The Livingston Formation in the 

Madison Range of Southwestern Montana 

By RUSSEll G. TYSDAL, 

DOUGLAS j. NICHOLS, and 

GARY R. WINKLER 

U.S. GEOLOGICAL SURVEY BULLETIN 1665 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1987 

For sale by the 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center 

Box 25425 

Denver, CO 80225 

Library of Congress Cataloging in Publication Data 

Tysdal, Russell G. 

The Livingston Formation in the Madison Range of southwestern Montana. 

(U.S. Geological Survey bulletin; 1665) 

Bibliography: p. 

Supt. of Docs. no.: I 19.3:1665 

1. Livingston Formation (Mont.) 2. Geology-Montana-Madison Range. 

I. Nichols, Douglas J. II. Winkler, Gary R. Ill. Title. IV Series. 

QE75.B9 no. 1665 557.3 s 86-600200 

[QE685] [557.86' 6] 
CONTENTS 

Abstract 1 

Introduction 1 

Livingston Formation 3 

Lower member 3 

Middle member 9 

Upper member 9 

Age 11 

Regional correlation 13 

References cited 14 

FIGURES 

1. Geologic map showing outcrop areas of Livingston Formation in the 

Madison and Gallatin Ranges, locations of paleontological collections, and 

sample sites of igneous rocks. 2 

2. Correlation chart showing relationships of the Livingston Formation in the 

Madison Range, with the type area of the Livingston Group in the Livingston area, and the Elkhorn Mountains Volcanics in the Elkhorn 

Mountains. 4 

3. Grid for classification of volcanic igneous rocks. 5 

4. Schematic cross section showing general stratigraphic relationships of the 

Livingston Formation in the Madison Range outcrop belt. 7 

5. Laharic breccia in the lower member of the Livingston Formation. 8 

6. Rounded volcanic boulder in upper member of the Livingston 

Formation. 9 

7. Stratigraphically significant pollen and spores from the Livingston Formation of the Madison Range and underlying beds. 12 

TABLES 

1. Data on igneous rocks of the Livingston Formation in the central part of 

the Madison Range. 6 

2. Kevex X-ray analyses for selected trace elements of welded tuffs from the 

Livingston Formation. 8 

3. K-Ar ages and analytical data of samples from lower member of Livingston 

Formation. 13 

Contents Ill 

The Livingston Formation in the 

Madison Range of Southwestern Montana 

By R. G. Tysdal, D. J. Nichols, and G. R. Winkler 

Abstract 

The Livingston Formation in the Madison Range of 

southwestern Montana is a sequence of volcanic and volcaniclastic rocks that is subdivided into three mappable units which, 

in ascending order, are named informally the lower, middle, 

and upper members. The lower member is a composite unit 

composed of mudstone, siltstone, sandstone and conglomeratic 

sandstone, and minor tuff, olivine basalt, and volcanic conglomerate. The middle member is composed of somber-colored 

volcanic flows and flow breccias of dacitic to andesitic composition, with lesser tuff and basalt. The lower two-thirds of 

the upper member consists of well-rounded volcanic clasts in 

a volcaniclastic sandstone matrix; the upper third is chiefly sandstone with local lenses of conglomerate. This upper third is transitional into the overlying Sphinx Conglomerate, a synorogenic 

deposit present in the Madison Range. 

The Livingston Formation of the Madison Range is of 

Cretaceous age and probably was deposited during the early 

to middle parts of the Campanian Stage. The age is based on 

a combination of megafauna! and palynological data from 

below and within the Livingston, K-Ar dates on tuff units from 

within the lower member, and K-Ar and 40Arf39Ar dates on intrusive rocks that postdate deformation of the sequence. 

INTRODUCTION 

The name Livingston Formation originally was applied by Weed (1893) to a thick sequence of volcaniclastic 

sedimentary strata, including agglomerate, in the vicinity of Livingston, Montana. Peale (1896) broadened the 

area of application to include predominantly pyroclastic 

rocks preserved near Sphinx Mountain in the Madison 

Range; in Jefferson Canyon, about 110 km west of 

Livingston; and near Maudlow, about 70 km northwest of Livingston (fig. 1). Strata subsequently assigned 

to the Livingston Formation varied from one author to 

another until the 1960's when, during extensive mapping in the Livingston area, Roberts (1963, 1972) 

restricted rocks assigned to the unit, raised the unit to 

group status, and defined four new formations within the 

group (fig. 2). In this paper we describe the volcaniclastic 

and volcanic rocks of the Livingston of the Madison 

Range; interpret the general depositional environment of 

the facies; and date the sequence by a combination of 

paleontologic and radiometric dating, and the time of 

deformation. 

Livingston rocks of the Sphinx Mountain area were 

first mapped and described by Peale (1896) in the Three 

Forks Folio. A larger scale map was published by Beck 

(1960), who recognized a tripartite division to the unit. 

Hadley (1969) mapped the Livingston strata northwest 

of Sphinx Mountain and described the three subunits in 

more detail (Hadley, 1980). In an unpublished Ph. D. 

dissertation, Hall ( 1961) mapped and briefly described 

rocks from two previously unrecognized areas of Livingston strata in the western part of the Gallatin Range 

(fig. 1), correlated them with the Livingston of the 

Madison Range, and speculated that intrusive rocks of 

Lone Mountain may have been a source for the volcanic 

and volcaniclastic rocks. The present study, an outgrowth 

of geologic mapping (Tysdal and Simons, 1985; Tysdal, 

1986) for the Madison Range Wilderness Study Area, 

describes and interprets Livingston rocks of the Madison 

Range only. Livingston rocks described by Hall (1961) 

in the Gallatin Range appear to be similar in many 

respects, although Hall did not subdivide them. 

The name Livingston was not used by Hadley 

(1969, 1980) for the sequence in the Madison Range. He 

believed the rocks correlated with the lower member of 

the Elkhorn Mountains Volcanics, the nearest outcrop 

of which is about 75 km to the northwest. We follow 

Peale (1896) and Beck (1960) and use the name Livingston, to preserve historical precedence and to retain 

the regional correlation inherent in this usage. We retain 

formational status for the sequence in the Madison 

Range, and the three mapped units are treated as informal members. The three members are restricted to such 

a small area (about 60 km2

) of the Madison Range that 

introduction of one or more formation names seems unwarranted. Correlative Livingston rocks of the Gallatin 

Range occupy an even smaller area and have not been 

subdivided. 

