CARIBOU

WILDERNESS

LASSEN VOLCANIC NATIONAL PARK

AREA OF MAP Magee Volcano Hat Creek Basalt

Poison Lake chain

Latour

Volcanic

Center

Dittmar Volcanic Center

Yana Volcanic

Center

Maidu Volcanic Center

Caribou

Volcanic Field

Tuscan

Formation

Lake Almanor Graben

Clear Creek Fault

Hat Creek Fault

Hat Creek

Graben

Brokeoff

Volcano

Central Plateau

Lassen Volcanic Center

Battle Creek Fault

Thousand 

Lakes Valley (TH) Old Station (OS) Swains Hole (SW)

Viola (VI)

Manzanita 

Lake (MZ) West Prospect Peak (WP) Prospect Peak (PP)

Grays Peak (GP)

Lyonsville (LY) Mineral (MN) Stover Mountain (ST)

Reading Peak (RP) Mount Harkness (MH)

Chester (CH)

Red Cinder (RC)

Bogard Buttes (BB)

Poison Lake (PL)

Murken Bench (MB) Jellico (JL) Corders Reservoir (CR)

Lassen Peak (LP)

Harvey Mountain (HM) Champs Flat (CF)

Straylor Lake (SL) Bullard Lake (BL)

Westwood West (WW)

Canyondam (CD)

Westwood East (WE)

Greenville (GR)

Pine Creek Valley (PC) Antelope Mountain (AM)

Swain Mountain (SM) Pegleg Mountain (PM)

Miller Mountain (MM) Jacks Backbone (JB)

Hatchet Mountain Pass (HM) Burney Mountain West (BW) Burney Mountain East (BE)

Whitmore (WH)

Montgomery Creek (MC)

Finley Butte (FB)

Inwood (IN) Hagaman Gulch (HG)

Manton (MT)

Inskip Hill (IH)

DeWitt Peak (DW) Panther Spring (PS) Barkley Mountain (BK) Onion Butte (OB)

Shingletown (SH)

Childs Meadows (CM)

Humboldt Peak (HP) Humbug Valley (HV) Almanor (AL)

