Prepared in cooperation with the National Park Service

Surficial Geologic Map of Mesa Verde National Park,

Montezuma County, Colorado

Pamphlet to accompany

Scientific Investigations Map 3224

U.S. Department of the Interior

U.S. Geological Survey
Front cover photos. Top left to right. Cliff Palace, photograph taken May 31, 2006, Spotted Owl 

(courtesy of the National Park Service). Bottom left to right. Spruce Tree House (courtesy of the 

National Park Service), Collared Lizard (courtesy of the National Park Service).
Surficial Geologic Map of Mesa Verde 

National Park, Montezuma County, 

Colorado

By Paul E. Carrara

Prepared in cooperation with the National Park Service

Scientific Investigations Map 3224

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Carrara, P.E., 2012, Surficial geologic map of Mesa Verde National Park, Montezuma County, Colorado: 

U.S. Geological Survey Scientific Investigations Map 3224, 22 p. pamphlet, 1 sheet, scale 1:24,000.
iii

Contents

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

History and Geography ........................................................................................................................1

Climate....................................................................................................................................................1

Vegetation ..............................................................................................................................................2

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

Geology of Mesa Verde National Park.......................................................................................................3

Sedimentary Rocks...............................................................................................................................3

Igneous Rocks.......................................................................................................................................5

Major Surficial Deposits in Mesa Verde National Park ..........................................................................5

Landslides ..............................................................................................................................................5

Introduction...................................................................................................................................5

Location of Landslides in Map Area.........................................................................................5

Age of Landslides.........................................................................................................................7

Importance of Landslide Recognition ......................................................................................8

Loess.......................................................................................................................................................8

Introduction...................................................................................................................................8

Loess in Mesa Verde National Park .........................................................................................9

Age of Loess in Southwestern Colorado .................................................................................9

Colluvium Derived from Menefee Formation ...................................................................................9

Introduction...................................................................................................................................9

Location in the Map Area.........................................................................................................10

Geologic Mapping........................................................................................................................................10

Description of Map Units............................................................................................................................11

Surficial Deposits................................................................................................................................11

Artificial-fill Deposits.................................................................................................................11

Alluvial Deposits.........................................................................................................................11

Alluvial and Colluvial Deposits ................................................................................................12

Colluvial Deposits.......................................................................................................................13

Landslide Deposits ...........................................................................................................14

Eolian Deposits...........................................................................................................................15

Bedrock Units......................................................................................................................................16

References Cited..........................................................................................................................................20

Figures

1. Index map showing location of Mesa Verde National Park in the southwestern 

corner of Colorado with place names mentioned in the text. ...............................................2

2. Stratigraphic section of Mesa Verde National Park...............................................................4

3. Photograph taken near mile 2 of the entrance road showing two small hills of 

Mancos Shale capped by Point Lookout Sandstone landslide rubble (Qrr).......................6

4. Photograph of large landslide viewed from the Navajo Canyon View Point .....................7

5. Photograph of tilted pinyon pine on the toe of a small landslide in Wickiup Canyon.......8
iv

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Mass

ton 0.9072 metric ton

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Mass

metric ton 1.102 tons 

 Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F-32)/1.8

Vertical coordinate information is referenced to National Geodetic Vertical Datum of 1929

Horizontal coordinate information is referenced to North American Datum of 1927 (NAD 27)

 DIVISION OF QUATERNARY TIME

 USED IN THIS REPORT1

Period or subperiod Epoch Age

Quaternary Holocene 0–11.7 ka

 late 11.7–130 ka

 Pleistocene middle 130–780 ka

 early 0.780–2.59 my

1

Ages of time boundaries are modified from Bowen and Gibbard (2007) and U.S. Geological 

Survey (2010). Ages are expressed in ka for kilo-annum (thousand years) and Ma for mega-annum 

(million years).
Introduction

History and Geography 

Mesa Verde National Park in southwestern Colorado 

(fig. 1), was established in 1906 to preserve and protect the 

artifacts and dwelling sites, including the famous cliff 

dwellings, of the Ancestral Puebloan people who lived in the 

area from about A.D. 550 to A.D. 1300. In 1978, the United 

Nations designated the park as a World Heritage Site. The 

geology of the park played a key role in the lives of these 

ancient people. For example, the approximately 600 cliff 

dwellings are closely associated with the Cliff House Sandstone of Late Cretaceous age which weathers to form deep 

alcoves. In addition, the ancient people farmed the thick, red 

loess (wind-blown dust) on the mesa tops, which because of 

its particle size distribution has good moisture retention properties. The soil in this loess cover and the seasonal rains of the 

“Arizona monsoon” allowed these people to grow their crops 

of corn, beans, and squash on the broad mesa tops. 

Today, geology is still an important concern in the Mesa 

Verde area because the landscape is susceptible to various 

forms of mass movement (landslides, debris flows, rockfalls), 

swelling soils, and flash floods that can affect the park’s archeological sites and its infrastructure of roads, septic systems, 

utilities, and building sites.

The map encompasses an area of about 100 mi2

 (260 km2) 

and includes all of Mesa Verde National Park, a small part of 

the Ute Mountain Indian Reservation that borders the park on 

its southern and western sides (fig. 1), and some Bureau of 

Land Management and privately owned land to the north and 

east.

Mesa Verde is essentially a broad gently sloping upland 

surface, called a cuesta, that dips to the south. It is dissected 

by a series of generally north-to-south-trending, steep-walled 

canyons containing ephemeral streams that drain south to the 

Mancos River (fig. 1). The northern escarpment of the cuesta 

includes Park Point, the highest point in the park, at an elevation of 8,571 ft (2,612 m), and drops abruptly more than 

2,000 ft (610 m) into Montezuma Valley where the town of 

Cortez is located. This escarpment with its high erosion rate 

has receded back (south) such that the upper parts of Morefield 

and Prater Canyons (fig. 1) have been removed by erosion. 

These canyons are called “beheaded valleys” because the 

upper parts of their drainages have been removed and their 

valley floors simply begin abruptly at the escarpment. At the 

southern edge of the upland surface, approximately 9–10 miles 

(14.5–16 km) from the northern escarpment, elevations range 

from about 6,700 to 6,900 ft (2,040–2,100 m) and the canyons 

that have been incised into it are as much as 1,000 ft (305 m) 

deep. Along the eastern boundary of the park, the eastern 

escarpment drops more than 1,500 ft (455 m) into the Mancos 

Valley. Two of the high mesas, Big Mesa and Whites Mesa, 

have scattered stream-worn pebbles and cobbles on their 

surfaces, indicating that in the past an ancestral Mancos River 

flowed across this area. Canyon cutting probably began in the 

early Pleistocene (2.588–0.78 Ma). 

Climate

The climate of the Mesa Verde National Park region is 

typical of much of the semiarid southwest. Winters are generally mild with distinct cold snaps, summers are warm, and precipitation is light in most years. The prevailing wind is from 

the south to southwest. Climate records from February 1922 to 

December 2010 from a station at an elevation of about 7,100 ft 

(2,165 m) on Chapin Mesa, near the park headquarters (fig. 1), 

indicate a mean January temperature of 29.1°F (-1.6°C) and a 

mean July temperature of 71.9°F (22.2°C) (Western Regional 

Climate Center, 2011). The lowest temperature on record is 

-20°F (-29°C), which occurred on January 13, 1963. The highest temperature on record is 102°F (39°C), which occurred on 

July 24, 1936. Mean annual precipitation in the park is 18.15 in. 

(46 cm) and is fairly evenly distributed throughout the year 

with 1.5 to 2 in. (3.8 to 5.1 cm) falling in most months except 

May (1.07 in., 2.7 cm) and June (0.61 in., 1.5 cm) when a dry 

period commonly occurs. After this dry period, the summer 

precipitation is usually in the form of intense thunderstorms 

often accompanied by hail. The thunderstorms occur about 

40 days each year, mainly in July and August. Average annual 

snowfall totals 81 in. (206 cm) (Western Regional Climate 

Center, 2011).

Surficial Geologic Map of Mesa Verde National Park, 

Montezuma County, Colorado

By Paul E. Carrara
2 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

Vegetation

Several vegetation zones are present in the Mesa Verde 

National Park area because of its semiarid climate, moderate 

altitude, and relief. The two most extensive vegetation types 

are the pinyon-juniper forests (Pinus edulis and Juniperus 

osteosperma), and Petran chaparral or montane shrubland 

of Gambel oak (Quercus gambellii) and Utah serviceberry 

(Amelanchier utahensis) (Floyd and others, 2000). Pinyon 

pine and Utah juniper dominate the lower elevations, from 

5,700 to about 7,400 ft (1,735 to about 2,255 m), of the mesas 

and canyon slopes in the southern area of the park and the 

lower northern and eastern sides of the escarpment. Douglas 

fir (Pseudotsuga menziesii) and ponderosa pines (Pinus ponderosa) are also found at these low elevations in well-shaded 

canyons. At the lower elevational boundary, the pinyons and 

junipers are small and widely spaced; with increasing elevation, they become larger and more closely spaced, forming 

dense woodlands. The ground under the pinyon-juniper forests 

is commonly bare and rocky, but may support a sparse cover 

of shrubs, such as big sagebrush (Artemisia tridentate) and 

bitterbrush (Purshia tridentat), and various grasses and forbs. 

Above about 7,400 ft (2,255 m), in the northern park area, 

the pinyon-juniper forest gives way to a chaparral dominated 

by Gambel oak and Utah serviceberry with mixed conifers, 

including ponderosa pine and Douglas fir. These two vegetation zones have similar floristic composition, but differ in 

appearance and species abundance. Hence, the chaparral may 

contain scattered pinyon or juniper trees, and many of the 

chaparral’s shrub species also grow in the understory of the 

pinyon-juniper woodlands (Floyd and others, 2000). 

Figure 1. Index map showing location of Mesa Verde National Park in the southwestern corner of Colorado with place names 

mentioned in the text.

