Logs of Exploratory Boreholes Drilled for Palos Verdes Properties, 1968-1969 Appendix A: Logs of Exploratory Boreholes Drilled for •
Palos Verdes Properties, 1968-1969
Locations of the respective boreholes are shown on
Plate 5 , and coordinate values are given in Appendix B .
Surface elevations are representative of the ground surface
at the time the holes were drilled. Bedrock intervals
•
penetrated by the boreholes lie stratigraphically in the
lower part of the Middle division and in the upper part of
the Lower division of the Altamira Shale Member of the__"
Monterey Formation.
Borehole P.V.P. No . 1 Surface Elevation 207 feet
Depth Interval Thickness Description a
(Feet ) (Feet)
0 - 96 96 Active landslide,_?
, rubble .
Angular shale fragments and
some larger limestone blocks
in a clay-rich matrix. Ancient,
inactive failure surface at
87 feet.
96 - Active failure surface .
96 - 200 104 Inactive landslide, rubble .
Rock fragments generally larger
and more abundant. Blocks of
shale exhibiting bedding common
below 135 feet . Inactive fail-
ure surface at 130 feet .
411
231
411
Depth Interval Thickness Description
(Feet) (Feet)
200-214 14 Bedrock, basal section of
Portuguese Tuff, granular with
a wax-like texture .
214-225 11 Rhythmically-bedded tuffaceous
and silty shale with thin
siltstone and tuff interbeds .
Attitude of bedding nearly
horizontal .
•
Borehole F.V.P. No . 2 Surface Elevation 228 feet
Depth Interval Thickness Description
(Feet ) (Feet)
0-165 165 Active landslide, rubble . •
Angular shale fragments and
numerous limestone blocks in
a clay-rich matrix. Basal 8
feet severely deformed.
r
l 5 - Active failure surface .
165-186.5 21 .5 Rhythmically-bedded tuffaceous
and silty shale with bentonit-
Ized tuff interbeds .
Borehole P.V.P. No . 3 Surface Elevation 279 feet
Depth Interval Thickness Description
(Feet) (Feet)
0-119 119 Active landslide, rubble .
Angular shale fragments in
matrix that ranges from
411 granular to clay-rich.
232
1
•1
Depth Interval Thickness Description
(Feet) (Feet) 411
j119 - Active failure surface .
1 119-148 29 Rhythmically-bedded shales,
with gradation from silty in
. upper part of interval to
f bentonitic in lower part.
Prominent jointing,. Two-
foot layer of bentonitic -
.
. tuf
entonitic -
tuf f from 138 to 140 feet.
1 148-199 _
51 Portuguese Tuff, upper 9 '
feet bentonitic, lower-42
feet hydrothermally altered
to a hard, vesicular texture .
1199-214 15 Interbedded shale, siltstone
and tuff, all of which are
-I.
J hydrothermally altered. III
214-217 3 Hard, silicified, aphanitic
tufr.
217-223 6 Breccia of basalt and silici-
fled lithic tuff fragments in
a calcite matrix. Numerous
Ismall vugs lined with cal-
cite crystals .
I223-232 9 Medium-grained, massive
basaltic rock.
1 232-242 10 Rh thmica_1
Y y-bedded shale with
hydrothermally altered tuff
1 interbeds .
242-251
9 Calcareous subfeldspathic
ilithic wacke .
411
233
I
411
Depth Interval Thickness Description
(Feet) (Feet)
251-254 3 Rhythmically-bedded silty
shale .
254-258 14 Breccia of . silty shale
fragments in calcite-rich,
fine-grained m_trix. Abundant
• small pyrite grains in
matrix. (Result of post- `
lithification slumping ? )
258-263 5 Badly fractured tuffaceous
and silty shale . Beds offset
vertically as much as one
inch.
263-304 41 Rhythmically-bedded silty and
411 tuffaceous shale with tuff
interbeds . Fractures common
near upper contact, but
decrease in number with depth.
•
Borehole P.V. P. No . 1 Surface Elevation 389 feet
Depth Interval Thickness Description
(Feet) (Feet)
0-139 139 Inactive landslide, weathered
rubble . Angular fragments of
siliceous and cherty shale
in a clay-rich matrix.
