Table T12. Petrographic summary of Site 1138 basement units.

Basement Unit Rock type Thickness
(m)		 Phenocrysts Rock
(%)		 Groundmass Core, section,
interval (cm)
 
 
 
183-1138A-
1 Aphyric trachyte 19.50 PL <1 PL, CPX, GL, OPQ 74R-1, 27-29; 75R-1, 5-6
2 Bedded pumice lithic breccia 24.29
 

3 Moderately plagioclase-phyric basalt 5.98 PL 10 PL, CPX, GL, OPQ 80R-1, 52-56
4 Moderately plagioclase-phyric basalt 2.39 PL 3 PL, CPX, GL, OPQ 80R-2, 101-103; 80R-3, 18-22
5 Sparsely plagioclase-phyric basalt 6.28 PL 3 PL, CPX, GL, OPQ, OL 80R-5, 17-20
6 Aphyric basalt 2.84
  PL, CPX, GL, OL, OPQ 81R-2, 26-27; 81R-2, 129-132
7 Sparsely plagioclase-phyric basalt 6.80 PL 4 PL, CPX, GL, OL, OPQ 81R-5, 2-5
8 Sparsely plagioclase-phyric basalt 2.20 PL 1 PL, CPX, GL, OL, OPQ 82R-1, 126-128
9 Sparsely plagioclase-phyric basalt 7.42 PL, CPX 2 PL, CPX, GL, OPQ, OL 82R-5, 69-71
10 Aphyric basalt 5.44 PL 1 PL, CPX, GL, OL, OPQ 83R-4, 34-37
11 Aphyric basalt 2.41 PL <1 PL, CPX, GL, OL, OPQ 83R-6, 22-23
12 Aphyric basalt 3.05 PL <1 PL, CPX, GL, OPQ 84R-1, 7-8; 84R-1, 30-34
13 Sparsely plagioclase-phyric basalt 8.38 PL 1 PL, CPX, GL, OPQ, OL 84R-5, 13-15; 84R-5, 100-101
14 Aphyric basalt 3.17
  PL, CPX, GL, OL, OPQ 85R-1, 107-110
15 Aphyric basalt 6.43 PL <1 PL, CPX, GL, OPQ, OL 85R-2, 123-124
16 Aphyric basalt 0.73
  PL, CPX, GL, OPQ, OL 86R-1, 44-46
17 Aphyric basalt 3.03 PL <1 PL, CPX, GL, OPQ 86R-2, 115-118; 86R-3, 32-34
18 Aphyric basalt 5.84
  PL, CPX, GL, OPQ 86R-3, 148-149
19 Sparsely plagioclase-phyric basalt 9.70 PL, CPX 3 PL, CPX, GL, OL, OPQ 87R-2, 110-113; 87R-3, 10-13
20 Aphyric basalt 1.36
  PL, CPX, GL, OPQ 88R-1, 87-89
21 Aphyric basalt 9.64 PL <1 PL, CPX, GL, OPQ 88R-2, 126-129
22 Aphyric basalt 8.30 PL <1 PL, CPX, GL, OPQ 89R-2, 119-122

Note: PL = plagioclase, CPX = clinopyroxene, GL = glass, OPQ = opaques, OL = olivine.