U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

MARK SCHAEFER, Acting Director

Any use of trade names in this publication is for descriptive purposes 

only and does not constitute endorsement by the U.S. Government

For additional information 

write to:

Copies of this report can be obtained 

from:

Robert H. Mariner 

U.S. Geological Survey 

345 Middlefield Road, MS 470 

Menlo Park, CA 94025

email: 

rmariner@mailrcamnl .wr.usgs.gov

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
Preliminary Chemical and Isotopic Data for Waters 

from Springs and Wells on and near Medicine Lake 

Volcano, Cascade Range, Northern California

By R.H. Mariner, W.C. Evans, and M. Huebner 

U.S. Geological Survey Open-File Report 98-2

Menlo Park, California 

1998
Contents

Page 

Abstract..................................................................................................................... 1

Introduction............................................................................................................... 1

Purpose and scope........................................................................................... 3

Acknowledgments........................................................................................... 3

Methods andproceedures......................................................................................... 5

Results and discussion.............................................................................................. 6

Summary................................................................................................................. 19

Refererences........................................................................................................... 20

Illustrations

Figure 1. Location map showing study area, northeastern California..................... 2

Figure 2. Location map of springs sampled on the Fall and Tule Rivers................ 4

Figure 3. Regional map showing chloride concentrations in water samples........... 8

Figure 4. 5D vs 518O for all samples........................................................................9

Figure 5. 8D vs 818O for springs and wells.............................................................. 9

Figure 6. Map of temperatures of springs sampled along the Fall and Tule

Rivers.............................................................................................................. 11

Figure 7. Map of chloride concentrations in sampled springs along the Fall

and Tule Rivers..............................................................................................12

Figure 8. Plot of sodium versus chloride for selected springs along the Fall,

Tule, and Pit Rivers........................................................................................ 14

Figure 9. Map of alkalinities of springs sampled along the Fall and Tule Rivers.. 15 

Figure 10. Map of pH's in springs sampled along the Fall and Tule Rivers.......... 16

Figure 11. Plot of deuterium versus chloride for springs sampled along

the Fall and Tule Rivers................................................................................. 18

Tables

Table 1. Chemical and isotopic data for selected springs, wells, and lakes

on and adjacent to Medicine Lake Volcano................................................. 21

in
ABSTRACT

Cold springs on and adjacent to Medicine Lake Volcano discharge dilute 

mixed cation - bicarbonate waters of neutral to slightly alkaline pH. Chloride 

values in cold waters from springs and shallow wells on the volcano are low and 

generally increase radially outward from Medicine Lake. Chloride concentrations 

at high elevations are similar to values for precipitation. Higher chloride 

concentrations occur in wells within Lava Beds National Monument (11 mg/L) and 

at the headquarters for the Tule Lake National Wildlife Refuge (109 mg/L). Little 

Valley Hot Springs, near the southern edge of the study area, has 120 mg-Cl/L. 

Leakage from the high temperature geothermal system at Medicine Lake Volcano 

(~ 1,000 mg-Cl/L) has not been found. Isotopic values for cold springs and wells 

on and adjacent to the volcano range from -84 to -106%o 8D and from -12.2 to - 

14.4%o 818O and plot near the global meteoric water line. Water discharged by 

cold springs at the head of the Fall and Tule Rivers change somewhat in chemical 

and isotopic composition across the complex. Spring temperatures decrease from 

east to west. Chloride concentrations are highest in springs in the middle of the 

complex decreasing slowly eastward and sharply at the western edge. Deuterium 

values are most depleted in the middle of the complex. Deuterium versus chloride 

plots for these waters show no relationship to known geothermal waters. 

Deuterium and oxygen-18 values for the large discharge cold springs in the Fall 

River Valley are compatible with, but do not prove, recharge on Medicine Lake 

Volcano.

INTRODUCTION

Medicine Lake Volcano (fig. 1) is a large Pleistocene and Holocene shield 

volcano made up of basaltic to rhyolitic rock. The volcano is located about 35 

miles ENE of Mt. Shasta in northern California and it sets on Pliocene basalts that 

are underlain by tuffs and basalt flows of Miocene age (Anderson, 1941). 

Medicine Lake, about 3/4 mi.2 in surface area, occupies the western end of a 

caldera-shaped depression in the top of the volcano. Anderson (1941) reported 

that most of Medicine Lake was less than 20 feet deep, although a depression in 

the eastern end of the lake was almost 150 feet deep. Medicine Lake Volcano has 

been active on at least 17 occasions over the last 12,000 years (Donnelly-Nolan, 

1990), but no hot springs or major fiimaroles discharge on the mountain. The
42°00'

. § 41°30'-

J

41°00'

Klamath 

National 

Wildlife 

Refuge

Lava Beds

National

Monument

Proposed Fourmile Hill 

Geothermal Development

Tule Lake

Tule Lake 

National 

Wildlife 

Refuge \

Clear

Lake

National

Wildlife

Refuge

122°00'

Proposed-Tdephone 

, Flat Geothermal Ajea

Medicine 

Lake

/

Study location

Ahjumawi 

Lava Springs 

State Park Bieber

 . River McArthur

121°30' 

Longitude

121°00'

Figure 1. Location map showing study area, northeastern California.
nearest hot spring occurs just north of Ahjumawi Lava Springs State Park, 

approximately 30 miles SSE of Medicine Lake. The "hot spot", an area of warm 

ground and several weak fumaroles about 3 l/2 miles ENE of Medicine Lake, is the 

only visible thermal feature. Cold springs occur on the higher parts of the 

mountain, but are particularly rare on the flanks of the volcano. The only streams 

on the mountain are associated with springs and persist for at most a few miles 

before disappearing into the porous volcanics. A few shallow wells are present 

near the east end of Medicine Lake and at widely spaced intervals on the flanks of 

the mountain. The major discharge of cold water near Medicine Lake Volcano 

occurs at the head of the Fall and Tule Rivers on the north side of the Fall River 

Valley (fig. 2). These cold springs are located about 35 miles SSE of Medicine 

Lake (fig. 1) and discharge water at a rate of 1,200 to 1,500 cubic feet per second 

(Clapp and Hoyt, 1906). Studies by California Department of Water Resources 

(1960) and Thompson and Chappell (1983) showed that most waters in the Fall 

River Valley are the sodium bicarbonate type but that the eastern and western 

edges of the valley have calcium-magnesium bicarbonate waters.