VIOLA

MANTON

WESTWOOD

CHESTER

MINERAL

OLD 

STATION

MILL

CREEK

Rock Creek

Manzanita

Lake

Bailey Creek

Manzanita Creek

Onion Creek

Huckleberry Lake

Mill Creek

Juniper

Lake

Lake

Almanor

Mountain

Meadows

Reservoir

Echo

Lake

Silver

Lake

Warner Creek

Digger Creek

Lost Creek

Hat Creek

Hat Creek

Hat Creek

Hat Creek

upper Manzanita Creek

Butte

Lake

Cone

Lake

Butte Creek

Bidwell

Spring

Poison

Lake

Gem Lake

Eleanor Lake

Jewel Lake

Turnaround

Lake

Triangle Lake

East

Island Lake

Lake

Glen

Lake Beauty

Lake Hidden

Lakes

Long

Lake Posey

Lake

Bailey Creek

Snag

Lake

Evelyn

Lake

North Emerald Lake

& South 

Divide Lakes

Rim

Lake

Rock Creek

Domingo North Fork Feather River Spring

Rice Creek

Growler

Hot Spring

Buzzard

Springs

Wilson

Lake

Devils Kitchen Hot Springs Creek

Kings Creek

Nanny Creek

Martin Creek

South Fork Battle Creek 

Judd Creek 

Cabin

 Spring

Rock

Spring

Bailey Creek

North Fork Battle Creek

Big Lake

Mud 

Lake

Robbers

Spring

Pine Creek

Jakey

Lake

Widow

Lake

Bumpass Hell

Forest

Lake

Bench

Lake

Boiling

Springs

Lake

Kings

Creek

Falls

Summit Creek

Bathtub 

Lake

Cowboy

Lake

Feather

Lake

Lost

Spring

Duck

Lake

Onion

Springs

North

Battle

Creek

Reservoir

Dry

Lake

Cold

Boiling

Lake

Canyon Creek

Hidden

Lake

Terrace

Lake

Lost Creek

Lost Creek

Big Spring

Horseshoe

Lake

McCumber

Reservoir

Canyon Creek

Digger Creek

South Fork Digger Creek

North Fork Battle Creek

South Fork Bailey Creek

North Fork Bailey Creek

Panther Creek

Susan River

West

Sulphur

Creek

East S

ulphur

C re

ek

Mill Creek

Panther Creek

Willow Creek

Drakesbad Sulphur Works

B

enner Creek

Gurnsey Creek

Cluster

Lakes

Twin

Lakes

Deer

Creek

Badger Mountain

West 

Prospect Peak

Prospect

Peak

Cinder

Cone

Fantastic Lava Beds

Potato 

Butte

Little

Potato Butte

hill

4709

Box Canyon

Sugarloaf Peak

Hat Creek Rim

Wilcox

Peak

Bear Wallow

Butte

Devils Rock

Garden

Logan 

Mountain

Freaner

Peak

Tumble

Buttes

Ashpan

Butte

Huckleberry

Mountain

Deep

Hole

Deer

Flat

Hat

Mountain

Lassen

Peak

Raker

Peak

Table Mountain

Sunflower

Flat

Chaos

Crags

Survivors

Hill

Chaos Jumbles

Eskimo

Hill

Camp

Forward

Red Rock

Mountain

Hootman 

Ranch

Grays

Peak

Mount

Conard

Brokeoff

Mountain

Loomis

Peak

Eagle 

Peak

Mount

Diller

Bluff Falls

quarry

Morgan

Mountain

Christie

Hill

Doe Wild Cattle Mountain Mountain

Blue Ridge

Fairfield

Peak

Crater

Butte

Pilot

Mountain

Grassy Swale

Saddle Mountain

Mount

Harkness

Mount

Hoffman

Cameron

Meadow

North

Caribou

middle

Caribou

South

Caribou

Mud Creek Rim

Flatiron Ridge

Kings Creek

Meadows

Sifford

Mountain Kelly Mountain

Warner Valley

Reading Peak

Bogard

Buttes Bogard

Buttes

Ranger

Station

Campbell

Mountain

Pegleg

Mountain

Goodrich

Mountain

Star 

Butte

Swain

Mountain

Red 

Cinder

Badger Flat

Twin 

Buttes

Black

Butte

Grays

Valley

Pine Creek Valley

Red

Mountain

Red Lake

Mountain

Grayback Ridge

Crescent

Crater

Manzanita Chute

Sunrise

Peak

Ash

Butte

Signal

Butte

Cal 

Mountain

Blacks Mountain

Cone

Mountain

Harvey

Mountain

Poison

Butte

Crater Lake

Mountain

hill

2109

Black

Cinder

Rock

Bonte

Peak

Bond Valley

Heckle

Ranch

Red 

Cinder

Cone

Ice Cave

Mountain

North Stover Mountain

Stover Mountain

Little

Round

Valley

Cowslip Campground

Cold Creek

Butte

Hampton Butte

Lassen

Lodge

Rocky

Peak

Digger 

Butte

hill

4110

Inskip 

Hill

Volta

powerhouse

Eagle Canyon

Cherry Thicket

Latour

Butte

Buck

Butte

hill

6138

hill

6770

section 5

hill

5410

Hat Creek

Hill

Butte Creek Rim

Butte Creek

Ranch

Parhams 

Point

hill

5885

hill

7416

Swains

Hole

Butte Creek

Campground

section

36Pole Spring road

hill

1879

