Borehole Log February 12, 14-16, 1996 •
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BOREHOLE LOG
Project: 1996 PORTUGUESE BEND LANDSLIDE STUDY Boring No.: P8S-3 Sheet 1 of 3.
GPS boring location: N4,018,412 E4,17/2839 GPS boring a eva ton: 215.6'
Drillers: A. Parra to 98 fees with AP 1000 air rig; E. Sanduval 216.5 feir-i71iTh CHE 95 core rig
Drilling company: Layne Environmental Services Drilled on: 2/12/96 and 2/14-16/96
Geology logged by: D. Cole; R. Crook; P. Ehlig
Depth Lithic Description
(feet) log
0- -./ Landslide debris (0 to 118')
Topsoil; yellowish Drown silty clay with rock fragments; becomes lighter colored with depth.
•�o
D✓.
10- OQ
of
• 20- C� .
/A71
30- C'j
*Cr!
40- "!':;.i Old alluvium with subangular rock fragments in a sandy, silty clay matrix; light yellowish
-e:
• 50- rI.A
60-
o,
�� Extensive chert fra
to gsnents in material like that above.
70-
tN
es... Bentonite fragments in silty clay matrix.
SD-
81 to 84' Bentonite; white to cream colored.
s7 84 to 90' Breccia with abundant small sandstone fragments.
y .
90- 90 to 98' Rock fragments in a clay rich matrix; clay forms balls in drill pipe. •
=�n
98- .- - Completed drilling to 98 feet with air hammer at 12:55 on 2/12/96
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Date Core Run Recovery 'Depth Graphic Dip Descriptive log
and box in feet, in log of
times S & base feet bedding
2/14/96 98- • �/ Landslide debris (to 118 feet) •
1 1 3.0/3.0 - 1 'Bentonite; very fine-grained; unfractured; med. soft;
100% 100- 7� mottled in shades of pale yellow, orange, white and purple.
13:27 101.5
i Bentonitic tuff containing volcanic granules and pebbles.
Gravel, rock fragments to 26 long in silty clay matrix;
105- _(% light yellowish brown.
CORE LOG PBS-3, Sheet 2 of 3.
Date Core Run Recovery Depth Graphic Dip Descriptive log
and box in feet, in log of
times 5 & base feet bedding
1 2 5.0/5.0 105-
1005 v Gravel; sandy, silty, clayey matrix; lacks bedding;
13:55 106.5 _ yellowish brown (2.5Y6/4).
2 3 5.0/5.0 110- \A•
100% _ G 'same as above'
14:15 111.5 _ my-
_ --
2
2 4 4.9/5.0 115- 10 'same as above'
14:45 985 - nP
116.5 = Y J
3 5 4.8/5.0 - 58:15 118' Base Of slide; 0.1 inch stiff clay with slicks;
965 120- jc; gypsum semi-below.
6:15 Siltstone with thinly interbedded ver fine-grained
15:15 121.5 - sandstone; dark gray to very dark gray (5Y4/1-3/1);
_ a few fish scales and small phosphate lenses; gypsum
6 5.0/5.0 % 8:14 seams parallel bedding.
--
i 121.5 to 121.9' Bed of internally massive silty mdstone;
15:37 4 1005 125- black (SY2.5/2); mod. hard.
126.5 - 126' Fracture inclined at 45 degrees.
�� 8:15
127.5' Sandstone bed 1.75 inches thick; fine-grained;
-.7.:*1 dark gray (2.5Y4/0).
7 5.0/5.0 - V.-;:::: 128.6 to 129.0' Fine-grained sandstone bed; dark gray
100% 130- k (2.5Y4/0)
I6:05I31.5 - � ; 130.5 to 131.5' Dolomitic
siltstone; laminated; hard; gray.
r,
5 8 4.9/5.0 -
985 135_ r 8:18
16:40 136.5 I
2/15/96136.7' 1.5 cm thick bentonite bed.
07:00 _- ✓
5 9 4.1/5.0 _ pr:-.F.
Interbedded siltstone and nudstone; very thinly bedded;
09:55 82% 140- .. 8:17-18
141.5
142' start of bentonitic cTaystone interbedded with
siltstone; may be reworked from Portuguese Tuff.
145- PT
6 10 6.2/7.5 -- �..� Porto it Tuff (146 to 204.7')
83% _ %,2,/ 8:15 Very fine-grained bluish gray bentonite in upper part.
12:15 149.0 - ?-J 149 to 150' very waxy bentonite.
11 2.6/2.5 150- -
12:35 1045 151.5
' - 151 to 152' soft sediment deformation in bentonite.
12 5.0/5.0 _- ;l L' Sandy tuff continues downward to base of Portuguese Tuff.
L3:45 7 1005 155- ;J 8:17
156,5 - zV,
•:
13 5.0/5.0 - 1-1.i.
,4:15 100% 160- ;�
161.5
: 0(
14 5.0/5.0 -
4 8 100% 165-
.54164.5 to 165.7' soft sediment deformation.
• 166.5 -
Ilk
- '1/� White sandy tuff; bedding faint.
15 5.0/5.0 -
5:17100Z 170- •:.':
171.5
- - 171' slump structure (soft ediment deformation).
CORE LOG P8S-3, Sheet 3 of 3.
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Date Core Run Recovery Depth Graphic Dip Descriptive log
and box in feet, in log of
times % & base feet bedding
2/15/96 - S.).FF granule conglomerate with scattered pebbles resting on
8/9 16 5.0/5.0 - l t undulating contact on laminated chocolate brown organic-
100% 175- o •c rich mudstone. 172.2 to 175.4 graded beds 1.5 to 3 ' thick
176.5 - alternate with dark organic rich beds up to 0.2' thick.
15:52 - � 175.4 to 177.9' graded tuff bed with granules at bottom.
) , 8:16 178.7 to bottom at 181.7 sandy to pebbly lithic tuff; minor
9 17 5.2/5.0 - i-:;.,.!i bedding,
100% 180-
16:27 181.7 -
- '''N•! 183.5 to 192.5 thick beds of white sandy tuff; scattered
-9/10 18 5.0/5.0 1.- pyrite.
100% 185- t -N!
17:08 186.5 - }} "�
2/16/96 _ �/ '!
�
fO•l
10 19 5:0/5.0 - !
100% 190- r
08:22 191.5 - P :�
10/11 20 %.0/5.0 - -,
100%. 295= •,j
09:22 196.5 - S�f
11 21 5.0/5.0 -
100% 200-
. 09:40 201.5
-
11/12 22 5.0/5.0 - ��" 204.7 Base of Portuguese 7�
100% 205- i! underlain by laminated siliceous siltstone.
10:15 206.5
- B:12-16
12 23 5.0/5.0 - 7-:-
100%
100% 210- is
11:10 211.5 - ,✓-�
13 24 4.9/5.0 - ,r 214.2 to 215.5' bentonitic lapilli tuff.
98% 215- AV
11:38 216.5 - Laminated siltstone; dark brownish gray; organic rich.
Total depth 216.5; 2' PVC pipe installed to below slide base.
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