disseminated charcoal

?

?

?

?

?

?

?

?

?

?

? ?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

 2tfm

 2tfm

2tfm

2tf

2tf

2tf

1df

2tf

2tf(?)

 2tfa

 2tfa

 2tfm

 2tfm

 2tfm

2tf

3gf

1df 1df

1df

3gf

3gf

3gf

3gf

3gf

3gf

2tf

3gf

 2tfa

2tf

2tf

2tf

2tf

2tf

 2tfm

2tf

2tf

 2tfm

 2tfm

 2tfm

 2tfa

 2tfa

 2tfa

 2tfa

 2tfm

OSL-LLS1

15,910 ± 1,060 yr

R-LLS3

4,150–3,980 cal. yr B.P.

R-LLS4

3,370–3,240 cal. yr B.P.

R-LLS5

3,320–3,080 cal. yr B.P.

R-LLS7

3,350–3,180 cal. yr B.P.

R-LLS9-1

310–280 cal. yr B.P. (73%)

170–150 cal. yr B.P. (25%)

R-LLS1

680–560 cal. yr B.P.

R-LLS6

910–760 cal. yr B.P.

R-LLS9-2

500–430 cal. yr B.P. (63%)

380–320 cal. yr B.P. (36%)

R-LLS9-3

510–430 cal. yr B.P. (79%)

360–330 cal. yr B.P. (20%)

R-LLS2

900–690 cal. yr B.P.

S8

EAST

WEST

3

4

3 4

5

7

6

5

6

8 9

10

9

7

8

10

2

1

2

1

11

12

11

12

13 

14

15

13 

14 15

3 3

DESCRIPTION OF TRENCH UNITS

Depression-fill deposits (earthquake event 2 evidence)—Poorly stratified silt loam 

with coarse sand and scattered gravel; charcoal rich

Trough-fill sediment sequence, undifferentiated (earthquake event 3 

evidence)—Includes mass-wasting (2tfm) and alluvial (2tfa) deposits; facies 

vary vertically and laterally

Mass-wasting facies—Mainly gravelly to very gravelly coarse sandy loam; 

massive, poorly sorted and matrix supported

Alluvial facies—Mainly gravelly to very gravelly coarse sandy loam; moderately 

stratified, moderately sorted and clast supported

Glaciofluvial deposits (late Pleistocene Pinedale glaciation)—Folded and 

extensively sheared; sandy loam with red, clayier interbeds underlying poorly 

stratified coarse sandy loam and overlying poorly stratified, moderately sorted, 

very gravelly sandy loam (at base of trench)

EXPLANATION OF TRENCH SYMBOLS

Krotovina—Queried where uncertain

Contact—Solid where accurately located, dashed where approximately located, 

queried where uncertain

Internal contact—Accurately located

Internal contact—Approximately located, queried where uncertain

Soil horizon boundary

Top of buried O horizon (organic mat)

Base of A horizon developed in underlying unit—Locally also forms the base of 

buried O horizon (at meter 5–6)

Fault—Solid where accurately located, dashed where approximately located, queried 

where uncertain. Arrows indicate direction of relative movement

Fissure boundary

Dated sample—All ages are 2-sigma ranges rounded to nearest decade; radiocarbon 

calibration from Stuiver and others (2017). Probabilities are shown for 

multimodal ranges from calibration of radiocarbon ages

Radiocarbon-dated charcoal sample with calibrated age—Sample number and 

age shown

Undated charcoal sample—Sample number shown

Radiocarbon-dated pine tree litter with calibrated age—Sample number and 

age shown

Sediment sample with optically stimulated luminescence (OSL) age—Sample 

number and age shown 

String grid placed during trenching

Grid-node tag placed during trenching

Trench grid—Horizontal and vertical distances denoted in meters (arbitrary 

reference frame). Interval is 1 meter

1df

2tf

2tfm

2tfa

3gf

4

Photograph of the view to the 

south of an area where sediment 

has ponded against the 

uphill-facing antithetic scarp (the 

topographic bench). Person is 

standing approximately at the 

location selected for the Lily Lake 

south trench.

1df

2tf(?)

1df

3gf

 2tfa

 2tf

 2tfm

 2tfm

 2tf

 2tf

 2tfm

 2tfm

 2tfa

 2tfa

 2tf

3gf

?