139-146 7 Inactive landslide rubble as
above, except a marked grada-
tional decrease in weathering
411 with depth.
234
Depth Interval Thickness Description 110
(Feet) (Feet)
1L6-301 155 Inactive landslide of
relatively unweathered rubble .
Two large bedded blocks
penetrated at intervals of
185-219 feet and 241-258
feet . Fragments of silty and
tuffaceous shales more
abundant in this interval .
301 - Inactive failure surface .
•
301-326 25 Rhythmically-bedded tuffaceous
• and silty shales with thin
tuff interbeds .
326-388 -62 Portuguese Tuff, distinctly
layered, with gross gradation •
in grain size increasing with
depth. Basal two feet altered
similar to rock in lower part
of unit in borehole 3 .
388-409 ' 21 Unusually hard interval of
tuffaceous and silty shale
with interbeds of tuff and
siltstone .
409-415 6 Disturbed, fractured zone of
softer tuffaceous shale .
Abundant small pyrite crystals
near base .
415-423 8 Rhythmically-bedded silty and
tuffaceous shale with silt-
stone interbed.
L23-428 5 Lithic wacke . 411
235
411
Depth Interval Thickness Description
(Feet) (Feet)
428-430 2 Rhythmic ally-bedded tuffaceous
shale .
•
Borehole P.V.P. No . 5 Surface Elevation 383 feet
Depth Interval Thickness Description
(Feet) (Feet)
0- 53. 53 - Active landslide
rubble .
Angular fragments of •
siliceous and cherty shale
in a clay-rich matrix. A
few larger limestone blocks .
53 - Active failure surface .
411 53-178 125 Inactive landslide rubble as
above .
178 - Inactive failuresu_ �rf
ace .
178-186 8 Bedrock, fine-grained,
layered bentonitic tuff .
186-230 44 Rhythmically-bedded silty and
• tuffaceous shale with inter-
beds of tuff, siltstone and
one layer of dolomite . This
interval exhibits a gradation
to more silicified rocks at
depth. Units near bottom are
cherty, almost flint-like .
•
236
•
Borehole P.V. P. No . 6 Surface Elevation 395 feet 411
Depth Interval Thickness Description
(Feet) (Feet)
0-169 169 Active landslide, rubble.
Upper part .of interval
contains abundant cherty and
siliceous shale fragments and
a few very hard limestone
blocks in a clay-rich matrix.
Below approximate depth of
130 feet, rock fragments
consist of silty and tuffaceous
shale .
169 - Active failure surface .
169-175 6 Rhythmically-bedded tuffaceous
shale .
111
175-183 8 Very bentonitic, layered tuff.
183-211 28 Rhythmically-bedded tuffaceous
and silty shale with a few
thin tuff interbeds .
•
•
211 -217 6 Predominantly coarse-grained
bentonitic tuff with tuffaceous
shale interbeds exhibiting
post-lithification offset
across bedding surfaces .
217-269 52 Portuguese Tuff, exhibiting
a gross increase in grain
size with increase in depth.
Bentonitization moderate .
269-275 6 Tuffaceous shale with two
thin siltstone interbeds.
237
SDeoth Interval Thickness Description
(Feet) (Feet)
275-278 3 Slightly bentonitized gran-
ular tuff with incorporated
thin layers of siltstone .
278-294 16 Rhythmically-bedded tuffaceous
and silty shale with numerous
tuff interbeds .
294-297 3 Very hard, layered aphanitic
turf.
297-304 7 Rhythmically-bedded tuffaceous
and silty shale .
304-315 11 Subfeldspathic lithic wacke .
315-349 34 Rhythmically-bedded tuffaceous
and silty shale with a few
411 thin interbeds of tuff and
siltstone .
Borehole P.V.P. No . 7 Surface Elevation 493 . feet
Depth Interval Thickness Description
(Feet) .(Feet)
0 - 85 85 Inactive landslide, rubble .
Angular fragments of diatoma-
ceous, cherty, siliceous and
silty shales in a matrix
varying from granular to clay-
.
rich. Ancient failure surfaces
cut at 33 feet and 58 feet .
85 Inactive failure surface .
4085 - 89 4 Interbedded silty and
tuffaceous shales .
238
Depth Interval Thickness Description
(Feet) (Feet) 411
89-156 67 Portuguese Tuff, exhibiting
a gross increase in grain
size with increase in depth.
