This striking view to the southeast across the

summit of Cinder Cone shows the double-rimmed

crater at the top of the 700-foot-high volcanic cone

of loose scoria. The inset photo shows an aerial

view, looking to the northwest, of the cone and its

surrounding lava flows and ash deposits. Many

people were misled by the youthful appearance of

these volcanic features into believing “eyewitness

accounts” of eruptions here during the 1850’s.

U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet-023-00

2000

How Old is “Cinder Cone”?—Solving a Mystery in

Lassen Volcanic National Park, California

U.S. GEOLOGICAL SURVEY and the NATIONAL PARK SERVICE—OUR VOLCANIC PUBLIC LANDS

C

US SG

 inder Cone in Lassen Volcanic National Park is a

700-foot-high volcanic cone. Its

age has been controversial

since the 1870’s, when many

people thought it was only a few

decades old. Later, the cone and

associated lava flows were

thought to have formed about

A.D. 1700 or during a 300-yearlong series of eruptions ending

in 1851. However, recent studies

by U.S. Geological Survey

(USGS) scientists, working in

cooperation with the National

Park Service to better understand volcano hazards in the

Lassen area, have firmly established that Cinder Cone was

formed in eruptions about 1650.

After traveling through northern California

in the spring of 1851, two gold prospectors

reported seeing an erupting volcano that “threw

up fire to a terrible height.” They further

claimed that they walked 10 miles over rocks

so hot that their boots were entirely destroyed.

Their story is only one of several reports from

that time that were later assumed to describe an

eruption of “Cinder Cone,” a volcanic feature

located in what is now the northeast corner of

Lassen Volcanic National Park.

Cinder Cone is a 700-foot-high cone of

loose scoria. Scoria forms when blobs of gascharged lava are thrown into the air during an

eruption and cool in flight, falling as dark

volcanic rock containing cavities created by

trapped gas bubbles. The summit of Cinder

Cone has a crater with a double rim, probably

created by fluctuating eruptive activity late in

its formation. The cone also has several associated blocky lava flows, and a related, widespread ash deposit identifiable for 8 to 10

miles from the cone.

There are actually two scoria cones at Cinder

Cone—the remnants of a nearly completely

buried earlier cone can be seen on the larger

cone’s south side. Much of the earlier cone was

probably destroyed by lava flows erupting from

its base. Blocks of red, cemented scoria within

the Painted Dunes lava flows (see geologic

map) are pieces of this earlier cone, which

were carried away by the flowing lava.

Beginnings of a Controversy

The eruptions and volcanic history of Cinder Cone have been an ongoing controversy

for more than a century, in part because of the

starkly beautiful contrast between the very

new looking, unvegetated cone and lava flows

and the surrounding mature forest. In the early

1870’s, H.W. Harkness, a medical doctor and

observant amateur scientist from San Francisco, visited and described the Cinder Cone

area (Harkness, 1875). He was impressed by

the apparent youthfulness of the volcanic

features, and described a number of lines of

evidence that he interpreted to mean that

Cinder Cone was only about 25 years old.

After presenting his findings at a meeting of

the California Academy of Sciences, Harkness

was contacted by Henry Chapman, an Academy member, who told him of hearing the

gold prospectors tell their story. He was also

contacted by several others who claimed to

have witnessed a volcanic eruption in the

Lassen area around 1851, including a Dr. O.M.

Wozencraft. Harkness thought that all these

tales of volcanic activity might be related to an

eruption of Cinder Cone.

The circumstances surrounding these reports are somewhat obscure and inconsistent.

Several reports of “volcanic eruptions” in the

Lassen area had appeared in northern California newspapers in the 1850’s, but Harkness

was probably unaware of them. In the earliest

of these, published in the August 21, 1850,

edition of the Daily Pacific News, a San Fran-
The first geologist to study Cinder Cone was Joseph

S. Diller. He made many careful observations and

correctly concluded in his 1891 report that “Whatever may be the historical testimony as to the time

of the eruption, the geologic evidence clearly

demonstrates that it must have occurred long before

the beginning of the present century” (before 1800).

cisco newspaper, an unnamed observer reported seeing an erupting volcano with “burning lava still running down the sides.” In 1859,

the San Francisco Times printed an article in

which Dr. Wozencraft and a companion were

purported to have seen, from a position somewhere west of the Lassen area, flames in the

sky that they attributed to a volcanic eruption.