1df

2tf

2tfm

2tfa

3gf

Depression-fill deposits

Trough-fill sediment sequence, undifferentiated

Alluvial facies

Mass-wasting facies

Glaciofluvial deposits

EXPLANATION

Outline of large clasts

Contact—Solid where accurately located, dashed 

 where approximately located

Fault—Solid where accurately located, dashed 

 where approximately located

Internal contact—Accurately located

Base of soil A horizon

Internal contact—Approximately located

2 3 4 5 6 7 8 9 10

2

1

3

4

2

1

3

4

EAST WEST

 Simplified log of the south wall of Lily Lake south trench colored to emphasize folding and faulting.

Meters

15

Meters

11 12 13 

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

1df 3gf

 2tf

 2tf

 2tf

 2tfa

2tfm

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42

2,716

2,714

2,712

2,710

2,708

2,718

2,720

2,716

2,714

2,712

2,710

2,708

2,718

2,720

?

?

?

~6.5 m

EAST WEST

Distance, in meters (m)

Elevation, in meters (m)

0

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42

Topographic profile across the fold scarp 

(expressed as a bench) at the Lily Lake south 

trench (extracted from 0.25-m digital elevation 

model). The profile is shown in relation to the 

top of glaciofluvial deposits (3gf) observed in 

the trench and inferred beyond the trench 

(short-dashed line that merges with ground 

surface). Faulting observed in the trench 

accounts for ~1 m of the ~6.5 m of vertical 

separation estimated by projecting the 

far-field hillslopes; the remaining separation is 

accomodated by folding. Vertical throw is 

uncertain but is less than the vertical 

Ground surface separation across the fold scarp.

2tfm

2tfa Alluvial facies

Mass-wasting facies

1df

2tf

3gf

Depression-fill deposits

Trough-fill sediment sequence, undifferentiated

Glaciofluvial deposits

Contact—Solid where accurately located, dashed 

where approximately located

EXPLANATION

Fault—Solid where accurately located, dashed 

where approximately located

? Inferred top of glaciofluvial deposits

Light detection and ranging (lidar) 

shaded-relief orthoimage (with 

southeast illumination; south is to 

the top) showing location of the 

Lily Lake north (lat 40°52.857' N., long 

110°48.731' W.; not logged) and 

Lily Lake south (lat 40°52.837' N., long 

110°48.731' W.) trenches across the 

antithetic, east-facing fold scarp 

in Utah. See figure 1 of pamphlet 

for regional context. 

2724

2716

2712

2720

2716

2712

2708

2724

2720

2716

2708

2712

2716

2720

2724

2724

2728

2704

2700

Lily Lake north trench

Lily Lake south trench

Lily 

Lake

Base from 0.25-meter digital elevation model created 

from data provided by the U.S. Forest Service

CONTOUR INTERVAL 2 METERS

0 30 60 90 120 METERS

0 100 200 300 FEET

N

110°48'45"

40°52'45"

110°48'40"

40°52'55"

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3430

Sheet 2 of 3

Pamphlet accompanies map

1

U.S. Geological Survey

2

Utah Geological Survey

3

Istituto Nazionale di Geofisica e Vulcanologia

4

Michael W. West and Associates, Inc.

Lily Lake South Trench—South Wall Photomosaic and Site Geomorphology, Bear River Fault Zone, Utah

By 

Suzanne Hecker,1 Christopher B. DuRoss,2 David P. Schwartz,1 Francesca R. Cinti,3 Riccardo Civico,3 William R. Lund,2

Adam I. Hiscock,2 Michael W. West,4 Tarka Wilcox,4 and Alivia R. Stoller1

2019 

Editing and cartographic design by Monica Erdman

Manuscript approved for publication March 8, 2019

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not 

imply endorsement by the U.S. Government.

This map or plate is offered as an online-only, digital publication. Users should be aware that, because of 

differences in rendering processes and pixel resolution, some slight distortion of scale may occur when 

viewing it on a computer screen or when printing it on an electronic plotter, even when it is viewed or 

printed at its intended publication scale.

Digital files available at https://doi.org/10.3133/sim3430

Suggested citation: Hecker, S., DuRoss, C.B., Schwartz, D.P., Cinti, F.R., Civico, R., Lund, W.R., Hiscock, A.I., 

West, M.W., Wilcox, T., and Stoller, A.R., 2019, Stratigraphic and structural relations in trench exposures 

and geomorphology at the Big Burn, Lily Lake, and Lester Ranch sites, Bear River Fault Zone, Utah and 

Wyoming: U.S. Geological Survey Scientific Investigations Map 3430, 8 p., 3 sheets, 

https://doi.org/10.3133/sim3430.

ISSN 2329-132X (online)

https://doi.org/10.3133/sim3430