COLORADO

37°15'

37°07'30“

108°30' 108°22'30“

Mancos Cortez

Point Lookout

Park

Headquarters

Long House

Cliff Canyon

Montezuma Valley

Navajo Canyon

Mancos Canyon

Big Mesa

Park Point

Knife Edge

Wickiup Canyon

Cliff Palace

Nusbaum Gap 

Whites Canyon

Long Mesa

Montezuma Valley

overlook

School Sec Canyon

Navajo Canyon

View Point

Whites Mesa

McElmo

Creek

Mancos

River

Far View

Visitor Center

Chapin

Mesa

UTE MOUNTAIN

INDIAN RESERVATION

UTE MOUNTAIN

INDIAN RESERVATION

MESA VERDE

NATIONAL PARK

Morefield Canyon

Prater

Canyon

Park entrance

Tunnel

Long

Canyon

MESA TOP

LOOP ROAD Spruce Tree

House

Soda 

Canyon

Imagery from 1-meter NAIP (National Agriculture Imagery Program) data accessed 2011

Mesa Verde

National Park

0

0

1 2 3 4 5 MILES

1 2 3 4 5 KILOMETERS

160

160

491
Geology of Mesa Verde National Park 3

Acknowledgments

This research was supported by the National Cooperative 

Geologic Mapping Program of the U.S. Geological Survey 

and is a contribution to the “Geology of the Parks and Federal 

Lands of the Southwest” project. The author was visited and 

(or) assisted in the field at various times by Mary L. Gillam, 

consulting geologist; Diana E. Anderson, R. Scott Anderson, 

and Taylor J. Joyal, Northern Arizona University; Fumiyasu 

Arakawa, Crow Canyon Archaeological Center; Robert W. 

Blair Jr., Fort Lewis College; Kimberlee M. Gerhardt, consulting geologist; David A. Gonzales, Fort Lewis College; 

R. Mark Leckie, University of Massachusetts; and the 

following U. S. Geological Survey personnel: Harlan Goldstein, Marith C. Reheis, Richard L. Reynolds, and James C. 

Yount; their ideas and suggestions were greatly appreciated. 

Discussions with Marilyn Coyler and Linda Martin, National 

Park Service; Mary O. Griffitts, consulting geologist; Douglas 

K. Ramsey, National Resources Conservation Service; and 

Daniel R. Muhs, and Michael P. Pantea, U.S. Geological Survey, also added greatly to this manuscript. Jim Messerich and 

Paco Van Sistine, U.S. Geological Survey, provided invaluable 

support in the Photogrammetric and GIS labs, respectively. I 

gratefully acknowledge the helpful comments of David Lidke 

and Richard F. Madole, U.S. Geological Survey, who kindly 

reviewed earlier drafts of this manuscript. I also wish to thank 

the National Park Service, Mesa Verde National Park, for various logistical help and specifically George San Miguel, Natural 

Resource Officer, and Bruce Heise, National Park Service, for 

supporting and encouraging this study. 

Geology of Mesa Verde National Park

Sedimentary Rocks

Four geologic formations (fig. 2), all Late Cretaceous 

(99.6–65.5 Ma) in age and dipping gently to the south, are 

exposed in the Mesa Verde area (Wanek, 1954, 1959; Haynes 

and others, 1972; Griffitts, 1990; Condon, 1991; Leckie and 

others, 1997). From oldest to youngest these are the Mancos 

Shale, Point Lookout Sandstone, Menefee Formation and 

Cliff House Sandstone. The upper three formations comprise 

the Mesaverde Group (fig. 2), a name that has been applied 

to sandstones and coal-bearing units of Upper Cretaceous age 

over large areas of the Rocky Mountains and the Southwest 

(Wanek, 1959). 

The lowest formation exposed in Mesa Verde National 

Park is the Mancos Shale (fig. 2), a thick sequence of gray 

to black fissile shale containing siltstone, and fine-grained 

sandstone beds that are generally less than a foot thick (30 cm), 

deposited in a deep-water marine environment in the Late Cretaceous sea (Leckie and others, 1997). Near the park entrance, 

in the section below Point Lookout (fig. 1), Wanek (1959) measured about 2,000 ft (610 m) of Mancos Shale but excluded the 

transitional zone with the overlying Point Lookout Sandstone. 

Leckie and others (1997) measured a total Mancos Shale 

thickness of about 2,240 ft (685 m) in this same area. This formation is prone to landsliding where exposed on steep slopes, 

such as those along the northern and eastern escarpments. 

Overlying and gradational with the Mancos Shale is the 

Point Lookout Sandstone of the Mesaverde Group (fig. 2). The 

Point Lookout Sandstone was deposited as barrier beaches and 

near-shore sands (Griffitts, 1990) as the Late Cretaceous sea 

retreated to the south. The lower part of this formation consists 

of interbedded yellowish-gray and light-brown, fine-grained, 

cross-bedded sandstone and olive-gray to gray, sandy, fossiliferous shale. Sections along the northern escarpment measured 

by Wanek (1959) indicate its thickness ranges between 80 and 

125 ft (25 and 38 m) in the Mesa Verde area. The upper part 

consists of thick to massive beds of yellowish-gray, paleorange, and light-gray, fine- to medium-grained, cross-bedded 

sandstone. Again, sections in the Mesa Verde area, along the 

northern escarpment measured by Wanek (1959) indicate a 

thickness of about 250 ft (75 m). The formation forms much of 

the cap rock in the northern park area and is generally stable, 

but is prone to rockfall where the underlying Mancos Shale 

has undercut it. 

The Menefee Formation conformably overlies the Point 

Lookout Sandstone (fig. 2) and consists of gray to grayishorange lenticular, cross-bedded sandstone and gray to brownish-gray and black carbonaceous shale, coal beds, and bentonitic clay beds. This formation was deposited in a broad coastal 

plain environment (Condon, 1991), indicating further retreat 

of the Late Cretaceous sea. In the Mesa Verde area, the Menefee Formation is about 350–400 ft (105–120 m) thick (Wanek, 

1959) and forms broad slopes, usually with a thick overlying 

colluvial cover, within many of the park’s canyons. This colluvial cover is prone to failure on steep slopes and forms many 

of the landslides shown on the accompanying map. Because 

there are few areas in the park where one can actually see the 

Menefee Formation because of the thick colluvial cover, the 

colluvial cover is mapped as a separate map unit (Qcmf). 

The Cliff House Sandstone overlies the Menefee Formation (fig. 2). This sandstone consists of a grayish-orange to 

pale-yellow, fine-grained, thick-bedded sandstone deposited 

in a shallow near-shore marine environment (Wanek, 1959), 

indicating a northward transgression of the Late Cretaceous 

sea. In the southern part of the park, the formation commonly 

consists of two massive, cliff-forming sandstone beds, each 

more than 100 ft (30 m) thick, separated by a thin shale unit 

(Griffitts, 1990). A maximum thickness of about 400 ft (120 m) 

is present in the Echo Cliff section of Navajo Canyon (Wanek, 

1959) and can be viewed from the Navajo Canyon View 

Point (fig. 1). The upper sandstone bed weathers to form deep 

alcoves in which many of the cliff dwellings have been built 

(Wanek, 1959; Griffitts, 1990). Generally, this formation is 

stable, although rockfalls sometimes occur from the ceilings of 

the alcoves and along the massive cliff walls. The Cliff House 

Sandstone intertongues at its base with the underlying Menefee Formation. 
4 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado Mesaverde Group

Point Lookout Sandstone

330-375 ft (100–115 m) thick

Marine origin—Deposited nearshore

Mancos Shale

2,000-2,240 ft (610–685 m) thick

Marine origin—Quiet offshore

Stratigraphic Units within Mesa Verde National Park

Sandstone interfingering with shale

94 m.y.

82 m.y.

80 m.y.

350-400 ft (105–120 m) thick

Terrestrial—River floodplain and 

 coastal swamp enviroments

400± ft (120± m) thick

Marine origin—Deposited nearshore

Minette dike

Navajo Canyon

25.65±0.08 m.y.

Minette dike 

Mancos Canyon

24.97± 0.12 m.y.

Cliff House Sandstone Menefee Formation Point Lookout Sandstone

EXPLANATION

Fine sandstone

Cross-bedded sandstone

Sandstone with shale perlings

Shale with sandstone lenses

Peat swamp muck

Shale

Figure 2. Stratigraphic section of Mesa Verde National Park (after Griffitts, 1990). Ages given are from 

Cobban and others (2006), W.A. Cobban, USGS, personal commun. (2007), and Peters (2011a, 2011b).
Major Surficial Deposits in Mesa Verde National Park 5

Igneous Rocks 

At several locations in the Mesa Verde area dikes and 

diatremes of minette rock are exposed (Wanek, 1954, 1959; 

Condon, 1991; Griffitts, 1999). Minette is a potassic (K) mica 

lamprophyre (ultrapotassic igneous rock of deep origins), 

commonly greenish-gray to black in color. Basically, minette 

is a phlogopite-rich, potassic basalt (D.A. Gonzales, Fort 

Lewis College, personal commun., 2010). The rocks exposed 

in the study area are characterized by an aphanitic (very 

fine-grained) groundmass of minerals dominated by sanidine 

(bladed to poikilitic), diopside, phlogopite, and minor apatite. 

Phenocrysts (relatively large, conspicuous crystals) in these 

rocks include the minerals phlogopite, diopside, and less commonly olivine (Semken, 2003; Gonzales and others, 2010), 

that comprise less than 10 percent to more than 50 percent of 

the rock (D.A. Gonzales, Fort Lewis College, written commun., 2011). Minette forms by cooling from a potassic-rich 

lamprophyre melt. The geochemical signatures indicate partial 

melting of lithospheric mantle (Gonzales and others, 2010). 

Dikes are well exposed in the soft Menefee Formation and 

Mancos Shale, and form gullies where they have intruded into 

the more resistant Cliff House and Point Lookout Sandstones. 

In Navajo Canyon (fig. 1), there is a well-exposed vertical dike 

that is about 10–15 ft (3–5 m) wide, and stands about 30–45 ft 

(9–14 m) above the surrounding Menefee Formation, which 

it intrudes. In Mancos Canyon (fig. 1) a near-vertical minette 

dike intrudes the Mancos Shale and has a maximum thickness 

of about 6 ft (2 m) and at its southern end stands about 15 ft 

(4.6 m) above the Mancos Shale. In some locations, calcite- and 

fluorite-rich breccias occur in minette dikes and diatremes and 

extend into adjacent country rock. These vein-breccia zones 

are interpreted as dominantly late-stage volatiles associated 

with mafic magmas (D.A. Gonzales, Fort Lewis College, written commun., 2011). Samples from two minette dikes within 

the park yielded 40Ar/39Ar ages of about 25 million years 

(Peters, 2011a and 2011b) indicating that they are of Oligocene age (33.9–23.03 Ma; U.S. Geological Survey, 2010).

