We present the first combined U-Pb ages and Lu-Hf isotope data of zircon grains from the southern Ouaddaï area in Eastern Chad in the Central Africa Orogenic Belt. Zircon xenocrysts from granites and detrital zircons from quartzites of the Ouaddaï document crustal accretion from depleted mantle sources at 3.0 ± 0.5 Ga, rarely up to 3.8 Ga, and for subsequent reworking during four magmatic events, during the Neoarchean at ca. 2.6 Ga (εHf_t = −7.0 to 4.6), Paleoproterozoic at ca. 1.9–2.1 Ga (εHf_t = −17.7 to 5.3), Mesoproterozoic at ca. 1.1 Ga (εHf_t = −15.3 to 5.9), and Neoproterozoic/early Cambrian at 635–540 Ma (εHf_t = −31.1 to 1.4). Superchondritic εHf_t values point to new crust addition during all four events. Metamorphic zircon rims yield a Concordia age of 600 ± 2 Ma, and provide evidence that greenschist to amphibolite-facies metamorphism affecting the quartzites occurred between syn-tectonic (635 Ma) and post-kinematic (540 Ma) granite intrusions. Our new set of zircon data, combined with field relationships, also indicate that the quartzite precursor rocks were deposited between 1045 and 635 Ma, possibly after 670 Ma in a basin that subsequently became the Central Africa Orogenic Belt. The detritus was supplied from surrounding cratons, although the sources of the Mesoproterozoic zircons remain ambiguous. Comparison of age-εHf_t data from worldwide sources suggests sediment supply from the Irumide, Katanga and Mozambique belts, located to the south-east of the Congo Craton. Paleogeographic reconstructions further require sediment transport prior to final closure of several oceanic basins surrounding Central and Northern Africa during the Neoproterozoic, comprising the Khomas and Mozambique oceans

我们提供了中非造山带东部乍得东部Ouaddaï地区南部锆石颗粒的第一个U-Pb年龄和Lu-Hf同位素数据。Ouaddaï的花岗岩中的锆石异晶体和Ouaddaï的石英岩中的碎屑锆石记录了贫化地幔源在3.0±0.5 Ga（很少到3.8 Ga）时产生的地壳增生，并在随后的四个岩浆事件中进行了重新加工，大约是在新石器时代。2.6 Ga（下εHf_吨 = -7.0到4.6），古元在约 1.9-2.1镓（εHf_吨 = -17.7至5.3），中元在约 1.1 Ga（下εHf_吨 = -15.3至5.9），和新元/在635-540马（εHf早寒_吨 = -31.1至1.4）。SuperchondriticεHf _Ť值指向在所有四个事件期间新添加的地壳。变质锆石辋产生600±2 mA的协和年龄，并提供证据证明绿到影响石英岩角闪岩相变质之间发生的顺式-tectonic（635马）和后运动（540 Ma）的花岗岩侵入。我们的一组新的锆石数据，再加上场关系，也表明，石英岩前体岩石沉积在1045至635 Ma之间，可能是在670 Ma之后沉积在一个盆地中，该盆地后来成为中非造山带。碎屑由周围的克拉通提供，尽管中元古代锆石的来源仍然不明确。比较年龄εHf _ŧ来自世界各地的数据表明，来自刚果（金）东南部的伊鲁米德带，加丹加带和莫桑比克带的沉积物供应。在新元古代，包括霍马斯和莫桑比克的海洋，中非和北部非洲周围的几个海洋盆地最终关闭之前，古地理重建还需要泥沙输送