by Alex Gugel , all rights reserved
Capitol ReefGeology and Stratigraphy Column |
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Capitol Reef National Park
National Park Service
U.S. Department of the Interior
Geology
“Geology knows no such word as forever.” —Wallace Stegner
Capitol Reef National Park’s geologic story reveals a nearly complete set
of Mesozoic-era sedimentary layers. For 200 million years, rock layers
formed at or near sea level. About 75-35 million years ago tectonic
forces uplifted them, forming the Waterpocket Fold. Forces of erosion
have been sculpting this spectacular landscape ever since.
Deposition
Uplift
If you could travel in time and visit Capitol
Reef 245 million years ago, you would not
recognize the landscape. Imagine a coastal
park, with beaches and tidal flats; the water
moves in and out gently, shaping ripple marks
in the wet sand. This is the environment
in which the sediments of the Moenkopi
Formation were deposited.
Visiting Capitol Reef 180 million years ago,
when the Navajo Sandstone was deposited,
you would have been surrounded by a giant
sand sea, the largest in Earth’s history. In this
hot, dry climate, wind blew over sand dunes,
creating large, sweeping crossbeds now
preserved in the sandstone of Capitol Dome
and Fern’s Nipple.
Now jump ahead 20 million years, to 225
million years ago. The tidal flats are gone and
the climate supports a tropical jungle, filled
with swamps, primitive trees, and giant ferns.
The water is stagnant and a humid breeze
brushes your face. Oxygen-rich river water
oxidized the iron in the sediments, giving the
Chinle Formation its lavender and red colors,
while the reducing environment of stagnant
bogs gave it the greens and grays.
All the sedimentary rock layers were laid
down at or near sea level. Younger layers were
deposited on top of older layers. The Moenkopi
is the oldest layer visible from the visitor center,
with the younger Chinle Formation above it.
The Castle is Wingate Sandstone; the Kayenta
Formation that formerly capped it has eroded
away, but is still visible atop the red cliffs behind
it. White domes of Navajo Sandstone comprise
the highest and youngest layer seen from the
visitor center.
The movement of, and the interaction
between, Earth’s tectonic plates created the
different environments in which Capitol
Reef’s nineteen rock layers were formed. Few
of these sedimentary layers would be visible,
however, if not for the Laramide Orogeny, a
massive mountain building event that likely
reactivated an ancient buried fault between
75 and 35 million years ago. The compression
associated with the Laramide Orogeny gave
rise to a one-sided fold, or monocline, in the
earth’s crust within the Colorado Plateau.
area of otherwise nearly horizontal layers.
The layers on the west side of the Fold have
been lifted more than 7,000 feet (2134 m)
higher than corresponding layers on the east.
The Waterpocket Fold is the longest exposed
monocline in North America and is nearly 90
miles in length. It is the main reason Capitol
Reef National Monument was established in
1937.
The Waterpocket Fold is a classic monocline:
an enlongated fold with one steep side in an
Erosion
Capitol Reef’s spectacular scenery reflects
not only the underlying structure of the
Waterpocket Fold, but also the differing
degrees of resistance to weathering and
erosion seen in each rock layer.
Water is the dominant erosional force in
Capitol Reef, with wind playing only a minor
The folding and tilting of the rock layers allow
you to travel through 280 million years of
Capitol Reef’s geologic history in just fifteen
miles by driving through the park on State
Route 24.
role. Flash floods are the most dramatic
display of erosion in action. Floodwaters
propel debris, sediment, cobbles, and
boulders, increasing water’s carving power.
Deposition and uplift in Capitol Reef have
created a unique window into Earth’s history,
revealed through the power of erosion.
Cenozoic andesite
Wingate
Sandstone
Navajo Sandstone and
Kayenta Formation
Sandstone
Deeply-buried
fault
Additional information on the geology of Capitol Reef National Park is available on our website (www.nps.gov/care)
which also links to the Capitol Reef Natural History Association, a non-profit cooperating association that sells
publications on Capitol Reef ’s natural and cultural history.
Marine
Transition between tidal
flats and dune fields
Shallow marine, tidal flats,
& sabkhas (sandy salt flats)
Vast region of sand dunes
West-flowing rivers
Sand dunes
Forested basin with rivers,
swamps, & lakes
River channels
Gently sloping coastal
plain, fluctuating sea level
Grayish-green sandstone & siltstone
Earthy, red, very fine-grained
sandstone & gypsum
Interlayered red sandstone,
siltstone, & gypsum
Tan sandstone
White crossbedded sandstone
Interlayered white sandstone & red
siltstone
Sandstone, often stained dark red
Interlayered sandstone, siltstone, &
bentonitic mudstone
White sandstone
Mostly dark red siltstone &
mudstone; minor yellowish
limestone
Gray dolomitic limestone
White crossbedded sandstone
0-80 feet
450-750 feet
300-100 feet
50-100 feet
800-1100 feet
350 feet
350 feet
350-550 feet
0-90 feet
500-1000 feet
70-100 feet
400+ feet
www.nps.gov/care
Beach & dune sands
Marine
Sand dunes
Fremont River Gorge &
Goosenecks of Sulphur Creek
Fremont River Gorge
Miners Mountain, Egyptian Temple,
& base of Chimney Rock
Discontinuous; cap of Chimney Rock
Slopes below Fruita Cliffs; contains
petrified wood & uranium
Fruita Cliffs & Circle Cliffs
Top, ledgy portion of Fruita Cliffs;
Hickman Bridge
Capitol Dome, Navajo Dome, &
Grand Wash Narrows
Cap of Golden Throne
Forms red V-shaped chevrons on
east side of Waterpocket Fold
Cathedrals of Cathedral Valley
Caps cathedrals of Cathedral Valley
Cliffs at east park entrance
Tidal flats
Thinly-bedded, reddish siltstone;
thick, wavy gypsum on top
206 MYA
248 MYA
290 MYA
MYA = Million Years Ago
Shinarump
Member
White Rim Sandstone
Kaibab Limestone
Moenkopi Formation
Chinle Formation
Wingate Sandstone
Kayenta Formation
Navajo Sandstone
Page Sandstone
Carmel Formation
Entrada Sandstone
Curtis Formation
Summerville Formation
Salt Wash Member
Brushy Basin Member
150-300 feet
Morrison
Formation
Bentonite Hills; along Notom-Bullfrog
Road north of Burr Trail
Vast river systems;
bentonite clays from
altered volcanic ash
White crossbedded sandstone (Salt
Wash) & candy-striped mudstone
(Brushy Basin)
180-700 feet
144 MYA
Jurassic
Triassic
Permian
Coastal
Cedar Mountain Formation
Conglomerate and mudstone layers
0-100 feet
Mancos Shale
North and east of the Hartnet Road
river ford
Tan sandstone, oyster shell fossils
0-50 feet
Factory Butte and badlands near
Caineville
Muley Canyon Sandstone
Masuk Formation
Tarantula Mesa Sandstone
Capitol Reef Stratigraphy Column
Rivers and Floodplains
Mostly dark gray shale interlayered
with sandstone
2000-3000 feet
65 MYA
Age
Dakota
Dakota Sandstone
Sandstone
Shallow sea that bisected
North America
Shale interlayered with sandstone
West side of Henry Mtns.,
east of Strike Valley
Landforms
Oyster Shell Reef; locally absent
Floodplains, coastal areas,
and marine
1200-1450 feet
(combined)
Location / Remarks
Cretaceous
Paleoenvironment
Rock Type
Thickness
San Rafael Group
Glen Canyon Group
EXPERIENCE YOUR AMERICA™
11/15