Major Surficial Deposits in Mesa 

Verde National Park

Three major surficial geologic units dominate the Mesa 

Verde area: landslides, loess, and the thick colluvial cover 

derived from the Menefee Formation.

Landslides 

Introduction

Landslide is a general term for landforms produced by a 

wide variety of gravity-driven mass movements, including various types of flows, slides, topples and falls, and combinations 

thereof produced by the slow to rapid downslope transport 

of surficial materials or bedrock. Landslide movement takes 

place on an inclined failure surface that separates the displaced 

material above from intact substrata below. 

Landslides are a dominant surficial feature in the Mesa 

Verde area, comprising about 8.8 mi2

 (23 km2), or about 

9 percent of the map area. More than 150 landslides, most 

previously unrecognized and unmapped, have been identified 

in the map area. These landslides range in size from small 

(0.01 mi2

–0.026 km2) debris flows (Qdf), earthflows (Qef), 

and rockfalls (Qrf), to large (greater than 0.50 mi2

–1.30 km2) 

rock avalanches (Qrr), and translational-rotational landslides 

(Qtr) (Varnes, 1978). Landslide morphology and topographic 

relief between the head and toe suggest that some of the larger 

landslide deposits may be more than 100 ft (30 m) thick.

Physical characteristics common to landslides that aided 

in their identification included: (1) headwall scarps, (2) hummocky topography, including closed depressions, (3) bulging 

landslide toes, (4) deflection of ephemeral stream channels by 

landslide toes, (5) bedrock blocks with anomalous dips and 

strikes, (6) displaced masses of geologic units downslope from 

their sources, and (7) vegetation scarring, especially along the 

northern escarpment. Low sun-angle in the early morning and 

late afternoon enhanced the visibility of the subdued topography of many older landslide deposits and was a useful aid to 

their identification in the field. 

Location of Landslides in the Map Area

Within the Mesa Verde National Park area many landslides occur in the Menefee Formation and Mancos Shale. 

Landslides are present both along the northern and eastern 

escarpments and within the canyons of the park. Along the 

steep slopes of the northern and eastern escarpments both 

the Menefee Formation and Mancos Shale commonly fail as 

debris flows (Qdf), and the Mancos Shale also fails as translational or rotational landslides (Qtr), such as the large landslide 

near the head of Morefield Canyon. On the escarpments, many 

of the slopes underlain by Mancos Shale are bare of vegetation indicating very high rates of erosion and ongoing masswasting processes.

Prior to 1957, the entrance road into Mesa Verde National 

Park traversed the steep Mancos Shale slopes along the northern escarpment between the heads of Morefield and Prater 

Canyons. This 1.5-mile (2.4 km) section of road was known as 

the “Knife Edge” (fig. 1). Landslide movement in the eastern 

part of the Knife Edge consisted of mostly large blocks of 

weathered shale which disintegrated into debris slides and, in 

wet weather, into small mudflows as they moved downslope 

(Varnes, 1949). Movement in the western part was mainly by 

rockfall and, to a lesser extent, rockslides (Varnes, 1949). This 

section of road was eventually considered too treacherous to 

maintain by the National Park Service (Martin, 2005). In 1957 

a 1,400-ft (427 m) tunnel was constructed between Morefield 

and Prater Canyons (Dobrovolny and others, 1954; Bohman, 

1958) resulting in the abandonment of the Knife Edge section. 
6 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

From the head of Morefield Canyon one can walk a section of 

this old road along the park’s Knife Edge Trail. From the Montezuma Valley Overlook (fig. 1), at the head of Prater Canyon, 

visitors can view the remains of this road as it traversed the 

steep Mancos Shale slope below the Knife Edge. By bypassing 

and abandoning the Knife Edge section of road, the present 

entrance road traverses only about 1.6 miles (2.6 km) of steep 

Mancos Shale slopes along the eastern face of Point Lookout. 

Mass-wasting of the underlying Mancos Shale along the 

northern and eastern escarpments also undercuts the overlying 

Point Lookout Sandstone, which then fails as large rockfalls, 

rock avalanches, and (or) debris flows. This rubbly sandstone 

debris buries the shale, protecting it from erosion. Evidence 

of this process can be observed along the first few kilometers 

of the park entrance road where several small hills and ridges 

of Mancos Shale are capped by a jumble of sandstone blocks 

derived from the Point Lookout Sandstone (fig. 3). These hills 

and ridges stand above adjacent areas because the sandstone 

rubble acted as a protective cap that shielded the underlying 

Mancos Shale from erosion.

The Menefee Formation and the colluvial deposits 

(Qcmf) derived from this formation, are prone to failure on 

steep slopes and are the sources of many of the large translational or rotational landslides (Qtr) in the park’s canyons. One 

of these large landslides can be observed from Navajo Canyon 

View Point (fig. 4). Here, the landslide forced the ephemeral 

stream channel to the eastern side of the canyon, temporarily 

damming the canyon and forming a flat-valley floor underlain 

by alluvium upvalley from the landslide. On the northern and 

eastern escarpments, detritus from the Menefee Formation 

commonly fails as debris flows (Qdf). Recent debris flows on 

these rims are highlighted by scarring of the slope vegetation. 

Much of the road between Montezuma Valley Overlook 

and the Park Point (fig. 1) turnoff is on the Menefee Formation. Parts of this section of road had to be rerouted because 

the soft organic-rich shales and thin-bedded, brittle coal layers 

of the formation are too unstable to allow the road to be maintained safely (Griffitts, 1990). 

Figure 3. Photograph taken near mile 2 of the entrance road showing two small hills of Mancos Shale capped by Point Lookout 

Sandstone landslide rubble (Qrr). Photograph taken Aug. 26, 2007.

Hills capped by Point Lookout Sandstone landslide rubble (Qrr)

Mancos Shale

(Km)
Major Surficial Deposits in Mesa Verde National Park 7

Age of Landslides

Landsliding in the Mesa Verde area was probably more 

active during the Pleistocene Epoch, which ended about 

11,700 years ago, when the climate in this region was at times 

wetter and cooler than present. In addition, during these times, 

because of the wetter conditions, canyon incision probably 

occurred at a faster rate than at present. A deposit (Qrr) on a 

hill near the entrance station to Mesa Verde National Park 

demonstrates an ancient age for some of the landslide deposits 

shown on this map. The hill, at an elevation of 7,388 ft (2,252 m), 

is approximately 300 ft (91 m) above the surrounding terrain 

and is capped by about 30 ft (9 m) of Point Lookout Sandstone 

rubble. The rubble consists of sand to boulders as large as 10 ft 

(3 m) in intermediate diameter and was emplaced by a large 

rockfall, rock avalanche, or debris flow originating from the 

Point Lookout Sandstone. That this hill is now 300 ft (91 m) 

above the surrounding terrain of Mancos Shale and the nearest 

outcrop of Point Lookout Sandstone is at Point Lookout, about 

1.5 miles (2.4 km) to the south, suggests that an extended 

period of erosion, possibly on the order of several hundreds of 

thousands of years, has occurred since the deposition of this 

deposit. 

However, landsliding is still an ongoing process in Mesa 

Verde National Park. Because the park has only one entrance 

road which traverses a steep slope of Mancos Shale along the 

eastern side of Point Lookout, a landslide along this slope 

has the potential to trap thousands of visitors inside the park. 

Plazak (1989) documented a history of landslides along this 

section of road that he was able to compile from many different sources. He cautions the reader that this may be only a 

partial list as records were incomplete and often vague in their 

location description. 

One of the more notable landslides Plazak (1989) was 

able to document occurred after an exceedingly wet autumn in 

1978. During the spring of 1979, a series of landslide movements along the east side of Point Lookout closed the entrance 

road for more than a month (Plazak, 1989; Smith, 2002). 

The first landslide occurred on April 28th, when 100,000 ft3 

(2,830 m3) of material slumped onto a 200-ft (61 m) section 

of the road. Before this first landslide could be cleared from 

the road, a second landslide on April 30th deposited about 

680,000 ft3

 (19,250 m3) of material onto the road north of the 

first slide (Plazak, 1989). In addition, on May 27th, a 250-ft 

(76 m) section south of the two previous landslides involving one lane of the road moved downslope, further delaying 

the reopening of Mesa Verde National Park (Plazak, 1989). 

Over the years, millions of dollars have been spent keeping 

the park’s road system open (G. San Miguel, National Park 

Service, written commun., 2005). 

Further evidence of ongoing landslide activity is indicated by tilted pinyon and juniper trees on a small landslide 

(fig. 5) in the Menefee Formation in Wickiup Canyon (fig. 1) 

in the southwestern part of the park. The tilted trees indicate 

landslide movement during the lifetime of the trees. Tree-ring 

analysis of increment cores taken from several of the tilted 

trees indicated the landslide occurred in 1986. In addition, 

many small landslides in Mesa Verde National Park were 

recorded between 1974 and 2006 (Marilyn Coyler, National 

Park Service, written commun., 2006). Other recent landslides 

on the northern and eastern escarpments are indicated by fresh 

scars in vegetation. 

Navajo Canyon View Point landslide (Qtr)

Cliff House Sandstone (Kch)

Figure 4. Photograph of large landslide viewed from the Navajo Canyon View Point (fig. 1). Note that the landslide has forced the 

ephemeral-stream channel to the eastern side of the canyon. In addition, the landslide temporarily dammed the canyon, forming a flat 

valley floor underlain by alluvium upstream (beyond the photo to the right). Photograph taken Aug. 28, 2005.
8 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

Importance of Landslide Recognition

Many of the landslides depicted on this map are probably 

stable because they date to the Pleistocene and hence formed 

under a different climatic regime. However, the recognition 

of these landslides is important because natural and humaninduced factors can alter stability. Reduction of lateral support 

(for example, by excavations or roadcuts), removal of vegetation (for example, by fire or development), or an increase in 

pore-water pressure caused by heavy rains or snowmelt may 

result in a decrease in internal shear strength and hence, in the 

reactivation of the landslide or parts of landslide. 

Loess

Introduction

Loess is an accumulation of wind-blown silt and lesser 

amounts of fine sand and clay. Commonly massive and in 

places calcareous, it is usually homogeneous and highly 

porous. Loess deposits form a “blanket” that covers large areas 

obscuring the underlying bedrock. In the Midwestern United 

States, loess deposits cover more than 1.740 million mi2

(4.5 million km2

). The youngest loess (Peoria Loess) in this 

area is more than 130 ft (40 m) thick in places (Bettis and others, 2003). In many areas loess develops into highly rich soils 

and forms some of the most agriculturally productive terrain in 

the world.