Introduction 
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Figure 1 (above and facing page). Geologic map showing outcrop areas of Livingston Formation in the Madison and Gallatin Ranges, locations of paleontological collections (A- G) and sample sites of igneous rocks (1-8). Map compiled from Tysdal and Simons (1985), McMannis and Chadwick (1964), Hall 

(1961), and unpublished data. 
EXPlANATION 

Ou Unconsolidated sedimentary rocks (Quaternary) 

Tv Volcanic rocks, undivided (Tertiary) 

Dacite intrusive rocks (Upper Cretaceous) 

Sphinx Conglomerate (Upper Cretaceous) 

Livingston Group, upper member (Upper Cretaceous) 

Livingston Group, middle member (Upper Cretaceous) 

Livingston Group, lower member (Upper Cretaceous) 

Livingston Group, undivided (Upper Cretaceous) 

In Gallatin Range, Cretaceous rocks older than Livingston 

Group; in Madison Range, Cretaceous rocks older than 

Virgelle Sandstone, and unmapped areas of Cretaceous 

dacitic intrusive rocks (Upper Cretaceous) 

(?)Everts Formation and Virgelle Sandstone, undivided 

(Upper Cretaceous) 

Sedimentary rocks, undivided (Mesozoic and Paleozoic) 

Metamorphic rocks, undivided (Archean) 

---- Contact-Dashed where approximately located 

-~-- Fault-D, downthrown side; U, upthrown side 

_.___. __ • ._ Thrust fault-Teeth on upper plate 

4----+-- Anticline-Showing trace of axial plane and direction of plunge 

....__--+-- Syncline-Showing trace of axial plane and direction of plunge 

Bedding 

Inclined 

Overturned 

Fossil locality 

Igneous-rock locality 

Petrologic study of volcanic material in the 

sedimentary rocks of the Livingston Group in the Livingston area indicated that much of it was derived from 

the Late Cretaceous Elkhorn Mountains Volcanics, 

associated with emplacement of the Boulder batholith 

(McMannis, 1955; Klepper and others, 1957; Roberts, 

1963, 1972). Local volcanic source rocks occur near 

Maudlow (Skipp and McGrew, 1977); south of Big 

Timber, about 50 km east of Livingston (Weed, 1893; 

Parsons, 1942); and near Flathead Pass in the Bridger 

Range, about 75 km northwest of Livingston (Weed, 

1893) (fig. 1). We suggest that most of the volcaniclastic 

strata and associated volcanic rocks of the Livingston in 

the Madison Range also were derived locally. 

LIVINGSTON FORMATION 

The Livingston Formation within the Madison 

Range is preserved only in a northwest-trending erosional 

remnant that forms an outcrop belt about 19 km long 

and as much as 5 km wide in the west-central part of the 

range (fig. 1). The formation is composed of three informal units, which Hadley (1980) named, in ascending 

order, the volcanic sandstone unit, volcanic breccia unit, 

and volcanic conglomerate unit. We have renamed these 

units the lower, middle, and upper members, respectively. The preserved sequence has a maximum thickness of 

about 1 ,000 m. Representative igneous rocks from the 

various members that make up the formation were 

analyzed chemically (table 1), and the data were used for 

classification according to the method of De la Roche and 

others (1980), as shown on figure 3. 

The volcanic and volcaniclastic rocks of the outcrop belt in the Madison Range can be interpreted as both 

vent and alluvial facies, following criteria outlined by Parsons (1965, 1969) and Smedes and Prostka (1972) for 

rocks in and near Yellowstone National Park. A vent 

facies ideally is characterized by angular poorly sorted 

breccias, dike swarms, stocks, plugs, and (or) laccoliths. 

Away from an intrusive center, vent facies rocks intertongue with alluvial facies rocks, which are composed of 

water-laid volcaniclastic strata of conglomerate, sandstone, and siltstone as well as airfall tuff. Volcanic units 

become thin away from the vent area, whereas the sorting, rounding, and fineness of clasts in the sedimentary 

units increase away from the vent area. 

Lower Member 

The lower member ranges from about 60 to 250 m 

thick and is a heterogeneous assemblage of mudstone, 

siltstone, sandstone and conglomeratic sandstone, welded 

tuff, olivine basalt, and volcanic conglomerate. The 

member is an alluvial facies sequence in which the variety and thickness of sedimentary units increase to the 

southeast (fig. 4). 

The most widespread, and thickest, unit in the 

lower member is a volcaniclastic sandstone that Hadley 

( 1980) briefly described from exposures at the northwest 

end of the outcrop belt in the Madison Range. The unit 

is recognized along the entire length of the belt, is thickest 

in the southern exposures, and is composed chiefly of 

angular fractured crystals of basalt constituents cemented 

by chlorite. Some outcrops have an admixture of rounded 

grains of volcanic rock composed of felted plagioclase 

laths, and others contain pebbles and cobbles of basalt. 

Steep to shallow tabular and trough crossbeds are common. The sandstone locally is conglomeratic, much more 

so in the northwestern part of the belt than southeastward, with lenses as much as several meters thick of 

subangular to well-rounded pebbles of red, green, and 

dark-gray chert and volcanic rocks, including tuff. The 

Lower Member 3 
>- ~ 

E 'Cii 

(/) 

~ (j) .E 

WESTERN INTERIOR ZONE FOSSILS a:: UJ Q) 2 3 E <( (.!) c: 

(No specific K·Ar age has been UJ <{ 2 ELKHORN MADISON LIVINGSTON 

determined for fossils in braces) w >- til § MOUNTAINS RANGE AREA (.!) z <( 0 "0 ... :J Q) 

<t 

= (/) 

::( (1) 

~ :e.. 

Billman 

70 Creek 

Baculites reesidei 70.3 Formation 

Baculites cuneatus 71.6 F 

72 

Baculites compressus 73.2 

Didymoceras cheyennense 73.7 Exiteloceras jenneyi 

Didymoceras stevensoni 73.8 74 c: 

0 

·.;:::; (1) 

Didymoceras Miner nebrascence (1) 

c. E Creek 

0 Formation LL 

Elkhorn c. 