section

30

hill

2232

old railroad grade

Calif. Hwy 44

hill

1868

hill

1942

hill

1974

hill

hill 2001

1921

hill

1925 hill

1919

hill

1882

hill

1784

hill

1791

hill

1816

Stephens Campground

section

 11

Caribou

Peak

section 16

hill

2283 hill

2213

hill

8030

hill

7602 hill

7741

hill

7603

section

25

section

 22

Small

Butte

Bumpass

Mountain

Mount

Helen

Lassen Peak 

parking lot

Ski Heil Peak

Diamond

Peak

Mill Creek Plateau

Deer Creek Meadows

Meadows

Soldier

hill 8283

Vulcans

 Castle

section 27

Krummholz

Lost Creek Plateau

Painted

Dunes

 hill

7243

hill

2078

hill

2096

hill

2091

hill

2088

hill

2106

hill

2023

hill

2008

hill

1986

hill

2060

hill

2023

hill

2092

hill

2146

hill

7114

hill

7143

hill

7346

section

 19

Manzanita

Mountain

section 20

Nobles Trail

Emigrant Ford

hill

6122

hill

6051

Little

Logan

Butte

hill

6924

hill

8198

hill

6869

Mill Canyon

Pilot

Pinnacle

Crescent

Cliff

Hazen

Flat

hill

6964

Turner

Mountain

hill

7139

Bunchgrass Valley

Little 

Bunchgrass

Meadow

Glassburner

Meadows

Spencer

Meadow

Battle Creek

Meadows

Mineral

Summit

Feather River

Meadows

Dyer Mountain

Little Dyer

Mountain

Meadows

Anklin

Indian Meadow

Childs

Meadows

Twin

Meadows

Dersch

Meadows

Emigrant Pass

Paradise

Meadows

Hay 

Meadow

Little Hot

Springs Valley

Twin

Bridges

Cone Lake road

Blue Lake Canyon

Devastated

 Area

Forwards Mill Road

Plantation Gulch

Pittville Road

0 5 10 KILOMETERS

0 5 10 MILES

121°45'

40°20'

40°40'

121°37.5'

40°20'

121°7.5'

121°7.5'

40°40'

40°22’30”

40°15’

40°30’

40°37’30”

40°45’

40°22’30”

40°15’

40°30’

40°37’30”

40°45’

121°52’30” 121°45’ 121°37’30” 121°30’ 121°22’30” 121°15’ 121°07’30” 121°00’

121°52’30” 121°45’ 121°37’30” 121°30’ 121°22’30” 121°15’ 121°07’30” 121°00’

Figure 2. Map showing areas of published geologic mapping, Lassen Volcanic National Park and vicinity, California. The topographic base for the geologic 

map (sheet 1) was created by mosaicking pertinent 1:24,000 U.S. Geological Survey quadrangles into a single file which was then reduced to the 1:50,000 

map scale. The geologic and topographic databases for the map area are presented as individual quadrangles at 1:24,000 in the accompanying CD-ROM 

(Muffler and others, 2010) and are available online (http://pubs.usgs.gov/sim/2899/).

Figure 4. A. Generalized geologic map of Lassen Volcanic National Park and vicinity (sheet 1) and additional unpublished geologic mapping in surrounding areas to the east, west, and south. The figure was created by importing the ArcInfo digital database (of which the geologic map, sheet 1, is a 

part) into Adobe Illustrator and then generalizing the more than 500 map units in the database into 11 major geologic entities. Emphasized are the location, extent, and ages of five large volcanic centers and Caribou Volcanic Field. Light blue areas are lakes. B. Generalized geologic map of 

Lassen Volcanic National Park and vicinity, California, adapted from part of figure 4A and emphasizing regional volcanic rocks, both calc-alkaline and tholeiitic. On figure 4A, regional calc-alkaline volcanic rocks shown as two units. On figure 4B, these are divided into five age groups (from 

youngest to oldest, a–e) with age boundaries at 125, 450, 788, and 1,810 ka. Prominent regional calc-alkaline edifices, chains, and flows are labeled. Light blue areas are lakes. C. Generalized geologic map of Lassen Volcanic National Park and vicinity, California, adapted from figure 4A. The 

major geologic entities of Lassen Volcanic Center are discriminated, and the location, extent, and stratigraphy of the Lassen Volcanic Center are emphasized by muting the colors of all other units. Figure based on geologic map (sheet 1). Light blue areas are lakes.