In an area of southwestern Colorado that includes Mesa 

Verde National Park, soil surveys indicate that reddish-colored 

eolian deposits blanket an area of more than 3,750 mi2

(9,700 km2

) (Price and others, 1988). Arrhenius and Bonatti 

(1965) referred to these reddish-colored deposits as the “Mesa 

Verde Loess”. The average thickness of the eolian deposits in 

this area is uncertain, but Price and others (1988) suggested 

that some of the deposits may be more than 6 ft (2 m) thick, 

although much of it may not exceed 3 ft (1 m) in thickness. 

Along a southwest-to-northeast transect from the Colorado–

Utah border to the Dolores River, the silt content in eolian 

deposits ranged from about 22 to 56 percent (Price and others, 

1988, their table 2). Furthermore, with increasing distance 

northeast from the Colorado-Utah border (and hence the 

San Juan River) the silt content increased, whereas the sand 

content decreased, indicating that for the Mesa Verde area the 

direction of the winds that deposited the eolian material was 

from the south-southwest (Price and others, 1988). Possible 

Figure 5. Photograph of tilted pinyon pine on the toe of a small landslide in Wickiup Canyon (fig. 1). The 

tilted tree indicates landslide movement during its lifetime. Tree-ring analysis of increment cores taken from 

several trees on this landslide indicate movement occurred in 1986. Photograph taken June 12, 2006. 
Major Surficial Deposits in Mesa Verde National Park 9

sources for the eolian deposits include; (1) the large areas of 

sparse vegetation to the southwest containing reddish-colored 

sedimentary rocks, (2) alluvium of the San Juan River, also to 

the southwest, that contains abundant reddish-colored rocks in 

its drainage basin, and (3) a combination of the above possible 

sources (Price and others, 1988).

Loess in Mesa Verde National Park

In Mesa Verde National Park large areas of the mesas 

are blanketed by loess (Ramsey, 2003) such that loess comprises about 6.7 mi2

 (17.5 km2) or about 7 percent of the map 

area. Arrhenius and Bonatti (1965) inspected two man-made 

exposures of loess within the park that have since been filled 

in. One of the exposures, referred to as the “new garbage pit,” 

was about 1.85 mi (3 km) south of the park’s headquarters 

near the southern boundary of the park on Chapin Mesa 

(fig. 1). Here the loess was about 9 ft (2.75 m) in thickness. At 

this exposure, upper and lower loess units were distinguished. 

In the upper loess, which was about 3.5 ft (1.1 m) thick, two 

loess units were recognized (Loess 1 and 2). The lower loess 

(Loess 3), which contains more coarse material, indicating that 

it was transported by higher velocity winds than the overlying 

loess (1 and 2), is about 5.5 ft (1.70 m) thick. This lower loess 

had the most marked soil development including a welldefined stage III morphology in a calcic soil that is about 2.5 ft 

(75 cm) thick and referred to as the “basal caliche” by Arrhenius and Bonatti (1965). Analysis of the calcic soil indicated a 

concentration of 54 percent calcium carbonate, corresponding 

to an almost complete filling of the pore spaces between grains 

(Arrhenius and Bonatti, 1965). Although the “new garbage 

pit” exposure no longer exists, the layer containing stage III 

carbonate morphology can be viewed at some of the pithouse 

and kiva exhibits along the Mesa Top Loop Road on Chapin 

Mesa where it is easily recognized as a prominent white layer 

1.5–3 ft (0.5–1 m) below the surface. 

The other section, referred to as the “juniper section,” was 

about 1 mi (1.6 km) northeast of the park’s headquarters. Here 

the loess was only about 2.5 ft (0.75 m) thick, and two loess 

units were identified: zones 1 and 2 (Arrhenius and Bonatti, 

1965). Again, the lower loess (zone 2) contained more coarse 

material than the upper loess (zone 1). Based on this difference 

in grain-size distribution, zone 1 at the juniper section was 

correlated with loess 1 and 2 at the “new garbage pit,” and zone 

2 at the juniper section was correlated with loess 3 at the “new 

garbage pit” (Arrhenius and Bonatti, 1965).

Age of Loess in Southwestern Colorado

Evidence suggests that loess deposits in southwestern 

Colorado were deposited by a series of eolian events during the 

Quaternary. Hunt (1956, p. 38) thought that the loess deposits 

were pre-Wisconsin in age (older than about 75,000 years). 

Arrhenius and Bonatti (1965) concluded that the earliest loess 

at the “new garbage pit” exposure (loess 3) was probably 

pre-Wisconsin, possibly Sangamon in age (between about 

125,000 and 75,000 years ago). Furthermore, the presence of a 

stage III carbonate horizon in loess 3 suggests that it is middle 

Pleistocene in age (780,000 to 130,000 years ago) (Machette, 

1985). 

A late Pleistocene age for loess in the Dolores area 

is indicated by a radiocarbon age of 15,970±155 yr B.P. 

(SI–6137) (19,116±157 cal yr, Fairbanks and others, 2005), 

obtained from a vertebra of a semi-articulated musk ox 

(Symbos cavifrons) skeleton recovered from loess overlying 

a terrace along the Dolores River. The terrace, now under 

McPhee Reservoir, was about 10 mi (16 km) downstream 

from Dolores, Colorado (Clay and others, 1984; McDonald 

and others, 1987) and contained two loess units. The skeleton 

was preserved in the Ck horizon of the upper loess, and the 

radiocarbon age was interpreted as indicating that the last 

major period of loess deposition occurred no earlier than about 

19,000 cal yr, and probably began at about that time (Clay and 

others, 1984; McDonald and others, 1987; Price and others, 

1988). 

Holocene ages are indicated for loess deposits in the 

Hatch Point–Canyon Rims area of Utah. Here, loess deposits, 

are about 6 ft (2 m) thick and contain two units (Goldstein 

and others, 2010). On the basis of soil development, optically 

stimulated luminescence (OSL) ages, and one radiocarbon 

age, the lower unit was deposited between about 10,500 and 

7,500 yr B.P. and the upper unit was deposited between about 

6,000 and <1,400 yr B.P. (Goldstein and others, 2010). Based 

on radiocarbon ages of carbon in soil carbonate and organic 

carbon concentrated from the loess at the “new garbage pit,” 

loess 1 and 2 were thought to be deposited in two stages, one 

more than 4,000 radiocarbon years ago and the other more 

than 3,000 radiocarbon years ago, respectively (Arrhenius and 

Bonatti, 1965). 

Deposition of loess is an ongoing process in the Four 

Corners area. Dust storms are common in this area during 

the spring and larger events leave a noticeable film of sticky, 

reddish silt (G. San Miguel, National Park Service, written 

commun., 2011). In the Canyonlands National Park area of 

Utah, ongoing eolian-silt additions to soils on upland sandstone surfaces have been demonstrated using mineralogical, 

magnetic, and geochemical data (Reynolds and others, 2001). 

Hence, the evidence suggests loess deposits in the southwest 

may have been deposited by different eolian events that span a 

wide range of ages. 

Colluvium Derived from the Menefee Formation

Introduction

Colluvium, for the purposes of this map, is any loose, 

heterogeneous, and incoherent mass of soil material or rock 

fragments that were transported and deposited by gravity by 
10 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

slow mass-movement processes, chiefly creep. Because the 

Menefee Formation weathers so rapidly, there are few areas in 

the park, except for road cuts and landslide scars, where one 

can actually see this formation. This loose, weathered material 

derived from the Menefee Formation then creeps downslope 

to form a thick colluvial cover, which for the purpose of this 

report is mapped as a separate unit (Qcmf). These deposits 

comprise about 18.6 mi2

 (48 km2), or about 18.5 percent of the 

map area. On slopes within the park this unit consists mainly 

of poorly stratified, poorly sorted, matrix- to clast-supported, 

cobbly boulder gravel. The unit also contains gray (10YR 

6/1), clayey silt and pale-brown (10YR 6/3) fine sandy silt and 

pods of black (10YR 2/1) weathered coal and scattered white 

(10YR 8/2), angular sandstone pebbles, cobbles, and boulders. 

This colluvial cover is prone to failure on steep slopes and 

forms many of the landslides shown on the accompanying 

map. This unit also probably contains older landslide deposits 

that were not recognized in the field or on the aerial photographs because they do not have a well-defined morphology; 

hence, the number of landslides depicted on the map probably 

represent a minimum value. 

Location in the Map Area

In the narrow valleys in the western map area the colluvium commonly mantles steep, now vegetated, slopes that 

extend from the base of the Cliff House Sandstone down to the 

valley axis virtually filling these valleys with colluvium. In the 

wider valleys in the eastern map area the colluvium mantles 

steep slopes that extend downward to the broad valley bottom. 

In the lower part of Morefield and Prater Canyons (fig. 1), the 

unit includes earthflow-like features that emanate from the 

Menefee Formation and consist of clast-supported lobes 6–

10 ft (2–3 m) high. The lobes extend from the valley walls to 

near the valley axis. Movement here may have occurred on 

bentonite layers within the Menefee Formation. 

Geologic Mapping

A variety of methods were used to map the surficial 

deposits and bedrock units in Mesa Verde National Park 

including: (1) compilation from existing geologic maps 

(Wanek, 1954, 1959; Haynes and others, 1972; Colton and 

others, 1975; Condon, 1991; and Griffitts, 1999); (2) stereoscopic analysis of 1:12,000-scale color National Park Service 

aerial photographs taken in 2004, and 1:40,000-scale black 

and white aerial photographs of the National Aerial Photography Program taken in 1999 (http://eros.usgs.gov/#/Find_Data/

Products_and_Data_Available/Aerial_Products), and (3) 

fieldwork from 2006 to 2011. Where units were exposed 

and could be examined, detailed information was noted such 

as: geomorphic form, stratigraphic relationship, thickness, 

percentage of clasts, lithology of clasts, size range of clasts, 

degree of clast roundness (Powers, 1953), estimation of sand, 

silt, clay fraction of the matrix, matrix color, degree of sorting, 

type of bedding (if any), and vegetation cover. Data from these 

accessible areas were then extrapolated to the less accessible 

areas. In addition, samples were collected for grain-size analyses to better characterize specific units, and at several localities 

samples were also collected for radiocarbon and 40Ar/39Ar dating. Map unit boundaries were plotted on a digital orthophoto 

base with the use of a photogrammetric stereo plotting instrument (Kern PG–2). Metric units are now used exclusively in 

the following explanations and unit descriptions; conversions 

to English equivalents are given in the Conversion Factors at 

the front of this report. 
Description Of Map Units 11

Description Of Map Units

Surficial Deposits

Surficial deposits in Mesa Verde National Park consist of artificial fill, alluvial, colluvial, landslide, and eolian deposits. 