In this report we make available chemical and isotopic data for cold springs, 

wells, lakes, and streams sampled on and adjacent to Medicine Lake Volcano. 

This set includes data for the large-discharge cold springs at the head of the Fall 

and Tule Rivers. Although some interpretation is given, our primary purpose is to 

make the data available to individuals, companies, and government agencies 

interested in the potential development of geothermal resources on Medicine Lake 

Volcano. Some of the data may be relevant to completion of environmental 

impact statements and/or environmental impact reports for the possible geothermal 

projects on Medicine Lake Volcano.

Acknowledgments

We would like to thank Whit Budge (Spring Creek Ranch), Andy Lakey 

(Rainbow Springs), and especially Peter Stent (1000 Springs Ranch) who 

permitted us to sample springs on their properties in the Fall River Valley. We 

would also like to thank Rick Poore at Thousand Springs Ranch and Dan Rajnus at 

Spring Creek Ranch for taking time to show us springs that they thought might be
41°7.5'

Unn.sprs. 4 ,g Rainbow Spring

41°5'

to

h-*

o 

U>

o

Ahjumawi Lava 

Springs State 

Park

Spr. at N end 

of Big Lake

A Unn. spr. #1

Unn. spr. #2

Spr. at N. end 9 ; Crystal Springs

ofJaSheCr \\ ; i* :;-.J

N

1 mile

Scale

Figure 2. Location map showing springs sampled on the Fall and Tule Rivers
good sampling sites. Janie and Rob Painter were interested enough to contact us 

and to make a special trip from Mt. Shasta City to let us sample the well at their 

cabin on the east end of Medicine Lake. Access to U. S. Forest Service wells was 

provided by Randy Sharp (well near Medicine Lake) and Brad Reed (well east of 

Medicine Lake and covered by 8 inches of fresh snow). We also wish to thank 

Craig Dorman and Chuck Barrett at Lava Beds National Monument for their 

interest in the provenance of waters at the monument.

METHODS AND PROCEDURES

The methods used in sample collection and field determinations of pH and 

alkalinity are described in detail by Presser and Barnes (1974). The pH was 

measured in the spring or pumped sample and the pH electrode standardized 

against two buffers of known pH at each site. Alkalinity was determined by acid 

titration immediately after the sample was collected from the spring, well, river, or 

lake. Alkalinity values were determined again in the laboratory as a check on the 

field-determined values. Both titrations were carried out to the inflection point 

rather than to a predetermined pH. The raw water sample was filtered through a 

0.45fim pore-size filter using compressed nitrogen or compressed air as the 

pressure source. Filtered samples were stored for later analysis in plastic bottles. 

Samples for metals and silica were acidified to at least pH 2 with concentrated 

nitric acid. Water temperatures, where determined, were measured with a 

combination temperature/conductivity probe or a mercury-in-glass thermometer. 

Samples for isotope analysis were collected without field treatment in glass bottles 

with polyseal caps. In the laboratory, silica (SiO2), calcium (Ca), magnesium 

(Mg), sodium (Na), and potassium (K) were determined on an automated 

inductively-coupled plasma emission spectrometer. Potassium values from this 

instrument are not as accurate as from a double-beam atomic absorption 

spectrophotometer. Potassium values are uncertain by about 0.2 mg/L (milligram 

per liter) when concentrations are less than 10 mg/L. Chloride (Cl), bromide (Br), 

nitrate (NO3 ), phosphate (PO4), and sulfate (SO4) were determined on a computer 

controlled automated ion chromatograph. Isotope samples were analyzed in two 

different laboratories. Oxygen isotope values were determined in the USGS stable 

isotope laboratory in Menlo Park. Deuterium values were determined in the USGS 

stable isotope laboratory in Reston, Virginia because the mass spectrometer used
for deuterium in the Menlo Park laboratory was down. These labs often compare 

samples so the results should be completely interchangeable.

The number of significant figure shown for chemical constituents in this report 

generally follow the guidelines given by Fishman and Friedman (1989). 

Exceptions occur for calcium, magnesium, and sodium in the concentration range 

from 10 to 25 mg/L. Fishman and Friedman (1989) suggest reporting two 

significant figures for values greater than 10 and units and tenths for values less 

than 10. To report values of 9.8 or 9.9 infers that the value is known to an 

accuracy near 1 percent, but to report 10 or 11 with no values in between infers 

that the value is known to only 10 percent. We believe that between 25 and 10 

mg/L the values are known to between 1 and 2 percent. In this concentration range 

we report values to tenths because it is the tenth value that is uncertain not the 

units value. Determining pH in dilute waters is very time consuming because the 

electrodes respond very slowly. Although most meters show pH values to 

hundredths, we report pH values only to tenths in this report because of uncertainty 

about the electrode coming to equilibrium.

RESULTS AND DISCUSSION

Chemical and isotopic data for sampled waters are shown in table 1. All cold 

spring and well waters are dilute (< 1,000 mg/L TDS) and have bicarbonate 

(HCO3 ) as the major anion. Calcium (Ca), magnesium (Mg), and/or sodium (Na) 

are the dominant cations and pH values are neutral to slightly alkaline in most 

waters. Ca-Mg-HCO3 waters dominate at higher elevations; Na-Ca-Mg-HCO3 

waters occur only at lower elevations. The only hot spring in the study area (Little 

Valley Hot Springs with t = 76°C) discharges a Na-HCO3 water. Isotope values 

for most cold spring and well waters range from -79 to -108 permil in 8D and -12.2 

to -14.7 permil in 518O. The few cold spring and well water outside this range 

have been altered by evaporation. Thermal water from Little Valley Hot Springs is 

more depleted in deuterium (8D = -113 permil) than any cold water sampled in the 

area.

