As per the legend on X-sect, the dark blue is oxide carb...

As per the legend on X-sect, the dark blue is oxide carb enrichment similar to WA1 yes... though in detail the two may be very different beasts. Air Core holes will not drill fresh rock, so the bottom of hole is usually semi-fresh rock and blade refusal (unless depth/water prevents AC from reaching basement rock). Note that the carbonatite in blue is weathered much deeper than the country rock the carb intruded... this is because carbonate minerals that make up most of carb intrusions are easily weathered, so oxidation goes deeper than in the country rocks at sides. This section doesn;t show any Carbonatite Basement -Fresh, although it's possible EAL256 hit basement but they chose not to include an interoperated carb basement boundary?