Deposits shown on this map are generally greater than 1 m thick; thinner, discontinuous deposits are not shown and are incorporated with the underlying map unit. Residual material on bedrock and some artificial fills are not mapped. Many of the contacts 

between surficial map units are approximate because the contacts are commonly poorly exposed or gradational. For instance, the 

contacts between colluvial deposits derived primarily from the Menefee Formation (Qcmf) and adjacent landslides (primarily 

Qtr) within many of the canyons of the park are characteristically poorly exposed.

Previous geologic maps of Mesa Verde National Park (Griffitts, 1999) or the park and surrounding area (Wanek, 1954 and 

1959; Haynes and others, 1972; Condon, 1991) show the Menefee Formation occupying large areas of the park. The trouble with 

this depiction is that there are very few areas in the park where one can actually see this formation because it is usually overlain 

by a thick colluvial cover prone to landsliding. The emphasis of this map is placed on the unconsolidated surficial deposits. 

Hence, in many areas the thick overlying colluvial cover (unit Qcmf) is shown on the map instead of the underlying Menefee 

Formation as shown on previous maps. 

Divisions of Quaternary time that are given in the descriptions of the surficial deposits and shown in the front of the report 

and on the map sheet are modified from Bowen and Gibbard (2007) and U.S. Geological Survey (2010). They are: Holocene, 0–

11,700 yr ago; late Pleistocene, 11,700–130,000 yr ago; middle Pleistocene, 130,000–780,000 yr ago; and early Pleistocene 

780,000–2,588,000 yr ago.

Age assignments for surficial deposits are based chiefly on stratigraphic relations, degree of erosional modification of 

original-surface morphology, degree of soil development, and radiometric ages.

Grain-size terminology for the surficial deposits is based on both visual estimates in the field and laboratory analyses. 

Grain-size analysis was carried out on more than 50 samples that included loess, alluvial, and colluvial units. Terminology 

follows the modified Wentworth grade scale (American Geological Institute, 1982). In descriptions of surficial deposits, the term 

“clast” refers to particles greater than 2 mm in diameter, whereas the term “matrix” refers to particles less than 2 mm in size.

Dry matrix colors of the surficial deposits were determined by comparison with a Munsell Soil Color Chart (Munsell Color, 

1973). The colors of the surficial deposits reflect those of the sediments and (or) bedrock from which they are derived.

Artificial-fill Deposits

af Artificial fill deposits (latest Holocene)—Compacted and uncompacted material composed mostly of varying 

amounts of silt, sand, and rock fragments derived from nearby bedrock or surficial deposits. Unit includes 

large fills beneath sections of the park entrance road consisting predominantly of locally derived pale-olive 

(5Y 6/3) silty sand containing scattered pebble- and cobble-size angular clasts derived from the Point Lookout Sandstone (Kpl). Unit also includes small stock pond dams in the northeastern map area that consist of 

pale-olive (5Y 6/3) sandy silt, silt, clayey silt, and silty clay derived from the nearby alluvial and colluvial 

deposits (Qac) in this area, that were in turn derived from the Mancos Shale (Km). Flat-topped mounds 

resulting from the infilling of two small reservoirs built by the Ancestral Puebloans in Morefield and Prater 

Canyons near the southern boundary of the park (Wright, 2006) are also included in this unit. These mounds, 

both about 60 to 70 m in diameter and 4.5 to 6 m high, consist of water-laid sands, silts, and clays (Wright, 

2006). Thickness ranges from about 1 m to more than 10 m 

 Hazard: poorly compacted fills may be subject to settlement when loaded.

Alluvial Deposits

Qa Alluvium deposited by small ephemeral streams (Holocene and late Pleistocene)—Alluvium underlying 

ephemeral stream channels, low terraces, and flat valley floors in the lower reaches of Long, Navajo, and 

Soda Canyons. In Navajo Canyon and at one location in Soda Canyon, unit was deposited just upstream from 

landslide dams. Unit consists predominantly of brown (10YR 5/3) to yellowish-brown (10YR 5/4), massive 

to distinctly stratified, silty fine sand and fine sand. Locally contains minor amounts of dark yellowish-brown 

(10YR 4/4), silty clay beds. A charcoal fragment, about 330 cm below the surface in an exposure of silty clay 

in Navajo Canyon, yielded a radiocarbon age of 2,235±30 yr B.P. (WW–6350) (2,257±59 cal yr, Fairbanks 

and others, 2005). The exposure is just upstream from the large landslide that dammed the canyon and is 

visible from the Navajo Canyon View Point (figs. 1 and 4). The radiocarbon age: (1) provides a minimum 

age (probably a very minimum age) for the landslide, and (2) indicates a sedimentation rate of about 150 cm/

1,000 yr behind the landslide dam. Estimated maximum thickness 20 m

 Hazard: low-lying areas of unit adjacent to stream channel may be subject to periodic flooding. 
12 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

Qam Alluvium deposited by the Mancos River (Holocene and late Pleistocene)—Alluvium underlying the Mancos 

River channel, flood plain, and adjacent low terraces near the southeastern border of the map. Upper 1–2 m 

of unit consists of light-yellowish-brown (10YR 6/4) massive, silty fine sand to medium sand that locally 

contains minor amounts of pebbles and cobbles in lenses generally less than 25 cm thick. Lower part of 

unit, which is poorly exposed and of unknown thickness, consists of subrounded to rounded, pebble-cobble 

gravel. Clasts consist mainly of quartzite and intermediate volcanics as well as sandstone derived from the 

nearby Point Lookout Sandstone (Kpl). Some clasts have thin (1–2 mm), white calcium carbonate coats. 

Matrix in gravel consists of very pale-brown (10YR 7/4) sandy silt and silty sand. Gravel thickness in this 

unit is estimated to be 5–10 m 

 Resource: quartzite clasts in this unit may have been used as a resource by the Ancestral Puebloans for 

axe heads, knives, and blades. 

 Hazard: low-lying areas within unit may be subject to periodic flooding. 

QTrg Residual gravel (middle Pleistocene to Pliocene?)—Area of residual gravels, originally deposited by an ancestral Mancos River before the present valley system was developed (Atwood, 1911). Unit consists of scattered 

rounded and subrounded pebbles and cobbles and a few small boulders on a bedrock surface of Cliff House 

Sandstone (Kch). Gravels consist mainly of resistant lithologies, predominantly fine- and coarse-grained 

quartzite, with a few basalts and intermediate volcanics from the La Plata Mountains to the northeast. Unit 

is located on the high northern ends of Big Mesa and Whites Mesa (fig. 1) in the southeastern part of Mesa 

Verde National Park about 425 to 520 m above the Mancos River. In the park this unit is present only as 

areas of scattered clasts; south of the park, in the Ute Mountain Indian Reservation, near the southern end of 

Chapin Mesa these gravels range in thickness from 3 to 6 m (Pantea, 1996). A similar deposit near the town 

of Palisade, Colorado, about 210 km to the north was estimated to be about 3.8 m.y. based on the average 

rate of down cutting of the nearby Colorado River (Carrara, 2000).

 Resource: quartzite clasts in this unit may have been used as a resource by the Ancestral Puebloans for 

axe heads, knives, and blades. 

Alluvial and Colluvial Deposits

Qac Alluvial and colluvial deposits, undivided (Holocene and late Pleistocene)—Predominately a mix of alluvium 

and colluvium, including sheetwash and debris-flow deposits. In the canyons in the eastern park area unit 

Qac consists mainly of fine-grained alluvium in narrow, incised ephemeral-stream channels and colluvium 

that extends from the base of adjacent slopes to the margins of the stream channel. Alluvium consists primarily of brown (10YR 4/3), grayish-brown (10YR 5/2), and yellowish-brown (10YR 5/4), massive to stratified, 

silt, silty fine sand and sand. In places contains angular to subrounded pebbles and cobbles of sandstone in 

beds and lenses 5–25 cm thick. Also, in some places contains beds of laminated silty fine sand and clayey silt 

5–10 cm thick and thin buried soils (humic horizons). Colluvium consists predominantly of brown (10YR 

4/3), massive, silty fine sand with scattered subangular to subrounded sandstone pebbles and cobbles. Estimated maximum thickness 25 m.

 Resource: soils developed in this unit in the lower portions of both Morefield and Prater Canyons were 

used by the Ancestral Puebloans for farming as evidenced by the remains of two small reservoirs (Wright, 

2006) and archeological sites in both of these canyons.

 Hazard: low-lying areas of unit adjacent to stream channel may be subject to stream flooding and debris 

flows. 

 In parts of the northern map area unit Qac underlies large areas of low relief that are dissected in places 

by deep gullies. Here the unit consists of interbedded pale brown (10YR 6/2), silty fine sand layers and 

pebble gravel beds 5–25 cm thick. Gravel consists of mostly imbricated chips of Mancos Shale (Km) and 

sparse sandstone pebbles from the Point Lookout Sandstone (Kpl). Also contains grayish-brown (10YR 5/2), 

massive to stratified, silty clay containing scattered pebbles derived from the Mancos Shale. Clayey alluvium 

is soft, sticky, and plastic where moist; tough, hard, and blocky where dry. Thickness 2–5 m. 

 In parts of the eastern map area along the Mancos River unit Qac underlies areas of low relief that are 

dissected in places by deep gullies. Here, this unit also includes flash-flood and debris-flow deposits 1–

2 m thick, consisting of light-brownish-gray (10YR 6/2), weakly stratified, silty fine sand containing scattered subangular to subrounded sandstone pebbles and cobbles. Also contains clast-supported gravel, about 

1 m thick, consisting of subangular to subrounded sandstone pebbles, cobbles, and boulders. The largest 

boulders are about 1 m3

. Matrix consists of yellowish-brown (10YR 5/4) medium sand. At a site in the 

southeastern park area the unit consists of 1 m of pebble gravel overlying 50 cm of poorly sorted, angular to 
Description Of Map Units 13

subangular pebbly cobble gravel. Gravel consists primarily of sandstone clasts derived from the Point Lookout Sandstone (Kpl). Thickness 2–5 m.

