units >=1000 km2: 189  on a dome: 53
contact  openings n=  5 plains n= 25 | FeO_wt: 14.92 vs 14.95 (p=0.75) | TiO2_wt: 3.00 vs 3.90 (p=0.11) | Th_ppm: 5.31 vs 5.17 (p=0.87) |
outside  openings n= 48 plains n=111 | FeO_wt: 13.36 vs 12.65 (p=0.033) | TiO2_wt: 1.99 vs 1.48 (p=0.0021) | Th_ppm: 1.86 vs 1.92 (p=0.69) |
all      openings n= 53 plains n=136 | FeO_wt: 13.50 vs 12.97 (p=0.1) | TiO2_wt: 2.01 vs 1.61 (p=0.055) | Th_ppm: 2.00 vs 2.13 (p=0.19) |