::l 

Baculites scotti 0 

Baculites gregoryensis 76 

Baculites perplexus (late form) (.!) 

Baculites gilberti c: 76.8 Sample Baculites perplexus (early form) .!!! c: 

c: no. 2 

Baculites sp.(smooth) (1) 0 

c. 

Baculites asperiformis E F (1) 

Baculites maclearni 78 u Mountains c: 

B Cl 

(/) c: Cl 

c: 

·:;;: > 79.7 :.J 

Bacu/ites obtusus 79.3 ...J 

80.0 80 79.8 Sample Cokedale no. 1 Formation 

Bacu/ites sp.(weak flank ribs) 80.8 volcanics 

Baculites sp.(smooth) } 

82 

Scaphites hippocrepis Ill 

Scaphites hippocrepis II 

F F Scaphites hippocrepis I 

84 

Desmoscaphites bassleri 84.4 Everts(?) Eagle 

Formation Sandstone 

Slim Telegraph 

Desmoscaphites erdmannii c: Creek 

Clioscaphites choteauensis (1) Formation ·c: 

C/ioscaphites vermiformis 86 B Sam c: Clioscaphites saxitonianus (1) 

Scaphites depressus, Inoceramus (j) 

undulatoplicatus 

Scaphites ventricosus, Inoceramus Formation 

involutus Cody 

c: Shale 

88 (1) (part) '(j 

Scaphites preventicosus, Inoceramus (1) 

88.7 

·c: 

deform is 0 

u 

4 The livingston Formation, Madison Range, Montana 
Figure 2(facing page). Correlation chart showing relationships 

of the Livingston Formation in the Madison Range, with the 

type area of the Livingston Group in the Livingston area and 

the Elkhorn Mountains Volcanics in the Elkhorn Mountains 

southeast of Helena. Boundaries of the Upper Cretaceous 

stages, Western Interior fossil zones, and potassium-argon ages 

are adapted from Obradovich and Cobban (1975), except that 

the radiometric ages are recalculated for new 40Ar decay constants (Steiger and Jager, 1977). Column 1 is modified from 

Robinson and others (1968), Gill and Cobban (1973), Smedes 

(1966), and Klepper and others (1957). Column 2 is from the 

present study. Column 3 is from Roberts (1972), as modified 

by Skipp and McGrew (1977). F-boundary dated with fossils, 

and correlates with zone fossils of leftmost column. Rboundary dated by K-Ar date, and correlates with million-year 

column. *At the one locality where C. saxitoniatus was found 

in the Virgelle Sandstone in the Madison Range, the fossil is 

associated with 5. depressus (range zone indicated by vertical 

bar); hence, the two faunal zones overlap. This differs from 

findings in north-central Montana where C. saxitoniatus is 

wholly younger than 5. depressus (Cobban, oral commun., 

1984). 

MILLICATIONS 

Phonolite 

Ne 

-

-1000 1000 

lenses commonly are trough crossbedded, with troughs 

as much as 2m across. Interlayered in the lower member 

in the southeasternmost part of the outcrop belt are abundant beds of greenish- and dark-gray carbonaceous 

mudstone, bentonitic mudstone, and a few thin beds of 

bentonite and biotite-bearing tuff. Some mudstone contains discontinuous coaly lenses about 1 em thick and as 

much as 1 m long. 

The basal contact of the lower member generally 

is marked by an abrupt increase of volcanic grains, which 

makes the member much darker than the underlying 

strata. In a few places the lower member is demonstrably 

transitional downward through a few meters into the 

underlying strata, and the contact is chosen at the horizon 

where volcanic grains become the dominant constituent. 

In the zone of transition, the member is a mixture of 

rounded quartz grains associated with abundant rounded 

volcanic-rock fragments and angular broken grains of 

plagioclase and minor potassium feldspar, clinopyroxene, 

and biotite. The matrix is chloritized and contains minor 

~ns 

Qz 

2000 3000 MILLICATIONS 

Figure 3. Grid for classification of volcanic igneous rocks (from De Ia Roche and others, 1980), showing plots of samples analyzed 

in table 1. Sample locality numbers are those offigure 1. Grid used with permission of Elsevier Scientific Publishing Company. 

lower Member 5 
Q'\ 

-1 

::r 

~ 

r-

;r 

:;· Table 1. Data on igneous rocks of the Livingston Formation in central part of Madison Range. OQ 

"' 0 

:::s Sample Field Location Rock name Geologic occurrence Chemical analysis (wt percent) "TT 

0 locality No. (lat N., long W.) (Classification 

3 no. scheme of Si02 Al20 3 FeT03 MgO CaO Na2o K2

0 Ti02 P20s MnO LOI 

a (correlates with De Ia Roche cs-

? figs. 1 and 3) and others, 1980) 

~ Cl 

c.. 1 80MWk237C 45 007 '07 " N. Rhyodacite Gray welded tuff in 65.7 15 2.19 0.65 2.91 4.45 1.36 0.48 0.1 0.05 6.32 ;;;· 

0 111~4'W"W. lower member. :::s 

~ 

Cl 2 81MTz840E 45 007 '07 " N. Rhyolite Brown welded tuff in 68 15.5 2.69 .49 .94 3.81 6.05 .49 <.05 .07 .51 :::s 

OQ 

!0 111 ~4' W" w. lower member. ~ 0 

~ 3 82MTz1767 45 °12' 20" N. Alkali rhyolite Brown welded tuff in 68.8 15.4 2.49 .55 .66 4.37 6.03 .53 .11 .03 .93 Cl 

:::s 

Cl 1110J2'12"W. middle member. 

4 80MWk237A 45 007' 07" N. Basalt Flow in lower 47.1 7.93 9.43 20.4 6.53 1.14 2.51 .42 .52 .18 3.12 

111 ~4' W" w. member. 

5 82MTz1756 45 °13 '07 " N. Basalt porphyry Intrudes lower 53.7 19.7 7.01 1.21 6.57 3.90 3.33 .85 .66 .24 2.17 

111 OJ2' 22" w. member. 

6 80MWk218A 45 °W' 20" N. Trachyandesite Flow in middle member 56.1 17.8 6.54 2.17 4.92 3.83 5.15 .88 .70 .10 1.23 

111 ~7' W" w. 