The change from Ca-Mg-HCO3 waters, which dominate at higher elevations, 

to Na-HCO3 and Na-Ca-Mg-HCO3 waters, which occur only at lower elevations, is 

due to a series of water-rock reactions that exchange calcium and magnesium from
the water with sodium from the rock. This natural softening is a commonly 

observed process (Hem, 1985). Generally, waters with a higher proportion of 

sodium have had more water-rock reaction than waters dominated by calcium.

Chloride concentrations are lowest in cold springs and wells at high elevations 

and generally increase radially from Medicine Lake (fig. 3). However the rates of 

increase are variable on different sides of the volcano. Chloride concentrations in 

cold springs and shallow wells increase slowly from 0.25 mg/L at Medicine Lake 

to 4.6 mg/L in one of the large discharge cold springs at the head of the Fall River. 

Chloride concentrations increase more rapidly to the east and north of Medicine 

Lake. Dissolved chloride concentrations of more than 100 mg/L occur only in 

Little Valley Hot Springs and the well at Tule Lake National Wildlife 

Headquarters. A chloride concentration of 11 mg/L was found at the well used by 

the National Park Service in Lava Beds National Monument. Hotchkiss (1968) 

reported 12 mg-Cl/L for the same well. Water temperatures at both wells are 

higher than expected at this altitude assuming that temperature-altitude relations 

are similar to those found by Nathenson (1990) at Crater Lake. However, it is not 

clear that these chloride-bearing waters are associated with the high temperature 

system(s) on Medicine Lake volcano. Both waters could be associated with small 

low-temperature geothermal systems that derive their heat from a higher than 

normal geothermal gradient, or they could even be associated with geothermal 

systems similar to those near Bieber (about 40 miles southeast of Medicine Lake), 

west of Alturas (about 40 miles east-southeast of Medicine Lake), or in the 

Klamath Valley (about 35 miles northwest of Medicine Lake). The paucity of 

samples makes it impossible to establish relationships between the nonthermal 

waters of Lava Beds National Monument or the well at Tule Lake National 

Wildlife Refuge headquarters and any of the known geothermal waters.

Isotope values for cold springs, shallow water wells, and lakes of Medicine 

Lake Volcano and the surrounding area cover a wide range of values (table 1 and 

fig. 4). Samples from lakes (fig. 4) are isotopically shifted by evaporation as are 

the samples from Lost River (outflow from Clear Lake), the Dock well, Pumice 

Stone well, and the well at the Tule Lake National Wildlife headquarters. The 

most depleted water in the study area (-113 permil) is from Little Valley Hot 

Springs. At -113 permil 8D, it is at least 5 permil more depleted in deuterium than 

any cold water sampled on Medicine Lake Volcano. If the cold spring isotope
f 1

Chloride - Medicine Lake Area

41.8

41.6

41.4

41.2

41

Tule Lake 

National 

Wildlife 

Refuge 

2-3 Headquarters

4 5

10

Lava Beds National 

^ Monument

2.1

0.13 0 . 29 024/ 

 ^*^ 0.

0.24

Medicine Lak 

54

0.25

0.36 3

0.30

0.54

0.57

Little Valley Hot Spring

0.44

4.6

5.7

i i

121.8 121.6 121.4 121.2 121 120.8

Longitude

Figure 3. Map showing chloride concentrations in water samples
-50

-70

-90

co -HO

g

<D

-130

^ Fall River area

 Medicine Lk. V. 

AEastofMed.Lk-V. 

B Hot springs and wells, i c? y

 Lakes

Tule L. - 1

1 Blanche L

9 Tule L. - 2

 'SullseyeL. 

Medicine L.

 Medicine L. 

 Tule L. Nat. Wildlife

Refuge Headq. 

Pumice Stone well

Geothermal wells on 

Medicine Lake Volcano

Hot springs and 

wells of the Modoc 

Plateau and Klamath Falls

-16 -12 -8 -4 0

18 8 O (permil)

Figure 4. 5D vs 818O for all samples (GMWL is the global meteoric water line)

a

<D 

&

^

-85

-95

-105

-115

-125

Fall River Valley 

Medicine Lake Volcano 

East of Medicine Lake Volcano 

Hot springs and wells 

Modoc Plateau 

and Klamath Falls

-15 -14 -13

5 O (permil)

-12

Figure 5. 8D vs 518O for springs and wells (GMWL is the global meteoric water line)
compositions in table 1 and Figure 4 are typical of current precipitation (and 

recharge) on Medicine Lake volcano, then Little Valley Hot Springs discharges 

water that recharges elsewhere or is more than 10,000 years old. Of course, it is 

possible that a set of cold spring and well samples collected during August and 

September of 1997 may not be representative of the true isotopic composition of 

recharge on the volcano over an extended period of time. Precipitation from 

summer thunder showers may have shifted the composition of short circulation 

ground waters to more enriched values. At high altitudes in the Steens Mountains 

of southeastern Oregon, 5D values of shallow circulation springs became less 

depleted in deuterium by 6 to 7 permil between early July and mid September 

(unpublished data, R. Mariner). Medicine Lake Volcano (most of which is 6,500 

to 7,900 feet in elevation) is not as high as the Steens Mountains (up to 9,600 feet 

in elevation) but meteorological conditions at Medicine Lake Volcano may be 

influenced by Mt. Shasta (14,162 feet elevation) to the west. A more detailed look 

at the isotopic data (fig. 5) shows some differences apparently associated with 

location. Springs and wells east of Medicine Lake all appear to be shifted by about 

0.5 permil in 8 18O relative to the global meteoric line of Craig (1961). Springs and 

wells on, to the west, or south of Medicine Lake Volcano appear to be shifted 

about -0.2 permil in 8 18O relative to the global meteoric water line. Several 

springs in the area have been sampled in previous years. Older samples from 

Crystal, Lost, and Schonchin springs (table 1) are more depleted in deuterium and 

more enriched in oxygen-18 (generally nearer to the global meteoric water line) 

than the 1997 sample set.