 Ages: radiocarbon ages were obtained from exposures in alluvium in this unit in Whites and Morefield Canyons near the southern park boundary. In Whites Canyon, a radiocarbon age of 350±30 yr B.P. 

(WW–6348) (411±58 cal yr, Fairbanks and others, 2005) was obtained from a charcoal fragment collected at 

a depth of 120 cm in massive silty sand. In Morefield Canyon a radiocarbon age of 415±30 yr B.P. (WW–

6349) (488±28 cal yr, Fairbanks and others, 2005) was obtained from a charcoal fragment at a depth of 130 cm 

in a sequence of sandy silts and silts. These radiocarbon ages indicate that the upper part of the alluvium in 

these canyons was deposited during the last several hundred years. Hence, the subsequent incision of these 

fills which resulted in the exposures from which the charcoal was collected occurred no more than several 

hundred years ago, and may have been in part aggravated by cattle grazing in these canyons prior to the 

establishment of the park in 1906 (Thompson, 2007, p. 8). An additional radiocarbon age of 8,315±51 yr B.P. 

(WW–6818) (9,334±82 cal yr, Fairbanks and others, 2005) was obtained from a charcoal fragment collected 

at a depth of about 5 m in an exposure of light-yellowish-brown (10YR 6/4) massive, silty fine sandy alluvium near the head of Prater Canyon.

 Hazard: in both the northern and eastern map areas, unit Qac is subject to piping (erosion by percolating water resulting in the formation of tunnels or pipes through which fine-grained material is removed) and 

gullying. Gullies within unit are subject to flash floods and debris flows. In these areas, unit may contain 

swelling clays. In addition, unimproved roads in these areas become sticky and very slippery when wet, and 

at times are virtually impassable.

Qf Fan deposits (Holocene and late Pleistocene)—Fan-shaped deposits at the mouths of gullies and small tributaries in Morefield and Prater Canyons. Unit was deposited mainly by ephemeral stream flow, flash floods, 

and debris flows. Consists of dark-grayish-brown (10YR 4/2), brown (10YR 4/3, 5/3), and yellowish-brown 

(10YR 5/4), poorly stratified, unsorted, silty fine sand, sand, and pebbly sand. Clasts consist of subangular 

to subrounded sandstone pebbles derived from the Point Lookout Sandstone (Kpl). Unit locally includes colluvial deposits and sheetwash alluvium. Thickness 3—15 m

 Hazard: unit is subject to flooding or debris flows. 

Colluvial Deposits 

Qcmf Colluvial deposits derived from the Menefee Formation (Holocene and late Pleistocene)—On slopes 

underlain by the Menefee Formation (Kmf), this unit consists of mainly matrix- to clast-supported, cobbly 

boulder gravel deposited by mass-wasting processes, chiefly creep. Includes gray (10YR 6/1), clayey silt 

and pale-brown (10YR 6/3) fine sandy silt, containing pods of black (10YR 2/1) weathered coal, yellowishbrown (10YR 5/4), silty fine sand containing scattered white (10YR 8/2), angular to subangular sandstone 

pebbles, cobbles, and boulders derived from sandstone beds within the Menefee Formation and the overlying 

Cliff House Sandstone (Kch). Unit contains many boulders >1 m3 in volume. In the narrow valleys in the 

western map area, the colluvium commonly mantles steep, vegetated, slopes that extend from the base of the 

overlying Cliff House Sandstone down to the valley axis, virtually filling these valleys with colluvium. In the 

eastern part of the map area, in the lower part of Morefield and Prater Canyons, unit includes earthflow-like 

features emanating from the Menefee Formation that consist of clast-supported lobes 2–3 m high extending 

from the valley walls to near the valley axis. Clasts consist of angular to subrounded pebble, cobble, and 

boulder-sized sandstone clasts in a matrix of yellowish-brown (10YR 5/4), silty sand. Movement may have 

occurred on bentonite layers within the Menefee Formation. Exposed thickness about 5 m; estimated maximum thickness 20 m

 Hazard: unit includes undifferentiated rockfall, debris-flow, and landslide deposits too small to show 

at map scale. Unit also probably contains older landslide deposits that were not recognized in the field or on 

the aerial photographs because they do not have a well-defined morphology. Hence, unit is subject to a wide 

range of geologic hazards. 

Qcm Colluvial deposits derived from the Mancos Shale (Holocene and late Pleistocene)—Mapped at the base of 

slopes at the heads of Morefield and Prater Canyons. Consists of mainly poorly exposed light-brownish-gray 

(10YR 6/2), massive, sandy silt, silt and clayey silt containing scattered subangular sandstone pebbles and 

cobbles derived from the overlying Point Lookout Sandstone (Kpl). Estimated thickness 3–10 m

 Hazard: unit may have moderate to high swelling potential due to presence of expansive clays and may 

also contains sulfate minerals that are corrosive to conventional concrete and metal pipes. 
14 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

Landslide Deposits

Qrf Rockfall deposit (late Holocene)—Areas of large, scattered subangular sandstone boulders deposited by rockfall. Mapped at several localities in the park: in Morefield and Prater Canyons south of the entrance road 

about 0.5 and 1.2 km respectively, and along the western side of Wetherill Mesa. In Morefield Canyon the 

deposit consists of about 100 boulders, derived from the Point Lookout Sandstone (Kpl) off the eastern side 

of the valley. The boulders are scattered over a distance of 250 m along the valley floor. Here the boulders 

are commonly more than 1 m3 and the largest boulder is approximately 100 m3. Some of the boulders have 

a lichen cover; others have little or no lichens, suggesting multiple rockfall events. In Prater Canyon the 

deposit consists of about 25 boulders, derived from the Point Lookout Sandstone, scattered over a distance 

of 50 m in the middle of the valley floor such that it is not clear what side of the valley they originated from. 

Here, many of the boulders are less than 1 m3 and the largest boulder is less than 10 m3. The two small 

deposits along the western side of Wetherill Mesa are derived from the Cliff House Sandstone (Kch). 

 Hazard: although rockfall deposits are mapped at only several locations where they are large enough to 

show at the map scale, rockfalls are common in Mesa Verde National Park. Many of the slopes beneath the 

Cliff House (Kch) and Point Lookout (Kpl) Sandstone cliffs are susceptible to rockfalls. For instance, the 

large landslide (Qtr) that can be viewed from the Navajo Canyon View Point contains many rockfall boulders 

derived from the Cliff House Sandstone on its surface (fig. 4). In February 2012, a large slab of rock came 

off the cliff of the Point Lookout Sandstone about 5 km from the park’s entrance where the road traverses a 

steep slope along the eastern side of Point Lookout. As the slab fell it broke apart into large boulders one of 

which landed on the road (estimated at 18 metric tons) and another larger boulder (estimated at 218 metric 

tons) came to rest about 25 meters above the road and presented a further hazard to the road and traffic. Both 

boulders were subsequently blasted and removed (data accessed March 26, 2012 at http://www.nps.gov/meve/

parknews/ 12_06_rocking_meve.htm).

Qdf Debris-flow deposits (late Holocene)—Unit deposited by debris flows originating primarily from the Menefee 

Formation (Kmf) along the parks northern escarpment. Mapped unit consists of head scarp and lobate toe. 

Consists of poorly sorted and unstratified clast-supported pebble-cobble gravel with some boulders in a 

brown and pale-brown (10YR 5/3 and 6/3) silty sand matrix. Clasts are mainly angular and subangular 

sandstone. Largest clasts are about 1 m3. Also consists of light-brown (7.5YR 6/4) silty sand and sand, 1–2 m 

thick, containing scattered angular and subangular sandstone cobbles and boulders. Recent debris flows are 

indicated by scarring of the vegetation. Estimated thickness as much as 10 m

 Hazard: areas within unit may be subject to flash floods or debris flows. 

Qef Earthflow deposit (Holocene)—Unit deposited by earthflow originating within the Menefee Formation (Kmf). 

Unit consists of matrix to clast supported, unsorted, yellowish-brown (10YR 5/4), silty fine sand that contains subangular to subrounded sandstone clasts. Mapped at one location in the park; approximately 1 km 

southeast of Park Point, where it descends a steep slope and forms a lobate toe at head of School Section 

Canyon (fig. 1). Estimated thickness about 10 m 

 Hazard: unit is probably stable unless its vegetation cover is removed or its toe is excavated. 

Qtr Translational and rotational landslide deposits (Holocene and late Pleistocene)—Unit consists of heterogeneous mixture of unconsolidated surficial material and rock fragments in a wide range of sizes deposited primarily by translational and rotational types of movement (Varnes, 1978). The size and lithology of the clasts 

and grain-size of the matrix depend on the various bedrock and surficial units involved in the landslide. 

Unit mapped primarily in the canyons of the park and along the entrance road on the eastern side of Point 

Lookout, and is derived mainly from the Menefee Formation (Kmf) and Mancos Shale (Km). In some 

instances a landslide deposit originating from a valley wall abuts a landslide deposit originating from the 

opposite valley wall, such as near the head of Morefield Canyon. Here, a landslide from the western valley wall abuts a larger landslide that originated from the eastern valley wall. In these instances a contact is 

shown between the two landslides to indicate they are indeed separate landslide deposits. Unit may locally 

include small alluvial and talus deposits too small to show at the map scale.

 Landslide deposits derived from the Menefee Formation consist of unsorted, unstratified, pale-yellow 

(5Y 7/4), light-yellowish-brown (2.5Y 6/4), and dark-grayish-brown (10YR 4/2) silty sand and sandy silt. 

These deposits commonly contain angular and subangular sandstone clasts derived from within the Menefee Formation or the overlying Cliff House Sandstone (Kch). The Menefee Formation forms many large 

translational and rotational landslides within the canyons of the park. An excellent example of one of these 
Description Of Map Units 15

large landslides can be observed from Navajo Canyon View Point (fig. 4). Here, the landslide forced the 

ephemeral-stream channel to the eastern side of the canyon that temporarily dammed the canyon and formed 

a flat-valley floor underlain by alluvium (Qa) upvalley from the landslide.

