The Hedesunda granite complex covers a rectangular area of ca 800 km² within the Bergslagen lithotectonic unit of the Paleoproterozoic Svecofennian orogen in east-central Sweden. It is dominated by coarse porphyritic and generally undeformed granitoids whose position within the Svecofennian orogenic evolution has been controversial. New U–Pb SIMS dating of zircon confirms earlier TIMS results, showing that it is a composite intrusion made up of an older phase at ca 1865 Ma, forming the bulk of the massif, and a younger phase at ca 1785 Ma, forming a circular intrusion in the north-central area and an elongated body further west. The two generations have very different geochemistry. The older Hedesunda I intrusion ranges from diorite through tonalite and granodiorite to granite in composition, is dominantly metaluminous, calc-alkaline, magnesian, I-type and volcanic arc-related, and probably formed by melting of juvenile Svecofennian lower crust due to basaltic underplating during an extensional ‘intra-orogenic’ phase shortly after the main subduction-related early-orogenic Svecofennian magmatism. The younger Hedesunda II intrusions are purely granitic, dominantly peraluminous, alkali-calcic, K-rich, and ferroan, with A-type and within-plate-type characteristics, and formed penecontemporaneously with post-collisional shoshonitic intrusions in southern Finland, again presumably by crustal melting due to basaltic underplating in an extensional setting towards the end of the Svecofennian orogeny.

Hedesunda花岗岩复合体覆盖约800 km ²的矩形区域瑞典中东部古元古代Svecofennian造山带的Bergslagen岩相构造单元中。它以粗斑状和一般未变形的花岗岩为主，它们在Svecofennian造山带演化中的位置一直存在争议。锆石的新的U–Pb SIMS测年证实了TIMS的更早结果，表明它是复合侵入岩，由年龄约1865 Ma的较旧相组成，占断层块的主体，以及年龄约1785 Ma的较年轻相，形成了圆形入侵中北部地区，并向西延伸一个细长的物体。这两个世代具有不同的地球化学。Hedesunda I较早的侵入物从成分从闪长岩到斜方晶石和花岗闪长岩再到花岗岩，主要为金属，钙碱性，镁质，I型和火山弧相关，可能是由与俯冲作用有关的早期造山运动的主要Svecofennian岩浆作用后不久的伸展“造山运动”阶段内玄武质基底发育所致，使Svecofennian的下部地壳融化形成的。较年轻的Hedesunda II侵入体是纯花岗岩的，主要为高铝质，钙质，富钾和二茂铁，具有A型和板内型特征，在芬兰南部与碰撞后的肖肖尼纪侵入体呈准同时期形成。在Svecofennian造山运动末期，在伸展的环境中由于玄武质基底作用而引起的地壳融化。