7 81MTz854D 45 °W' 20" N. Trachyte ----do---- 57.5 17.1 7.25 1.81 3.36 5.43 4.73 .65 .44 .23 .86 

111 ~7' W" w. 

8 82MTz1686 45 009' 00" N. Dacite Autoclastic flow 62.9 16 5.99 1.73 4.96 3.86 2.71 .61 .26 .w .87 

111 ~3'32" w. breccia in middle 

member. 
SE NW 

Figure 4. Schematic cross section showing general stratigraphic relationships of the Livingston Formation in 

the Madison Range outcrop belt. Wavy line indicates diastem, jagged line indicates intertonguing. Ks, Sphinx 

Conglomerate; Klu, Kim, and Kll are upper, middle, and lower members, respectively, of Livingston Formation; Ke(?), Everts(?) Formation. 

calcite. The sandstone ranges from moderately to poorly sorted, although some strata contain abundant 

magnetite grains sorted into distinct layers. In one place 

the lower part of the member intertongues with beds and 

lenses, as much as 100m thick, of light-gray, well-sorted, 

fine- to medium-grained, quartz-rich "salt and pepper" 

sandstone like that of the underlying strata. Calcite cement is common. Trough crossbeds are common and 

slump structures were observed in some outcrops. Such 

units probably represent stream-channel deposits. 

Basalt is a widespread rock type of the lower 

member, with flows ranging from about 8 m to as much 

as 60 m thick. The basalt contains olivine phenocrysts; 

the matrix is composed chiefly of plagioclase and lesser 

clinopyroxene and magnetite. Both the phenocrysts and 

matrix are altered, containing widespread chlorite and 

lesser calcite. Some flows are vesicular, with radiating 

fibrous calcite filling the vesicles. At least one flow has 

a rubbly breccia texture. Within the lower member, basalt 

flows are thickest toward the southeastern end of the outcrop belt in the Madison Range (fig. 4). The basalt flows 

everywhere overlie the basaltic volcaniclastic sandstone 

unit of the lower member. No basalt flows underlie the 

sandstone, which indicates the sands were eroded from 

basalt flows outside the present outcrop area. In the 

northernmost part of the outcrop belt, no basalt was 

found by us or Hadley (1980) in the lower member, but 

basalt does occur within the overlying middle member. 

It is unknown if this latter basalt is time correlative with 

that of the lower member. 

Welded tuff units are common in the upper part 

of the lower member. The two prominent ones are a gray 

tuff and a stratigraphically higher brown tuff. The gray 

tuff is only a few meters thick and is 60 to 70 percent 

welded glass shards, with phenocrysts of plagioclase (15 

to 20 percent), and lesser biotite (1 to 8 percent), 

clinopyroxene (1 to 5 percent), hornblende (1 to 2 percent), and opaques (2 to 3 percent). The glass in one sample from near Lizard Lakes (fig. 1, loc. 1) shows almost 

no devitrification and the phenocrysts are not altered. 

The brown welded tuff is the most abundant of the 

tuff units and is as much as 100m thick. It is composed 

of about 50 percent glass shards, most of which are 

devitrified; plagioclase phenocrysts (25 percent); biotite 

(5 percent); quartz (5 percent); opaques (<5 percent); and 

pumice fragments (15 percent). The pumice fragments 

and glass shards are stretched and flattened, forming a 

flow texture in which shards are molded against the 

phenocrysts and pumice fragments. 

The brown tuff, although the thickest tuff unit, is 

not present in all of the observed outcrops. It overlies 

different rock units at different places, and its thickness 

varies from place to place. The tuff was deposited on a 

surface that is a diastem, but its abrupt changes in 

thickness and discontinuous nature, including absence 

from some sections, suggests that its upper surface also 

is a diastem. This is definitely the case at several localities, 

because the tuff is overlain by different types of nonmarine sedimentary rock units. 

A similar brown welded tuff is present within the 

overlying middle member in the northwestern part of the 

outcrop belt (fig. 4). Its geologic setting is discussed in 

the next section, ''Middle member,'' but its significance 

is considered here. Table 2 compares selected trace 

elements of brown welded tuff from the lower member 

(fig. 1, loc. 2) with brown tuff from the middle member 

(fig. 1, loc. 3), and compares both with the gray tuff. 

The two brown tuffs have similar concentrations of the 

listed elements, but differ significantly from those of the 

gray tuff. These same relations exist for the major 

elements, as shown in table 1. These data, combined with 

the identical appearance of the brown tuffs, and their 

similar thickness, suggest they represent the same volcanic 

event. Hence, they constitute a time line, and show that 

the middle unit at the northwestern end of the belt in the 

Madison Range was being formed at the same time as 

part of the fluvial strata of the lower unit at the southeastern end of the belt (fig. 4). 

Volumetrically minor tuff units higher in the upper part of the lower member differ from the brown and 

Lower Member 7 
Table 2. Kevex X-ray analyses for selected trace elements of 

welded tuffs from the Livingston Formation. 

[Detection limit for each element is shown above elemental abbreviation. Values in parts per million] 

Sample 

locality Description 6 5 4 3 3 3 

no. Rb Sr y Zr Nb Mo 

Gray tuff (lower 

member). 83 802 27 264 11 0 

2 Brown tuff (lower 

member). 141 249 26 278 13 7 

3 Brown tuff (middle 

member). 150 236 22 258 10 3 

gray tuffs by being 75-85 percent glass shards, largely 

devitrified, with 5-10 percent plagioclase phenocrysts, 

and fewer rock fragments. Mafic minerals make up less 

than 1 percent of the constituents. In addition, these tuffs 

are only slightly flattened and distorted; flow structures 

are not common. The shards are sharply angular and 

include local unbroken glass-bubble walls and abundant 

Y -shaped shards. The tuffs are commonly tan, green, 

or light gray, only a meter or two thick, and are 

discontinuous. 