Figure 5. Map showing regional tectonic setting of area from Sacramento Valley to California-Nevada border, including Lassen Volcanic 

National Park and vicinity, California (modified and updated from Guffanti and others, 1990). Light-yellow background indicates volcanic 

rocks of late Tertiary to Holocene age, including both the Cascade Arc and Basin and Range volcanism. Orange dots indicate the location of 

volcanic vents younger than about 7 Ma (older vents not shown). The large majority of vents are regional calc-alkaline volcanoes. Thin violet 

lines show the location of faults. Dashed red lines show the approximate position of the arc axis at the times indicated, and dashed black lines 

indicate the approximate southern terminus of arc volcanism at the times indicated. About 12 Ma, the axis of the Lassen segment was near the 

California-Nevada border. Since then, the arc axis has migrated westward to its present position. Simultaneously, the width of the arc 

narrowed (Guffanti and others, 1990). Thick blue lines indicate the estimated present-day depth to the subducted Gorda Plate. C, Caribou 

Volcanic Field; D, Dittmar Volcanic Center; Ln, Lassen Volcanic Center; Lt, Latour Volcanic Center; M, Maidu Volcanic Center; S, Snow 

Mountain Volcanic Center; Y, Yana Volcanic Center. Green background indicates Paleozoic to Mesozoic metamorphic-plutonic basement of 

the Sierra Nevada and Klamath Provinces (small outliers of volcanic rocks not shown). Figure 6. Generalized geologic map showing the location and extent of volcanic sequences 

and chains in the Caribou Volcanic Field. See figure 4A for location of Caribou Volcanic 

Field relative to Lassen Volcanic National Park. Figure based on geologic map (sheet 1) and 

additional unpublished geologic mapping to the east. Light blue areas are lakes.

Figure 1. Map of northeastern California showing locations of geologic map area and Lassen Volcanic National 

Park, California (adapted from Christiansen and others, 2002). 

Figure 3. Shaded relief map derived from digital elevation model of the Lassen Volcanic National Park and vicinity, California, and the surrounding area, showing geographic and geologic locations discussed in the pamphlet. Quadrangle names are followed by two-letter abbreviations (in parentheses), which 

are noted in the Description of Map Units and table 3 to indicate the quadrangle(s) and the database(s) where a given geologic unit is mapped. Color-coded labels: red, large volcanic and geologic features; black, geographic features (mountains, towns, hills, and sections used in unit names); blue, water 

features (lakes, creeks, springs). Note that similarly named features are found in different quadrangles.

