The Nyong Complex and the Yaoundé Group represent two crustal sequences of West Gondwana in Cameroon. We use U-Pb zircon geochronology on meta-sedimentary rocks to analyze their depositional age, provenance, and age of the high-grade metamorphic overprint. Due to the undoubtedly Precambrian age of these rocks, we also pursue questions regarding the veiling of the provenance signal by subsequent overprints, the diversity of the sources, and the role of crustal reworking in such an old setting. Although both the Nyong and the Yaoundé meta-sedimentary rocks were strongly affected by the Pan-African orogeny, Discordia analysis and the evaluation of remnant concordant zircons allow addressing these classic provenance questions with the LA-ICP-MS U-Pb zircon technique. We show that the Nyong Complex meta-sedimentary rocks likely have a <2.4 and> 2.2 Ga depositional age (∼Rhyacian, early-middle Paleoproterozoic) and were locally sourced from the Meso-Neoarchean Congo Shield (∼2.8 Ga); they were overprinted during the Paleoproterozoic Eburnean orogeny (∼2.2–2.0 Ga). The Yaoundé Group meta-sedimentary rocks likely have a <0.7 Ga depositional age (Cryogenian, middle Neoproterozoic); they lack a major Archean source, and have distinct, likely locally-sourced Eburnean (∼2.0 Ga), and Tonian-Cryogenian (∼1.0 and 0.7 Ga) sources. The meta-sedimentary rocks of both units share the Pan-African (∼0.6 Ga) orogenic overprint. Our study highlights the limited source diversity of these old basin deposits with a provenance from the few existing crustal masses.

Nyong Complex和YaoundéGroup代表了喀麦隆西冈瓦纳的两个地壳序列。我们在准沉积岩上使用U-Pb锆石年代学来分析其沉积年龄，物源和高级变质叠印的年龄。由于这些岩石无疑是前寒武纪时代，因此我们还要追究有关随后叠印的物源信号的遮盖，来源的多样性以及在这样的旧环境中地壳再造的作用的问题。尽管Nyong和Yaoundé沉积沉积岩都受到泛非造山运动的强烈影响，但Discordia分析和对残余一致锆石的评估仍可以通过LA-ICP-MS U-Pb锆石技术解决这些经典的物源问题。我们表明，Nyong复杂的准沉积岩可能具有<2.4和> 2。2 Ga的沉积年龄（〜Rhyacian，早中古元古代），是局部地来自中新西伯利亚刚果盾（〜2.8 Ga）；它们在古元古代Eburnean造山运动（〜2.2–2.0 Ga）中被套印。Yaoundé组的准沉积岩可能具有<0.7 Ga的沉积年龄（冰晶石，新元古代中期）。它们缺乏主要的太古宙源，并且具有独特的，可能是本地来源的埃本族（约2.0 Ga）和Tonian-Cryogenian（约1.0和0.7 Ga）源。两个单元的准沉积岩都具有泛非（〜0.6 Ga）造山带。我们的研究强调了这些旧盆地沉积物的来源多样性有限，现有的地壳物质很少。它们在古元古代Eburnean造山运动（〜2.2–2.0 Ga）中被套印。Yaoundé组的准沉积岩可能具有<0.7 Ga的沉积年龄（冰晶石，新元古代中期）。它们缺乏主要的太古宙源，并且具有独特的，可能是本地来源的埃本族（约2.0 Ga）和Tonian-Cryogenian（约1.0和0.7 Ga）源。两个单元的准沉积岩都具有泛非（〜0.6 Ga）造山带。我们的研究强调了这些旧盆地沉积物的来源多样性有限，现有的地壳物质很少。它们在古元古代Eburnean造山运动（〜2.2–2.0 Ga）中被套印。Yaoundé组的准沉积岩可能具有<0.7 Ga的沉积年龄（冰晶石，新元古代中期）。它们缺乏主要的太古代资源，并且有独特的，可能是本地来源的埃本族（约2.0 Ga）和Tonian-Cryogenian（约1.0和0.7 Ga）源。两个单元的准沉积岩都具有泛非（〜0.6 Ga）造山带。我们的研究强调了这些旧盆地沉积物的来源多样性有限，现有的地壳物质很少。0 Ga）和Tonian-Cryogenian（〜1.0和0.7 Ga）源。两个单元的准沉积岩都具有泛非（〜0.6 Ga）造山带。我们的研究强调了这些旧盆地沉积物的来源多样性有限，现有的地壳物质很少。0 Ga）和Tonian-Cryogenian（〜1.0和0.7 Ga）源。两个单元的准沉积岩都具有泛非（〜0.6 Ga）造山带。我们的研究强调了这些老盆地沉积物的来源多样性有限，现有的地壳物质很少。