In one place near the south easternmost part of the 

outcrop belt is a 30-m-thick lahar deposit of breccia and 

conglomerate (fig. 5). The lahar is an unsorted and 

unstratified deposit consisting of subangular to rounded 

basaltic pebbles, cobbles, and boulders up to 0.5 m in 

diameter set in a fragmental volcaniclastic sandstone 

matrix. The clasts make up about 60 to 70 percent of the 

deposit. Some of the clasts are of a porphyritic basalt of 

a type known only from sills that intrude the base of the 

lower member and the top of the underlying strata at the 

northwesternmost part of the outcrop belt, suggesting a 

source area northwest of the preserved deposit. The lahar 

is believed to represent a stream-valley deposit which, like 

present-day lahars, typically is preserved on a valley floor 

some distance from its source area (Crandell, 1971, p. 4; 

Fisher and Schmincke, 1984, p. 297). 

In the Madison Range, the lower member is largely an alluvial facies deposit in which the variety and 

thickness of sedimentary units increase to the southeast 

(fig. 4). The basal basaltic volcaniclastic sandstone, the 

only unit of the lower member that occurs throughout 

the outcrop belt, shows a southeastward thickening that 

coincides with a decrease in the abundance and thickness 

of pebble conglomerate lenses. The "maturity" of the 

sandstone itself shows only a marginal increase to the 

southeast, but interlayered mudstone beds are present at 

the southeast and not at the northwest. The general 

overall pattern, therefore, shows a southeastward 

decrease in grain (clast) size and an increase in sorting. 

8 The Livingston Formation, Madison Range, Montana 

According to the vent facies/alluvial facies model 

presented earlier, fossil trees and other plant material are 

common in the alluvial facies, but not in the vent facies; 

this relationship reflects erosion of vegetation from the 

flanks of a vent area and deposition in adjacent lowlands, 

or vegetation in the lowlands to start with (Smedes and 

Prostka, 1972). In the Madison outcrop belt, large 

fragments of palm tree trunks, as well as particulate plant 

debris, are common in the volcaniclastic sandstone of the 

lower member. Leaf collections from the member have 

been made by Peale (1896) and Hall (1961). 

The conglomeratic lahar deposit present in the 

lower member at the southeastern end of the outcrop belt 

also fits the expected pattern. Lahars typically occur on 

valley floors some distance from their source (Crandell, 

1971, p. 4); thus preservation of isolated bodies is to be 

expected, representing deposits in topographic lows at the 

time interval of deposition, and not found closer toward 

the vent area. 

Figure 5. Laharic breccia in the lower member of the Livingston Formation. Hammer for scale; handle is about 35 em 

long. 
The sequence of units in the lower member differs 

from place to place within the outcrop belt of the 

Madison Range. Nevertheless, there is an overall pattern 

to the sequence. The basaltic volcaniclastic sandstone 

makes up the basal part of the member, and is directly 

overlain by basalt in most outcrops. The brown welded 

tuff is consistently upsection from the basalt flows. Not 

all sections contain the brown welded tuff, however. In 

at least five of nine observed sections in the southeastern 

half of the belt, basalt is directly overlain by flow and 

flow breccia of the middle member of the sequence. In 

the other sections, strata of siltstone, sandstone and conglomeratic sandstone, and welded tuff occur in between. 

Middle Member 

The middle member of the Livingston Formation 

in the Madison Range is composed chiefly of purple to 

mauve volcanic flow breccia of dacite to andesite composition and lesser flow breccia of trachyte to 

trachyandesite composition. The volcanic breccia unit is 

thickest in the northwestern part of the outcrop belt where 

it is estimated to be 300 to 400 m thick (Hadley, 1980, 

p. 80) (fig. 4). Hadley (1980) described these rocks as 

several types of clinopyroxene, hornblende, or biotitebearing andesite breccia firmly cemented in a matrix of 

finer particles of the same material. He noted units 15 m 

or more thick, showing no sorting or bedding, with interbeds of finer grained tuff-breccia and coarse 

volcaniclastic sandstone. In some places within the breccia unit, thick bodies of slightly brecciated pyroxene 

andesite may represent lava flows. 

Brown biotite-bearing welded tuff, correlated with 

that of the lower member, was observed by us in three 

places in the lower middle part of the middle member in 

the northwestern part of the outcrop belt. At one of the 

localities, the tuff is several meters thick and is overlain 

and underlain by purple flow breccia. The upper breccia 

is overlain by a sequence about 100 m thick of deeply 

weathered olivine basalt. 

The trachyte to trachyandesite flow occurs on the 

north side of the central part of the outcrop belt, near 

locality 7. This flow is as much as 50 m thick, and much 

of it shows a flow alinement of elongate zoned plagioclase 

phenocrysts. The upper part is a flow breccia, in which 

the zoned plagioclase phenocrysts and rock fragments are 

more nearly equidimensional and are not alined. Some 

of the clasts are as much as 20 em across. 

The middle member of the formation represents the 

"zenith" of volcanic activity for rocks preserved in the 

Madison Range outcrop belt. The breccia of the middle 

member is thickest and most varied at the northwestern 

end of the belt, and is represented by only a single 

autobreccia flow at the southeastern end of the belt. 

Concentration of the variety and thickness of extrusive 

rocks at the northwestern end of the belt, as well as the 

occurrence there of porphyritic basalt sills within the 

lower member and the underlying Cretaceous strata, suggests that the northwestern end may be a vent area, or 

at least is closer to a vent area than rocks at the 

southeastern end of the belt. 

Upper Member 

The upper member of the Livingston Formation has 

a maximum thickness of about 200 m. The lower and 

middle parts of the member consist of well-rounded clasts 

of volcanic rocks in a volcaniclastic sandstone matrix. The 

clasts commonly range from 10 to 50 em in diameter but 

some are as large as 150 em (fig. 6). They are representative of the volcanic rocks present in the lower two 

members of the formation, particularly the reddish-purple 

flow breccia of the middle member. Other specifically 

identified clasts include olivine basalt, minor biotitebearing welded tuff, and a few igneous clasts for which 

no comparable outcrop is known. The matrix is coarsegrained sandstone of angular lithic fragments of volcanic 

rocks-chiefly plagioclase, with lesser clinopyroxene, 

potassium feldspar, hornblende, biotite, quartz, magnetite, and volcanic-rock fragments. The rocks are poorly 

cemented by calcite, hematite, and (or) chlorite. 

