U. S. Geological Survey Professional Paper 1563



Table 2. Radiocarbon dates pertaining to age of tephra layers at Mount St. Helens.

W-2993 Wood, from Sugar Bowl deposit

1,150

±60 Crandell and others (1981)
W-5343 Wood, from Sugar Bowl deposit

1,200

±200 Crandell and Hoblitt (1986)
W-3138 Wood, from below Sugar Bowl deposit

1,410

±70 Crandell and others (1981)

 

 

 

 

 

W-2990 Wood, above layer Bu

1,620

±50 Crandell and others (1981)
W-2527 Charcoal, between layers Bu and Bo

1,740

±70 Crandell and others (1981)
W-2924 Peat, above layer Bi

1,780

±60 Crandell and others (1981)
W-2925 Peat, below layer Bi

1,850

±60 Crandell and others (1981)
W-2923 Charcoal, above layer Bh

2,200

±60 Crandell and others (1981)

 

 

 

 

 

W-2541 Charcoal, within set P

2,670

±70 Crandell and others (1981)
W-2829 Charred wood, between sets Y and P

2,930

±60 Crandell and others (1981)
W-2675 Charred wood, between sets Y and P

2,960

±50 Crandell and others (1981)
W-3262 Wood, from Lahar

3,280

±90 Crandell and others (1981)

 

 

 

 

 

W-2549 Charred wood, within set Y

3,350

±50 Crandell and others (1981)
W-3144 Charred wood, within set Y

3,380

±60 Crandell and others (1981)
W-1752 Charred wood, beneath layer Yn

3,510

±80 Crandell and others (1981)
W-3911 Charcoal, below set Y

3,850

±70 Crandell and others (1981)
W-2677 Charcoal, below set Y

3,900

±50 Crandell and others (1981)
W-1751 Charcoal, beneath set Y

4,680

±80 Crandell and others (1981)

 

 

 

 

 

W-2587 Charcoal, within set J

8,300

±90 Crandell and others (1981)
W-2702 Charcoal, within set J

8,430

±100 Crandell and others (1981)
W-2991 Charcoal, within set J

8,900

±70 Crandell and others (1981)
W-3257 Wood, above set J

9,170

±100 Crandell and others (1981)
W-5722 Peat, above Jb, Conboy bog

9,260

±300 This study
W-5731 Peat, above Jg, Fargher Lake

10,580

±250 This study
W-3548 Wood, below Jg, South Fork Toutle

10,710

±150 Crandell and others (1981)
W-5718 Peat, above Jb, Conboy

10,740

±250 This study
W-5724 Peat, below Jg, Fargher Lake

10,980

±250 This study
W-5719 Peat, below Jy(?), Fargher Lake

11,580

±250 This study

 

 

 

 

 

W-2868 Charcoal, between S and J, Rd 140

12,110

±110 Crandell and others (1981)
W-2870 Charcoal, between S and J, Rd 140

11,550

±230 Crandell and others (1981)
W-2866 Charcoal, between S and J, Rd 140

11,900

±190 Crandell and others (1981)
W-2832 Charcoal, below set J

11,700

±90 Crandell and others (1981)
W-2441 Charcoal, below set J

11,880

±110 Crandell and others (1981)

 

 

 

 

 

W-3133 Peat, above upper set S

12,120

±100 Crandell and others (1981)
W-3141 Charcoal, beneath part of set S

12,910

±160 Crandell and others (1981)
W-3136 Peat, beneath upper set S

13,650

±120 Crandell and others (1981)

 

 

 

 

 

W-2413 Charcoal, above set K

18,560

±180 Crandell and others (1981)
W-4531 Charcoal, above set K

19,160

±250 Crandell and others (1981)
W-2540 Charcoal, below sets M and K

20,350

±350 Crandell and others (1981)
W-2976 Charcoal, within set C

36,000

±2,500 Crandell and others (1981)
W-2661 Charcoal, within set C

37,600

±1,300 Crandell and others (1981)
W3259 Charcoal, within(?) set C

more than 42,000

 

Crandell and others (1981)