# The MnO-TiO2-P2O5 discrimination diagram for basalts and
# basaltic andesites (45-54 wt% SiO2) (after Mullen, 1983)
#
# 07-10-2001 by IWW <warmada@altavista.net>
#
set term postscript enhanced monochrome 'Roman' 10.5
set output 'diskrim.ps'
set size square 0.535,0.65
set angle degrees
set noborder
set xrange [-10:100]
set yrange [-10:100]
set noxtics
set noytics
set key 100,90
# plot triangular coordinate system
#gx(x,y) = x + y * cos(60)
gx(x,y) = 100 - (x + y) + y * cos(60)
gy(x,y) = y * cos(30)
set label 41 'MnO x 10' at -2.5,-3.5 center font 'Times,12'
set label 42 'TiO_2' at 50,90 center font 'Times,12'
set label 43 'P_2O_5 x 10' at 100,-3.5 center font 'Times,12'
set label 44 'oceanic-' at 49,58.5 left
set label 45 'island' at 49,55 left
set label 46 'tholeiite' at 49,51.5 left
set label 47 'MORB' at 42.5,41 center
set label 48 'island-arc' at 30,35 center
set label 49 'theleiite' at 30,31.5 center
set label 50 'ocean-island' at 72.5,25 center
set label 51 'alkali basalt' at 75,21.5 center
set label 52 'boninite' at 19,12.5 center
set label 53 'calc-alkali basalt' at 50,7.5 center
plot 'diskrim.dat' index 1 using (gx($1,$2)):(gy($1,$2)) notitle with lines 1, \
'diskrim.dat' index 2 using (gx($1,$2)):(gy($1,$2)) notitle with lines 2, \
'diskrim.dat' index 0 using (gx($1,$2)):(gy($1,$2)) notitle with lines 1
#pause -1
reset
# data arrangement (diskrim.dat)
# ------------------------------
# each data cluster should be separated by 2 LS
# that is gnuplot syntax for plotting with index
# boundary lines for triangle
# index 0
100 0 0
0 100 0
0 0 100
100 0 0
# MnOx10 TiO2 P2O5x10
# solid line
# index 1
23 77 0
30 29 41
8 0 92
41 59 0
41 27 32
28 27 45
# dashed line
# index 2
61 39 0
61 18 21
21 18 61
30 29 41
0 45 55