The Lomagundi-Jatuli Event(LJE)refers to the significant positive carbon isotope excursion in seawater constituents that occurred immediately after the increase in atmospheric oxygen content during the Paleoproterozoi...The Lomagundi-Jatuli Event(LJE)refers to the significant positive carbon isotope excursion in seawater constituents that occurred immediately after the increase in atmospheric oxygen content during the Paleoproterozoic(2.22-2.06 Ga).Theδ^(13)C values of 46 dolostone samples collected from the Paleoproterozoic Yongjingshao Formation varied in the range of 0.05‰-4.95‰(V-PDB;maximum:4.95‰)in this study,which may be related to the multicellular eukaryotes in the Liangshan Formation in the Yimen Group.They are much higher than theδ^(13)C values of marine carbonates(-1.16‰on average).Theδ^(13)C values of other formations in the Paleoproterozoic Yimen Group are negative.The notable positive carbon isotope anomalies of the Yongjingshao Formation indicate the response to the LJE at the southwestern margin of the Yangtze Block,which is reported for the first time.Furthermore,they are comparable to theδ^(13)C values of carbonates in the Dashiling Formation of the Hutuo Group in the Wutaishan area in the North China Craton,the Wuzhiling Formation of the Songshan Group in the Xiong'er area,Henan Province,and the Dashiqiao Formation of the Liaohe Group in the Guanmenshan area,Liaoning Province.Therefore,it can be further concluded that the LJE is a global event.This study reveals that LJE occurred in Central Yunnan at 2.15-2.10 Ga,lasting for about 50 Ma.The macro-columnar,bean-shaped,and microfilament fossils and reticular ultramicrofossils of multicellular eukaryotes in this period were discovered in the Liangshan Formation of the Yimen Group.They are the direct cause for the LJE and are also the oldest paleontological fossils ever found.The major events successively occurring in the early stage of the Earth include the Great Oxygenation Event(first occurrence),the global Superiortype banded iron formations(BIFs),the Huronian glaciation,the Great Oxygenation Event(second occurrence),the explosion of multicellular eukaryotes,the positive carbon isotope excursion,and the global anoxic and selenium-rich sedimentary 展开更多
在大气压条件下,气隙距离为12 mm时,针—板DBD结构在不同的气体介质中会表现出不同的放电模式。当气体介质为氩气、放电电压为4 k V时,放电电压的正半周期表现为丝状放电模式,放电电压的负半周期为类辉光放电模式。当气体介质为氮气、...在大气压条件下,气隙距离为12 mm时,针—板DBD结构在不同的气体介质中会表现出不同的放电模式。当气体介质为氩气、放电电压为4 k V时,放电电压的正半周期表现为丝状放电模式,放电电压的负半周期为类辉光放电模式。当气体介质为氮气、放电电压为12 k V时,放电为电晕放电模式,但电压的正负半周期电晕放电模式也存在区别,在电压的负半周期,电流脉冲更加规则。当放电电压升高到15 k V,放电电压的正、负半周期会出现不同的放电模式,正半周期为丝状放电模式,负半周期呈现类辉光放电模式。在空气条件下,放电电压为12 k V时,存在和氮气条件下相似的电晕放电模式,而当放电电压为15 k V时,在整个周期只表现出丝状放电模式。展开更多
基金financially supported by the project entitled 1∶50000 Regional Geological Survey of Samaki,Yinmin,Guicheng,and Shugu Sheets in Yunnan Province(D201905)organized by the Land and Resources Department of Yunnan ProvinceTraining Object Project of technological innovation talents in Yunnan Province(202205AD160073)+2 种基金the project entitled“1∶50000 Regional Geological Survey of Dazhuang,Fabiao,Ditu,and Dianzhong Sheets in Yunnan Province”(S53A00722001048-007)“Joint Foundation Project between Yunnan Science and Technology Department and Yunnan University”(CY21624103)the project entitled“Area Summary and Service Product Development of Regional Geological Surveys in Yunnan Province”initiated by the China Geological Survey(121201102000150012-02)。
文摘The Lomagundi-Jatuli Event(LJE)refers to the significant positive carbon isotope excursion in seawater constituents that occurred immediately after the increase in atmospheric oxygen content during the Paleoproterozoic(2.22-2.06 Ga).Theδ^(13)C values of 46 dolostone samples collected from the Paleoproterozoic Yongjingshao Formation varied in the range of 0.05‰-4.95‰(V-PDB;maximum:4.95‰)in this study,which may be related to the multicellular eukaryotes in the Liangshan Formation in the Yimen Group.They are much higher than theδ^(13)C values of marine carbonates(-1.16‰on average).Theδ^(13)C values of other formations in the Paleoproterozoic Yimen Group are negative.The notable positive carbon isotope anomalies of the Yongjingshao Formation indicate the response to the LJE at the southwestern margin of the Yangtze Block,which is reported for the first time.Furthermore,they are comparable to theδ^(13)C values of carbonates in the Dashiling Formation of the Hutuo Group in the Wutaishan area in the North China Craton,the Wuzhiling Formation of the Songshan Group in the Xiong'er area,Henan Province,and the Dashiqiao Formation of the Liaohe Group in the Guanmenshan area,Liaoning Province.Therefore,it can be further concluded that the LJE is a global event.This study reveals that LJE occurred in Central Yunnan at 2.15-2.10 Ga,lasting for about 50 Ma.The macro-columnar,bean-shaped,and microfilament fossils and reticular ultramicrofossils of multicellular eukaryotes in this period were discovered in the Liangshan Formation of the Yimen Group.They are the direct cause for the LJE and are also the oldest paleontological fossils ever found.The major events successively occurring in the early stage of the Earth include the Great Oxygenation Event(first occurrence),the global Superiortype banded iron formations(BIFs),the Huronian glaciation,the Great Oxygenation Event(second occurrence),the explosion of multicellular eukaryotes,the positive carbon isotope excursion,and the global anoxic and selenium-rich sedimentary
文摘在大气压条件下,气隙距离为12 mm时,针—板DBD结构在不同的气体介质中会表现出不同的放电模式。当气体介质为氩气、放电电压为4 k V时,放电电压的正半周期表现为丝状放电模式,放电电压的负半周期为类辉光放电模式。当气体介质为氮气、放电电压为12 k V时,放电为电晕放电模式,但电压的正负半周期电晕放电模式也存在区别,在电压的负半周期,电流脉冲更加规则。当放电电压升高到15 k V,放电电压的正、负半周期会出现不同的放电模式,正半周期为丝状放电模式,负半周期呈现类辉光放电模式。在空气条件下,放电电压为12 k V时,存在和氮气条件下相似的电晕放电模式,而当放电电压为15 k V时,在整个周期只表现出丝状放电模式。