Honey

Lake

Goose

Lake Upper

Alkali

Lake

Middle

Alkali

Lake

Lower

Alkali

Lake

Tule

Lake

Clear Lake

Reservoir

Eagle

Lake

Lake

Almanor

Shasta Lake

Pine Creek

Susan River

Sacramento River

Pit

Middle Fork

Pit River

Battle Creek

Butte Creek

Mill Creek

Deer Creek

North Fork

e

Butte Cr ek

Hat Creek

rehtaeF

reviR

River

McCloud

River

Sacramento River

Willow Creek

Caribou

Wilderness

Lassen Volcanic National Park

5 

5 

ETTUB

YTNUOC

L A S S E N

COUNT Y

MODO C

COUNT Y

PLUMA S

COUNT Y

SHAS TA

COUN T Y

SISKI Y O U

COUNT Y

T E HAM A

COUNT Y

139 

139 

299 

299 

299 

299 

32 

36 

36 36 

44 

44 

89 70 

89 

89 

89 

89 

99 

97 395 

395 

395 

A21 

17 

AREA OF MAP 

122° 121° 120°

42° 

41° 

40° 

OREGON

CALIFORNIA

ADAVEN

AINROFILAC

EDACSAC

EGNAR

Redding

Weed

Alturas

Burney

Corning

Mount Shasta

Quincy

Westwood

Anderson

Red Bluff

Susanville

Chester

Greenville

Shingletown

Manton

Viola

Mineral

Old Station

Fall River Mills

Tulelake

0 SRETEMOLIK 05

0 30 MILES 

Cassel 

11 Williams (1932)

11

10 Wilson (1961)

10

 3 Lerch (1987)

3

 4 Clynne (1984)

4

 6 Muffler and others (1982a)

6

 1 Christiansen and others (2002)

1

 2 Borg (1989)

2

7

 7 Macdonald (1965)

Macdonald (1964)

8

 8

Macdonald (1963)

9

 9

 5 Till and others (1983)

5

Lassen Volcanic

National Park

AREA OF MAP

JACKS BACKBONE

THOUSAND LAKESVALLEY

OLD STATION

SWAINS HOLE

POISON LAKE

VIOLA

MANZANITA LAKE

WEST PROSPECT PEAK

PROSPECT PEAK

BOGARD BUTTES

GRAYS PEAK

LASSEN PEAK

READING PEAK

MOUNT HARKNESS

RED CINDER

LYONSVILLE

MINERAL

CHILDS MEADOW

STOVER MOUNTAIN

CHESTER

HARVEY MOUNTAIN

PINE CREEK VALLEY

SWAIN MOUNTAIN

WESTWOOD WEST

121° 45' 121° 30' 121° 15' 121° 00'

40° 30'

40° 45'

40° 15'

EXPLANATION

3.5

Age

(Ma)

0.5

1.0

1.5

2.0

2.5

3.0

0

Tuscan

Formation

Glacial and 

sedimentary

deposits

Maidu

Volcanic

Center

Dittmar

Volcanic

Center

Yana

Volcanic

Center

Latour

Volcanic

Center

Lassen

Volcanic

Center

Caribou

Volcanic

Field

0.1

0.2

0.3

0.4

0.5

0

Age

(Ma)

Figure 4C

Eagle Peak

sequence

0.6

0.7

0.8

Mill Canyon

sequence

Rockland 

stage

Lassen 

stage

Brokeoff 

Volcano

Mt. Diller

sequence

Twin Lakes

sequence

younger

older

Bumpass

sequence

e

d

c

b

a

Figure 4A Figure 4B

Regional calc-alkaline

volcanic rocks

Regional

low-K

oliviine

tholeiites

Volcanic Centers

EXPLANATION

(Figures 4A, 4B, 4C)

121°45'

40°20'

AREA OF MAP

40°30'

122°00'

121°37.5' 121°00'

40°00'

40°40'

121°7.5'

Pre-Tertiary Rocks

Tuscan Formation

Maidu Volcanic Center

Lassen Volcanic Center

Latour Volcanic Center

Yana Volcanic Center

Dittmar Volcanic Center

Caribou

Volcanic

Field

Lake

Almanor

Lassen Volcanic National Park

0

0 10 MILES

20 KILOMETERS

4A

Lassen Peak

Lassen Volcanic National Park

40°20'

121°37.5' 121°7.5'

40°40'

0

0 5 MILES

10 KILOMETERS

AREA OF FIGURE 6

4C

Lassen Volcanic

National Park

Red Lake 

Mountain

Bogard

Buttes

West

Prospect 

Peak

 Table

Mountain

Hootman

 Ranch

Badger

Mountain Prospect 

Peak

Sifford 

Mountain

Mount

Harkness

Cal Mtn.

