Abstract The Mesoarchean crust of the plutonic belt of the Memve'ele area lies in the southwestern part of the Ntem Complex (NTC), Cameroon. Emplacement of these rocks resulted from both gravity and tectonic driven vertical flow perpendicular to the direction of shortening at the time of partial melting and magmatic accretion. Such deformation patterns suggest the occurrence of a long-lived hot orogen and may explain a nearly isobaric retrograde pressure-temperature (P-T) path recorded within high-T, low- to medium-P metamorphic rocks. However, in the Memve'ele shear zone (MSZ), a metamorphic gradient runs from granulite to green-schist facies. Structural analysis reveals four continuous ductile deformations. The first stage is characterized by the emplacement of dome and basin structures, the second stage is marked by coeval diapiric movements and a transpressional shear zone, the third stage is marked by both transpressional and lateral flow regimes, and the last stage is marked by horizontal constrictional strain. These features indicate that the Mesoarchean crust is affected by a long-lived horizontal shortening deformation (D1-D3) coeval with vertical movements in which concentric cleavages occur around domes. Thus, the studied area can be considered as exemplifying an “Early Earth” style tectonics. The structural patterns in the MSZ contain zone of high-strain rocks belonging to the deep and shallow/mid crusts that have recorded transpressional tectonics. The compressional strain regime in which results coeval steep to shallow dipping structural features and “dome and basin” geometries associated to MSZ activities contributed to maintaining a stable crustal thickness in the Memve'ele area during Mesoarchean orogeny.

中文翻译：

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来自 Memve'ele 地区（Ntem 复合体-喀麦隆西南部）的中太古代深成岩带的地壳生长：“早期地球”挤压构造的证据。

摘要 Memve'ele 地区深成带中太古代地壳位于喀麦隆 Ntem 杂岩体 (NTC) 的西南部。这些岩石的就位是重力和构造驱动的垂直于部分熔融和岩浆增生时缩短方向的垂直流的结果。这种变形模式表明存在一个长期存在的热造山带，并且可以解释在高 T、低到中 P 变质岩中记录的近等压逆行压力-温度 (PT) 路径。然而，在 Memve'ele 剪切带 (MSZ) 中，变质梯度从麻粒岩到绿片岩相。结构分析揭示了四个连续的延性变形。第一阶段的特点是就位圆顶和盆地结构，第二阶段以同期底辟运动和横压剪切带为标志，第三阶段以横压流态和横向流态为标志，最后一个阶段以水平收缩应变为标志。这些特征表明中太古代地壳受到长期水平缩短变形 (D1-D3) 的影响，该变形与垂直运动同时发生，其中圆顶周围发生同心解理。因此，研究区域可以被认为是“早期地球”式构造的例证。MSZ 的构造模式包含属于深、浅/中地壳的高应变岩石带，这些岩石已记录了挤压构造。