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Characterizing episodic orogenesis and magmatism in eastern China based on detrital zircon from the Jiaolai Basin
American Journal of Science ( IF 1.9 ) Pub Date : 2019-06-01 , DOI: 10.2475/06.2019.03
Rui Zhao , Qingfei Wang , Jun Deng , M. Santosh , Xuefei Liu , Yayun Liang , Hanyu Cheng

The eastern China region is composed of the North China Craton (NCC) and the Yangtze Craton (YC), both of which underwent episodic orogenesis and magmatism. The Jiaolai extensional basin occurs at the southeastern boundary between the NCC and YC. Here we employ combined age and trace element data on detrital zircon grains in the Cretaceous Laiyang Group of the Jiaolai Basin to gain insights on magmatism and average melt compositions of the Archean to Cretaceous source rocks. Detrital zircon data suggest that the eastern China region was characterized by five main stages of crustal evolution and magmatism. The ∼2500 Ma detrital zircon population with positive εHf(t) values trace new crustal growth during the Archean. Most Paleoproterozoic zircon grains are characterized by negative εHf(t) values indicating reworking of the ancient crust. Additionally, the Y/Gd ratios indicate a thickened crust, and the low Ce/Ce* and Eu/Eu* values suggest low oxygen fugacity conditions of magmatism during this period. The Neoproterozoic zircon population displays low U/Yb ratios suggesting less input of slab fluid during juvenile crust generation along the western and northern margins of the YC. The Triassic zircon have high U/Yb and low Th/U ratios denoting extensive involvement of slab fluid and crustal metamorphism during the collision between the NCC and YC. The Th/Nb and Hf/Th ratios of Cretaceous detrital zircon grains are similar to those from arc-related/orogenic setting, and their Hf isotopes are consistent with melting of a composite crust with YC crust wedged into the NCC crust.

中文翻译:

基于胶莱盆地碎屑锆石的华东幕式造山和岩浆作用特征

华东地区由华北克拉通(NCC)和扬子克拉通(YC)组成,两者都经历了幕式造山和岩浆作用。胶莱拉张盆地位于华北华北和YC 的东南边界。在这里,我们利用胶莱盆地白垩纪莱阳群碎屑锆石颗粒的年龄和微量元素数据,深入了解太古宙至白垩纪烃源岩的岩浆作用和平均熔体成分。碎屑锆石资料表明,华东地区具有地壳演化和岩浆作用五个主要阶段的特征。具有正 εHf(t) 值的 ∼2500 Ma 碎屑锆石群跟踪太古宙期间新的地壳生长。大多数古元古代锆石颗粒的特征为负的 εHf(t) 值,表明古地壳的再加工。此外,Y/Gd 比值表明地壳增厚,Ce/Ce* 和 Eu/Eu* 值低表明这一时期岩浆活动的氧逸度较低。新元古代锆石群显示出较低的 U/Yb 比率,表明在 YC 西部和北部边缘的新生地壳生成期间板片流体的输入较少。三叠系锆石具有高 U/Yb 和低 Th/U 比值,表明在 NCC 和 YC 碰撞过程中广泛参与了板片流体和地壳变质作用。白垩纪碎屑锆石颗粒的 Th/Nb 和 Hf/Th 比值与弧相关/造山环境相似,其 Hf 同位素与 YC 地壳楔入 NCC 地壳的复合地壳熔融一致。低的 Ce/Ce* 和 Eu/Eu* 值表明这一时期岩浆活动的氧逸度较低。新元古代锆石群显示出较低的 U/Yb 比率,表明在 YC 西部和北部边缘的新生地壳生成期间板片流体的输入较少。三叠系锆石具有高 U/Yb 和低 Th/U 比值,表明在 NCC 和 YC 碰撞过程中广泛参与了板片流体和地壳变质作用。白垩纪碎屑锆石颗粒的 Th/Nb 和 Hf/Th 比值与弧相关/造山环境相似,其 Hf 同位素与 YC 地壳楔入 NCC 地壳的复合地壳熔融一致。低的 Ce/Ce* 和 Eu/Eu* 值表明这一时期岩浆活动的氧逸度较低。新元古代锆石群显示出较低的 U/Yb 比率,表明在 YC 西部和北部边缘的新生地壳生成期间板片流体的输入较少。三叠系锆石具有高 U/Yb 和低 Th/U 比值,表明在 NCC 和 YC 碰撞过程中广泛参与了板片流体和地壳变质作用。白垩纪碎屑锆石颗粒的 Th/Nb 和 Hf/Th 比值与弧相关/造山环境相似,其 Hf 同位素与 YC 地壳楔入 NCC 地壳的复合地壳熔融一致。新元古代锆石群显示出较低的 U/Yb 比率,表明在 YC 西部和北部边缘的新生地壳生成期间板片流体的输入较少。三叠系锆石具有高 U/Yb 和低 Th/U 比值,表明在 NCC 和 YC 碰撞过程中广泛参与了板片流体和地壳变质作用。白垩纪碎屑锆石颗粒的 Th/Nb 和 Hf/Th 比值与弧相关/造山环境相似,其 Hf 同位素与 YC 地壳楔入 NCC 地壳的复合地壳熔融一致。新元古代锆石群显示出较低的 U/Yb 比率,表明在 YC 西部和北部边缘的新生地壳生成期间板片流体的输入较少。三叠系锆石具有高 U/Yb 和低 Th/U 比值,表明在 NCC 和 YC 碰撞过程中广泛参与了板片流体和地壳变质作用。白垩纪碎屑锆石颗粒的 Th/Nb 和 Hf/Th 比值与弧相关/造山环境相似,其 Hf 同位素与 YC 地壳楔入 NCC 地壳的复合地壳熔融一致。
更新日期:2019-06-01
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