LA-ICP-MS U–Pb dating of detrital rutile and zircon from the Reynolds Range: A window into the Palaeoproterozoic tectonosedimentary evolution of the North Australian Craton
LA-ICP-MS U–Pb dating of detrital rutile and zircon from the Reynolds Range: A window into the Palaeoproterozoic tectonosedimentary evolution of the North Australian Craton
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DOI：
10.1016/j.precamres.2014.10.006
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发表时间：
2014-12
影响因子：
3.8
通讯作者：
Delia Rösel;T. Zack;S. Boger
中科院分区：
文献类型：
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作者：
Delia Rösel;T. Zack;S. Boger
澳大利亚中部Arunta地区的古元古代雷诺兹山脉由一系列浅海碎屑沉积物（雷诺兹山脉群）组成，覆盖在浊积岩（陆氏岩组）和小砂岩（“未命名砂岩”）的深水层序上。从这些岩石的碎屑金红石和锆石中收集的U-Pb年龄数据表明，这些层序具有非常相似的年龄谱，尽管在地层较年轻的Reynolds Range群中有明显的年轻化趋势。直接位于雷诺兹山脉群不整合之下的“未命名砂岩”碎屑锆石的主要年龄成分为约1860 Ma，年龄分布在约3.2 - 2.0 Ga之间，年龄成分较少，为1830-1805 Ma。同一岩石的金红石碎屑产生单峰年龄谱，平均年龄约为1840 Ma。雷诺兹山脉群的碎屑锆石年龄谱相似，尽管最年轻的年龄群更年轻，年龄在1800ma到1780ma之间。这些岩石的金红石碎屑产生单峰年龄谱，平均年龄约为1790 Ma。虽然观察到的年龄差异是微妙的，但我们认为这些差异仍然标志着来源的重大变化。我们将“未命名砂岩”中1860 - 1820 Ma碎屑锆石和1840 Ma碎屑金红石的优势，以及先前发表的陆德尔岩层物源研究中约1860 Ma碎屑锆石年龄群的特征归因于霍尔斯溪-松溪造山带的隆起和侵蚀。这个造山带标志着北澳大利亚和金伯利克拉通之间的碰撞，这一事件可以追溯到1835 Ma到1810 Ma之间，其中包含了来自金伯利克拉通前陆的1860 Ma的稍微古老的岩石。相比之下，我们将较年轻的金红石和锆石的流入，以及随着雷诺兹山脉群沉积开始而观察到的明显的相变化，归因于物源区域向亚彭库造山带的转移，这标志着西澳大利亚和北澳大利亚克拉通的碰撞，时间约为1800-1765 Ma。来源的变化也与金红石微量元素组成的显著差异相一致。陆着岩组和雷诺山脉群在地层上与北澳大利亚克拉通大部分地区的沉积岩相关。我们认为，这表明在大约1840 Ma至1780 Ma期间，北澳大利亚克拉通内部存在空间连续的盆地条件，尽管该盆地的侵蚀和排水系统受到北澳大利亚克拉通西北和西南边缘碰撞和造山运动的强烈影响。
The Palaeoproterozoic Reynolds Range of the Arunta Region, central Australia, comprises a series of shallow marine clastic sediments (Reynolds Range Group) which overlies deeper water sequences of turbidites (Lander Rock Formation) and minor sandstones (“unnamed sandstone”). U–Pb age data collected from detrital rutile and zircon in these rocks indicates these sequences contain very similar age spectra, although with a notable and important shift to younger ages within the stratigraphically younger Reynolds Range Group. Detrital zircons from the “unnamed sandstone” directly underlying the unconformity with the Reynolds Range Group contain a major age component at ca. 1860 Ma, together with a wide spread of ages between ca. 3.2 and 2.0 Ga and a minor age component of 1830–1805 Ma. Detrital rutile from the same rock yield a unimodal age spectrum with a mean age of ca. 1840 Ma. The detrital zircon age spectrum from the Reynolds Range Group is similar, although the youngest cluster of ages is younger and dates to between 1800 Ma and 1780 Ma. Detrital rutile from these rocks yield a unimodal age spectrum with a mean age of ca. 1790 Ma. Although the observed differences in ages are subtle, we suggest these nevertheless mark a significant change in provenance.We attribute the predominance of 1860–1820 Ma detrital zircon and 1840 Ma detrital rutile within the “unnamed sandstone” and the characteristic ca. 1860 Ma detrital zircon age cluster in previously published provenance studies from the Lander Rock Formation to uplift and erosion of the Halls Creek–Pine Creek Orogen. This orogenic belt marks collision between the North Australian and Kimberley cratons, an event dated to between 1835 Ma and 1810 Ma and which incorporates marginally older rocks dating to 1860 Ma from the foreland of the Kimberley Craton. By contrast we attribute the influx of younger rutile and zircon, together with a distinct facies change observed with the onset of the deposition of the Reynolds Range Group, to a shift in provenance region to the Yapungku Orogen, which marks the collision between the West Australian and North Australian cratons and is dated to ca. 1800–1765 Ma. A change in provenance is additionally consistent with significant differences in rutile trace element composition.The Lander Rock Formation and the Reynolds Range Group are stratigraphically correlated with sedimentary rocks that overly large parts of the North Australian Craton. We suggest this indicates spatially continuous basinal conditions within the North Australian Craton between ca. 1840 Ma and 1780 Ma, although the erosion and drainage systems feeding this basin were strongly influenced by the collision and orogenesis along the northwest and southwest margins of the North Australian Craton.