Detrital zircon U-Pb ages in the Rif Belt (northern Morocco): Paleogeographic implications
Detrital zircon U-Pb ages in the Rif Belt (northern Morocco): Paleogeographic implications
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裂谷带（摩洛哥北部）碎屑锆石 U-Pb 年龄：古地理意义
DOI：
10.1016/j.gr.2018.12.008
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发表时间：
2019
影响因子：
6.1
通讯作者：
N. Evans
中科院分区：
文献类型：
--
作者：
A. Azdimousa;A. Jabaloy‐Sánchez;C. Talavera;L. Asebriy;F. González;N. Evans
外裂谷和马格里布复理石杂岩（包括所谓的毛里塔尼亚期内复理石单元）中、新生代岩石中碎屑锆石U-Pb年龄分布非常相似，强烈表明外裂谷和整个马格里布复理石杂岩是同一个非洲西北部古岩浆岩的一部分。这些模式包括罕见的古生代锆石颗粒，显示出Sehoul块的影响。新元古代和古元古代的颗粒丰富，埃迪卡拉纪的锆石人口占主导地位，约。590 Ma，这可能来源于Variscan摩洛哥Mesetas，西非盆地的北方组成部分，或来自中央高阿特拉斯和阿尔加纳盆地的三叠纪沉积物。还观察到中元古代锆石年龄在1.1和1.6 Ga之间（在组合年龄谱中占15%），最近的来源是在西非东部的中部。运输的中元古代颗粒的西北非洲paleomargin需要向北的河流系统平行于非洲的中大西洋大陆边缘。相比之下，样品从内部里夫或阿尔沃兰域是不同的外部里夫和马格里布复理石杂岩，特别是在中元古代锆石的稀缺性，这表明阿尔沃兰域是不是一个源区的锆石发现在非洲西北部的paleomargin。
Detrital zircon U-Pb age distributions in Mesozoic and Cenozoic rocks from the External Rif and Maghrebian Flysch Complex (including the so-called Mauretanian internal flysch units) are very similar, strongly suggesting that the External Rif and the entire Maghrebian Flysch Complex were part of the same NW African paleomargin. These patterns include scarce Paleozoic zircon grains that show influence from the Sehoul Block. Neoproterozoic and Paleoproterozoic grains are abundant with a dominant Ediacaran zircon population at ca. 590 Ma, which could have been sourced from the Variscan Moroccan Mesetas, the northern components of the West African Craton, or from Triassic sediments from the Central High Atlas and Argana basins. Mesoproterozoic zircon ages between 1.1 and 1.6 Ga were also observed (15% in the combined age spectra), the nearest sources for these being in the central part of the West African Craton. Transport of the Mesoproterozoic grains to the NW African paleomargin requires northward-directed fluvial systems parallel to the Central Atlantic continental margin of Africa. In contrast, samples from the Internal Rif or Alborán Domain are different to those from the External Rif and Maghrebian Flysch Complex, especially in the scarcity of Mesoproterozoic zircons, suggesting that the Alborán Domain was not a source area for zircons found in the NW African paleomargin.