was formed by the anatexis of the two pyroxene plagioclase granulite, that the garnet enderbite was formed by the anatexis of sillimanite garnet gneiss, and that the hypersthene trondhjemite was formed by the anatexis of the leucocratic two pyroxene plagioclase granulite. The U Pb dating of the zircon indicates that the formation of the charnockite and granulite was related to the Archean Proterozoic upwelling of a mantle plume (hot spot) around 2 500 Ma, in Yishui area, Shandong Province.
基金financially supported by National Natural Science Foundation of China (41372072)Natural Science Foundation of Education Department of Anhui province (KJ2016A025)+1 种基金Dr. Startup Foundation, Anhui university (J10113190090)the State Key Laboratory of Geodynamics, Northwest University
文摘1 Introduction The North Qinling orogenic belt is characterized by diverse rocks,multi-phase tectonic-magmatic events,which is composed of not only basement rocks of the Qinling Group,but also numerous magmatic rocks in
文摘The Pilbara region of Western Australia is one of only two areas on Earth–the other being the Kaapvaal Craton of southern Africa–that contain well preserved,nearcontinuous geological records of crustal evolution from the Paleoarchean into the late Paleoproterozoic.The Pilbara is famous for hosting fossil evidence of early life(stromatolites and microfossils),and for containing a record of the early Archean atmosphere.The geological record extends from granite–greenstone terranes and overlying clastic basins of the 3.53–2.83 Ga Pilbara Craton,across a major unconformity,to a series of 2.78–1.79 Ga volcanic and sedimentary successions.Between 3.53–3.23 Ga,a succession of mantle plume events formed a thick volcanic plateau on older continental crust,remnants of which include enclaves of c.3.6 Ga granitic gneiss and abundant 3.8–3.6 Ga inherited and detrital zircons.During each of the plume events,the volcanic plateau was intruded by crustally-derived granitic rocks,leading to vertical deformation by partial convective overturn.By 3.23 Ga,these processes had established thick continental crust that was then rifted into three microplates separated by c.3.2 Ga basins of oceanic crust.Subsequent plate tectonic processes to 2.90 Ga included subduction,terrane accretion,and orogeny.From 2.78–2.63 Ga the northern Pilbara Craton was affected by minor rifting,followed by deposition of thick basaltic formations separated by felsic volcanic and sedimentary rocks(Fortescue Basin).Rifting in the southern Pilbara resulted in progressively deepening marginal basin sedimentation,including thick units of banded iron formation(Hamersley Basin:2.63–2.45 Ga).
文摘The Anshan- Benxi area is one of the important places of the Precambrian in the North China craton, in which a lot of old geological bodies were found, including the Baijiafen mylontized granitic gneiss of 3.8 Ga ,the Chentaigou gneissic granite of 33 Ga and the supracrustal rocks and associated granites of relatively younger ages .Based on the age data and other geological information obtained in recent yeais, mis paper establishes fourfold-divison scheme of the Archaean in the Anshan-Benxi area .The time boundaries are 2.5,2.8,3.2 and 3.6 Ga, corresponding to those recommended by the International Sub-commission on Precambrian Stratigraphy . This paper also discusses some questions related to the crustal evolution of the early history, and indicates that it is possible to find out more residual crustal materials of older than 2.8 Ga.
文摘With the support of the National Natural Science Foundation of China,the Ministry of Science and Technology of China,and the Chinese Academy of Sciences(CAS),the research team led by Prof.Zhu Min(朱敏)at the CAS Key Laboratory of Vertebrate Evolution and Human Origins,Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Acadedy of Sciences,discovered a
基金supported by the Institute of Geology and Geophysics,Chinese Academy of Sciences(Grant Nos.IGGCAS202102,IGGCAS-201904)the National Natural Science Foundation of China(Grant Nos.42288201,41704080,42274114)the National Key Research and Development Program of China(Grant No.2022YFF0503200)。
文摘The spatiotemporal evolution of lunar impact craters is crucial for investigating lunar interior structure,internal and external dynamic processes,and interplanetary impact history.Advances in lunar crater identification are reviewed based on topography and gravity data,and the features and mechanisms of topographic or buried craters are analyzed regarding morphology,gravity anomalies,gravity gradients,and the underlying crust-mantle interface relief.Based on the compiled crater catalog,the early lunar impact flux and thermal evolution are further discussed according to the basin ages and their interior structures.For some ancient impact basins,the crater size-frequency distribution measurements revealed age discrepancies from previous studies,suggesting that the lunar late heavy bombardment event started at~3.95 Ga.The degraded bulge structures of the crust-mantle interface beneath mare basins reveal that these basins formed on the lunar crust surface under high-temperature conditions and underwent prolonged relaxation compared to highland basins.Finally,we reveal that the up-to-date identification of lunar buried craters remains inaccurate and incomplete,preventing us from accurately reconstructing lunar and interplanetary impact histories.Therefore,we propose that a gravity model constructed using localized orthogonal basis functions can be useful for identifying lunar craters.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40925012 and 40821091)the Ministry of Science and Technology of China (Grant No. 2007FY110200)the Chinese Academy of Sciences (Grant No. KZCX2-EW-117)
文摘The fluvio-lacustrine sedimentary sequences in the Nihewan Basin, northern China, are important for studying Quaternary land mammal evolution and Paleolithic settlements in the high-latitude temperate East Asia. Here we report new magnetostrati- graphic results that constrain age of the Hougou Paleolithic site in this basin. Magnetite and hematite were identified as carriers of the characteristic remanent magnetizations, with the former being dominant. Magnetic polarity stratigraphy shows that the Hougou sequence recorded the very late Matuyama reverse chron and the Brunhes normal chron. The age of the Hougou Paleolithic site was estimated to be 395 ka based on an averaged rate of sediment accumulation. The combination of our mag- netostratigraphy and previously published chronological data for early Paleolithic or human sites in the high-latitude northern China may document a persistent colonization of the hostile high-latitude areas of the eastern Old World during the mid- die-early Pleistocene.