Springs that generate the Fall River, Spring Creek, Lava Creek, Ja She Creek, 

and Big Lake (fig. 2) in the Fall River Valley are of particular interest because 

their discharge rates are unusually large, their site of recharge is unknown, and 

their relation to the geothermal waters, if any, is uncertain. Although all of the 

springs discharge at essentially the same elevation, discharge temperatures range 

from 9.1° to 12.8°C. Temperatures of the springs are variable but generally 

decrease from east to west (fig. 6) and are higher than the 8.6°C expected based on 

the temperature-altitude relation noted by Nathenson (1990) for cold springs at 

Crater Lake. If a high temperature geothermal water is providing the heat then 

chloride concentrations should also decrease from east to west. However, chloride 

concentrations (fig. 7) increase slowly from east to west, attaining a maximum of 

4.5 and 4.6 mg/L at the unnamed spring on Spring Creek and Rainbow Spring on

10
Spring temperatures (°C) C

o

u> 

o

Ahjumawi Lava 

Springs State 

Park

Spr. atNend 

of Big Lake

*

12.8

-41°7.5t

Thousand Springs

12.1

i Spr. at N. end Q . Crystal Springs 

 ofJaSheCr.

0

l_

N

t 1 mile

_J

Scale

Figure 6. Map of temperatures of springs sampled along the Fall and Tule Rivers.
Chloride concentrations 

(mg/L) in sampled springs

41°7.5'

Thousand Springs Unn. spr. #1

4.5

!/i Unn. spr. #1 '' ^

4.2

4.6

Rainbow $pring

(I

41°5'

Unn. spr. #2

Fall River

Ahjumawi Lava 

Springs State 

Park

4.0

i Spr. at N. end f ; Crystal Springs

i ofJaSheCr. ** ;- .

3.9

e River

H U ?

Spr. at N end 

of Big Lake 

0

, ~ M

3.4

Big Lake

N

t 1 mile

Scale

Figure 7. Map of chloride concentrations in sampled springs along the Fall and Tule Rivers.
the Fall River in the western third of the complex and then decrease to a low of 1.1 

mg/L in the westernmost unnamed spring on the Fall River.

A plot of Na vs Cl (fig. 8) produces an unusual triangular shaped feature. 

Mixing water from Rainbow Spring or the unnamed spring on Spring Creek with a 

dilute ground water could produce all of the sodium and chloride values observed 

in waters to the west of and including the unnamed spring at the headwaters of 

Lava Creek. However, most springs on Lava Creek must have sodium and 

chloride compositions like the springs further east because the sample of Lava 

Creek taken at the road bridge plots on the constant sodium but variable chloride 

line (fig. 8). The few springs and streams sampled south of McArthur, along the 

Pit River and Hat Creek, have ratios of sodium to chloride which are very different 

from values for the springs along the Fall and Tule Rivers (fig. 8). However, the 

sample from a stream draining into the Pit River from a hot spring located 

approximately seven miles east-southeast of McArthur could represent the thermal 

but low chloride water which makes up part of the discharge of the cold springs 

along the Tule River. No data appears to be available for the chemical and 

isotopic composition of this hot spring.

Alkalinity generally decreases from east to west across the complex (fig. 9) 

and follows discharge temperature. Bicarbonate-rich thermal waters are usually 

associated with low-temperature geothermal systems. Spring pH values are 

surprisingly variable (table 1). Four of the five springs at the western edge of the 

system increase in pH from west to east (fig. 10) but one spring clearly breaks the 

trend. This site was checked at a later date with two meters and the pH value 

reproduced. Similar pH values occur in springs on Spring Creek and Lava Creek, 

and may indicate that some process is altering pH values in these waters shortly 

prior to discharge. We speculate that this could be contact with the atmosphere or 

soil gas from which CO2 could be dissolved. Dissolution of CO2 shortly prior to 

discharge would bring the pH down.

Chemical compostion of cold springs can be expected to change over time due 

to differential rates of fluid movement through the system and to variable amounts 

of dilution. Three springs in Adjumawi Lava Springs State Park have been 

sampled in different years (Table 1) and show small differences in dissolved 

constituent and light stable isotope compositions. Dissolved constituents are

13
B

O 

00

1612

8

0

Stream from hot spring 

near the Pit River

0 1

Tributary to Pit River Tributary to Fall River 

0 Tributary to Tule River

\\% r< **J

Rock Spring 7. 1Rising River 7.2

Big Spring 8.6

Stream from 14.2

hot spring

^

2.4

1.11.0

1.3

Figure 8. Plot of sodium versus chloride for selected springs along the Fall, Tule, and Pit Rivers.
Alkalinities as bicarbonate (mg/L)

Ahjumawi Lava 

Springs State 

Park

Spr. at N end 

of Big Lake

122

Thousand Springs

A

fl'i 

JL73 " «J^83

Unn. sprs. " 90 

Rainbow// 

Spring //

Unn. spr. #1 /]

86

Unn. spr. #1

83 Big Lake

106

Spr. at N. end 9 Crystal Springs ofJaSheCr. ---

e River

0

l_

N

r Imile

_J

Scale

Figure 9. Map of alkalinities of springs sampled along the Fall and Tule Rivers.
pH's of sampled springs

41°7.5r

Thousand Springs Unn.spr.#l A

7.4

«^_ 

Unn. sprs. *3W

Rainbow /T8.4 

Spring //

Fall River

o 

u>

o

Unn. spr. #1

7.6

II r Unn. spr.

x^i :a

 .#2

Ahjumawi Lava 

Springs State 

Park

_ j 8.2

i Spr. at N. end Q Crystal Springs 

i ofJaSheCr. { *

8,3

e River

ir^ Fall River ^|

' J

Spr.atNend 

of Big Lake

Big Lake

N

. r

i

1 mile

I

Scale

Figure 10. Map of pH's in springs sampled along the Fall and Tule Rivers.
present at lower concentrations in the 1997 samples than in the 1993 samples. 