Poison Lake chain

Mud Creek Rim

Hat Creek Rim

Red Cinder Caribou chain

 chain

Bidwell 

 Spring

 chain

Sugarloaf

 chain Tumble 

 Buttes

 chain

Grays

Peak

Huckleberry

 Lake

40°20'

121°37.5' 121°7.5'

40°40'

0

0 5 MILES

10 KILOMETERS

4B

Lassen

Volcanic

National

Park

90 km

130 km

Honey Lake

Eagle Lake

Lake Almanor 

BASIN AND RANGE

SIERRA

NEVADA

KLAMATH

MTNS

AREA OF MAP

41°

0 50 KILOMETERS

0 30 MILES

122° 121° 120°

40°

0 Ma

3 Ma

S

D

Y

M

Ln

C

Lt

CALIFORNIA –NEVADA STATE BOUNDARY

10–12 Ma

Cascade Arc at 0 Ma

3 Ma

Hat Creek Graben

Lake Almanor Graben

Walker Lane

SACRAMENTO VALLEY

Lassen

Volcanic

National

Park

Poison

Lake

chain

Red

Cinder

chain

Sunrise

Peak

sequence

Bidwell

Spring

chain Cone

Lake

chain

Beauty

Lake

sequence

Island

Lake

sequence

Caribou

sequence

Triangle

Lake

sequence

Echo

Lake

sequence

0

0 5 MILES

10 KILOMETERS

40°40'

121°22.5' 121°5'

40°22.5'

Tuya

chains

EASTERN BOUNDARY OF MAP AREA

unit

bb12

Poison Lake chain

Bogard Buttes

hill

2298

Red

Cinder

hill

7711

Lassen

Peak

Black

Butte

Twin Buttes

(south cone)

Prospect

Peak West

Prospect

Peak

Bidwell Spring chain

Cone Lake

chain

hill North 8030 Caribou

South

Caribou

hill

7643

hill

7143 hill

6760

Star

Butte Swain

Mountain

Red Cinder chain

Caribou chain Echo Lake sequence

hill

2232

Feather Lake

Caribou Volcanic Field

Panorama looking west from the west flank of Campbell Mountain, 1⁄2 mile southwest 

of the summit (Antelope Mountain quadrangle). Visible on the skyline are vents for 

six sequences/chains of the Caribou Volcanic Field. At the left is the Echo Lake 

sequence, represented by Star Butte (basaltic andesite of Star Butte, unit mes, ~300 

ka) and hill 6760 (basaltic andesites of Echo Lake, unit mee1, 302±36 ka). To the 

immediate right is the Caribou sequence, represented by hill 7143 (basaltic andesite of 

Hay Meadow, unit mch, 375–400 ka), South Caribou (basalt of South Caribou, unit 

bcs, ~350 ka), hill 7643 (basaltic andesite of middle Caribou, unit mcm, 362±33 ka), 

and North Caribou (basaltic andesites of North Caribou, with unit mcn5 at the 

summit, ~350 ka). In the center is the Red Cinder chain, represented by hill 8030 

(basalt of hill 8030, unit br80, 25–40 ka), Red Cinder (basaltic andesite of Red Cinder, 

unit mrr, 25–40 ka)—at 2,553 m the highest elevation in the eastern part of the map 

area (Sheet 1)—and hill 7711 (basalt of section 25, unit br25, 40–70 ka). To the right 

of center is the Bidwell Spring chain, represented by the cinder cone of Black Butte 

(basaltic andesites of Black Butte, unit mdb2, 50–70 ka) and the south cone of Twin 

Buttes (basalt of Twin Buttes, unit bdt, 46.3±3.4 ka). The north cone of Twin Buttes is 

hidden by the basalt of hill 2232 (unit bl22, 220±14 ka, part of the Cone Lake chain). 

