21

22

20

19

21

22

20

19

0 1 2 3 4 5 6 7 8 9 10 11 12

0 1 2 3 4 5 6 7 8 9 10 11 12

West meters East

TRENCH N1 NORTH WALL

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

? ?

? ?

? ?

?

07N10

07N09 07N11

07N13

07N15

07N14

07N16

07N20

07N24

07N29

07N28

07N25

07N05

DISTURBED

ZONE

(BIOGENIC

OR TECTONIC?)

E4

E2

E3

E1

12 11 10 9 8 7 6 5 4 3 2

21

20

19

meters

22

21

20

19

22

12 11 10 9 8 7 6 5 4 3 2 1 0 -1

1 0 -1

07N30

07N27

07N23 07N17

07N18

07N16

07N19

07N12 07N06

07N07

07N31

(BULK)

07N08

07N04

07N01 07N02

07N03

07N21

07N22

07N26

1

5

3

7

9

POLLEN

SAMPLES

East West

E5+

E4

E2

E3

u100 E1

u110

u80

u90

u50

u60

u30

u30 u30

u60

u50

u40

u40

u30

u40

u20 u20 u20

u10

u30

u20

u10

u10

u30

u20 u30

u10

u10/20

u10

u40

u70

TRENCH N1 SOUTH WALL

k k

k

st

Plow Zone/ Historical A-Horizon (Top Soil)

br

u60/

u50

mixed

u30/40

mixed u50/60

sheared

&

fissured

u20

u40/30: At base, clay-rich silt

like u30, but color of u40

zone of

pervasive

sand-filled

cracks: roots

or tectonic?

zone of

pervasive

sand-filled

cracks: shrink-swell

or tectonic?

fissure fills or

 root zones?

?

?

?

?

?

?

?

Orange mottled silty

fine-medium sand

Dark gray brown sandy

silt (young soil)

Gray brown sandy silt

Orange mottled silty

very fine to fine sand

Orange pebbly sand

u90

u80

Orange mottled silty 

fine-medium sand u100

u70

u50

u40

u60

EXPLANATION

Gray sandy silt

Contact––Dashed, approximate;

 dotted, inferred

Fault––Dashed, approximate;

 dotted, inferred

Event horizon

Unit number

Krotovina––I nfilled burrow

Minor shear

Fissure or crack––Open or filled

 voids without distinguishable

 slip, possibly tectonic in origin

Radiocarbon sample location––

 Rectangle indicates bulk samples 

u80

00A21

E3

ABBREVIATIONS

k

br

bsc

cl

gc

gv

m

sd

st

rk

fault breccia

blocky scarp colluvium

clay

gray clay

gravel

medium

sand

silt

rock

!. !. !.

!.

!.

!.

!.

!.

!.

!.

!.

!.

100 50 0 100 Meters

Legend

Trench [2007-2009]

CPT 2004

Mason Rd

modern (post-1896) ditch

abandoned

channel segment

Borings [2007-2009]

20

21

22

23

19

18

24

25

26

27

16

28

17

29

15

30

19

24

17

16

25

22

23

30

24

21

17

21

19

23

19

25

24

30

30

25

15

17

15

29

22

23

23

22

26

21

18

28

22

22

24

27

23

24

19

25

22

15

Boring

SNC07

 (Sheet 5)

Boring

“stake 11”

2006 Pit

 (Sheet 4)

07S (Sheet 3)

1896 mapping of creek

Hennessey Cr

tluaF yellaV neerG

INSET MAP, trenches

 (sheets 1 & 2)

N1

N2

N3

N4

4 m04

U.S. Department of the Interior

U.S. Geological Survey 

This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters and

between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and

proportions may not be true on plots of this map.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1-888-ASK-USGS

Available on World Wide Web at http://pubs.usgs.gov/of/2012/1011/

Any use of trade, firm, or product names in this publication is for descriptive purposes only and does not imply endorsement by the U.S.

Government

Manuscript approved for publication January 13, 2012

1 0 1 2 3 4 5 6 7 FEET

1 .5 0 1 METER

Logs and Data from Trenches Across and Near the Green Valley Fault 

 at the Mason Road Site, Fairfield, Solano County, California, 2006-2009

By

James J. Lienkaemper, Robert R. Sickler, Shannon A. Mahan, Johnathan Brown, Liam M. Reidy, and Mindy A. Kimball

2012

Figure 1. Location of Mason Road site on Green Valley fault (yellow square indicates area shown in Figure 2 

below). Holocene faults (USGS & CGS, 2006), those active in past 11,000 years, shown in red.

Figure 2. Mason Road fault investigation site on Green Valley fault (fault, red dashes). The historical location 

Hennessey Creek transfered approximately from topographic mapping done in 1896, shown as dashed and dotted 

yellow line, suggests a large right-lateral stream offset along the fault. Cone penetration tests (CPT, magenta dots; 

Bennett and others, 2011) and 2006 pit (green oval) were done to examine geometry and relative ages of offset 

buried stream sediments. At borings (blue stars), we took continuous sediment samples (Bennett and others, 2011), 

including charcoal for radiocarbon dating. Trenches N1-N4 and 07S (yellow/black lines) showed evidence (in 

N1-N4) of multiple recent earthquakes. Topographic contours (in brown, in meters) from our detailed 2004 

mapping in areas where contours shown. Basemap, USGS color digital orthophoto quadrangles, October 2002.

Open-File Report 2012-1011

Sheet 1 of 5

Pamphlet accompanies map