An Experimental investigation of primitive magmas from the Kermadec Arc

The investigation focus is to determine in the primitive Southern Kermadec basalt, (SiO2 = 49.64%, Mg1.2, MgO = 9.10wt%, normative olivine = 14.58%) the stable mineral assemblage at pressures of 0.5-1.5GPa, temperatures of 1100-1200 C and varied H2 O contents. These data will be used to make an informed hypothesis as to whether the basalt represents a primary melt composition i.e an unmodified result of peridotite melting in the Southern Kermadec arc. Little work has been done on the origin of the more primitive magmas or on the type of mantle they originate from. This is important to understand the nature of the evolution of the Kermadec arc system. A piston cylinder solid media apparatus was utilised and 3.5wt% H2 O was added to the capsule because this is what has been shown to be common in the mantle wedge in arc systems and from the composition of the basalt, is likely to be close to the original magma water content. Results from mineral and glass analysis show H2 O and Fe play significant roles in the crystallisation of the minerals present in the sample. Upon completion of this investigation, we will be able to characterise the parental magma source of the basalt and comparisons can be made to other known volcanic compositions in the area.