At the far right is the Poison Lake chain (100–110 ka), with the basalts and basaltic 

andesites of Bogard Buttes (unit 12) at the furthest right. The Caribou Volcanic Field 

left of the Red Cinder chain (center skyline) is highly modified by glaciation, whereas 

the terrain to the right is unglaciated and displays original constructional forms. Just 

barely visible in the distance behind the Poison Lake chain and Twin Buttes are 

Prospect Peak (unit ap, 247±56 ka) and West Prospect Peak (unit awp, 300–400 ka), 

both regional calc-alkaline volcanoes. The prominent, snow-covered peak in the far 

distance is Lassen Peak (unit dl, 27±1 ka), part of the Eagle Peak sequence of the 

Lassen domefield. At the far left of the panorama is Swain Mountain, a basaltic 

andesite regional calc-alkaline shield volcano (unit msw, 1,570±35 ka). At the far 

right of the panorama are Bogard Buttes, the bulk of which (including hill 2298) is the 

dacite of Bogard Buttes (unit Tdb, ~2,300 ka). 

Photographs by Patrick Muffler.

Eagle

Peak

Lassen Peak

hydrothermal

alteration

Bumpass

Mountain

Mt. Helen

Ski Heil Peak

May 19–20, 1915 flow

rhyodacite of

Kings Creek

dacite of Lassen Peak

parking lot

upper Little Hot Springs Valley

travertine

travertine

fumaroles, acid hot springs, and

mudpots in landslide deposits

andesite of Mount Diller andesite of Mount Diller

andesite of Mount Diller

andesites of Mill Canyon

andesites of Mill Canyon

andesites of Mill Canyon

East Sulphur Creek

Little Hot Springs Valley

View looking north from Calif. Hwy 89 on the west side of Little Hot Springs Valley (Lassen Peak quadrangle). Lassen Peak 

(unit dl, 27±1 ka), rhyodacite of Kings Creek (unit rk, 35±1 ka), and Eagle Peak (unit re, 66±4 ka) are part of the Eagle Peak 

sequence. Ski Heil Peak (unit ds, 244±10 ka), the dacite of Lassen Peak parking lot (unit dpl, 250–260 ka), Mount Helen (unit 

dh, 249±12 ka), and Bumpass Mountain (unit db, 232±8 ka) are domes of the Bumpass sequence; Ski Heil Peak is mantled by 

tephra from the eruption of Eagle Peak. The resistant andesite of Mount Diller (unit amd, 387±10 ka), part of the Diller 

sequence, marks the rim of the erosional amphitheater in Brokeoff Volcano. The underlying andesites of Mill Canyon (unit 

amc, 590–470 ka) consist of interbedded flows and breccias (many hydrothermally altered) and are highly eroded by glacial, 

fluvial, and landslide processes. Active thermal features include acid hot springs and mud pots and fumaroles that are concentrated in landslide deposits near East Sulphur Creek, as well as neutral to alkaline travertine-depositing hot springs higher in 

the valley. 

Photograph by Patrick Muffler.

rhyodacite flow of

Kings Creek

remnant of

May 19–20, 1915 flow

proximal Devastated Area

Lassen Peak

dacite of

hill 8283

moraine Survivors Hill

(moraine)

block from 

May 14–19 , 1915 dome

May 19–20, 1915 

avalanche deposits 

May 19–20, 1915 

debris-flow deposits 

lithic pyroclastic-flow deposit

from partial collapse of 

the dome of Lassen Peak

Devastated Area

Crescent Crater

Lassen Peak and the Devastated Area

View of Lassen Peak and the Devastated Area looking south from Emigrant Pass a few hundred meters north of the Devastated Area 

Parking Lot on Calif. Hwy 89 (West Prospect Peak quadrangle). Area with sparse trees marks the paths of the avalanche and debrisflow deposits of May 19–20, 1915 (unit sw9) and the pyroclastic-flow and fluid debris-flow deposits of May 22, 1915 (unit pw2; 

Clynne and others 1999; Christiansen and others, 2002). The 3-m block in the foreground is derived from the May 14-19 dacite dome 

