Refs.:
Oh, C. W., Liou, J. G. and Maruyanma, S. (1991). Low-temperature eclogites and eclogitic schists in Mn-rich metabasites in Ward Creek, California; Mn and Fe effects on transition between blueschist and eclogites. J. Petrol., 32, 275-301.
www.minsocam.org/msa/Handbook/Winchite.PDF.