Early Cretaceous A-type granitic plutons are widely distributed in Shandong Peninsula,which are of great significance to understanding the regional tectonic evolution.Here we report geochemical characteristics,geochro...Early Cretaceous A-type granitic plutons are widely distributed in Shandong Peninsula,which are of great significance to understanding the regional tectonic evolution.Here we report geochemical characteristics,geochronological results,and zircon Hf-O isotope compositions of Wulian granites to reveal its origin and geological significance.Wulian granites share most characteristics of the A_(2)-type granite.Zircon U-Pb LA-ICPMS analysis for Wulian A-type granites yields average age of 116.6±2.1 Ma.Zircon O isotope values range from 4.20‰to 5.57‰,and these values are marginally identical to or slightly lower than those of mantle zircon(5.3‰±0.3‰).Zirconε_(Hf)(t)values(-26.1--23.5)indicate an enriched source.Integrated zircon Hf-O isotope compositions indicate that the source region of Wulian granites involves the components of ancient oceanic crust.Apatites from Wulian granites have the lower chlorine(0.06 wt.%-0.15 wt.%)and higher fluorine contents(2.11 wt.%-2.48 wt.%)compared with Haiyang pluton,together with their high(La/Gd)_(N),(La/Yd)_(N) and low(Gd/Yb)_(N) ratios and high oxygen state magma reflected from zircon,signifying that slab derived component was added into the overlying mantle region through fluid/melt.The geochemical characteristics of Wulian granites could be explained by the ridge(between the Izanagi and Pacific plates)subduction model,which began to influence the tectonic evolution of the Xuhuai region and Shandong Peninsula since~130±5 Ma.The following slab window between two plates plausibly explains regional extension,resulting in hot magma upwelling and the formation of the A-type granite belt.Integrating the Lower Yangtze River belt and Shandong Peninsula A-type granite proves the northward movement of the ridge between the Pacific Plate and Izanagi Plate.展开更多
Objective To conduct a survey on the prevalence of active pulmonary tuberculosis among 65 year olds or above.Study subjects would include those with characteristics of TB suspicious symptoms,diabetes and close contact...Objective To conduct a survey on the prevalence of active pulmonary tuberculosis among 65 year olds or above.Study subjects would include those with characteristics of TB suspicious symptoms,diabetes and close contacts.Methods Purpose-sampling method was applied to choose 3 counties in Shandong province as the study sites,relying on the local basic public health service,for those elderly under 65 years old or above.展开更多
基金supported by the National Natural Science Foundation of China(No.91958110)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42020203)。
文摘Early Cretaceous A-type granitic plutons are widely distributed in Shandong Peninsula,which are of great significance to understanding the regional tectonic evolution.Here we report geochemical characteristics,geochronological results,and zircon Hf-O isotope compositions of Wulian granites to reveal its origin and geological significance.Wulian granites share most characteristics of the A_(2)-type granite.Zircon U-Pb LA-ICPMS analysis for Wulian A-type granites yields average age of 116.6±2.1 Ma.Zircon O isotope values range from 4.20‰to 5.57‰,and these values are marginally identical to or slightly lower than those of mantle zircon(5.3‰±0.3‰).Zirconε_(Hf)(t)values(-26.1--23.5)indicate an enriched source.Integrated zircon Hf-O isotope compositions indicate that the source region of Wulian granites involves the components of ancient oceanic crust.Apatites from Wulian granites have the lower chlorine(0.06 wt.%-0.15 wt.%)and higher fluorine contents(2.11 wt.%-2.48 wt.%)compared with Haiyang pluton,together with their high(La/Gd)_(N),(La/Yd)_(N) and low(Gd/Yb)_(N) ratios and high oxygen state magma reflected from zircon,signifying that slab derived component was added into the overlying mantle region through fluid/melt.The geochemical characteristics of Wulian granites could be explained by the ridge(between the Izanagi and Pacific plates)subduction model,which began to influence the tectonic evolution of the Xuhuai region and Shandong Peninsula since~130±5 Ma.The following slab window between two plates plausibly explains regional extension,resulting in hot magma upwelling and the formation of the A-type granite belt.Integrating the Lower Yangtze River belt and Shandong Peninsula A-type granite proves the northward movement of the ridge between the Pacific Plate and Izanagi Plate.
文摘Objective To conduct a survey on the prevalence of active pulmonary tuberculosis among 65 year olds or above.Study subjects would include those with characteristics of TB suspicious symptoms,diabetes and close contacts.Methods Purpose-sampling method was applied to choose 3 counties in Shandong province as the study sites,relying on the local basic public health service,for those elderly under 65 years old or above.
