U–Pb ages and source composition by Hf-isotope and trace-element analysis of detrital zircons in Permian sandstone and modern sand from southwestern Australia and a review of the paleogeographical and denudational history of the Yilgarn Craton
U–Pb ages and source composition by Hf-isotope and trace-element analysis of detrital zircons in Permian sandstone and modern sand from southwestern Australia and a review of the paleogeographical and denudational history of the Yilgarn Craton
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DOI：
10.1016/j.earscirev.2004.05.005
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发表时间：
2005
影响因子：
12.1
通讯作者：
J. Veevers;A. Saeed;E. Belousova;W. Griffin
中科院分区：
文献类型：
--
作者：
J. Veevers;A. Saeed;E. Belousova;W. Griffin
使用激光烧蚀微探针电感耦合等离子体质谱仪 (LAM-ICPMS) 对来自二叠纪柯利煤系和奥尔巴尼省北部的现代沙子的碎屑锆石进行了 U-Pb 年龄分析，并使用激光烧蚀微探针多接收器电感耦合等离子体质量分析了 Hf 同位素成分 光谱仪（LAM-MC-ICPMS）。通过电子微探针 (EMP) 和 ICPMS 分析来测定痕量元素。这种技术的结合使得不仅可以确定每个颗粒的年龄，还可以确定宿主岩浆的性质和来源，无论是地壳还是新生地幔，以及基于贫化地幔源的模型年龄（TDM），它给出了锆石结晶的岩浆源材料的最小年龄。与单独的年龄数据相比，应用于碎屑锆石套件的综合分析给出了更独特、更容易解释的物源区地壳演化图景。二叠纪和三叠纪沉积物中的锆石已通过灵敏的高分辨率离子微探针 (SHRIMP) 进行了 U-Pb 年龄分析，还分析了 Hf 同位素和微量元素。珀斯盆地北部的牧羊犬、二叠纪和早三叠世岩石中的锆石的年龄谱峰值约为 1200 Ma，可以追溯到奥尔巴尼省。然而，铪同位素组成的差异表明科利煤系和珀斯盆地北部砂岩并非源自奥尔巴尼省北部或长英质花岗岩沿海地带。珀斯盆地样本的第二个峰值年龄为 600-500 Ma，可以追溯到 Leeuwin 地块。其中一处现代沙地的主峰为 2616 Ma，可以追溯到 Yilgarn 克拉通。这些分析与之前发表的 U-Pb 锆石年龄光谱相结合，为古地理历史提供了见解。伊尔加恩克拉通在 1700 Ma 处从北部倾斜，在 1350-1140 Ma 和 490 Ma 处从东南部倾斜，其东部在 300 Ma 处向东倾斜，南部在 300-255 Ma 处从奥尔巴尼省向西北倾斜。磷灰石裂变径迹分析和镜质体反射研究的剥蚀数据表明，耶尔加恩克拉通被约 5 公里厚的二叠纪和中生代沉积岩覆盖，这些沉积岩几乎完全被新生代移除，可能是因为该克拉通位于延伸至印度洋东部和东南部的裂谷系统的肩部之间。珀斯盆地的奥陶纪、二叠纪、早三叠世和第四纪沉积物来自元古代造山带。只有晚二叠纪样本中含有大量的太古宙（Yilgarn）锆石，但它们是直接来自克拉通还是从假设的沉积盖层中回收仍不得而知。侏罗纪时期沉积物流入量的增加与剥蚀率的峰值相匹配，似乎需要来自克拉通的主要供应。这个问题可以通过对快速堆积的侏罗纪地层中的锆石进行年代测定来解决。
Detrital zircons from the Permian Collie Coal Measures and modern sands on the northern part of the Albany Province have been analysed for U–Pb ages by a laser ablation microprobe-inductively coupled plasma mass spectrometer (LAM-ICPMS) and for Hf-isotope compositions by a laser ablation microprobe multi-collector inductively coupled plasma mass spectrometer (LAM-MC-ICPMS). Trace elements were determined by analysis on the electron microprobe (EMP) and the ICPMS's. This combination of techniques makes it possible to determine for each grain not only the age but the nature and source of the host magma, whether crustal or juvenile mantle, and a model age (TDM) based on a depleted-mantle source, which gives a minimum age for the source material of the magma from which the zircon crystallised. The integrated analysis, applied to suites of detrital zircon, gives a more distinctive, and more easily interpreted, picture of crustal evolution in the provenance area than age data alone. Zircons from Permian and Triassic sediments already analysed for U–Pb ages by a sensitive high-resolution ion microprobe (SHRIMP) were also analysed for Hf isotopes and trace elements. Zircons from Collie and Permian and Early Triassic rocks of the northern Perth Basin have an age spectrum with a peak at about 1200 Ma that can be traced to the Albany Province. Differences, however, in Hf-isotope composition indicate that the Collie Coal Measures and the northern Perth Basin sandstones were not derived from the northern part of the Albany Province or from the coastal strip of felsic granitoids. The Perth Basin samples have a second peak age of 600–500 Ma that can be traced to the Leeuwin Block. One of the modern sands has a major peak at 2616 Ma that can be traced to the Yilgarn Craton. Compiled with previously published U–Pb zircon age spectra, the analyses provide insights into the paleogeographical history. The Yilgarn Craton sloped from the north at 1700 Ma, from the southeast at 1350–1140 and 490 Ma, its eastern part to the east at 300 Ma, and the southern part to the northwest from the Albany Province at 300–255 Ma. Denudational data from apatite fission-track analysis and vitrinite-reflectance studies suggest that the Yilgarn Craton was covered by a ∼5-km-thick blanket of Permian and Mesozoic sedimentary rock that was almost entirely removed by the Cenozoic, possibly because the craton was situated between the shoulders of rift systems that grew into the eastern and southeastern Indian Ocean. Ordovician, Permian, Early Triassic, and Quaternary sediment of the Perth Basin came from Proterozoic orogens. Only the Late Permian sample contains significant populations of Archean (Yilgarn) zircons but whether they came direct from the craton or were recycled from the postulated sedimentary cover is not known. The increased influx of sediment during the Jurassic matched by a peak in the denudation rate would seem to require a primary supply from the craton. This question could be resolved by dating zircon from the rapidly accumulated Jurassic formations.