Paynes Spring and Crystal Spring near Medicine Lake have been sampled for 

chemical composition in 1987 and 1997. The 1997 sample from Crystal Spring is 

more dilute than the 1987 sample but the 1997 sample from Paynes Spring is more 

concentrated in all dissolved constituents than the 1987 sample.

The large discharge cold springs in the Fall River-Adjumawi area range from 

-99 to -102 permil in 8D and -13.3 to -13.7 permil in 8 18O and are within the 

envelope of isotopic values determined for waters from cold springs and shallow 

wells on Medicine Lake Volcano (fig. 4). It is isotopically permissible for these 

waters to recharge on Medicine Lake Volcano and the highlands that extends to the 

WSW. However, such evidence does not constitute proof that they recharge there. 

Informational billboards in Adjumawi Lava Springs State Park proclaim that the 

large discharge cold springs, which are a prominent feature of the park, are fed by 

underground streams from Tule Lake. The source of this "information" appears to 

be MacDonald (1966) and is apparently based on the difference in elevation 

between Tule Lake and the Fall River-Adjumawi area, and that large quantities of 

water have been observed to flow into the subsurface at Tule Lake without 

showing up again. However our chemical and especially our isotopic data (fig. 4) 

show that it is impossible for a significant amount of Tule Lake (Tule Lake Sump) 

water to be present in the large-discharge cold springs that feed the Fall and Tule 

rivers. Isotope data from waters of large-discharge cold springs between the Fall 

River Valley and Lassen Peak (Rose and others, 1966) are virtually identical to 

values from the large-discharge cold springs of the Fall River - Ahjumawi Lava 

Springs State Park. The available data do not allow us to determine the recharge 

source for the waters of the Fall River - Ahjumawi complex at this time.

A major question has been the relation, if any, of the waters in the largedischarge cold springs at the head of the Tule and Fall rivers to the hightemperature geothermal fluids on Medicine Lake Volcano or thermal waters like 

Little Valley Hot Springs. This aspect is investigated using the most conservative 

chemical constituent analyzed, chloride, and the most conservative isotopic 

constituent, deuterium. A plot of 5D vs chloride for data from the large discharge 

cold springs of the Fall River - Adjumawi area show a strong correlation (r=0.89) 

between the pair (fig. 11). If chloride and deuterium are being provided to the 

system by a high-chloride thermal water then the least squares line through the

17
« i

<D

CO

-90

-100

-110

-120

0

Geothermal System 

at Medicine Lake 1000mg-Cl/L

 Tule River - Lava Cr.

 Fall River - Spring Cr. 

B Modoc Plateau hot sprs.

Fall R. - Spring Cr. m I 

 Tule River - Lava Cr.

Little Valley 

Hot Spring

40 80 120 160

Chloride (mg/L)

Figure 11. Plot of deuterium versus chloride for springs sampled along the 

Fall and Tule Rivers.

18
values for the large discharge cold springs must extrapolate to the composition (8D 

and chloride) of the saline end member. Thermal fluid in the geothermal system 

on Medicine Lake volcano is between -94 and -97 permil 8D and has a chloride 

concentration of about 1,000 mg/L (lovenitti and Hill, written communication 

1997). Little Valley Hot Springs discharge water with only 120 mg-Cl/L but a 6D 

of about -115 permil. The least squares line for the data from the large discharge 

cold springs extrapolates to very depleted deuterium values at very low chloride 

concentrations (fig. 11). Based on this plot we must conclude that the chloride and 

deuterium values in these large discharge cold springs are a function of dilution 

with a low-chloride local ground water. Also, Na/Cl values for waters from these 

large-discharge cold springs are very constant at about 4, appreciably different 

from that of Little Valley Hot Spring (Na/Cl = 2) and the geothermal water from 

Medicine Lake Volcano (Na/Cl = 0.62). No indication exists that the waters 

discharged in these large-discharge cold springs are associated with the high 

temperature geothermal waters on Medicine Lake Volcano or with the waters of 

Little Valley Hot Spring.

SUMMARY

Dilute mixed cation-bicarbonate waters occur in cold springs and shallow 

wells adjacent to and on Medicine Lake Volcano. High-temperature geothermal 

waters are usually dominated by sodium and chloride. No trace of the highchloride thermal water present in deep wells drilled in the area just east of 

Medicine Lake has been located on, or near the volcano. Chloride concentrations 

in cold springs and cold wells at high elevations on the volcano are approximately 

the same as in precipitation. Chloride concentrations increase radially outward to 

about 5 mg/L in waters near the base of the volcano. Higher chloride 

concentrations occur in well waters in Lava Beds National Monument, at the 

headquarters for Tule Lake National Wildlife Refuge, and Little Valley Hot 

Spring. None of these waters can be shown to be associated with the known highchloride waters encountered by drilling on the volcano. Isotope values in cold 

springs and wells range from -106 permil 5D at higher elevations to -84 permil 8D 

at lower elevations and most plot near or on the global meteoric water line. All 

samples from lakes and streams draining lakes have isotopic compositions that 

show some degree of evaporation. The large discharge cold springs at the head of 

the Tule and Fall Rivers differ in chemical and isotopic composition in ways that

19
require dilution by low-chloride waters. No chemical connection has been 

established between the waters from these large-discharge cold springs and known 

chloride-rich geothermal fluids. Large-discharge cold springs along the Tule River 

may contain some water similar to that discharged by a hot(?) spring located 7 

miles east-southeast of McArthur along the Pit River. Isotope values for the large 

discharge cold springs of the Fall River Valley are similar to values of cold springs 

and wells on Medicine Lake Volcano indicating that it is permissible for these 

waters to recharge on Medicine Lake Volcano. However, it must be emphasized 

that this does not constitute proof that the waters discharged by these largedischarge cold springs recharge on Medicine Lake Volcano.

