The Mull Palaeogene dyke swarm: insights into the evolution of the Mull igneous centre and dyke-emplacement mechanisms

摘要: Geochemical data are presented for five large Palaeogene dykes, members of the Mull swarm in southern Scotland and northern England (the Moneyacres, Hawick-Acklington, Barrmill, Muirkirk-Hartfell Dalraith-Linburn dykes). The rock types range from basalt through andesite to dacite, although individual intrusions is more restricted. dykes divisible into two groups; those where compositional variation was generated by fractional crystallization basaltic magmas, it resulted variable degrees mixing silicic magmas. Several composite; marginal facies can be or less evolved than central facies. dyke magmas thought have originated stratified magma chambers beneath centre models show how different components were derived chambers. Some appear been terminated at near Southern Upland Fault, perhaps as a result chilling early pulses water fault. considerably complex previously recognized has significant input evolution magmatic system.