This study presents the first geochemical, mineralogical and petrological data on the mafic and ultramafic rocks of Texenna (Lesser Kabylia, north-eastern Algeria) with the aim of constraining their tectonic setting in the context of the Maghrebide belt. The magmatic-sedimentary complex of Texenna comprises serpentinite, metabasites (metagabbro, metadolerite and metabasalt with pillow-lava structures), and oceanic metasediments (radiolarite and calcschists). Serpentinites consist mainly of mesh textures and large bastites of lizardite, Cr-spinels altered to “ferritchromit” and chlorite, with chrysotile and chlorite veins. Their features are very similar to those of serpentinites collected from the seafloor. Pillow-lava metabasalts contain mineral assemblages of albite, epidote, chlorite, actinolite and titanite, and, despite metamorphism, have preserved many of the pillow-lava microstructures (former glassy, variolitic and spherulitic zones; former devitrification spherulites and gas vesicles; pseudomorphs after phenocrysts and microliths). Metadolerites and metagabbros have sometimes preserved their magmatic plagioclase, but are generally transformed into an assemblage of albite, calcic amphiboles, chlorite, epidote and titanite, a mineral assemblage typical of the static greenschist-facies hydrothermal metamorphism of an oceanic crust. Some deformation in the conditions of phengite-bearing greenschist-facies metamorphism is linked to the tectonic emplacement of the ophiolites in their current setting during the Maghrebide orogeny. Geochemically, the whole-rock compositions of the serpentinites indicate a harzburgite protolith, while the metabasites are tholeiitic and show the N-MORB signature for the pillow lavas and T-MORB to E-MORB affinities for the intrusive rocks (metadolerites and metagabbros). These results demonstrate for the first time that the magmatic-sedimentary complex of Texenna belongs to a true ophiolitic slice and indicate that the sedimentary cover of the Maghrebian Flysch domain was deposited over a true oceanic rather than a thinned continental crust. The Texenna ophiolites show analogies with many other ophiolites in the Western Mediterranean region, indicating that they represent remnants of the ancient oceanic lithosphere of the western Tethys (i.e., Maghrebian Tethys Ocean) that formed between Africa and Iberia during the Middle-Late Jurassic.

这项研究提出了关于特克森纳（Lesser Kabylia，阿尔及利亚东北部）的镁铁质和超镁铁质岩石的第一个地球化学，矿物学和岩石学数据，目的是在马格里布德带的背景下限制其构造环境。Texenna的岩浆-沉积复合体包括蛇纹岩，变质岩（变质岩，变质辉石和具有枕状熔岩构造的玄武岩）和海洋变质沉积物（放射铁矿和方解石）。蛇纹岩主要由网状织构和大型辉石组成，蜥蜴石，铬尖晶石改成“铁铬铁矿”和绿泥石，具有温石棉和绿泥石脉。它们的特征与从海底收集的蛇纹岩的特征非常相似。枕熔岩玄武岩包含钠长石，埃迪奥德，绿泥石，阳起石和钛铁矿的矿物组合，尽管发生了变质作用，保留了许多枕熔岩的微观结构（以前的玻璃状，方解石和球状区；以前的失透球状体和气泡；在表晶和微石后的假晶型）。变石和变辉石有时保留了其岩浆斜长石，但通常会转变成钠长石，钙质闪石，绿泥石，山石和钛铁矿的组合，这是典型的静态绿片岩相水热变质作用的矿物组合。含镁铁矿的绿片岩相变质条件下的某些变形与马格里布造山运动中蛇绿岩在当前环境下的构造定位有关。从地球化学角度看，蛇纹岩的全岩成分表明是哈兹伯格岩的原生岩，。这些结果表明，第一次的岩浆-沉积复杂Texenna的属于真正的蛇绿岩片，并指出是t他沉积盖层的马格里布复理石的域沉积在一个真正的海洋，而不是变薄陆壳。Texenna蛇绿岩与西地中海地区的许多蛇绿岩有相似之处，表明它们代表了中侏罗世时期在非洲和伊比利亚之间形成的西部特提斯（即马格里比斯特提斯洋）古代海洋岩石圈的残余物。