References Cited

Anderson, C.A., 1941, Volcanoes of the Medicine Lake Highland, California: 

University of California Publications Bulletin, Department of Geological 

Sciences, v. 25, p. 347-422.

California Department of Water Resources, 1960, Water quality investigations of 

Fall River Valley: California Department of Water Resources, Division of 

Resource Planning, 15 p.

Clapp, W.B., and Hoyt, J.C., 1906, Report of progress of stream measurements for 

the calendar year 1905: U.S. Geological Survey Water-Supply Paper 177, 

273 p.

Craig, H.W., 1961, Isotopic variations in meteoric waters, Science, p. 1702-1703.

Donnelly-Nolan, J.D., 1990, Geology of Medicine Lake Volcano, northern

California Cascade Range: Transactions of the 1990 Annual Meeting of the 

Geothermal Resources Council, v. 14, pt. 2, p. 1395-1396.

Fishman, M.J., and Friedman, L.C., 1989, Methods for the determination of 

inorganic substances in water and fluvial sediments: Techniques of Water 

Resources Investigations of the U.S. Geological Survey, book 5, chap. Al, 

545 p.

20
Hem, J.D., 1985, Study and interpretation of the chemical characteristics of natural 

water: U.S. Geological Survey Water-Supply Paper 2254, 263 p.

Hotchkiss, W.R., 1968, A geologic and hydrologic reconnaissance of Lava Beds 

National Monument and vicinity, California: U.S. Geological Survey OpenFile Report, 30 p.

Mac Donald, G.A., 1966, Geology of the Cascade Range and Modoc Plateau, in 

Geology of northern California, E.A. Bailey, ed., California Division of 

Mines and Geology Bulletin 190, p. 65-96.

Nathenson, Manuel, 1990, Temperatures in the vicinity of Crater Lake, Oregon, in 

relation to air and ground temperatures: U.S. Geological Survey Open-File 

Report 90-671, 19 p.

Presser, T.S., and Barnes, Ivan, 1974, Special techniques for determining chemical 

properties of geothermal water: U.S. Geological Survey Water-Resources 

Investigations 74-22, lip.

Rose, T.P., Davisson, M.L., and Criss, R.E., 1996, Isotope hydrology of

voluminous cold springs in fractured rock from an active volcanic region, 

northeastern California: Journal of Hydrology, v. 179, p. 207-236.

Thompson, T.H., and Chappell, R., 1983, Maps showing distribution of dissolved 

solids and dominant chemical type in ground water, Basin and Range 

province, northern California: U.S. Geological Survey Water Resources 

Investigations Report 83-4115-B,6p., 1 plate.

21
Table 1. Chemical and isotopic data for selected springs, wells, and lakes on and adjacent to Medicine Lake Volcano

[Chemical concentrations in milligrams per liter; isotope concentrations in parts per mil relative to standard mean ocean water]

ID/Name t(°C)

ML01RM97

McCloud River at

ML02RM97

Cub Spring

ML03RM97

Water tank below

GT05RM97 5.

Indian Spring

ML04RM97

Belnap Spring

ML05RM974 -

Bear Spring

ML06RM974 -

GT33JD791

Lost Spring

ML07RM975 -

GT44RM87

GT68JD821

Paynes Spring

pH jaS/cm

108

Algoma Campj

25

106

SiO2

26.3

ground

15.3

39.3

Ca

10.3

2.0

10.8

Mg

5.7

1.1

4.4

Na

3.6

1.1

4.2

K

0.9

.4

1.6

Cl

0.36

.44

.57

S04

0.17

.10

.36

HCO

62

15

63

3 SD

_

-84

-93

8 18O Coll. date Long. Lat.

7/29/97 121°52.9' 41°29.2'

-12.2 7/29/97 121°46.6' 41°14.0'

-13.2 7/29/97 121°31.7' 41°19.1'

Mayfield Spring

2 -

47

76

6.68/17° 64

_

67

7.6

-

20

22.2

28.9

26.8

-

45.9

44

-

7.3

4.0

6.7

8.3

-

5.5

4.8

-

4.9

2.2

4.3

1.7

-

2.6

2.3

-

2.9

2.0

2.4

2.6

-

3.8

3.9

-

1.3

.5

<0.1

<0.1

-

1.6

.4

-

.60

.54

.30

.13

-

.25

.2

-

-

.10

.09

.04

-

.56

.6

-

62

38

42

39

-

50

36

-

-

-91

-96

-96

-98

-

-95

-105

~/--/94 121°31.2' 41°21.3'

-12.8 7/29/97 121°47.7' 41°23.8'

-13.4 7/29/97 121°48.3' 41°27.4'

-13.5 7/29/97 121°46.9' 41°34.7'

-13.2 7/8/79

-13.6 7/30/97 121°33.7' 41°33.4'

-13.7 8/25/87

-13.6 7/16/82
ro

u>

Table 1. Chemical and isotopic data for selected springs, wells, and lakes on and adjacent to Medicine Lake Volcano continued 

[Chemical concentrations in milligrams per liter; isotope concentrations in parts per mil relative to standard mean ocean water]

ID/Name t(°C) pH nS/cm SiO2 Ca Mg Na K Cl SO4 HCO3 8D 8 18O Coll. date Long. Lat.