This article was widely reprinted and popularized in other papers, but no specific date or

location was given for their sighting. The

Shasta Republican noted on several occasions

in April 1859 that “the Dr.’s imagination is far

more active than any volcano in our County or

State.” It was in Harkness’ 1875 report that the

date of Wozencraft’s observation is first mentioned to be the winter of 1850–51.

Early Geologic Studies

The first geologist to study Cinder Cone was

Joseph Diller (Diller, 1891, 1893), who was

among the first U.S. Geological Survey

(USGS) scientists to study volcanoes. Diller

made careful observations of Cinder Cone and

interviewed many Native Americans and European trappers and settlers who were in the

Lassen region in 1850. None of them could

recall witnessing any volcanic activity in the

area. Diller knew that an “emigrant road” (the

Nobles Trail), used by settlers coming to California in the early 1850’s, passes close to the

base of Cinder Cone. He spoke with several

people who had “crossed the trail” in 1853.

They noted that a large, solitary willow bush

(Salix scouleriana) near the summit of Cinder

Cone was “as large then as now.” Today, more

than a century after Diller’s interviews, this

bush is still alive and little changed.

Because the “Scouler willow” at the summit

of Cinder Cone was already mature in 1853,

Diller concluded it was extremely unlikely

that an eruption could have occurred there in

the winter of 1850. He also noted that trees

rooted in volcanic ash erupted from the cone

were about 200 hundred years old and that the

oldest trees on related lava flows were about

150 years old. Diller believed he recognized

two eruptive sequences, which each produced

lava flows. However, he thought that only the

older eruption was explosive, creating Cinder

Cone and the ash deposits. In regard to the

explosive eruption, he concluded that “Whatever may be the historical testimony as to the

time of the eruption, the geologic evidence

clearly demonstrates that it must have occurred long before the beginning of the

present century” (before 1800). Diller therefore speculated that the explosive eruption had

occurred between about A.D. 1675 and 1700

and that the younger, quiet eruption was “certainly” sometime before 1840.

In the mid-1930’s, USGS volcanologist

R.H. Finch attempted to improve on Diller’s

work. On the basis of other studies done at

Cinder Cone, Finch thought (1) that there had

been at least five separate lava-flow events, as

suggested by crude, experimental magnetic

measurements (Jones, 1928); (2) that the

youngest lava flow was extruded in 1851,

accepting Harkness’ (1875) historical

“evidence” and ignoring Diller’s interviews

and conclusions; and (3) that there had been at

least two distinct explosive eruptions of the

cone (Finch and Anderson, 1930). Using these

assumptions and tree-ring measurements,

Finch proposed a complex and detailed

eruptive chronology for Cinder Cone that

spanned nearly 300 years (Finch, 1937). From

measurements of the rings of one particular

tree, which showed two periods of slow

growth, he thought that the two explosive

eruptions occurred in A.D. 1567 and 1666. He

also concluded that the five lava flows were

extruded in 1567, 1666, 1720, 1785, and 1851.

New Geologic Studies

After Finch published his work in 1937, few

additional studies were done on volcano hazards in the Lassen area. However, that changed

on May 18, 1980, when Mount St. Helens,

Washington, exploded in one of the most

devastating volcanic eruptions of the 20th

century. After the eruption, the USGS began

reevaluating the risks posed by other potentially active volcanoes in the Cascade Range,

including those in Lassen Volcanic National

Park. Since that time, USGS scientists have

been working in cooperation with the National

Park Service to better understand volcano

hazards in the Lassen area. As part of this

work, the history of Cinder Cone has been

reexamined. Most of the features of Cinder

Cone have changed little since Harkness first

described them in the 1870’s, but all of the

assumptions on which Finch based his conclusions have now been shown to be incorrect.

Through new field and laboratory work and

by reinterpreting data from previous studies,

USGS scientists have shown that the entire

eruptive sequence at Cinder Cone represents a

single continuous event. During this event, the

composition of the molten rock (magma)

feeding the eruption changed from basaltic

andesite to andesite and then back to basaltic

andesite, but with a higher titanium content.

Chemically, basaltic andesites are volcanic

rocks containing 53 to 57% silica (SiO2

), and

andesites are those containing 57 to 63%

silica. Though chemically distinct, the lava

flows and scorias at Cinder Cone are similar in

appearance. They are dark, fine-grained rocks,

containing a few visible crystals of the minerals olivine, plagioclase, and quartz.