(unit d4) at the summit of Lassen Peak and transported by the May 19–20 avalanche. Small dark crags just to right of the summit are 

remnants of the May 19–20, 1915 lava flow (unit d9). The composite dacite dome of Lassen Peak (unit dl, 27±1 ka) dominates the 

upper part of the view. Lithic pyroclastic-flow deposits (unit pfl) from partial collapse of the dome of Lassen Peak are exposed in the 

canyon of the headwaters of Lost Creek in center of view. Ridges flanking central area are glacial moraines (unit Qta), thinly 

covered by deposits of the 1915 eruption of Lassen Peak (Turrin and others, 1997; Christiansen and others, 2002). Cliffs on the left 

skyline are the rhyodacite lava flow of Kings Creek (unit rk, 35±1 ka), which erupted from a vent just south of Lassen Peak. The 

dacite dome of Crescent Crater (unit dc, 236±1 ka) dominates the right skyline, and the dacite dome of hill 8283 (unit d82, 261±5 ka) 

is barely visible at the extreme right skyline. 

Photograph by Michael A. Clynne.

rhyodacite flow

of Kings Creek

Reading

Peak Chaos Crags domes

B D E F

pumiceous pyroclastic-flow

and fall deposits

from Chaos Crags

Lassen Peak

remnant of 

May 19–20,1915 

dacite flow

Mount

Helen

Bumpass

Mountain Crescent

Crater

hill

Mount 8283

Conard

hill

6975

Fairfield

Peak

Hat

Mountain

Painted Dunes

Fantastic Lava Beds

Cinder Cone andesite flows

from Prospect Peak

andesite of

Raker Peak

Cinder Cone and Lassen Peak

View looking west-southwest from west flank of Sunrise Peak, just east of Butte Lake (Prospect Peak quadrangle). Skyline above 

timberline is the Lassen domefield. Reading Peak (unit dr, 212±5 ka), Bumpass Mountain (unit db, 232±8 ka), Mount Helen (unit dh, 

249±12 ka), Crescent Crater (unit dc, 236±1 ka) and hill 8283 (unit d82, 261±5 ka) are part of the Bumpass sequence. The rhyodacite 

flow of Kings Creek (unit rk, 35±1 ka), the composite dacite dome of Lassen Peak (unit dl, 27±1 ka) and the rhyodacite domes and 

pumiceous pyroclastic-flow and fall deposits of Chaos Crags (1,103±13 yr B.P.) are part of the Eagle Peak sequence. Fairfield Peak (unit 

mfp, 82±14 ka), Hat Mountain (unit ah, ~45 ka), and Cinder Cone (1666 C.E.) are vents for basaltic andesite and andesite flows of the 

younger Twin Lakes sequence. Visible flows from Cinder Cone include Painted Dunes (units mp1 and mp2) and Fantastic Lava Beds 

(units mf1 and mf2). Hill 6975 is the vent for the andesite and basaltic andesite of Cluster Lakes (unit acl, 250–300 ka), part of the older 

Twin Lakes sequence. The andesite of Raker Peak (unit ap, 270±18 ka) is also part of the older Twin Lakes sequence. Prospect Peak 

(unit ap, 247±56 ka) is a regional calc-alkaline andesite and basaltic andesite volcano. Mount Conard (unit amc, 590–470 ka) forms the 

southeast rim of the eroded amphitheater of Brokeoff Volcano. Specific camera location 0.33 mi at 272° from Sunrise Peak. 

Photograph by Patrick Muffler.

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.

For sale by U.S. Geological Survey, Information Services, Box 25286, 

Federal Center, Denver, CO, 80225, 1–888–ASK–USGS

Digital files available at http://pubs.usgs.gov/sim/2899/

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 2899

Sheet 3 of 3

Pamphlet and CD-ROM accompany map

Geologic Map of Lassen Volcanic National Park and Vicinity, California

By

Michael A. Clynne and L.J. Patrick Muffler

2010