The Grand Staircase 

Gray Cliffs White Cliffs Vermilion Cliffs 

Chocolate Cliffs 

Grand Canyon Grand Canyon

Zion National Park Service 

U.S. Department of the Interior 

Zion National Park 

The Geology of Zion 

Grand Canyon Bryce Canyon Zion Canyon 

Kaibab Plateau Pink Cliffs South Rim North Rim

Zion is located along the edge of a region called the Colorado Plateau. Uplift, tilting, and 

erosion of rock layers formed a feature called the Grand Staircase, a series of colorful 

cliffs stretching between Bryce Canyon and the Grand Canyon. The bottom layer of rock 

at Bryce Canyon is the top layer at Zion, and the bottom layer at Zion is the top layer at 

the Grand Canyon. 

The Geologic Story Zion National Park is a showcase of geology. The arid 

climate and sparse vegetation expose bare rock and 

reveal the park’s geologic history. 

Sedimentation 

Zion was a relatively flat basin near sea level 275 million years ago. As sands, gravels, and muds eroded 

from surrounding mountains, streams carried these 

materials into the basin and deposited them in layers. 

The sheer weight of these accumulated layers caused 

the basin to sink, so that the top surface always 

remained near sea level. As the land rose and fell and 

as the climate changed, the depositional environment fluctuated from shallow seas to coastal plains 

to a desert of massive windblown sand. This process 

of sedimentation continued until over 10,000 feet of 

material accumulated. 

Lithifi cation 

Mineral-laden waters slowly filtered through the 

compacted sediments. Iron oxide, calcium carbonate, 

and silica acted as cementing agents, and with pressure from overlying layers over long periods of time, 

transformed the deposits into stone. Ancient seabeds 

became limestone; mud and clay became mudstones 

and shale; and river sand and sand dunes became 

sandstone. Each layer originated from a distinct 

source and so differs in thickness, mineral content, 

color, and eroded appearance. 

Colorado 

New 

Mexico Arizona 

Utah 

The Colorado Plateau 

Uplift 

In an area from Zion to the Rocky Mountains, forces 

deep within the earth started to push the surface up. 

This was not chaotic uplift, but slow vertical hoisting of huge blocks of the crust. Zion’s elevation rose 

from near sea level to as high as 10,000 feet above sea 

level. 

Uplift is still occurring. In 1992 a magnitude 5.8 

earthquake caused a landslide visible just outside the 

south entrance of the park. 

Erosion 

This uplift gave the streams greater cutting force in 

their descent to the sea. Zion’s location on the western edge of this uplift caused the streams to tumble 

off the plateau, flowing rapidly down a steep gradient. These streams began eroding and cutting into 

the rock layers, forming deep and narrow canyons. 

Grain by grain the Virgin River has carried away 

several thousand feet of rock that once lay above the 

highest layers visible today. 

The Virgin River is still excavating. Upstream from 

the Temple of Sinawava, the river cuts through Navajo Sandstone, creating a slot canyon. At the Temple, 

the river has reached the softer Kayenta Formation 

below. Water erodes the shale, undermining the overlaying sandstone and causing it to collapse, widening 

the canyon. 

Volcanic Activity 

Volcanic vents, created as a result of the weakening 

of the Earth’s crust during uplift, allowed lava fl ows 

and cinder cones to form. Cinder was piled several 

hundred feet high in classic cone shapes and lava 

flowed into valleys. Cinder cones and black basalt 

flows are visible west of Rockville and on Kolob 

Terrace. 
 

 

 

 

 

 

 

 

 

Geology in Action 

Geologic Formations 

A landslide once dammed the Virgin River forming a lake. Sediments settled out of the quiet waters, 

covering the lake bottom. When the river breached 

the dam and the lake drained, it left behind a fl atbottomed valley. This change in the character of the 

canyon can be seen from the scenic drive south of 

the Zion Lodge near the Sentinel Slide. This slide was 

active again in 1995, damaging the road. 

Flash floods occur when sudden thunderstorms 

dump water on exposed rock. With little soil to 

absorb the rain, runoff occurs quickly. These fl oods 

often occur without warning and can increase 

water flow by over 100 times. In 1998, a fl ash fl ood 

increased the volume of the Virgin River from 200 

cubic feet per second to 4,500 cubic feet per second, 

again damaging the scenic drive at the Sentinel Slide. 

Geology is not something that “happened” in the past. It is a constant force that continues to change the landscape. Earthquakes, fl ash floods, and rockfalls are sudden reminders that the earth is dynamic. Rock falls are common in Zion. This 700-ton rock blocked the Zion-Mt Carmel Highway on the switchbacks for two days in February, 

2005. 

Rock Layer Appearance Where To See Deposition Rock Type 

Cinder cones 

and lava fl ows 

black layers 

and cones 

 Kolob Terrace and 

west of Rockville 

 lava fl ows 

and cinder cones 

basalt and 

cinders 

Carmel cliffs Mt. Carmel Junction shallow sea and 

coastal desert 

limestone, gypsum,

 sandstone 

Temple Cap 

Navajo 

Sandstone 

cliffs 

steep cliffs 

1,600 to 2,200 

feet thick 

red lower layers 

are colored by 

iron oxides 

 top of West Temple 

 tall cliffs of Zion 

Canyon; highest 

 exposures are West 

 Temple, Checkerboard 

Mesa 

believed to be the 

 tallest sandstone cliffs 

in the world 

desert 

desert sand dunes 

 covered 150,000 

 square miles

 shifting winds 

during deposition 

 created crossbedding 

sandstone

cross-bedded 

sandstone 

Kayenta rocky slopes throughout canyon streams siltstone and 

sandstone 

Moenave slopes and ledges lower red cliffs seen from streams and ponds 

 Zion Canyon Visitor Center 

siltstone and 

sandstone 

Chinle purplish slopes above Rockville streams shale, loose clay, 

conglomerate 

Moenkopi 

Kaibab 

chocolate cliffs 

with white bands 

cliffs 

 rocky slopes from 

 Virgin to Rockville 

escarpment along 

I-15 near Kolob Canyons 

shallow sea 

shallow sea 

shale, siltstone, 

mudstone, others 

limestone

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