Mg–Fe carpholites from aluminous schists in the Diahot region and implications for preservation of high‐pressure/low‐temperature schists, northern New Caledonia

Abstract Mg–Fe carpholite is widespread in the Diahot region of New Caledonia in highly aluminous schists and as veins in what was originally a clay‐rich hydrothermal alteration envelope about massive suphide deposits. These carpholites have Fe/(Fe + Mg) ratios of 0.03–0.65 and no significant Mn component. Mg‐carpholite + quartz occur in assemblages with chlorite or pyrophyllite, pyrophyllite + kaolinite and pyrophyllite + diaspore. Temperatures of 230–320° C and minimum pressures of 7 kbar are indicated for the Mg–Fe carpholite‐bearing rocks. The regional distribution of aragonite and Mg–Fe carpholite parallel to a major zone of dominantly transcurrent movement and oblique to the trend of the subduction complex indicates the high‐P/low‐T schists owe their rapid uplift and preservation to the vertical component of the transcurrent faulting.