In the East African Rift System (EARS) tectonic inheritance rules the location, the shape and the development of rift segments. Such lithospheric/crustal-scale inherited structures may be exploited by magma favouring its ascent to shallow crustal level and, possibly, to the surface producing volcanism. In the eastern branch of the EARS in southeast Kenya, the Pleistocene Chyulu Hills volcanic field (CHVF) is a volcanic range formed east of the main rift along a NW-SE trending Proterozoic crustal-scale shear zone (the Emali-Voi shear zone). The volcanic range consists of hundreds (at least 514) of scoria cones of basaltic composition, often coalescent and well-aligned along the trace of the crustal shear zone. Morphostructural and spatial analyses of vents and fractures in the CHVF show that vent density and clustering change moving south-eastward along the ridge mimicking the age pattern of volcanism with the youngest activity in the southeast of the CHVF. Notably, the parameters defining the vent self-similar clustering indicate a decreasing thickness of the upper brittle crust along the CHVF from about 12 km in the north-west to about 7 km in the southeast, in agreement with the crustal structure of the area as imaged by seismic and geophysical data sets. Here we propose an evolutionary model of the CHVF occurring at spatial and time scales quite different from that of magma-assisted rifting processes, where CHVF is an example of an embryonic rift stage with a focussed magma injection into the continental lithosphere localized along a weakness discontinuity represented by an inherited crustal shear zone.

在东非裂谷系统（EARS）中，构造继承决定着裂谷段的位置，形状和发育。岩浆可以利用这种岩石圈/地壳尺度的继承结构，将其上升到浅地壳水平，甚至可能上升到产生火山作用的地表。在肯尼亚东南部EARS的东部分支中，更新世的Chyulu Hills火山场（CHVF）是沿主要西北裂陷的NW-SE趋势元古代地壳规模剪切带（Emali-Voi剪切带）形成的火山岩带。 。火山范围由数百个（至少514个）玄武质组成的鳞屑锥组成，它们通常会聚结并沿着地壳剪切带的轨迹很好地对齐。CHVF火山口和裂缝的形态结构和空间分析表明，火山口的密度和聚类变化沿山脊向东南方向移动，模仿了火山活动的年龄格局，而该火山活动在CHVF的东南部最为年轻。值得注意的是，定义出气孔自相似聚类的参数表明，沿CHVF的上部脆性地壳厚度从西北约12 km减小到东南约7 km，与该地区的地壳结构一致。由地震和地球物理数据集成像。在这里，我们提出了CHVF的演化模型，该模型在空间和时间尺度上与岩浆辅助裂谷过程完全不同，