## 3 Results
### Mineral Compositions  
#### 3.2.1 Phlogopite  
Phlogopites were analysed in the remains of the lamproite section, in the peridotite close to the lamproite section and in the peridotite close to the melt trap in order to establish any systematic compositional variation across the profile of the peridotite section. Two compositional groups could be identified; one in the lamproite section with high TiO\({}_{2}\) and low Cr\({}_{2}\)O\({}_{3}\) (Table 3), and the other in the peridotite section with lower TiO\({}_{2}\) and higher Cr\({}_{2}\)O\({}_{3}\). No systematic variation could be recognized for phlogopites in the peridotite  
Figure 2: Back-scattered electron image of the peridotite section after Experiment G128 at 2 GPa and 1125 \({}^{\circ}\)C (OI + Cpx + Phl). Compositionally homogeneous xenomorphic phlogopite crystallizes interstitially between olivine and clinopyroxene. Olivine shows rounded and embaged grains indicating reaction (Melt + olivine \(\Rightarrow\) Phl) and light, Fe-rich rims due to approaching equilibrium of Mg# with the infiltrating melt. section (Figure 3) and so these are summarized in unison in Table 3. Phlogopites in the time series comparison (G138, 24 h; G131, 58 h; G137, 132 h) showed only small compositional differences with no consistent trend: phlogopite from the shortest and longest time-series runs were most similar, whereas those in the experiment with intermediate duration had a higher Al\({}_{2}\)O\({}_{3}\) and lower Cr\({}_{2}\)O\({}_{3}\), which may be attributable to the higher proportion of lamp in the capsule imparting stronger lamproite characteristics. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline Expt & G132 & & C132 & & G128 & & G128 \\ P (GPa) & 2 & & 2 & 2 & 2 & \\ T (’C) & 1050 & & 1050 & & 1125 & & 1125 \\ Duration (h) & 72 & & 72 & & 72 & & 72 \\ \hline Location & Residual & & interstitial in & & Residual & interstitial in & \\  & melt & s.d. & & peridotite & s.d. & melt & s.d. & peridotite & s.d. \\ \hline SiO\({}_{2}\) & 40.29 & 0.12 & 39.7 & 0.27 & 39.73 & 0.24 & 38.72 & 0.51 \\ TiO\({}_{2}\) & 5.14 & 0.43 & 1.2 & 0.08 & 6.98 & 0.37 & 1.26 & 0.11 \\ Al\({}_{2}\)O\({}_{3}\) & 11.86 & 0.1 & 14.7 & 0.28 & 11.49 & 0.27 & 15.99 & 0.43 \\ MgO & 20.12 & 0.36 & 23.2 & 0.17 & 17.98 & 0.22 & 22.4 & 0.25 \\ FeO & 6.19 & 0.22 & 3.7 & 0.14 & 7.42 & 0.2 & 3.68 & 0.09 \\ CaO & 0.03 & 0.05 & 0.0 & 0.02 & 0.05 & 0.03 & 0.03 & 0.02 \\ Na\({}_{2}\)O & 0.12 & 0.02 & 0.6 & 0.03 & 0.16 & 0.03 & 0.74 & 0.04 \\ K\({}_{2}\)O & 9.98 & 0.11 & 9.4 & 0.16 & 9.81 & 0.16 & 9.32 & 0.09 \\ Cr\({}_{2}\)O\({}_{3}\) & 0.17 & 0.07 & 1.7 & 0.21 & 0 In the 2 GPa experiments, phlogopites in the higher temperature experiment (1125 \({}^{\circ}\)C vs. 1050 \({}^{\circ}\)C) have slightly higher TiO\({}_{2}\) (7.0 vs. 5.1 wt%) and lower Cr\({}_{2}\)O\({}_{3}\) (0.07 vs. 0.17 wt%), emphasizing the polarization between mineral compositions in the lamproite and peridotite sections. Phlogopite did not occur at 2 GPa and 1125 \({}^{\circ}\)C in the liquidus experiments of [24], presumably due to a higher content of fluid components in those experiments. Phlogopites in the peridotite sections are distinct from those in the lamproite section, with higher Cr\({}_{2}\)O\({}_{3}\) (\(\approx\)1.7 vs. \(\leq\)0.2 wt%), Al\({}_{2}\)O\({}_{3}\) (15-16 vs. \(<\)12 wt%) and Na\({}_{2}\)O (0.60-0.74 vs. 0.12-0.16 wt%) and lower TiO\({}_{2}\) (1.0-1.3 vs. \(>\)5 wt%; Figure 3). The Mg# is buffered by the peridotite minerals at 90.4-91.8, in contrast to those in the lamproite section, which are more variable (Figure 3) and characteristic of those in magmatic lamproites [17].