Igneous Petrogenesis

Background:
The Rude Bawl Layered Intrusion is made up of layers of igneous rock, thought to be the remains of an ancient magma chamber that has completely cooled and crystallised.
U-Pb geochronology shows that the intrusion crystallised approximately 2100 million years ago. Since then, the intrusion has been deformed by tectonic processes. The effect of this deformation is that the intrusion is now tilted and eroded so that each layer of the intrusion is now exposed (Figure 1). The intrusion has been metamorphosed to greenschist-amphibolite facies during a period of regional metamorphism.
You have been given petrographic data (Figure 2) on the Intrusion which describes their primary igneous mineralogy as well as some of the metamorphic and alteration mineral assemblages imparted onto the rocks since their intrusion.
You have also been given whole-rock geochemical analyses (see attached .xls spreadsheet titled ‘Rude Bawl Intrusion Wholerock Geochemistry’) from representative samples collected from throughout the intrusion.