Proterozoic Evolution of the North Atlantic–Arctic Caledonides: Insights from Detrital Zircon Analysis of Metasedimentary Rocks from the Pearya Terrane, Canadian High Arctic
Proterozoic Evolution of the North Atlantic–Arctic Caledonides: Insights from Detrital Zircon Analysis of Metasedimentary Rocks from the Pearya Terrane, Canadian High Arctic
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北大西洋-北极喀里多尼德斯的元古代演化：加拿大高北极皮尔亚地体变沉积岩碎屑锆石分析的见解
DOI：
10.1086/677902
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
K. Piepjohn
中科院分区：
文献类型：
--
作者：
S. Malone;W. McClelland;W. von Gosen;K. Piepjohn
Pearya地体被认为是加拿大北极边缘唯一的外来地体，包括新元古代-早古生代盆地或被动边缘变沉积层序，其结构上与弧相关的古生代岩石并列，以及包含早新元古代正片麻岩的变质基底杂岩。新元古代硅质碎屑层序与罗迪尼亚分裂时形成的其他碎屑岩层相似，但其古地理起源和地壳亲缘性尚不确定。七个样品的碎屑锆石年龄光谱揭示了三组：A 组，在 c 处有许多峰。 1100–1800 Ma 和 c 处最年轻的种群。 1020马; B 组，由主导 c 定义。 970马龄峰值；和 C 组，主峰来自 c。 970–1800 Ma 和 c 的一小部分种群。 635–710 Ma 粒。 A 组的光谱与斯瓦尔巴群岛、东格陵兰岛和斯堪的纳维亚喀里多尼德群岛最新中元古代单元的数据相似，在所有这些地区观察到的普遍存在的中元古代年龄与来自劳伦西亚和波罗的海的格伦维尔-斯韦康诺威造山带的推导一致。 B 组中 930-970 Ma 年龄的主导反映了皮尔雅和斯瓦尔巴群岛该年龄岩浆岩的输入，而 C 组中观察到的 635-710 Ma 年龄与北极阿拉斯加-楚科奇地体和泰米尔-蒂马尼德地区单元中观察到的岩浆年龄重叠。皮尔雅地体的新元古代硅质碎屑地层起源于劳伦西亚东北部的远端，其位置与斯瓦尔巴群岛和东格陵兰埃莱奥诺雷湾超群的组成地体的位置相似，它们记录了罗迪尼亚长期分裂过程中沿新元古代汇聚边缘的沉积。
The Pearya Terrane, recognized as the only exotic terrane along the Canadian Arctic margin, includes a Neoproterozoic–early Paleozoic basinal or passive-margin metasedimentary sequence that is structurally juxtaposed with arc-related Paleozoic rocks and a metamorphic basement complex containing early Neoproterozoic orthogneiss. The Neoproterozoic siliciclastic sequence is similar to other clastic sections formed at the breakup of Rodinia, but its paleogeographic origin and crustal affinity are uncertain. Detrital zircon age spectra from seven samples reveal three groups: Group A, with numerous peaks at c. 1100–1800 Ma and the youngest population at c. 1020 Ma; Group B, defined by a dominant c. 970 Ma age peak; and Group C, with dominant peaks from c. 970–1800 Ma and a small population of c. 635–710 Ma grains. Spectra from Group A resemble data from the latest Mesoproterozoic units in Svalbard, East Greenland, and the Scandinavian Caledonides, with the ubiquitous Mesoproterozoic ages observed in all these regions compatible with derivation from the Grenville-Sveconorwegian Orogen of Laurentia and Baltica. The dominance of 930–970 Ma ages in Group B reflects input from magmatic rocks of this age in Pearya and Svalbard, while the 635–710 Ma ages observed in Group C overlap with magmatic ages observed in the Arctic Alaska–Chukotka Terrane and units in the Taimyr-Timanide region. The Neoproterozoic siliciclastic strata of the Pearya Terrane originated distal to northeastern Laurentia, in a position similar to that of the constituent terranes of Svalbard and the Eleonore Bay Supergroup of East Greenland, and they record deposition along a Neoproterozoic convergent margin active during the prolonged breakup of Rodinia.