## 4 Petrography
### Petrography of #110 Phlogopite  
The No. 110 pipe kimberlite contains a population of euhedral-subhedral phlogopite phenocrysts (#110 phlogopite, usually >150 \(\upmu\)m). These grains are in the form of laths, and serpentinization often occurs along the cleavage. Furthermore, the sample matrix in pipe No. 110 exhibits a high concentration of spinel. Apatite commonly occurs in close association with phlogopite, which indicates a strong correlation between the two minerals. The #110 phlogopite often exhibits a high degree of fracturing, likely the result of external forces. It is presumed that the kimberlite magma within this pipe experienced significant violent disturbances.  
\begin{table}
\begin{tabular}{l l} \hline
**Back-Scattered Electron Image** & **Cartoon Showing Zoning** & **Feature Description** \\ \hline  & High-Ti-Cr Core: \\  & anhedral(emphayed texture), \\  & Cr\({}_{2}\)O\({}_{3}\) = 0.2–1.6 wt.\%, \\  & TiO\({}_{2}\) = 2.2–3.5 wt.\%, Mg\({}^{\#}\) = 88.2 \\  & Low-Cr/Cr-Poor Rim: \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 0.2 wt.\%, TiO\({}_{2}\) = 2.5–5.4 wt.\%, \\  & Mg\({}^{\#}\) = 82.4 \\  & Rind I: \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 0.12 wt.\%, TiO\({}_{2}\) \textless{} 1.7 wt.\%, \\  & Mg\({}^{\#}\) = 88.4 \\  & Low-Ti-Cr Core: \\  & anhedral(emphayed texture), \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 1.0 wt.\%, \\  & TiO\({}_{2}\) \textless{} 1.3 wt.\%, Mg\({}^{\#}\) = 90.6 \\  & Low-Cr/Cr-Poor Outer Rim: \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 0.2 wt.\%, TiO\({}_{2}\) = 2.5–5.4 wt.\%, \\  & Mg\({}^{\#}\) = 82.4 \\  & Low-Ti-Cr Core: \\  & anhedral(emphayed texture), \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 1.0 wt.\%, TiO\({}_{2}\) \textless{} 1.3 wt.\%, \\  & Mg\({}^{\#}\) = 90.6 \\  & High-Ti-Cr Inner Rim: \\  & Cr\({}_{2}\)O\({}_{3}\) = 0.2–1.6 wt.\%, \\  & TiO\({}_{2}\) = 2.2–3.5 wt.\%, Mg\({}^{\#}\) = 88.2 \\  & Low-Cr/Cr-Poor Outer Rim: \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 0.2 wt.\%, TiO\({}_{2}\) = 2.5–5.4 wt.\%, \\  & Mg\({}^{\#}\) = 82.4 \\  & High-Ti-Cr Core: \\  & Cr\({}_{2}\)O\({}_{3}\) = 0.2–1.6 wt.\%, \\  & TiO\({}_{2}\) = 2.2–3.5 wt.\%, Mg\({}^{\#}\) = 88.2 \\  & Low-Cr/Cr-Poor Rim: \\  & Cr\({}_{2}\)O\({}_{3}\) \textless{} 0.2 wt.\%, TiO\({}_{2}\) = 2.5–5.4 wt.\%, \\  & Mg\({}^{\#}\) = 88.4 \\  & Rind II: \\  & Cr\({}_{2}\)O\({}_{3}\) \textgreater{} 0.2 wt.\%, TiO\({}_{2}\) = 2.5–3.5 wt.\%, \\  & Mg\({}^{\#}\) = 88.6 \\ \hline \end{tabular}
\end{table}
Table 1: Common zonal relationships of #50 phlogopite in this study.  
Figure 2: Representative images showing the different petrographic features of the No. 50 pipe kimberlite (**A**,**C**,**E**) and No. 110 pipe kimberlite (**B**,**D**,**F**). A and F are plane-polarized transmitted light photomicrographs. (**B**–**E**) are cross-polarized transmitted light photomicrographs. Ol—olivine, Phl—phlogopite.  
Figure 3: Back-scattered electron (BSE) image and X-ray elemental maps of a typical #50 phlogopite crystal from the No. 50 pipe kimberlite (Tlic-Talc). The colored scales on the right of each panel indicate the relative concentration of each element, i.e., “cool” colors (blue, black) = low concentrations, and “warm” colors (red, orange) = high concentrations. (**A**) Represents the Al concentration of the #50 phlogopite crystal, (**B**) represents the Ba concentration, (**C**) represents the Cr concentration, (**D**) represents the F concentration, (**E**) represents the Fe concentration, (**F**) represents the Mg concentration, (**G**) represents the Ti concentration, and (**H**) represents the Si concentration.  
Figure 4: Back-scattered electron images showing examples of #50 phlogopite in the No. 50 pipe kimberlite. Sp—Spinel, Serp—serpentine, Phl—phlogopite. (**a**) The core of the phlogopite crystals is often filled with serpentine, and the rim with spinel inclusions. (**b**) The darker low-Ti-Cr core with embayed texture. (**c**,**d**) Deformed, twisted phlogopite crystals. (**e**) The more euhedral high-Ti-Cr core. (**f**) The darker low-T-Cr core is surrounded by the lighter high-Ti-Cr inner rim.