This work investigates Mesoproterozoic volcanic rocks of the Haiber Flats, Barby, Welverdiend and Kairab Formations, and associated intrusive rocks in the Konkiep Terrane. Various correlations have been made in the past and recent dating work yields contrasting ages. U–Pb dating of zircons is applied in combination with Sm–Nd and Lu–Hf isotopes to determine the age, assess correlation and ascertain the much-debated tectonic setting.

Ion probe U–Pb zircon dating yields ages of 1218 ± 5 Ma, 1212 ± 4 Ma and 1212 ± 5 Ma (all errors 2σ) for three samples of the Haiber Flats Formation and 1219 ± 13 Ma, 1215 ± 19 Ma for the Barby Formation. The ages obtained for the Barby Formation agree with the 1217 ± 2 Ma and 1214 ± 5 Ma ages reported from previous investigations. Rocks mapped as the supposedly older Kairab rhyolite and felsic tuff gave younger ages of 1220 ± 4 Ma and 1222 ± 10 Ma, respectively, which are coeval with the Barby and Haiber Flats Formations. Two Gorab Gabbro samples, previously mapped as Kairab Formation, yield ages of 1341 ± 8 Ma and 1336 ± 8 Ma. These older ages are within error of two Welverdiend Formation samples which gave ages of 1344 ± 6 Ma and 1337 ± 9 Ma, and the formation was previously dated in the type area at 1327 ± 10 Ma. These ages confirm the reassignment of rocks originally mapped as tholeiitic Barby Formation into the Welverdiend Formation, north of a newly identified stratigraphic hiatus corresponding to the geophysically defined Wêreldend Lineament.

Sm–Nd and Lu–Hf isotopic signatures for the Barby, Haiber Flats and coeval Kairab samples indicate that they are co-magmatic and derived from partly depleted mantle contaminated by older crust. T_DM model ages of these samples range from 2.5 to 1.5 Ga with a major 2.2 to 1.8 Ga group. This suggests that the older crustal component was Paleoproterozoic but included some Archean material. The Welverdiend Formation and Gorab Gabbros show similarity in age, Sm–Nd and Lu–Hf characteristics and were probably derived from partially depleted mantle, or from a well-homogenised mixture of depleted mantle and older crust.

REE diagrams indicate enrichment in LREE (La–Gd) and a flat HREE pattern (Tb to Lu). On spidergrams, most samples are characterised by negative Nb–Ta anomalies and positive K and Pb anomalies which indicate a subduction-related setting (with positive Sr anomaly) or a reworked crustal origin. The similarity in ages, isotopic signatures and geochemistry confirms the correlation of the Barby and Haiber Flats Formation.

这项工作研究了Haiber Flats，Barby，Welverdiend和Kairab地层的中元古代火山岩，以及Konkiep地形中的相关侵入岩。过去已经进行了各种相关，最近的约会工作产生了年龄对比。锆石的U–Pb测年与Sm–Nd和Lu–Hf同位素结合使用，可以确定年龄，评估相关性并确定争议较大的构造背景。

对于三个Haiber Flats组样品，离子探针U–Pb锆石测年的年龄分别为1218±5 Ma，1212±4 Ma和1212±5 Ma（所有误差2σ），Barby样品的年龄为1219±13 Ma，1215±19 Ma编队。巴比组获得的年龄与先前调查报告的1217±2 Ma和1214±5 Ma年龄一致。被认为是较古老的Kairab流纹岩和长英质凝灰岩的岩石分别对应于Barby和Haiber Flats地层，年龄分别为1220±4 Ma和1222±10 Ma。两个Gorab Gabbro样品（先前映射为Kairab组），屈服年龄分别为1341±8 Ma和1336±8 Ma。这些较老的年龄在两个Welverdiend地层样品的误差范围内，这两个样品的年龄分别为1344±6 Ma和1337±9 Ma，并且该地层的日期以前在类型区域为1327±10 Ma。这些年龄证实了原本被绘制为可塑性的巴比组的岩石重新分配到了韦尔弗迪恩德组中，而这是在新识别的地层裂隙以北，该地层裂隙对应于地理上定义的韦勒尔丁线型。

Barby，Haiber Flats和同时期的Kairab样品的Sm-Nd和Lu-Hf同位素特征表明它们是共岩浆的，并且是由被旧地壳​​污染的部分耗尽的地幔衍生而来的。这些样品的T _DM模型年龄在2.5至1.5 Ga之间，主要的2.2至1.8 Ga组。这表明较旧的地壳成分是古元古代的，但包括一些太古代的物质。Welverdiend组和Gorab Gabbros在年龄，Sm-Nd和Lu-Hf特征上显示出相似性，并且可能来自部分贫化的地幔，或者源于贫化的地幔和较旧地壳的均质混合物。

REE图表示LREE（La–Gd）富集和平坦的HREE模式（Tb至Lu）。在蜘蛛图上，大多数样品的特征是Nb-Ta异常为负，而K和Pb异常为正，这表明与俯冲有关的环境（Sr异常为正）或地壳起源返工。年龄，同位素特征和地球化学的相似性证实了Barby和Haiber Flats组的相关性。