Contact of the middle and upper members is sharp; 

it is a diastem in some places but clearly is transitional 

Figure 6. Rounded volcanic boulder in upper member of the 

Livingston Formation. Head of hammer is about 20 em long. 

Upper Member 9 
in others. South of locality 7 (fig. 1), for example, sandstone of the upper member is interlayered with flow breccia in the uppermost part of the middle member. The 

change from breccia to sandstone is subtle because composition of the two types of rocks is the same. The top 

of the highest flow was chosen as the contact of the two 

members. 

Many of the cobbles and boulders in the lower part 

of the upper member are isolated within a sandstone 

matrix and do not touch one another. The strata are probably lahars, flood deposits, laid down by a rapidly moving slurry of boulders and finer material, similar to 

modern-day lahars described by Crandell (1971, p. 58-60) 

for the Mount Rainier, Washington, area and by 

Waldron (1967) in Costa Rica. Other conglomerates have 

a much lower matrix percent but may be of the same 

origin. 

The upper third of the upper member is chiefly 

sandstone, with local units of boulder conglomerate, 

abundant lenses of pebble conglomerate, and 

volumetrically minor mudstone. Conglomerate lenses are 

a few meters to several tens of meters wide, and range 

from a few centimeters to a few meters thick. Many show 

steeply inclined crossbeds and crosscutting erosional 

features characterisic of anastomosing channels. 

Upsection, the conglomerate lenses of the upper 

third of the upper member, in addition to volcanic clasts, 

contain increasing quantities of clasts of sedimentary 

rocks recycled from Mesozoic strata. Some of the clasts 

are from specifically recognizable units such as the 

gastropod limestone from the top of the Lower Cretaceous Kootenai Formation, oolitic limestone from the 

Middle and Upper Jurassic Ellis Group, and ochre 

mudstone from the Upper Jurassic Morrison Formation 

as well as sandstone and chert from formations not 

specifically identified. The calcareous cement of the 

member also increases in amount upsection. 

Along the southeastern limit of the outcrop area 

of the Sphinx Conglomerate (fig. 1), where the section 

is fairly well exposed, the upper part of the upper member 

of the Livingston Formation contains maroon-red 

mudstone, red and green mudstone, gray mudstone, and 

minor interbedded sandstone. These strata are overlain 

by pale-green, medium- to coarse-grained, pebbly sandstone that is transitional through about 30 m into the 

Sphinx Conglomerate. All of these strata described in the 

first part of this paragraph occur higher stratigraphically than the conglomerate layers and lenses, and are 2 or 

3m to several meters thick. The contact with the overlying Sphinx Conglomerate is transitional. The contact is 

placed at the base of the first occurrence of a conglomerate bed, largely composed of limestone clasts, 

cemented with reddish-orange hematitic muddy sandstone. Conglomerate lenses downsection from the red and 

10 The Livingston Formation, Madison Range, Montana 

green mudstone lack the reddish matrix of the Sphinx 

Conglomerate. 

Previous workers (Peale, 1896; Beck, 1960; Hall, 

1961; and Hadley, 1980) concluded that the strata of the 

Livingston Group lay unconformably beneath the Sphinx 

Conglomerate. Beck (1960), however, observed that near 

the eastern and northern part of Sphinx Mountain the 

contact "appears to be conformable," but noted angular 

discordance along the west side of the mountain. We 

follow Beck (1960) in concluding conformity of strata on 

the northeast side, as well as everywhere else except on 

the west side. There, the Sphinx Conglomerate lies directly on volcanic rocks of the middle member of the 

Livingston. The contact on the west may be an unconformity, but the possibility exists that it is a fault. 

Evidence for a structural interpretation was presented by 

Tysdal and others ( 1986). 

A series of turbidite beds overlies breccia of the 

middle member near the southeastern corner of the outcrop belt of the Madison Range and forms a localized 

unit at the base of the upper member. In a northwestsoutheast exposure along the face of a ledge, these strata 

occupy a V-shaped cut about 0.5 km wide that was eroded 

into the middle and lower members. The erosional depression probably was a pond or small lake. The turbidites 

were formed by the discharge of a sediment-laden stream, 

or streams, into the lake. The turbidite sequence is about 

30 m thick, and grades upward from clay and silt-size 

particles in the lower beds to sand-size materials in the 

upper beds. The upper half of the sequence contains some 

irregularly shaped clasts of ripped up turbidite layers like 

those lower in the sequence. Erosion scours are present 

at several intervals, immediately overlain by pebbly 

coarse-grained san~stone, rip-up clasts, and channel 

crossbeds; some layers show water escape structures. The 

uppermost layers of the sequence are very coarse grained 

sandstone with large-scale crossbeds and are stream channel deposits. 

Rocks in the lower half of the sequence are composed of clay to silt-size particles in turbidite layers a few 

millimeters to 1 or 2 em thick; some layers are varve-like. 

The strata have an overall color of grayish-pink to tan. Thin 

sections of the coarser grained turbidite sequence show 

a composition of detrital volcanic debris. The grains are 

angular, broken fragments, chiefly plagioclase, with lesser 

potassium feldspar, clinopyroxene, biotite, hornblende, 

volcanic-rock fragments, and minor quartz. The matrix 

and topmost part of turbidite layers are clay-size material 

that was not analyzed. Opaque grains (for example, magnetite) make up as much as 10 percent of some rocks. 

The upper member of the Livingston in general 

shows a southeastward and upward decrease in the 

number and thickness of conglomerate layers; clast size 

also decreases southeastward and upward (fig. 4). Limited 
measurement of paleocurrent structures indicates a 

southeastward transport direction. Following the concept 

of vent facies versus alluvial facies outlined previously, 

a vertical section near Sphinx Mountain indicates that the 

upper part of the member records deposition farther from 

the source area than does the lower conglomerate part 

of the member. However, the section may simply reflect 

an upward and southeastward decrease in the vigorousness of the depositional processes, and distance from the 

source need not have changed. Deposition of the upper 

member would then have coincided with a waning of 

volcanic activity in the vent area. 

Age 

Livingston Formation rocks of the Madison Range 

were assigned a Cretaceous age by Peale ( 1896) on the 

basis of a megafossil flora collected by him (Peale, in 

Knowlton, 1893, p. 44, 45) from strata between the Middle and North Forks of Bear Creek (fig. 1, approx. loc. 

