A Textural Record of Solidification and Cooling in the Skaergaard Intrusion, East Greenland

The clinopyroxene^plagioclase^plagioclase dihedral angle, cpp, gabbroic cumulates records the time-integrated thermal history the sub-solidus and provides a measure of textural maturity. in cpp through the Layered Series of the Skaergaard , East Greenland, demonstrate that the onset of crystallization clinopyroxene (within LZa), Fe^Ti oxides (at the base LZc) and apatite (at the base of UZb) as liquidus phases in bulk magma is recorded by a stepwise increase in textural , related to an increase in the contribution of latent heat to total heat loss to the surroundings and a reduction in the cooling rate at the crystallization front of the intrusion. onset of both liquidus Fe^Ti oxide and apatite crystallization marked by a transient increase in textural maturity, probably to overstepping before nucleation. Textural maturation at ^plagioclase^plagioclase triple junctions effectively ceases the uppermost parts of the Layered Series as a result of the pluton cooling below the closure temperature for dihedral change, which is 10758C. Solidification of the Layered of the Skaergaard intrusion occurred via the upwards of a mush zone only a few metres thick.