The earlier erupted group of volcanic deposits at Cinder Cone, which are relatively

titanium-poor, consist of the older scoria cone,

the Old Bench flow, the two Painted Dunes

flows, and the lower part of the widespread

This extremely young

looking lava flow (Fantastic

Lava Beds flow 2; see

geologic map) was the last

flow erupted at Cinder

Cone. Its unweathered,

rough surface misled early

visitors into believing that it

had been erupted no more

than a few decades before.
ash layer. The later erupted, relatively titanium-rich group consists of the large, younger

scoria cone, the upper part of the ash layer,

and the two Fantastic Lava Beds flows. Flow 2

of the Fantastic Lava Beds (see geologic map)

is the flow that everyone but Diller thought

had been erupted in 1851.

The ash on the Old Bench and Painted

Dunes lava flows is brightly oxidized because

it fell on the lava flows when they were still

hot. This oxidized ash belongs to the same

compositional group as the Fantastic Lava

INFRARED AERIAL PHOTO AND GEOLOGIC MAP OF THE CINDER CONE AREA

Beds flows, the last flows erupted at Cinder

Cone. All the volcanic materials at Cinder

Cone therefore represent a single eruptive

sequence that probably spanned no more than

a few months.

Another line of evidence for this conclusion

is the “paleomagnetic” record preserved in

Cinder Cone’s lava flows. As lava cools, the

local orientation of the Earth’s magnetic field

at that time is recorded in the rock as a “remanent” magnetization. If the pattern of past

variations in the orientation of the Earth’s

magnetic field in a region is known, scientists

can compare a remanent magnetization to that

pattern and may be able to identify one or

more time periods as short as a few decades in

which the flow could have cooled. Because

the orientation of the Earth’s magnetic field in

northern California during the 1850’s is well

known and is different from the remanent

magnetizations at Cinder Cone, the lava flows

there could not have been erupted in 1850 or

1851. Also, there are no discernible differences in the magnetic orientation recorded by

Butte Lake

Snag

Crater Butte Lake

20

40

80

40

20

20

10

10

4

2

YC

OC

OC

FL 2

FL 1

FL 1

PD 2

PD 2

PD 1

PD 1 PD 2

OB

d

d

g

g

g

g

CB

OV OV

OV

OV

OV

OV

OV

OV

OV

0 0.5 MILE

Old

Station

to Mineral

Lassen Peak LASSEN VOLCANIC

NATIONAL PARK

Cinder Cone

89

89

44

44

MAP

LOCATION

CALIF.

Area

of map FL 2

FL 1

PD 2

PD 1

OB

Cinder Cone

eruptive 

sequence

Younger scoria cone

Older scoria cone

Older 

rock 

units

d

g

CB

OV

diatomite (lake sediment)

glacial deposits

Crater Butte lavas

older volcanic rocks

Fantastic Lava Beds flow 2

Fantastic Lava Beds flow 1

Painted Dunes lava flow 2

Painted Dunes lava flow 1

Old Bench lava flow

Cinder Cone crater

Thickness of ash deposits in inches; 

dotted where buried by lava flows

Former extent of lake

YC

OC

10

EXPLANATION

The false-color aerial photo at upper left shows

Cinder Cone and its related volcanic deposits as

barren gray areas. The stark contrast with the

mature surrounding forest (red), which covers

older rock units, can be clearly seen. The geologic

map at right shows the various rock units that are

found in this area.
This trunk of a “quaking aspen,” a tree that

grows in wet ground near lakes or streams, was

toppled and partly buried by flow 1 of the Fantastic Lava Beds. A wood sample from this tree

provided a radiocarbon age that helped U.S.

Geological Survey scientists confirm that the

eruption of Cinder Cone occurred between A.D.

1630 and 1670. Additional radiocarbon ages that

are consistent with this age were obtained from

drowned trees in Snag Lake (see geologic map).

This lake formed when the Painted Dunes lava

flows blocked Grassy Creek, a stream draining the

central plateau of Lassen Volcanic National Park.