A). It is not clear, however, whether the collection was 

from the lower member or from the upper part of the 

underlying Everts(?) Formation. A leaf collection from 

Livingston strata in "sec. 30?, T. 7 S., R. 2E." (fig. 1, 

approx. loc. B) was assigned a Paleocene age by Erling 

Dorf (Hall, 1961, p. 81); and another flora (fig. 1, approx. loc. C) was assigned a "late upper Cretaceous" age 

by R. W. Brown (Hall, 1961, p. 81, 82). Freshwater 

gastropods and pelecypods collected by Beck (1960, 

p. 132) (fig. 1, approx. loc. D) are not age diagnostic. 

Our studies show that the maximum age of the Livingston strata is Campanian and that the minimum age 

is no younger than about mid-Maestrichtian. The age 

assignment was determined through ( 1) palynological 

dating of strata below and within the Livingston, (2) 

radiometric dating of welded tuffs within the Livingston, 

and (3) radiometric dating of dacite laccolithic rocks that 

Tysdal and others (1986) have shown to postdate deformation of the Livingston. 

The palynological sample from locality E (fig. 1; 

USGS paleobotany loc. no. D6285) is from the upper 

100 m of the strata that conformably underlie the Livingston rocks. The stratigraphic position of the sample could 

not be determined more precisely because of limited outcrops and the more than 1-km separation of the sample 

locality from the nearest Livingston outcrops. The sample was obtained from a dark-gray carbonaceous 

mudstone that underlies a unit of trough crossbedded 

"salt and pepper" sandstone. The sample from locality 

E yielded the following palynomorphs, some of which 

are shown in figure 7: 

Appendicisporites sp. 

Araucariacites sp. 

Callialasporites sp. 

Cicatricosisporites sp. cf. C. australiensis 

Cicatricosisporites sp. 

Complexiopollis? sp. 

Cupuliferoidaepollenites sp. 

Cyathidites minor 

Distaltriangulisporites sp. C 

Echinatisporis varispinosus 

Eucommiidites minor 

Foraminisporis wonthaggiensis 

Gleicheniidites senonicus 

Hazaria sp. 

Laevigatosporites sp. 

Nyssapollenites sp. 

Osmundacidites wellmanii 

Proteacidites retusus 

Pseudoplicapollis newmanii 

Taxodiaceaepollenites hiatus 

Triatriopollenites granulatus 

Zlivisporis novomexicanum 

"Sporites type 1" 

isoetalean microspores 

tricolpate pollen, unidentified 

The assemblage is indicative of latest Santonian or 

earliest Campanian age. Key forms in the assemblage are 

Distaltriangulisporites sp. C and Pseudoplicapollis 

newmanii, which on the basis of previously published 

records (Nichols and others, 1982, pl. 1) were not known 

to occur together. The previously known range of 

Distaltriangulisporites sp. C is limited to about the upper two-thirds of the Santonian, and Pseudoplicapollis 

newmanii is believed to have appeared first in the earliest 

Campanian. The co-occurrence of these species suggests 

an age at or near the Santonian-Campanian boundary for 

rocks just below the Livingston Formation. An independent evaluation of the maximum age of the assemblage is 

provided by the early Santonian ammonite Scaphites 

depressus. A specimen of this species (identified by W. 

A. Cobban, written commun., 1981) was collected by us 

from the base of the Virgelle Sandstone (fig. 1, loc. F), 

about 400 m stratigraphically below the palynomorph 

assemblage of locality E. 

The palynological sample of locality G is from a 

brown carbonaceous mudstone in the lower member of 

the Livingston from a locality in the east-central part of 

the outcrop area (fig. 1; USGS paleobotany loc. D6368). 

It was collected about 50 m above the base of the member 

and yielded the following palynomorphs, some of which 

are shown in figure 7: 

Appendicisporites sp. 

Aquilapollenites sp. 

Cicatricosisporites sp. 

Cupuliferoidaepollenites sp. 

Cyathidites minor 

Echinatisporis varispinosus 

Foraminisporis wonthaggiensis 

Gleicheniidites senonicus 

Age 11 
A B 

c D 

E F 

H I 

Figure 7. Stratigraphically sign ificant pollen and spores from the Livingston Formation of the Madison Range and underlying 

beds. a, b- Proteacidites spp.; c- Aquilapollenites sp. (equatorial view); d- Aquilapollenites sp. (polar view); e- Pseudoplicapollis 

newmanii; f - Complexiopollis? sp.; g, h- Distaltriangulisporites sp. C, (two levels of focus on the same specimen); i- Minerisporites 

pseudorichardsonii. Specimens in a-d and i are from the Livingston Formation . All specimens enlarged 1 OOOX except i, 1200X. 

Hazaria sp. 

Laevigatosporites sp. 

Microreticulatisporites sp. 

Minerisporites pseudorichardsonii 

Pityosporites sp. 

Proteacidites retusus 

Proteacidites spp. 

Pseudoplicapollis newmanii 

Schizeaeoisporites sp. 

Taxodiaceaepollenites hiatus 

Triatriopollenites granulatus 

Zlivisporis novomexicanum 

isoetalean microspores 

tricolpate pollen, unidentified 

trilete spores, unidentified 

The assemblage includes species characteristic of 

early Campanian age. The key species are Pseudoplicapollis newmanii, a form that appeared in the earliest Campanian and for which the earliest Campanian 

palynomorph biozone is named (Nichols and others, 

12 The Livingston Formation, Madison Range, Montana 

1982), and Aquilapollenites sp., a previously undescribed 

form. The species of Aquilapollenites present has not 

been reported from middle or late Campanian 

palynomorph biozones, and none of the other species of 

palynomorphs that characterize the middle or late Campanian are present in the assemblage from sample locality G. The megaspore Minerisporites pseudorichardsonii 

has been reported previously from the Santonian in 

Wyoming and the lower Campanian in Montana 

(Tschudy, 1976). Thus the palynological evidence indicates that the lower member of the Livingston is early 

Campanian in age, and it suggests that the unit dates from 

near the boundary of the P. newmanii and A. senonicus 

biozones (estimated absolute age about 81 m.y.). 