 Landslide deposits derived from the Mancos Shale are unstratified, pale-brown (10YR 6/3) sandy silt, 

silt, clayey silt, and silty clay. Along the entrance road, on the eastern side of Point Lookout (fig. 1), failure 

was found to be translational because it occurred on a slip plane separating weathered Mancos Shale from 

underlying unweathered Mancos Shale (Plazak, 1989). These deposits commonly contain about 5–10 percent 

angular to subangular sandstone cobbles and boulders derived from the overlying Point Lookout Sandstone 

(Kpl). An excellent example of a large landslide in the Mancos Shale is found at the head of Morefield 

Canyon. This area is below the stratigraphic boundary of the Mancos Shale and the overlying Point Lookout 

Sandstone, yet on a drive along the roads in this area one notices many large blocks of Point Lookout Sandstone and a hummocky topography typical of a landslide area. Here, many boulders are more than 1 m3

. In 

the roadcut at Nusbaum Gap (fig. 1), the pass on the entrance road between Mancos and Morefield Canyons, 

one can see an exposure showing intact Mancos Shale on the east, the slip surface of the large landslide, and 

the rubble of the large landslide in Morefield Canyon on the west. Based on the aerial extent and topographic 

relief between the landslide head and toe, some of the larger landslides in the park may exceed 30 m in 

thickness

 Hazard: as previously mentioned many of the landslides depicted on this map are probably stable 

because they date to the Pleistocene and hence may have formed under a different climatic regime. However, 

the recognition of these landslides is important because natural and human-induced factors can alter stability. 

Reduction of lateral support by erosion, excavations, or roadcuts, removal of vegetation by fire or development, or an increase in pore pressure by heavy rains, may result in a reduction of shear strength and the 

reactivation of landslides or parts of landslides. Some landslides in the park indicate that landsliding is still 

an ongoing process. As previously mentioned, the only entrance road into the park traverses a steep slope 

of Mancos Shale along the eastern side of Point Lookout. Plazak (1989) documented a history of landslides 

along this section of road that he compiled from many different sources. One of the more notable landslide 

events Plazak (1989) was able to document occurred during the spring of 1979 when a series of landslide 

movements along the east side of Point Lookout closed the entrance road for more than a month (Plazak, 

1989; Smith, 2002). 

Qrr Rock-rubble deposits (Holocene and Pleistocene)—Deposited by rock topples, rockfall, rock avalanches, and 

debris flows below the northern and eastern escarpments of the park. Consists mainly of clast-supported, 

unsorted, unstratified to poorly stratified, pebbly, cobble-boulder gravel. Clasts consist of angular to subangular sandstone pebbles, cobbles, and boulders derived from the Point Lookout Sandstone (Kpl). Boulders 

commonly >1 m3; one boulder capping a small hill west of the park’s entrance station was estimated to be 

about 75 m3 in volume. Matrix consists of pale-brown (10YR 6/3), yellowish-brown (10YR 5/6), or paleyellow (2.5Y 7/4) silty sand to sand. Unit underlies steep slopes along the northern and eastern escarpments 

and also caps isolated hills and ridges beyond the base of the escarpments. These hills and ridges stand above 

the general terrain because the sandstone rubble, acting as a protective cap, shields the underlying Mancos 

Shale (Km) from erosion. As previously mentioned, a deposit on a hill near the entrance station to Mesa 

Verde National Park demonstrates an ancient age for some of the rock-rubble deposits shown on the map. 

The hill, at an elevation of 2,252 m, is approximately 91 m above the surrounding terrain and is capped by 

about 9 m of Point Lookout Sandstone rubble. The rubble consists of sand to boulders as large as 3 m in 

intermediate diameter and was emplaced by a large rockfall, rock avalanche, or debris flow originating from 

the Point Lookout Sandstone. That this hill is now 91 m above the surrounding terrain of Mancos Shale and 

the nearest outcrop of Point Lookout Sandstone is at Point Lookout, about 2.4 km to the south, suggests that 

an extended period of erosion, possibly on the order of several hundreds of thousands of years, has occurred 

since the deposition of this deposit. Thickness commonly 5 to as much as 30 m

 Hazard: areas around unit may be prone to rockfall or dislodged large sandstone boulders. 

Eolian Deposits

Qlo Loess (Holocene to middle Pleistocene)—Poorly exposed predominantly reddish-brown (5YR 4/4 and 5/3) to 

yellowish-red (5YR 5/6), massive, fine sandy silt and silt deposited by wind probably from the desert to the 

southwest. In the Mesa Verde National Park area, unit rests unconformably on the bedrock surface of the 

Cliff House Sandstone (Kch) and forms a thick, continuous blanket on many of the mesa surfaces. Areas of 

loess shown on this map were taken from Ramsey (2003) with slight modification and correspond to 
16 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

his Morefield loam units. Size analyses of 19 samples indicate the loess commonly consists of 30 percent 

fine sand, 50 percent silt, and 20 percent clay. Arrhenius and Bonatti (1965) found that the loess consists 

predominantly of subrounded, goethite-stained quartz with lesser amounts of plagioclase and chlorite, and 

with amphibole and opaque minerals as accessories. Maximum thickness estimated to be 3–5 m

 Resource: the loess was a resource for the Ancestral Puebloans who farmed the soil that developed in 

the thick loess deposits, which because of its particle size distribution has good moisture retention properties (Price and others, 1988). This loess cover and the seasonal rains associated with the “Arizona monsoon” 

allowed these people to grow their crops, primarily corn, beans, and squash on the broad mesa tops. In addition, the loess was used as a mortar in the cliff dwellings. 

 Hazard: susceptible to soil erosion after fires and (or) removal of vegetation. 

Bedrock Units

Tm Minette dike (Oligocene)—A potassic (K) mica lamprophyre, greenish-gray to black in color, characterized by 

an aphanitic groundmass of sanidine, diopside, phlogopite, and apatite, and phenocrysts of diopside, and 

phlogopite, and less commonly olivine (Semken, 2003). Phenocrysts are commonly 1 mm to 1 cm in maximum 

dimension and comprise less than 10 percent to more than 50 percent of the rock (D.A. Gonzales, Fort Lewis 

College, written commun., 2011). At several locations in the area, minette dikes and diatremes contain calcite and fluorite breccias that appear to have formed from magmatic volatiles (Gonzales and others, 2010). 

Minettes are enriched in potassium (K2O approximately 6 percent by weight) and magnesium, and depleted 

in aluminum (Semken, 2003). Wave-length dispersive XRF on a sample from the minette dike in Navajo 

Canyon yielded the following results: SiO2 59.0 percent; Al2O3 11.32 percent; FeTO3 5.23 percent; MgO 

7.06 percent; CaO 6.91 percent; Na2O 1.74 percent; K2O 6.90 percent; TiO2 1.07 percent; P2O5 0.68 percent; 

and MnO 0.07 percent (T.L. Hannah, U.S. Geological Survey, written commun., 2006). Minettes form from 

a potassic lamprophyre melt; such melts originate at the crust-mantle boundary (Gerhardt and others, 2006). 

Occurs as discontinuous dikes, trending northeast, at several localities in Mesa Verde National Park and 

as dikes and diatremes in nearby areas (Wanek, 1959; Condon, 1991). Where exposed, minette commonly 

weathers to a yellowish-brown friable rock that disintegrates into angular to subangular, coarse sand-sized 

fragments, due primarily to the high concentrations of mica.

 Dikes are well exposed in the soft Menefee Formation and Mancos Shale, and form gullies where they 

have intruded into the more resistant Cliff House and Point Lookout Sandstones. Along the eastern 

side of Navajo Canyon a minette dike, trending approximately N20°E is dark gray, near vertical, about 

3–5 m wide, and rises about 10–15 m above the surrounding Menefee Formation (Kmf). This dike extends to 

the southwest and a small outcrop occurs on the west side of Navajo Canyon protruding above a thick 

colluvium (Qcmf) cover. The dike can be traced farther to the southwest and forms a straight-line gully 

in the Cliff House Sandstone (Kch) as it crosses Long Mesa. A poorly exposed dike to the north, trending 

N35°E, underlies a gully, about 5–10 m deep, in the Cliff House Sandstone on both sides of Spruce Canyon. 

In Mancos Canyon a minette dike, that intrudes the Mancos Shale (Km), can be traced intermittently for a 

distance of about 0.65 km. At its northeastern end the dike is about 2 m wide, commonly less than 1 m above 

the surrounding ground surface, and trends N38°E. At its southwestern end the dike is about 75 cm thick, 

near vertical, and stands about 5–6 m above the adjacent Mancos Shale. Here, a 10-cm-thick bake zone of 

slate, derived from the Mancos Shale, surrounds the dike. 

 Age: An Oligocene age (33.9–23.03 Ma, U.S. Geological Survey, 2010) is indicated by two radiometric ages obtained from minette dikes in Mesa Verde National Park. A 40Ar/39Ar age of 25.65±0.08 Ma was 

obtained on biotite from a sample of the minette dike exposed in Navajo Canyon and is interpreted as the 

intrusion age of the dike (Peters, 2011a). An additional 40Ar/39Ar age of 24.97±0.12 Ma was obtained on 

phlogopite from a sample of the minette dike exposed in Mancos Canyon and was again interpreted as the 

intrusion age of this dike (Peters, 2011b). 

 Resource: the Ancestral Puebloans used minette for several purposes. Because minette is friable and 

crumbles into sand-sized particles when it weathers, it was sometimes used as a temper in the pottery of 

the Ancestral Puebloans (Gerhardt and others, 2006; Arakawa and Gonzales, 2010). Aphanitic minette, a 

dark-colored, very fine-grained, hard, dense rock that is flakable, was used as a lithic resource (arrow heads, 

blades, scrapers) by the Ancestral Puebloans (Gerhardt and others, 2006). In Morefield Canyon the author 

noted a large piece of minette that had been used as a metate (a grinding stone). In addition, because the 

minette dikes weather to form deep gullies in the Cliff House Sandstone, these gullies were used as travel 

routes from the canyon bottoms to the mesa tops by the Ancestral Puebloans (Linda Martin, National Park 

Service, personal commun., Sept. 11, 2006). 
Description Of Map Units 17

Mesaverde Group (Upper Cretaceous)–Name applied to sandstones and coal-bearing units of Late Cretaceous age over large 

areas of the Rocky Mountains and the Southwest (Wanek, 1959). In Mesa Verde National Park the group 

comprises, from youngest to oldest, the Cliff House Sandstone, Menefee Formation, and Point Lookout 

Sandstone

Kch Cliff House Sandstone—Predominantly sandstone and minor siltstone, deposited in a shallow, near-shore marine 

environment of an advancing sea (Griffitts, 1990). In the northern part of the park the Cliff House Sandstone consists of yellowish-gray to yellowish-brown, fine-grained sandstone beds, as much as 3 m thick, 

but mostly consists of thin beds of soft sandstones and yellowish-gray shale, which wedge out to the south 

