Evidence for Early LREE-enriched Mantle Source Regions: Diverse Magmas from the c. 3{middle dot}0 Ga Mallina Basin, Pilbara Craton, NW Australia

The c. 2·97–2·95 Ga magmatic history ofthe Mallina Basin, in the Pilbara Craton of NW Australia, includeswhat is perhaps the most lithologically diverse magmatism ofany similar-sized Archaean terrain, and is unusual for similar-sizedterrains of any age. The magmatism includes light rare earthelement (LREE)-rich basaltic rocks, LREE-rich gabbros and rockswith boninite-like compositions (collectively the ‘Mallinamafic suite’), and high-Mg diorites (sanukitoids). TheMallina mafic suite is characterized by high primitive mantlenormalized (La/Nb)_PM (>3) and (La/Yb)_PM (>2), and non-radiogenicNd-isotopic compositions (     

The Archaean High-Mg Diorite Suite: Links to Tonalite-Trondhjemite-Granodiorite Magmatism and Implications for Early Archaean Crustal Growth

The 2·95 Ga Pilbara high-Mg diorite suite intrudes thecentral part of the Archaean granite–greenstone terrainof the Pilbara Craton, Western Australia, and shows many featurestypical of high-Mg diorite (sanukitoid) suites from other lateArchaean terrains. Such suites form a minor component of Archaeanfelsic crust. They are typically emplaced in late- to post-kinematicsettings, sometimes in association with felsic alkaline magmatism,and are either unaccompanied by, or post-date, tonalite–trondhjemite–granodiorite(TTG) magmatism, which comprises a much greater proportion ofArchaean felsic crust. The TTG series comprises sodic, Sr-richrocks with high La/Yb and Sr/Y ratios, thought to result frompartial melting of eclogite facies basaltic crust. High-Mg dioriteshares these characteristics but has significantly higher mg-number(     

Felsic Magmatic Evolution and the Role of Post-Collisional Process in Continental Crustal Growth at Convergent Margins: Insights from the Western Part of the Central Qilian Belt, Northwestern China

<正>1 Introduction Long-lived early Palaeozoic magmatism in the Qilian orogen,of the Northeastern Tibet Plateau,formed an extensive linear belt of plutonic and volcanic rocks as a result of subduction of the Proto-Tethyan Ocean beneath,and subsequent accretion of resulting arc crust onto,the proto-margin of the North China Craton(NCC)(Song et