ML08RM97 - 7.10/n°58 26.2 6.8 

Forest Service well at Medicine Lake

2.0

4.8 6.87 80 35.2 9.9 2.5

ML45RM972 - - 69 

Forest Service well in Arnica Sink

ML32RM974 12.5 6.82 104 

Dock well

GT31JD79' - - 

Baird Spring

GT31JD79- - - 

Pumice Stone well

2.1 .4 

ML09RM97 3.4 0.8

GT11JD81' - - -

Schonchin Spring

ML10RM975 2.6 6.71 46 31.8 4.9 1.6 

GT48RM87 7.9 - 35 8.3 3.1 

GT35JD791 - - - ... . 

Crystal Spring at Medicine Lake

ML42RM97 5.1 7.74 61 24.3 8.0 1.5 2.1 .7 

Private well at Medicine Lake

2.4 .7 

4.6 1.3

42.7 6.1 3.9 5.2 3.9

.24 

0.29

.24 

.1

.54 

.68 

.93

.60 31 -100 -14.1 7/30/97 121°35.0' 41°35.1'

0.36 49 -97 -13.8 7/30/97 121°33.7' 41°33.5'

- -98 -13.2 7/5/81

.27 38 -98 -13.8 7/31/97 121°36.5' 41°34.4'

.4 28 -95 -13.8 8/25/87

- -98 -13.5 7/8/79

.27 35 -99 -13.8 11/18/97 121°35.1' 41°34.7'

1.2 50 -13.8 11/18/97 121°33.9' 41°35.5f

1.3 51 -96 -12.5 9/7/97 121°43.3' 41°39.0'

. .106 -14.4 7/8/79 121°51.0' 41°34.3'

-91 -10.6 7/7/79 121°42.4' 41°34.3'
Table 1. Chemical and isotopic data for selected springs, wells, and lakes on and adjacent to Medicine Lake Volcano continued 

[Chemical concentrations in milligrams per liter; isotope concentrations in parts per mil relative to standard mean ocean water]

ID/Name t(°C) pH SiO2 Ca Mg Na K Cl SO4 HCO3 SD 6 18O Coll. date Long. Lat.

GT36JD791 - - _......

Tule Lake Municipal well

ML29RM974 11.2 7.60 190 40.9 14.7 10.9 6.9 1.5 2.1 2.3 107 -103 

Well at Tionesta Mountain Store

ML30RM974 13.9 7.67 181 40.5 14.8 11.9 4.8 0.7 2.1 2.3 109 -104 

Well at quarantine station

ML31RM974 17.58.01 201 41.4 12.2 9.5 15.7 2.9 3.0 1.8 120-101 

Well at Long Bell Station

ML44RM974 - 7.38 122 .6 15.5 5.7 1.5 2.1 .33 .3 70 -31 

Quaking Aspen Spring (pond) in Long Bell Game Refuge

ML26RM97 16.4 8.25 193 52.0 6.7 5.0 27.6 2.2 11 

Well at Lava Beds National Monument

ML27RM973 18.7 8.01 1170 52.8 43.1 52.1 124. 16.4 109 79 459 -79 

Well at Tule Lake National Wildlife Refuge Headquarters

ML28RM975 21 7.74 162 20.9 13.4 7.2 9.6 2.9 4.5 3.7 96 -65 

Lost River at the gage

ML22RM97 - - 68 38.6 5.0 2.0 5.3 1.2 1.31 1.58 45 -108 

Quaking Aspen Spring

- -127? -13.4 9/3/79 12T28.71 41°57.3'

-13.6 9/6/97 12ri7.4f 41°38.8'

-13.6 9/6/97 121°12.7' 41°36.7'

-13.3 9/6/97 121°24.9' 41°28.3'

+0.8 11/06/97 121°20.2' 41°30.5'

2.9 94 -106 -14.7 9/5/97 121°30.4f 41°43.0'

-8.6 9/5/97 121°33.8' 41°53.9'

-6.7 9/6/97 121°44.4( 41°54.6'

-14.1 8/15/97 120°54.2' 41°50.5'
Table 1. Chemical and isotopic data for selected springs, wells, and lakes on and adjacent to Medicine Lake Volcano -- continued 

[Chemical concentrations in milligrams per liter; isotope concentrations in parts per mil relative to standard mean ocean water]

ID/Name t(°C) pH M S/cm SiO2 Ca Mg Na K Cl SO4 HCO3 5D 8 18O Coll. date Long. Lat.

ML23RM97 - - 252 63.4 24.1 15.3 9.2 .7 1.21 

Blue Mountain Spring

ML33RM974 - - 162 - 2.3 

Irrigation well in Red Rock Valley

Fall River Valley

ML14RM974 9.2 7.47 136 30.6 11.8 7.2 5.0 1.5 1.1 

Unnamed spring #1 on the Fall River

ML11RM97 9.1 7.95 113 34.2 8.6 5.2 7.2 1.8 2.2 

Unnamed spring #2 on the Fall River

ML12RM97 11.2 8.17 142 39.8 8.4 6.0 12.1 2.5 4.0 

Unnamed spring #3 on the Fall River

ML13RM97 11.2 7.68 146 40.3 8.5 6.2 12.5 2.2 4.1 

Unnamed spring #4 on the Fall River

ML25RM974 12.0 8.36 161 41.6 8.8 6.7 14.2 2.7 4.6 

Rainbow Spring

ML15RM97 - - 146 37.9 9.0 6.3 12.1 2.2 3.9 

Spring Creek at the road bridge

ML40RM97 12.2 7.41 157 40.1 8.7 6.3 13.7 2.7 4.5 

Unnamed spring on Spring Creek

.08 179 -106 -13.9 8/15/97 120°50.1' 41°50.8'

2.1 102 -101 -14.2 9/7/97 121°57.0' 41°47.8'