Strongly bentonitized to a
wax-like texture .
156-179 23 Rhythmically-bedded tuffaceous
and silty shales with numerous
thin interbeds of tuff and
siltstone . Interval becomes
more waxy with increase in
depth.
179-185 6 Aphanitic, clayey tuff.
185-196 11 Interbedded silty shale and
siltstone . Bedding offset
vertically (less than one •
inch) in lower two feet.
196-202 6 Lithic wacke, massive .
202-206 4 Medium- to fine-grained .
• basaltic rock, vesicular in
middle of interval with
abundant pyrite crystals •in
both basalt and vesicles .
206-217 11 Rhythmically-bedded tuffaceous
and silty shales with silt-
stone interbeds .
217-222 5 Wax-like bentonitized tuff,
upper two feet aphanitic,
lower three feet characterized
by irregular bands of coarse-
grained tuff in aphanitic
tuff matrix.
239
410
Depth Interval Thickness Description
(Feet) (Feet)
222-256 34 Rhythmically-bedded tuffaceous
and silty shale with inter-
beds of tuff and siltstone .
Upper nine feet exhibits
fractures cemented with calcite
and minor offset of bedding
possibly due to post-lith-
ification slumping.
Borehole P.V.P. No. 8 Surface Elevation 356 feet
Depth Interval Thickness Description_
(Feet) (FOet)
0-205 205 Inactive landslide, rubble .
411 Angular fragments of diatoma-
ceous, cherty, siliceous,
silty and tuffaceous shales,
with a few larger limestone
blocks, in a clay-rich matrix.
Matrix of upper 121 feet is
dark, granular soil-like
material (fissure-fill ? ) .
205 , - Inactive failure surface
205-208 3 Moderately-granular benton-
itized tuff, very waxy .texture .
208-216 8 Rhythmically-bedded tuffaceous
and silty shales with interbeds
of granular tuff and siltstone .
216-279 63 Bentonitized Portuguese Tuff,
411
exhibiting a gross increase
in grain size with increase
240
Depth Interval Thickness Description
111
(Feet) (Feet)
• 216-279 (continued) in depth. Irregular, silty-
rich lenses, less than two
inches thick, in upper six
feet.
279-293 14 Interbedded tuffaceous shale
and wax-like, bentonitized tuff,
with two thin siltstone Sayers
near base .
1
293-301
8 Hard, granular devitrified
tuff, with two fractured,
wedge-like prisms of silt-
stone between 297-298 feet.
1 301-312 11 Rhythmically-bedded tuffaceous
shale with a few interbeds
-of siltstone and �ni._r^ ,�
g_ ar
bentonitized tuff.
312-322 10 Massive, medium-grained
o a_ned
calcareous subfeldspathic
lithic wacke . Hardness
increases with depth.
322-33 13 Coarse- to medium-grained
basaltic rock with abundant
microcrystalline pyrite .
335-338
3 Rhythmically-bedded silty
shale .
• 411241
411
Borehole P.V.P. No . 9 Surface Elevation 353 feet
Depth Interval Thickness Description
(Feet) (Feet) -
0 -127_ 127 Active landslide, rubble .
Angular fragments of tuffaceous
and silty shale and siltstone
in a clay-rich matrix. •
Weathered fragments of
Portuguese Tuff in upper 50
feet of hole . Inactive failure
surfaces at 54 feet, 66 feet,
69 feet and 105 feet. -
127 - Active failure -surface .
127-160 33 Rhythmically-bedded shale,
largely silty, but several
111 tuff-rich layers .
160-219 59 Portuguese Tuff, with a
distinct wax-like texture .
Grain size increases with
depth.
219-225 6 Rhythmically-bedded layers
of alternating silty and
tuffaceous shale, with a.
waxy, tuff interbed from
223 to 224 feet .
Borehole P.V.P. No . 10 Surface Elevation 658 feet
Depth Interval Thickness Description
(Feet) (Feet)
411 0 - 1 .5 1 .5 Artificial fill .
1 .5-52 50.5 Portuguese Tuff (upper part
0{
of unit eroded) . Upper 30
242
Depth Interval Thickness Description
411
(Feet) (Feet) •
1 .5-52 (continued) feet badly to moderately
weathered, lower 20 feet
granular with a distinct
waxy texture .
