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首页> 外文期刊>Lithos: An International Journal of Mineralogy, Petrology, and Geochemistry >Late Mesozoic-early Cenozoic intermediate-acid intrusive rocks from the Gerlache Strait area, Antarctic Peninsula: Zircon U-Pb geochronology, petrogenesis and tectonic implications
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Late Mesozoic-early Cenozoic intermediate-acid intrusive rocks from the Gerlache Strait area, Antarctic Peninsula: Zircon U-Pb geochronology, petrogenesis and tectonic implications

机译：晚期中生代早期新生代中生代中生代中生酸性侵入性岩石从Gerlache海峡地区，南极半岛：锆石U-PB地理学，化纤和构造含义

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This paper reports zircon U-Pb geochronology, whole-rock chemistry and Sr-Nd-Hf isotopic data of intermediate-acid intrusive rocks from the Gerlache Strait area, Antarctic Peninsula. These intrusive rocks can be divided into three groups. Group #1 has an emplacement age of ca. 117 Ma, and is further subdivided according to K2O contents into High-K (HKS) and Low-K (LKS) Subgroups. The HKS monzogranites are weakly peraluminous, and yield epsilon(Hf)(t) and epsilon(Nd)(t) values of +0.9 to +2.3 and +0.1 to +2.3, respectively, with corresponding model Nd ages (T-DM(Nd)) of 766-471 Ma, indicating that they were derived from the partial melting of dominantly early Neoproterozoic to early Paleozoic juvenile basaltic materials with minor involvement of sediments. In contrast, the LKS granodioritic magma was derived from partial melting of early Paleozoic juvenile basaltic materials with epsilon(Hf)(t) and epsilon(Nd)(t) values of +10.3 to +12.5 and +5.4 to +5.5, respectively, and corresponding T-DM(Nd) ages of 548-500 Ma. Group #2 consists of granite porphyry that formed at ca. 82 Ma and is characterized by positive values of epsilon(Hf)(t) (+5.1 to +8.1) and epsilon(Nd)(t) (+1.9 to +3.1) with weakly peraluminous chemistry and corresponding T-DM(Nd) ages of 712-548 Ma, suggesting that it was generated from partial melting of dominantly Neoproterozoic juvenile basaltic materials with minor involvement of sediments. Group #3 comprises dioritic-granodioritic rocks that were emplaced at ca. 62-54 Ma. These rocks have Mg# values of 39-46, and epsilon(Hf)(t) and epsilon(Nd)(t) values of +6.7 to +12.2 and +3.6 to +7.2, respectively, with corresponding T-DM(Nd) ages of 529-307 Ma, indicating that they were derived from partial melting of Paleozoic juvenile basaltic materials with minor injection of mantle materials. Spatially, the lithology of these plutons roughly changes from acid to intermediate from east to west, concomitant with increasing epsilon(Hf)(t) and epsilon(Nd)(t) values and decreasing initial Sr-87/Sr-86 ratios and T-DM(Nd) ages. This trend reflects changes in source characteristics from a Gondwana affinity to a juvenile crust affinity. Overall, the southeast-to-northwest migration of magmatism in the northern Antarctic Peninsula since the Mesozoic may have been related to retreating subduction of the paleo-Pacific plate. (C) 2018 Elsevier B.V. All rights reserved.
机译：本文报道了Zerlache海峡地区，南极半岛的中间酸性侵入岩石的锆石U-PB地理学，全岩化学和SR-ND-HF同位素数据。这些侵入式岩石可以分为三组。组＃1的施加年龄为CA。 117 mA，并根据K2O内容物细分为高k（HKS）和低k（LKS）子组。 HKS Monzogranites分别是弱衰弱的，并分别产生ε（HF）（T）和ε（Nd）（T）值，分别具有相应的Nd Ages（T-DM（ ND））766-471 MA，表明它们是源于沉积物的小古生代幼术玄武岩的部分熔化。相反，LKS细菌岩浆分别从早期古生代少年玄武岩材料的部分熔化，分别具有ε（HF）（T）和ε（Nd）（T）值分别为+ 10.3至+ 12.5和+ 5.4至+ 5.5的ε（T）和ε（T）值。相应的T-DM（ND）年龄548-500 mA。第2组由在CA形成的花岗岩斑岩组成。 82 mA，其特征在于ε（HF）（T）（+ 5.1至+ 8.1）和ε（nd）（t）（+1.9至+3.1）的阳性值，具有弱衰弱的化学和相应的T-DM（ND）年龄在712-548 mA，表明它是由占沉积物少参与的主导内古代幼玄型玄武岩材料的部分熔化产生。组＃3包括在CA所施加的Dioritic-Granodioritic岩石。 62-54 mA。这些岩石的Mg＃值为39-46，ε分别为39-46和ε（t）和ε（nd）（t）值，分别具有相应的t-dm（nd ）529-307 mA的年龄，表明它们源自古生代幼座玄武岩材料的部分熔化，轻微注射披风材料。在空间上，这些钚的岩性从酸到中间到西部大致变化，伴随着增加ε（hf）（t）和ε（nd）（t）值并降低初始sr-87 / sr-86比率和t -dm（nd）年龄。这一趋势反映了从Gondwana亲和力到少年外壳亲和力的源特征的变化。总体而言，由于中生代的北极半岛北极半岛岩浆迁移的东南至西北部迁移可能与古太平洋板拔下的俯冲有关。 （c）2018 Elsevier B.v.保留所有权利。

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