1.15 82 -94 -13.2 7/31/97 121°33.4' 41°07.1'

1.04 63 -99 -13.6 7/31/97 121°33.1' 41°07.0'

1.58 73 -101 -13.7 7/31/97 121°33.1' 41°07.0

1.67 83 -101 -13.7 7/31/97 121°33.0f 41°06.9'

1.75 90 -101 -13.6 9/5/97 121°33.0' 41°06.7'

1.59 84 -100 -13.5 7/31/97 121°31.1' 41°06.1'

1.63 86 -101 -13.8 11/4/97 121°30.6' 41°06.8'
Table 1. Chemical and isotopic data for selected springs, wells, and lakes in and adjacent to Medicine Lake Volcano -- continued 

[Chemical concentrations in milligrams per liter; isotope concentrations in parts per mil relative to standard mean ocean water]

ID/Name t(°C) pH SiO2 Ca Mg Na K Cl SO4 HCO3 5D 8 18O Coll. date Long. Lat.

ML41RM974 11.6 7.59 152 40.4 8.7 6.3 13.1 2.5 

Unnamed spring #1 at the head of Lava Creek

4.2

GT01JD81 1 - - .-...__ 

Unnamed spring #2 on Lava Creek

ML19RM97 - - 156 40.6 9.0 6.8 14.2 2.4 4.3 

Lava Creek at the road bridge

ML16RM97 12.1 172 39.1 9.8 7.1 14.0 2.1 4.0 

GT24RM93 12.0 8.15 - 39.2 10.4 7.3 14.7 2.9 4.4 

Spring north of Fish Trap at head of Ja She Creek

ML17RM97 12.4 - 177 38.7 10.5 7.4 14.5 2.2 3.9 

GT27RM93 12.0 8.26 - 39.2 11.2 7.7 15.2 2.7 4.4 

Crystal Spring at Adjumawi Lava Springs State Park

ML18RM97 12.8 8.28 184 37.3 11.9 8.6 14.1 2.6 3.4 

GT26RM93 12.8 8.16 - 37.6 12.1 8.5 14.4 3.1 3.6 

Spring at the north end of Big Lake

ML43RM974 - 8.70 203 24.6 15.8 2.6 22.8 2.5 5.7 

City well for McArthur and Fall River

Hot springs

GT73RM83 46 8.1 - 80.0 48 .3 235 5.4 120 

Little Valley Hot Spring

1.54 83 -100 -13.6 11/4/97 121°29.9' 41°07.2'

- -102 -13.5 »/«/81 121°29.4' 41°07.0'

1.78 89 -100 -13.6 8/2/97 121°29.4' 41°06.6'

1.9 106 -101 -13.4 8/1/97 121°27.4' 41°06.9'

- -101 -13.5 8/9/93

1.9 113 -99 -13.5 8/1/97 121°26.9' 41°06.7'

1.8 - -100 -13.4 8/9/93

1.7 122 -98 -13.3 8/1/97 121°24.5' 41°08.0'

1.1 - -99 -13.3 8/9/93

15.2 90 -100 -13.5 11/6/97 121°23.9' 41°03.1'

53 390 -113 -14.1 6/6/83 12T24.2' 41°13.8'
Table 1. -Chemical and isotopic data for selected springs, wells, and lakes in and adjacent to Medicine Lake Volcano ~ continued 

[Chemical concentrations in milligrams per liter; isotope concentrations in parts per mil relative to standard mean ocean water]

ID/Name t(°C) pH uS/cm

Lakes

GT45RM87 - 8.2

Blanche Lake

GT46RM87 - 7.6

Bullseye Lake

GT47RM87 - 7.8

GT35JD791 - -

Medicine Lake

ML20RM97 - - 800

Tule Lake Sump #1

ML21RM975 - - 800

Tule Lake Sump #2

SiO2 Ca Mg Na K Cl SO4 HCO3 5D

2.7 .6 .3 .8 .1 .2 .2 3 -53

1.3 .8 .4 1.2 .4 .2 0.7 8 -65

.9 1 .5 .9 .4 .2 .3 7 -69

. .73

18 218 234 -49

10 88 211 -63

6 18O Coll. date Long. Lat

-3.1 8/25/87 121°33.3' 41°34.1'

-6.7 8/25/87 121°34.4' 41°33.4'

-8.0 8/25/87 12P35.9' 41°34.7'

-7.5 8/17/79

-2.7 8/15/97 121°32.6' 41°52.7

-6.5 8/15/97 121°29.8' 41°52.3'

1 Isotope sample collected by Julie Donnelly-Nolan

2 Sample collected by running a bailer down the discharge pipe for the submersible pump. Analysis for cations and silica still pending

3 All samples collected in 1997 had less than 0.05 milligrams bromide (Br) per liter of water except for the well at Tule Lake National Wildlife Refuge 

Headquarters (0.44 mg/L).

4 All samples collected in 1997 had less than 0.05 milligrams nitrate (NO3 ) per liter of water except for Bear Spring (1.13 mg/L), Lost Spring (0.13 mg/L),

Dock well (0.14 mg/L), well at Tionesta (0.74 mg/L), well at quarantine station (0.74 mg/L), well at Long Bell Station (0.40 mg/L), Lost River (0.23 mg/L), 

Quaking Aspen Spring (0.10), well in Red Rock Lake Valley (0.53 mg/L), unnamed spring #1 on the Fall River (0.08 mg/L), Rainbow Spring (0.16 mg/L), 

unnamed spring #1 on Lava Creek (0.10 mg/L), and the city well for McArthur and Fall River (0.13 mg/L)

5 All samples collected in 1997 had less than 0.05 milligrams of phosphate (PO4) per liter of water except for Paynes Spring (0.08 mg/L) Crystal Spring at 

MedicineLake (0.07 mg/L), Lost River (0.05 mg/L), Tule Lake Sump #2 (0.12 mg/L)