Two potassium-argon dates (table 3) on biotite were 

obtained from previously described welded tuff units 

within the lower member of the Livingston. Both samples 

are from the southeastern corner of the outcrop belt (fig. 

1). The sample of locality 1, from the gray welded tuff, 

yielded an age of 79.8 ± 2.9 m.y. The sample of locality 
2, from the stratigraphically higher brown welded tuff, 

yielded an age of 76.8±2.5 m.y. Using the correlation 

table of Obradovich and Cobban (1975), as modified to 

reflect new decay constants for 40K (Steiger and Jager, 

1977), the sample from locality 1 clearly is of early to 

middle Campanian age; the sample from locality 2 is middle Campanian. 

In summary of the foregoing data, we consider the 

lower member of the Livingston in the Madison Range 

to be of early to middle Campanian in age. Palynology 

indicates the member is early Campanian, and radiometric dating indicates an early to middle Campanian age. 

The radiometric dates are from welded tuffs within the 

upper part of the lower member and are higher stratigraphically than the palynological sample. 

The minimum age of the Livingston Formation in 

the Madison Range is uncertain, but could be as young 

as Maestrichtian. No age determinations were made for 

rocks of the middle and upper members of the Livingston 

or for the overlying Sphinx Conglomerate, but a minimum age of Maestrichtian for both sequences was determined via timing of deformation relative to intrusion of 

laccolithic rocks centered at Lone Mountain (fig. 1) north 

of the Livingston outcrop belt. Both the Livingston and 

Sphinx strata occur within the Sphinx Mountain syncline, 

a northwest-trending fold that formed after deposition 

of the two units. Tysdal (1986) and Tysdal and others 

(1986) showed that the western end of the fold was subsequently deformed during eastward-directed thrusting of 

the Hilgard fault system, a series of north-trending faults 

and folds along the western side of the southern twothirds of the range. North of the Sphinx Mountain 

syncline, dacitic laccolithic rocks and dikes intruded structures of the Hilgard system. Several of the dikes extend 

as far south as the Livingston outcrop belt where they 

cut the Livingston, and one cuts the Sphinx Conglomerate 

as well. None of the dikes were satisfactory for dating, 

but because the laccolithic rocks also cut the Hilgard fault 

zone, they are used to provide a minimum age for the 

Livingston. 

Radiometric dating of hornblende dacite of the laccolithic rocks was reported by Tysdal and others (1986). 

K-Ar determinations on three hornblende separates 

yielded ages of 72.7±1.6 m.y., 72.7±4.6 m.y., and 

68.3±4.2 m.y. 40Ar/39Ar determinations on the separates that gave the latter two ages showed the hornblende 

release spectra were disturbed; one separate yielded ages 

of 69 to 85 m.y., and the other 67 to 71 m.y. The 85 m.y. 

age was discounted because it is greater than the known 

age of some of the deformed strata, and ages slightly 

older than the minimum 68-69 m.y. were probably caused 

by excess radiogenic argon. Hornblende from a dike gave 

a K-Ar age of 116 m.y., an age that is older than the 

Everts(?) Formation that the dike intruded, and older 

than the age of the entire Upper Cretaceous section. 

Table 3. K-Ar ages and analytical data of samples from lower 

member of Livingston Formation 

[U.S. Geological Survey analysts: Sample 1 - R. F. Marvin, H. H. 

Mehnert, K. Futa; sample 2 - R. J. Miller] 

Sample Analyzed K20 40Ar 40Ar Age (m.y.) 

locality minerals (percent) (moles/ total 40Ar ± 2 

no. gx 10-10) 

Biotite 6.865 8.066 .91 79.8±2.9 

2 --- do 6.60 7.456 .84 76.8±2.5 

Tysdal and others (1986) concluded that the age of 

emplacement for the laccolithic dike rocks was about 

68-69 m.y. Hence, the youngest Livingston strata of the 

Madison Range can be no younger than about midMaestrichtian. 

Regional Correlation 

Livingston rocks in the Madison Range originally 

were considered by Peale (1896) to be an outlier of the 

Livingston sequence that is preserved largely in the Livingston area. Hadley (1980) rejected this concept and considered the Madison Range strata to be a remnant of the 

Elkhorn Mountains Volcanics because of the apparent 

similarity of the Livingston in the Madison Range and 

the lower member of the Elkhorn Mountains Volcanics. 

The 79.8±2.9 m.y. date obtained for the lower welded 

tuff of the lower member of the Livingston is coincident 

with the 79.8 m.y. date (~ecalculated from 78 m.y., using 

new 40Ar decay constants, Steiger and Jager, 1977) cited 

by Robinson and others (1968), Tilling and others (1968), 

and Tilling (1974) for the climax of major volcanism of 

the Elkhorn Mountains Volcanics. The time span of the 

latter volcanism is not so firmly agreed upon, however, 

with the estimated span (using recalculated 40K decay 

constants) ranging from about 84 to 70 m.y. ago (Skipp 

and McGrew, 1977; Roberts, 1972; Robinson and others, 

1968; Klepper and others, 1957; Smedes, 1966). Even 

though the ages of the three sequences of rocks are correlative, we believe that a closer source is probable for 

most of the Livingston rocks of the Madison and the 

Gallatin Ranges. 

The Elkhorn Mountains Volcanics and once contiguous correlative rock units may have covered as much 

as 26,000 km2 of southwestern Montana during the Late 

Cretaceous (Smedes, 1966, p. 21). Volcanic and volcaniclastic sequences that at one time may have formed a part 

of the assemblage, but that now are isolated from the 

present area of concentration of the Elkhorn Mountains 

Volcanics (inset map of fig. 1), generally are known by 

other names. This came about because of independent 

Regional Correlation 13 
study in different areas, unique aspects of different rock 

sequences, and a lack of dates for some units, but also 

because local source areas exist for some units. Hence, 

even though the volcanic and volcaniclastic rocks of 

the Madison Range are timeequivalents of the Elkhorn 

Mountains Volcanics, and once may have been contiguous with them (as proposed by Hadley, 1980), 

another, closer source may be just as probable. 

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*U.S. GOVERNMENT PRINTING OFFICE: 1987-573-047/66,008 REGION NO.8