Water from Snag Lake seeps beneath the

Cinder Cone lava flows to supply Butte Lake,

2 miles to the north. Butte Lake is a remnant of

a larger lake that was partly filled by lava flows

during the eruption of Cinder Cone. A distinctive type of sediment, called diatomite, found

along the margins of the Fantastic Lava Beds

flows helps to indicate the former extent of that

larger lake, as does the quaking aspen, which

grew near the lake’s edge. The diatomite was

created by the accumulation on the lake

bottom of diatoms, microscopic single-celled

plants whose skeletons are made of opaline

silica. When advancing lava flows entered

the lake, they squeezed up some of the

diatomite along their margins (see geologic

map). Diatoms can provide information on

the ages and environments of ancient freshwater and marine deposits.

Graphic design by

Sara Boore and Susan Mayfield

Banner design by Bobbie Myers

For more information contact:

Lassen Volcanic National Park

P.O. Box 100, Mineral, CA 96063

(530) 595-4444

http://www.nps.gov/lavo/

or

http://volcanoes.usgs.gov/

See also Volcano Hazards of the Lassen Volcanic National

Park Area, California (USGS Fact Sheet 022-00) and

Eruptions of Lassen Peak, California, 1914 to 1917 (USGS

Fact Sheet 173-98).

COOPERATING ORGANIZATIONS

 Lassen Park Foundation

National Park Service

U.S. Forest Service

REFERENCES

Diller, J.S., 1891, A late volcanic eruption in northern

California and its peculiar lava: U.S. Geological Survey

Bulletin 79, 33 p.

Diller, J.S., 1893, Our youngest volcano: National Geographic

Magazine, v. 4, p.93-96.

Finch, R.H., 1937, A tree ring calendar for dating volcanic

events at Cinder Cone, Lassen Volcanic National Park,

California: American Journal of Science, v. 33, p.140-146.

Finch, R.H., and Anderson, C.A., 1930, The quartz basalt

eruptions of Cinder Cone, Lassen Volcanic National Park,

California: University of California Publications in the

Geological Sciences, v. 19, p. 245-273.

Harkness, H.W., 1875, A recent volcano in Plumas County:

California Academy of Sciences Proceedings, v. 5, p.408-

412.

Jones, A.E., 1928, Magnetism of Cinder Cone lava flows,

Lassen Volcanic National Park, California: Hawaiian

Volcano Observatory Bulletin, v. 16, p. 61-65.

Michael A. Clynne, Duane E. Champion, Deborah A. Trimble,

James W. Hendley II, and Peter H. Stauffer

any of the Cinder Cone lava flows, and so the

flows had to be extruded during an interval of

less than 50 years.

Although paleomagnetic evidence can be

used to rule out the 1850’s as the age of Cinder Cone, it does not provide an actual age for

its eruption. By measuring levels of carbon-14

in samples of wood from trees killed by the

TREES AND LAKES HELP SCIENTISTS DECIPHER THE GEOLOGIC HISTORY OF CINDER CONE

Cinder Cone has a related, widespread ash deposit,

seen here being examined by a U.S. Geological

Survey scientist, which is identifiable for 8 to 10

miles from the cone. On the Old Bench and Painted

Dunes lava flows, this ash is brightly oxidized

because it fell on the lava flows when they were

still hot. Because the oxidized ash has the same

composition as the last lava flows erupted at Cinder

Cone (the Fantastic Lava Beds flows), Cinder Cone

must have formed in a single eruptive sequence

that probably spanned no more than a few months.

eruption of Cinder Cone, USGS scientists

obtained a “radiocarbon” date for the eruption

of between A.D. 1630 and 1670. Such a date

is also consistent with the remanent magnetization preserved in the lava flows.

The series of eruptions that produced the

volcanic deposits at Cinder Cone were complex and are by no means completely understood. However, the new studies done by

USGS scientists refute the purported accounts

of an eruption in the early 1850’s and confirm

Diller’s (1891, 1893) interpretation that Cinder Cone erupted in the latter half of the 17th

century. They also suggest that the 1666 treering date proposed by Finch (1937) for his

“second” explosive eruption at Cinder Cone

might actually date the entire eruptive sequence.

This recent work of USGS scientists at

Cinder Cone, in cooperation with the NPS, is

helping to provide a better understanding of

volcano hazards in the Lassen Volcanic National Park area. The work of these scientists

is only part of the USGS Volcano Hazards

Program’s ongoing efforts to protect people’s

lives and property in all of the volcanic regions of the United States, including the Pacific Northwest, eastern California, Wyoming,

Alaska, and Hawaii.

Ash

Glacial till

1 foot

Lake diatom, magnified about 1,200 times