Table 1 MgO contents of juvenile tephra particles and the contents of accidental quartz grains in units T2 and R2 at Songaksan tuff ring.

From: Distinguishing between primary and secondary volcaniclastic deposits

Unit T2 R2 R2 R2 R2 R2 R2 R2 R2 R2
Location Loc. 1 Loc. 3 Loc. 5 Loc. 6 Loc. 9 Loc. 10 Loc. 11 Loc. 11′* Loc. 14 Loc. 16
Facies Primary Primary Primary Primary Wave-worked Wave-worked Wave-worked Wave-worked Primary Wave-worked
Number of juvenile particles 342 123 104 105 219 219 333 203 108 103
Average MgO (wt%) 3.70 4.57 4.63 4.50 3.97 3.78 3.96 3.82 4.61 3.90
Low-Mg tephra (%) 29.82 4.88 5.77 7.62 22.37 33.79 31.83 29.06 3.70 33.01
High-Mg tephra (%) 26.90 81.30 85.58 80.00 42.92 32.42 45.05 37.44 85.19 39.81
Intermediate-Mg tephra (%) 43.27 13.82 8.65 12.38 34.70 33.79 23.12 33.50 11.11 27.18
T2-derived tephra (%) 62 89 64 82 72
Vent-derived tephra (%) 38 11 36 18 28
Accidental quartz (%) 34.31 1.50 7.10 4.30 26.61 32.15 19.31 26.25 1.80 8.50
  1. *Loc. 11 is located between loc. 11 and 12.