The geochemistry of sediments is primarily controlled by their provenances,and different tectonic settings have distinctive provenance characteristics and sedimentaryprocesses. So, it is possible to distinctive proven...The geochemistry of sediments is primarily controlled by their provenances,and different tectonic settings have distinctive provenance characteristics and sedimentaryprocesses. So, it is possible to distinctive provenances, depositional environments and tectonicsettings in the development of a sedimentary basin with the geochemistry of the clastic rocks. Theanalytical results of the present paper demonstrate that sediments in the Songliao prototype basinare enriched in silica (SiO_2=66.48-80.51 percent), and their sumREE are 30-130 times of that ofchondrite with remarkable Eu anomalies. In discriminating diagrams of Eu/Eu* vs sumREE and (La/Yb)_Nvs sumREE, most samples locate above the line Eu/Eu*=1, on the right of the line Eu/Eu*/sumREE=1and under the line La/Yb)_N/sumREE=1/8, which indicates that the depositional environment ofsediments in the basin was oxidizing. In addition, variations of MgO, TiO_2, Al_2O_3, FeO + Fe_2O_3,Na_2O and CaO vs SiO_2 reflect a tendency of increasing mineral maturity of sediments in the basin.Analyses also show that the protolytes of the sediments in the basin were felsic igneous rocks, andthe Songliao prototype basin was in a tectonic setting of an island arc on an active continentalmargin, with violent sinistral strike-slip.展开更多
文摘The geochemistry of sediments is primarily controlled by their provenances,and different tectonic settings have distinctive provenance characteristics and sedimentaryprocesses. So, it is possible to distinctive provenances, depositional environments and tectonicsettings in the development of a sedimentary basin with the geochemistry of the clastic rocks. Theanalytical results of the present paper demonstrate that sediments in the Songliao prototype basinare enriched in silica (SiO_2=66.48-80.51 percent), and their sumREE are 30-130 times of that ofchondrite with remarkable Eu anomalies. In discriminating diagrams of Eu/Eu* vs sumREE and (La/Yb)_Nvs sumREE, most samples locate above the line Eu/Eu*=1, on the right of the line Eu/Eu*/sumREE=1and under the line La/Yb)_N/sumREE=1/8, which indicates that the depositional environment ofsediments in the basin was oxidizing. In addition, variations of MgO, TiO_2, Al_2O_3, FeO + Fe_2O_3,Na_2O and CaO vs SiO_2 reflect a tendency of increasing mineral maturity of sediments in the basin.Analyses also show that the protolytes of the sediments in the basin were felsic igneous rocks, andthe Songliao prototype basin was in a tectonic setting of an island arc on an active continentalmargin, with violent sinistral strike-slip.
