MnO-TiO2-P2O5: Petrotectonic Environments, Mullen

A ternary diagram using MnO, TiO2, P2O5 can discriminate between five petrotectonic environments of basaltic rocks (45–54% SiO2). Fields for mid-ocean ridge, island arc tholeiite, island arc calc-alkaline, ocean island tholeiite, and ocean island alkalic rocks were distinguished on the basis of 507 analyses from well-defined environments.

Ellen D. Mullen MnO/TiO2/P2O5: a minor element discriminant for basaltic rocks of oceanic environments and its implications for petrogenesis , 1983 [ref]

require('ggtern');

classifydiag.basalts_mullen <- function (wtp_data, ...)
{  
ds <- selectNames(wtp_data,c('Name','TiO2_wtp','MnO_wtp','P2O5_wtp'))

pts <- data.frame(Name=ds$Name,
                  X = ds$MnO_wtp*10,
                  Y = ds$TiO2_wtp,
                  Z = ds$P2O5_wtp*10);

labels <- c("MnO_wtp*10", "TiO2_wtp", "P2O5_wtp*10");
 
ret <- c();
ret$type <- "ternogram";
ret$points <- pts;
ret$labels  <- labels;
 
return(ret);
}