Along the eastern margin of the Mesoproterozoic Namaqua metamorphic province (NMP) of southern Africa are a bimodal volcano-sedimentary succession, the ∼1.13–1.10 Ga Koras Group, composed of rhyolitic porphyries and basaltic andesites, and the ∼1.11–1.07 Ga late- to post-tectonic granitoids of the Keimoes Suite. This review examines existing whole-rock major- and trace-element data, along with isotope chemistry (with some new isotopic data), to investigate the role these two magmatic successions played in terms of post-collisional magmatism of the eastern NMP near the boundary with the Archean Kaapvaal Craton. The Keimoes Suite comprises variably porphyritic biotite monzogranites and granodiorites, with a charnockitic member. They are metaluminous to weakly peraluminous, ferroan, and calc-alkalic. They exhibit large ion lithophile (LIL) element enrichment relative to the high field strength elements (HFSE) with depletions in Ba, Sr, Nb, P, Eu and Ti, and enrichments in Th, U and Pb. Isotopic values (ε_Nd(t): 2.78 to -2.95, but down to -8.58 for one granite, depleted mantle Nd model ages (T_DM): 1.62–1.99 Ga, but up to 2.55 Ga; initial ⁸⁷Sr/⁸⁶Sr: 0.652 82–0.771 30) suggest derivation from weakly to mildly enriched (and radiogenic) sources of Meso- to Paleoproterozoic age, the former of more juvenile character. The Koras Group is characterized by a bimodal succession of calcic to calc-alkalic, magnesian and tholeiitic basaltic andesites and mostly metaluminous to peralkaline rhyolitic porphyries. Two successions are recognised, an older, lower succession that extruded at ∼1.13 Ga, and a younger, upper succession at ∼1.10 Ga. The rhyolitic porphyries of both successions show similar LILE/HFSE enrichment and the same element enrichments and depletions as the Keimoes Suite granitoids. The upper succession is consistently more fractionated in terms of both whole-rock major and trace element chemistry, and, isotopically, has a greater enriched source component (ε_Nd(t)}: −0.69 to −4.26; T_DM: 1.64–2.44 Ga), relative to the lower succession (ε_Nd(t): 0.74–5.62; T_DM: 1.28–2.12 Ga). Crystal fractionation of plagioclase and K-feldspar appears to have played a role in bringing about compositional variation in many of the granites. These were derived from partial melting of mainly igneous with subordinate sedimentary sources from mostly lower crustal depths, although some granitoids have indications of a possible mantle source component. The lower succession of the Koras Group was derived by partial melting of subduction-influenced enriched mantle giving rise to mafic magmas that fractionated to give rise to the rhyolitic porphyries. The upper succession rhyolites were derived by crustal melting due to the input of mafic magmatism. Crystal fractionation was the main compositional driver for both successions. The Keimoes Suite granitoids and the Koras Group are associated with extensional regimes subsequent to the main deformational episode in the eastern NMP.

沿着南部非洲中元古代纳马夸变质区 (NMP) 的东缘是一个双峰火山-沉积序列，~1.13-1.10 Ga Koras 群，由流纹斑岩和玄武安山岩组成，~1.11-1.07 Ga到 Keimoes Suite 的后构造花岗岩。本综述检查了现有的全岩主量元素和微量元素数据，以及同位素化学（以及一些新的同位素数据），以研究这两个岩浆序列在边界附近东部 NMP 碰撞后岩浆作用中的作用与太古代卡普瓦尔克拉通。Keimoes Suite 包含多变的斑状黑云二长花岗岩和花岗闪长岩，以及一个炭质岩成员。它们是金属铝质至弱过铝质、铁质和钙碱性。与高场强元素 (HFSE) 相比，它们表现出大离子亲石性 (LIL) 元素富集，其中缺乏 Ba、Sr、Nb、P、Eu 和 Ti，富集 Th、U 和 Pb。同位素值 (ε _Nd ( t )：2.78 至 -2.95，但对于一块花岗岩，贫化地幔 Nd 模型年龄 ( T _DM )：1.62-1.99 Ga，但可降至 -8.58 ，但最高可达 2.55 Ga；初始⁸⁷ Sr/ ⁸⁶Sr: 0.652 82–0.771 30) 表明从中古元古代的弱到轻度富集（和放射成因）来源的推导，前者具有更幼年的特征。Koras 群的特征是钙碱性、镁质和拉斑玄武质安山岩的双峰序列，主要是金属铝质到过碱性流纹斑岩。识别出两个层序，一个较老的、较低的层序在 ~1.13 Ga 挤压，一个较年轻的较高层层序在 ~1.10 Ga。两个层序的流纹质斑岩显示出相似的 LILE/HFSE 富集和与 Keimoes 相同的元素富集和消耗套房花岗岩。就全岩主要和微量元素化学而言，上部层序始终更加分异，并且在同位素上具有更大的富集源组分（ε_Nd ( t )}：-0.69至-4.26；T _DM : 1.64–2.44 Ga), 相对于较低的序列( ε _Nd ( t ): 0.74–5.62; T _DM: 1.28–2.12 Ga)。斜长石和钾长石的晶体分馏似乎在导致许多花岗岩的成分变化方面发挥了作用。这些来自主要是火成岩的部分熔融，大部分来自下地壳深度的次要沉积源，尽管一些花岗岩具有可能的地幔源成分的迹象。Koras 群的下层序列是由受俯冲影响的富集地幔部分熔融产生的基性岩浆产生的，这些岩浆分馏产生流纹质斑岩。上层序流纹岩是由基性岩浆作用输入地壳熔融形成的。晶体分馏是两个系列的主要成分驱动因素。