Borehole Log March 19 - 20, 1996 BOREHOLE LOG IP-
Project: 1996 PORTUGUESE BEND LANDSLIDE STUDY Boring No.: PBS-10 Sheet 1 of 2
GPS boring Tocation: N4,018,350 E4,178,21$— GPS boring eTevaon: 170.4'
Drillers: A. Parra with AP 1000 air rig Drilling company: Layne EnvironBEFEir Services
Drilled on: 3/19-20/96 Geology logged by: 0. Cole
Depth Lithic Description
(feet) log
0- Landslide affected material (0 to 126.5 feet)
5:--/ 0 to 5o' Multicoloredangu ar rock fragments of mostly pebble size in a pale brown
^
C1 (10YR7/4) sandy silty clay matrix; a few carbonized wood fragments.
10- O i
\v
20- "s'-'e _
CI-
;ID
30- Q.i
t/7
-
40- a
-o-
50- Q . .•
..,..
ov
.- 56 to 65' Multicolored rock fragments to pebble size in clayey fine-grained sand
�y matrix; some bentonite granules.
60-
..-
' 65 to 74' Cobble size clasts of subangular to subrounded, hard, fine-grained
sandstone.
70- ••
•Q
- 74 to 83' Pebble size fragments of siltstone and bentonite in muddy matrix; of
Z a possible debris-flow origin.
80- :.6-1
83' Bedding in sandy sa�gle indicates alluvial origin.
90- �-- 90' Back into breccia of pebble size rocks in a muddy matrix; clasts are white,
0.31
�, reddish brown and dark yellow in color.
o.
100- •7�
v, `
^Q
110- .-
4;�-1 113 to 120' Bentonite containing rock fragments.
3 -3i
120- :?:-1 " 120 to 126' Very fine-grained sand; yellow orange.
BOREHOLE LOG PBS-10, Sheet 2
Alldepth lithic Description
(feet) log
120- :
126' Slide base; much firmer drilling; color change from shades of yellow, brown
and orange to unoxidized gray.
127 to 156' Laminated siltstone, mudrock and fine-grained sandstone with some
130- 1-7.:=-- bentonitic interbeds; dark olive gray (5Y3/1 to 5Y2/1).
135' Bentonitic sandstone bed.
140- .--
==. 146' Thin bentonite bed.
150- ,.
••P F. 153' Bentonitic sandstone bed.
156 to 209' Portuguese Tuff (bentonite); light to dark gray (N7 to N4); aphanitic
J
^N near top becoatng sandy near bottom.
160- CJ
J` -
170- �)�7'
)J
,5.
40 180- I .....„
vt--.)...L
v6
190- r
.,J
00- I,'
2 200 to 209' Coarse to very coarse-grained tuffaceous sandstone.
:_9. 209 to 212' Hard 'siltstone; dark olive gray (5Y3/1).
210-
—LI Total depth 212 feet.