52-58 6 Sandy to silty shale with
•
thin tuff layer at 57 feet.
58-76 18 Massive lithic wacke .
- 76-125 '
76-125 49 • Rh thmicalltuffaceous
Rhythmically-bedded
shale with interbeds of
siltstone and silty shale .
125-138 13 • Soft, wax-like clay material
with numerous deformed,
randomly-oriented bands of
•
granular tuff (post-
lithification slumping ? ) .
138-217 79 Rhythmically-bedded tuffaceous
and silty shale with a few
thin, wax-like tuff interbeds .
217-242 25 Medium-grained basaltic rock,
upper five feet vesicular.
Vesicles filled by gypsum,
calcite and Pyrite . Calcite-
filled fractures and dissem-
inated, fine-grained pyrite
common to lower 20 feet .
242-276 34 Rhythmically-bedded shale,
largely tuffaceous, but
locally silty. A few thin
waxy tuff layers .
•
243
411
Borehole P.V.P . No. 11
Surir Elevation_evation 23 feet
Depth Interval Thickness Description
(Feet) (Feet)
0 12 12 Active landslide, no core
recovered. •
12 - 28 16 Active landslide, largely
sheared and crushed, var-
iegated orange and gray -
bentonitic tuff, with minbr
shale fragments .
28 - 33 5 Active landslide, beach__ •
deposit of sand, shells and
rounded cobbles .
33 - Active failure surface .
4111- 33 - 34 1 Silty shale .
34 - 89 55 Portuguese Tuff, soft, with a
distinct wax-like texture.
Grain size increases with
depth.
89 -119 30 Rhythmically-bedded shale,
largely tuffaceous, but
locally silty. Numerous waxy
tuff interbeds, ranging in
thickness from less than one
inch to three feet .
119-123 L Tuffaceous lithic wacke .
123-134 11 Medium-grained basaltic rock
with abundant disseminated
pyrite and a few calcite-
filled fractures . Basal three
411 • feet has been altered to
• cherty texture .
244
Depth Interval Thickness Description
-. (Feet) (Feet) 411
134-141 7 Brecciated zone of
silicified shale fragments
cemented by chert-like
silica.
141-142 1 Silicifiedr tuff.
g_ anular .
142-1431 Very hard siltstone .
•
Borehole P.V.P . No . 12 Surface Elevation 21 feet .
Depth Interval Thickness Description '_.
(Feet) (Feet)..
•
0 - 10 10 Active landslide, no core
•
recovered.
10 - 55 45 Active landslide, rubble .
IIIAbove depth of 42 feet,
fragments consist of
•
•
weathered cherty and diatoma-
ceous shale . Below 42 feet,
rock fragments consist of
less-weathered silty and
- tuffaceous shale . Clay-rich
matrix throughout interval .
55 - Active failure surface .
55 - 66 11 Portuguese Tuff, lower part
of section. Granular, with a
wax-like texture .
66 - 69 3 Very clayey, sheared zone,
apparently an extremely
bentonitized aphanitic tuff.
•
•
245
•
Ilk
Depth Interval Thickness ss Description
(Feet) (Feet) •
69 - 77 8 Rhythmically-bedded shale,
largely silty, locally
tuffaceous . A few thin
layers of waxy aphanitic
tuff.
77 — 81 4 Breccia of calcite fragments
in an argillaceous wacke •
matrix. '
81 - 83 2 Thin-bedded siltstone .
•
83 - 85 2 Medium- to coarse-grained
bertonitized tuff.
8j-11..3 58 Rhythmically-bedded shale,
• largely tuffaceous, locally
silty. Numerous waxy tuff
interbeds up to two feet in
thickness .
143-146 3 Tuff, aphanitic and benton-
•
itized in upper two feet.
Basal one foot hydrothermally
altered to a hard, but
vesicular rock.
146-147 1 Severely fractured, hard
siltstone . Fractures cemented
with chert-like silica.
147-152 5 Medium-grained basaltic rock,
vesicular in upper one foot .
152-174 22 Rhythmically-bedded shales,
tuffaceous and silty, with
411 several granular tuff inter-
beds .
nter-
beds .
246