Basalt discriminant diagrams have been used to identify the tectonic setting of basaltic magmatism since the 1970s and have played an important role in reconstructing paleotectonic environments.However,the significant...Basalt discriminant diagrams have been used to identify the tectonic setting of basaltic magmatism since the 1970s and have played an important role in reconstructing paleotectonic environments.However,the significant increase in the availability of geochemical data has led to a reassessment of these diagrams,suggesting that some of the tectonic settings indicated by these diagrams are not accurate.Here,we use a database of global ocean island basalt(OIB),mid-ocean ridge basalt(MORB),and island arc basalt(IAB)geochemistry to propose a series of new tectonic discriminant diagrams based on the ratios of large-ion lithophile elements(LILEs)to high field strength elements(HFSEs).These new diagrams indicate that the LILE can be used to differentiate OIB,MORB,and IAB samples,meaning that LILE/HFSE ratios can discriminate between these basalts that form in different tectonic settings.Our new diagrams can correctly assign samples to OIB,MORB,and IAB categories more than 85%of the time,with the discrimination between OIB and MORB having an accuracy of slightly less than 85%.展开更多
基金Technological Leading Talents Program of Yunnan Province[grant number 2013HA001]the National Natural Science Foundation of China[grant number 41502076]+1 种基金the State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences program[grant number 81300001]the China Geological Survey[grant number 12120114013701].
文摘Basalt discriminant diagrams have been used to identify the tectonic setting of basaltic magmatism since the 1970s and have played an important role in reconstructing paleotectonic environments.However,the significant increase in the availability of geochemical data has led to a reassessment of these diagrams,suggesting that some of the tectonic settings indicated by these diagrams are not accurate.Here,we use a database of global ocean island basalt(OIB),mid-ocean ridge basalt(MORB),and island arc basalt(IAB)geochemistry to propose a series of new tectonic discriminant diagrams based on the ratios of large-ion lithophile elements(LILEs)to high field strength elements(HFSEs).These new diagrams indicate that the LILE can be used to differentiate OIB,MORB,and IAB samples,meaning that LILE/HFSE ratios can discriminate between these basalts that form in different tectonic settings.Our new diagrams can correctly assign samples to OIB,MORB,and IAB categories more than 85%of the time,with the discrimination between OIB and MORB having an accuracy of slightly less than 85%.