(Wanek, 1959, p. 695; Griffitts, 1990, p. 18). Here the unit forms slopes underlain by a thin colluvial cover 

consisting of unsorted, poorly stratified, clast-supported, angular to subangular, sandstone blocky rubble in a 

yellowish-brown (10YR 5/4) sandy matrix. In the southern part of the park this unit consists of two massive, 

white, yellowish-orange, brownish-yellow, and pale-brown fine- to medium-grained, cross-bedded, cliffforming sandstones separated by a thin, softer sandy shale section (Griffitts, 1990, p. 20). Iron concretions 

are common in the Cliff House Sandstone in the southern park area and are usually about 1 to 5 cm in diameter. Chemical analysis of two concretions indicated they consisted of 64 and 86 percent Fe2

O3 respectively 

(Debbie Waldon, SGS Lakefield Research Limited, written commun., 2008). At some locations in the park, 

such as along the trail to Spruce Tree House, near the park headquarters, the Cliff House Sandstone weathers 

into a polygonal pattern of grooves sometimes called “turtlebacks” (Griffitts, 1990, p. 20). In the park this 

unit underlies the broad mesa tops common in the southern portion of the park that can be readily viewed 

from the Far View Visitor Center. In the Mesa Verde National Park area, the Cliff House Sandstone intertongues at its base with the underlying Menefee Formation (Kmf) and the contact between the two units is 

usually placed directly above the uppermost coal bed (Griffitts, 1990, p. 54). In the northern part of the park 

the thickness of the Cliff House Sandstone was estimated to be about 20 m (Griffitts, 1990, p. 20), although 

some upper strata may have been removed by erosion. In the southern part of the park a maximum thickness 

of about 120 m is exposed in the Echo Cliff area (Wanek, 1959, p. 695).

 Resources: upper massive sandstone unit forms the deep alcoves that were used by the Ancestral 

Puebloans as building sites for their cliff dwellings. In addition, blocks of the Cliff House Sandstone were 

used as building material by the Ancestral Puebloans for their dwellings and for metates to grind their corn. 

More recently, many of the buildings constructed by the National Park Service, such as those at the park 

headquarters and museum were also constructed of blocks quarried from the Cliff House Sandstone. 

 Hazards: rockfalls have occurred along the massive cliffs and in the alcoves (Anderson, 1963).

Kmf Menefee Formation—Poorly exposed gray to grayish-orange lenticular cross-bedded sandstone and gray to 

brownish-gray and black carbonaceous shale, coal beds, and bentonitic clay beds. This formation was deposited in a broad coastal plain environment (Condon, 1991) adjacent to the Late Cretaceous sea. Informally 

divided into upper coal-bearing member, middle barren member, and lower coal-bearing member (Hayes 

and Zapp, 1955). The upper coal-bearing member consists of carbonaceous shale and lenticular coal beds 

interbedded with sandstone and siltstone beds (Condon, 1991). The middle barren member consists of massive, lenticular, cliff-forming, cross-bedded, light gray, fine- to medium-grained sandstone interbedded with 

siltstone and silty shale (Wanek, 1959; Griffitts, 1990; Condon, 1991). Abundant ironstone concretions occur 

in the sandstone or in the intervening shale (Wanek, 1959; Griffitts, 1990). The lower coal-bearing member 

consists of a yellowish-gray siltstone, carbonaceous shale, and coal interbedded with minor amounts of very 

fine to fine-grained sandstone. Conformably overlies and intertongues at its base with the Point Lookout 

Sandstone (Kpl) (Wanek, 1959). In the park, the contact between the continental Menefee Formation and the 

underlying marine Point Lookout Sandstone is easily recognized. The lower layers of the Menefee are very 

dark brown or black soft shales with thin beds of shiny black coal, that weather to form a colluvial slope, 

whereas the top of the Point Lookout Sandstone consists of a massive, yellow, yellowish-gray, light-gray, 

pale-orange, and pale-brown, fine- to medium-grained, cliff-forming, cross-bedded sandstone. In the Mesa 

Verde area, the Menefee Formation is about 105–120 m thick, although it reaches a thickness of about 245 m 

at the Colorado–New Mexico boundary (Wanek, 1959, p. 688)

 The Menefee Formation weathers rapidly and this loose weathered material then creeps downslope to 

form a thick colluvial mantle. Hence, except for road cuts and landslide scars, there are few good exposures 

of this formation in the park. On this map the majority of colluvium (Qcmf) mapped along the sides of canyons is derived from this formation.
18 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

 Resource: the Ancestral Puebloans used bentonitic clay layers within the Menefee for their pottery and 

farmed both the soils formed in this unit and colluvium derived from this unit in the broad Morefield and 

Prater Canyons in the eastern park area. Iron concretions from the Menefee Formation were used for hand 

axes and red ocher was obtained from the hematite in these concretions. Iron concretions and jet (carbonized 

wood) were also carved into decorative pendants, on display in the park’s museum. Coal beds in the park are 

relatively thin, usually not more than 50 cm thick and mostly thinner, but outside the park they are considerably thicker and have been mined (Griffitts, 1990, p. 53). In the early 1900s coal was mined from the 

Menefee Formation south of the towns of Mancos (Collier, 1919), and Cortez (Wanek, 1959). The Ancestral 

Puebloans do not appear to have utilized the coal resources for cooking or heating (Linda Martin, National 

Park Service, personal commun., Sept. 11, 2006). The Menefee Formation is also a rich resource for terrestrial fossils (Griffitts, 1990). 

 Hazard: the Menefee Formation is prone to failure on steep slopes and forms many landslides within 

the canyons of the park. Much of the road between Montezuma Valley Overlook and the Park Point turnoff 

is in the Menefee Formation. Parts of this section of the road have had to be rerouted because where the road 

was in unstable soft woody shales and thin-bedded brittle coal layers it was difficult to maintain (Griffitts, 

1990, p. 14–15). In addition, exposed coal seams can ignite in wildfires as occurred in Morefield Canyon in 

2000. Because the smoldering coal posed a risk of future ignitions it was extinguished through excavation 

with heavy machinery in 2005 (G. San Miguel, National Park Service, written commun., 2005). 

Kpl Point Lookout Sandstone—Predominantly sandstones and shales deposited as barrier beaches and near-shore 

sands in a shallow-water retreating sea (Griffitts, 1990). The upper part of the Point Lookout Sandstone 

consists of massive beds of yellow, yellowish-gray, light-gray, pale-orange, and pale-brown, fine- to 

medium-grained, cross-bedded sandstones and forms the light-colored cliffs capping the mesas along the 

north face of Mesa Verde seen from U.S. Route 160. Along the trail on the western side of Prater Ridge, a 

large flat surface of the upper part of the Point Lookout Sandstone has weathered into a polygonal pattern 

of grooves called “turtlebacks” by Griffitts, (1990, p. 20). This upper part also contains radioactive black 

sandstone deposits along the western and southwestern sides of Mesa Verde (Houston and Murphy, 1977). 

The lower part of the Point Lookout Sandstone consists of interbedded yellowish-gray and light-brown, finegrained, cross-bedded sandstone and olive-gray to gray sandy fossiliferous shale. Sandstone beds in lower 

part increase up section in thickness and abundance. Conformably overlies the Mancos Shale (Km), with 

which the basal part also intertongues. On some steep slopes a thin colluvial cover may form consisting of 

unsorted, poorly stratified, clast-supported, angular to subangular, sandstone pebbles, cobbles, and boulders 

in a yellowish-brown (10YR 5/4), silty fine sand or sandy matrix. Many of the clasts have a thin coating of 

calcium carbonate. Along the northern escarpment sections of the upper part of the Point Lookout Sandstone 

measured by Wanek (1959) indicate a thickness of about 75 m, whereas sections of the lower part range 

between 25 and 38 m. 

 Resource: some of the small alcoves formed in the upper massive sandstones, were occupied by the 

 Ancestral Puebloans (Griffitts, 1990, p. 53). In addition, this unit was sometimes used as metates to grind 

 corn. 

 Hazard: because the Point Lookout Sandstone forms cliffs and steep slopes and is underlain by the 

 easily weathered and eroded Mancos Shale, slopes beneath the Point Lookout Sandstone are prone to rockfall 

Km Mancos Shale (Upper Cretaceous)—Mostly a thick sequence of gray to black fissile shale interbedded with 

thin beds, generally less than 25 cm thick, of tan siltstone, fine-grained sandstone and limestone deposited 

in a deep-water marine environment. Fossils found in this formation include oysters, clams, snails, shark 

teeth, and ammonites. Mancos Shale slopes beneath outcrops of the Point Lookout Sandstone (Kpl) may be 

covered with a thin mantle of sandstone boulders not shown on this map. Unit intertongues at top with lower 

part of the Point Lookout Sandstone. On this map the upper boundary of the Mancos Shale is placed at the 

base of the lowermost sandstone of the Point Lookout Sandstone. Conformably overlies Dakota Sandstone 

in nearby areas. Weathered Mancos Shale or colluvium derived from the Mancos Shale has a gray “popcorn” 

texture when dry. Near the park entrance, in the section below Point Lookout (fig. 1), Wanek (1959) measured about 610 m of Mancos Shale, but excluded the transitional zone with the overlying Point Lookout 

Sandstone. Leckie and others (1997) measured a total Mancos Shale thickness of about 685 m in this same 

area.
Description Of Map Units 19

 Hazards: unit prone to landsliding and debris flows where exposed on steep slopes, such as along the 

northern and eastern escarpments of Mesa Verde National Park. Along these escarpments many of the slopes 

underlain by the Mancos Shale are steep and bare of vegetation, indicating high rates of erosion and ongoing mass wasting processes. Unit may have moderate to high swelling potential due to presence of expansive 

clays; contains sulfate minerals that are corrosive to conventional concrete and metal pipes. When wet, the 

surface of the Mancos Shale becomes sticky and very slippery, unimproved roads are virtually impassable 

when wet. 
20 Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

References Cited

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area [abs.]: Geological Society of America Abstracts with 

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Arrhenius, Gustaf, and Bonatti, Enrico, 1965, The Mesa Verde 

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Mesa Archeological Project, Memoirs of the Society for 

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Formation on U.S. Bureau of Public Roads Project 1-F, 

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Bowen, D.Q., and Gibbard, P.L., 2007, The Quaternary is here 

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Carrara— Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado—Scientific Investigations Map 3224