Large igneous provinces （LIPs） are considered a relevant cause for mass extinctions of marine life throughout Earth＇s history. Their flood basalts and associated intrusions can cause significant release of SO4 and ...Large igneous provinces （LIPs） are considered a relevant cause for mass extinctions of marine life throughout Earth＇s history. Their flood basalts and associated intrusions can cause significant release of SO4 and CO2 and consequently, cause major environmental disruptions. Here, we reconstruct the long-term periodic pattern of LIP emplacement and its impact on ocean chemistry and biodiversity from δ34Ssulfate of the last 520 Ma under particular consideration of the preservation limits of LIP records. A combination of cross-wavelet and other time-series analysis methods has been applied to quantify a potential chain of linkage between LIP emplacement periodicity, geochemical changes and the Phanerozoic marine genera record. We suggest a mantle plume cyclicity represented by LIP volumes （V） of V= （350-770） × 103km3sin（27πt/ 170 Ma）＋ （300-650）× 103 km3 sin（2πt/64.5 Ma ＋ 2.3） for t= time in Ma. A shift from the 64.5 Ma to a weaker -28-35 Ma LIP cyclicity during the Jurassic contributes together with probably independent changes in the marine sulfur cycle to less ocean anoxia, and a general stabilization of ocean chemistry and increasing marine biodiversity throughout the last -135 Ma. The LIP cycle pattern is coherent with marine biodiversity fluctuations corresponding to a reduction of marine biodiversity of -120 genera/Ma at 600 x 103 km3 LIP eruption volume. The 62-65 Ma LIP cycle pattern as well as excursion in -34Ssulfate and marine genera reduction suggest a not-vet identified found LIP event at - 440-450 Ma.展开更多
The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium de...The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium depth distribution from the front surface to 500 nm depth was found.The results indicate that an equilibrium deuterium distribution region from the front surface to a depth approximately equal to the mean range of implanted deuterons was formed in Yb during the implantation.The deduced deuterium concentration in the equilibrium deuterium distribution region was D/Yb = 22%.展开更多
文摘Large igneous provinces （LIPs） are considered a relevant cause for mass extinctions of marine life throughout Earth＇s history. Their flood basalts and associated intrusions can cause significant release of SO4 and CO2 and consequently, cause major environmental disruptions. Here, we reconstruct the long-term periodic pattern of LIP emplacement and its impact on ocean chemistry and biodiversity from δ34Ssulfate of the last 520 Ma under particular consideration of the preservation limits of LIP records. A combination of cross-wavelet and other time-series analysis methods has been applied to quantify a potential chain of linkage between LIP emplacement periodicity, geochemical changes and the Phanerozoic marine genera record. We suggest a mantle plume cyclicity represented by LIP volumes （V） of V= （350-770） × 103km3sin（27πt/ 170 Ma）＋ （300-650）× 103 km3 sin（2πt/64.5 Ma ＋ 2.3） for t= time in Ma. A shift from the 64.5 Ma to a weaker -28-35 Ma LIP cyclicity during the Jurassic contributes together with probably independent changes in the marine sulfur cycle to less ocean anoxia, and a general stabilization of ocean chemistry and increasing marine biodiversity throughout the last -135 Ma. The LIP cycle pattern is coherent with marine biodiversity fluctuations corresponding to a reduction of marine biodiversity of -120 genera/Ma at 600 x 103 km3 LIP eruption volume. The 62-65 Ma LIP cycle pattern as well as excursion in -34Ssulfate and marine genera reduction suggest a not-vet identified found LIP event at - 440-450 Ma.
基金Supported by National Natural Science Foundation of China(11275085,11305080,11405079 and 11505086)Fundamental Research Funds for Central University of China(lzujbky-2015-69 and lzujbky-2016-36)
文摘The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium depth distribution from the front surface to 500 nm depth was found.The results indicate that an equilibrium deuterium distribution region from the front surface to a depth approximately equal to the mean range of implanted deuterons was formed in Yb during the implantation.The deduced deuterium concentration in the equilibrium deuterium distribution region was D/Yb = 22%.
