Geology Rocky Mountain National Park is, in many respects, a huge outdoor geology museum. Spectacular vistas of nature's handiwork are readily accessible from your automobile and along more than 346 miles of trail. The park offers classic examples of geologic uplifts, erosion, and glaciation. Rock formations in the park are among the oldest in the United States. Mountain tops flattened by the relentless forces of erosion dominate a landscape of steep slopes, U- shaped valleys, crystal clear lakes, and moraine deposits left by glaciation.
Ancient Rocks
The park’s oldest rocks were formed when crustal plate movements subjected deeply buried sea sediments to intense pressure and heat. The resulting metamorphic rocks—schist and
Gneiss gneiss—are approximately 1.7 billion years old. Schist and gneiss were later intruded by magma which cooled some 1.4 billion years ago to form crystalline igneous rock— mostly silver plume granite.
Schist Schist and gneiss were later intruded by magma which cooled some 1.4 billion years ago to form crystalline igneous rock— mostly silver plume granite.
Granite
Uplift and Erosion About 70 million years ago there was an era The igneous rocks can be seen in the park's of uplift. Giant blocks of ancient crystalline Never Summer Mountains and on Specimen rock, overlain by younger sedimentary Mountain. Metamorphic volcanic ash rock, were fractured and thrust upward. forms can be at Lava Cliffs along Trail During the uplift, wind and water erosion Ridge Road. continued, moving loosened particles of rock to lower areas. After the sedimentary Faulting and upwarping continued to lift rocks were mostly gone, erosion continued the Rocky Mountain Front Range as much to remove some of the ancient Precambrian as 5,000 feet. By about two million years rocks until only a few isolated remnants ago, current elevations were in place. projected above the gently rolling Erosion continued to carve the landscape. landscape. The gentle slopes seen along Sedimentary layers on the eastern Trail Ridge Road and Flattop Mountain are plains had tilted with the uplift of the examples of this pre-glaciated landscape. mountains. Stream erosion of these tilted rock formations produced hogback ridges Some 25 million years ago volcanic near the towns of Lyons and Loveland. deposits of igneous rocks and windblown Differential movement along geologic faults ash settled on the older Precambrian caused mountain height variations and formations. creating waterfalls and large valley areas such as in Estes Park and the Kawuneeche Valley.
Park information is available at 970-586-1206 or on-line at www.nps.gov/romo EXPERIENCE YOUR AMERICA™
Present
11/06
10,000
4 periods of glaciation) of periods 4
The Ice Age (at least (at Age Ice The
glacial erosion. glacial
interesting shapes by millions of years of non- of years of millions by shapes interesting
areas had coarse-grained granite rounded into into rounded granite coarse-grained had areas
glaciated. The Twin Owls and Gem Lake Trail Trail Lake Gem and Owls Twin The glaciated.
mountaintops and at lower altitudes were not not were altitudes lower at and mountaintops
Some areas of the park on the high high the on park the of areas Some
display classic features of glaciation. of features classic display
of ancient erosion, while many of its valleys valleys its of many while erosion, ancient of
mountaintops show the spectacular effects effects spectacular the show mountaintops
Range of the Rocky Mountains, but the park's park's the but Mountains, Rocky the of Range
only a small part of the 200 mile-long Front Front mile-long 200 the of part small a only
Rocky Mountain National Park occupies occupies Park National Mountain Rocky
part of active glacial complexes in the park. park. the in complexes glacial active of part
glaciers," conglomerations of rock and ice, are are ice, and rock of conglomerations glaciers,"
A recent theory has suggested that "rock "rock that suggested has theory recent A Cenozoic
2,000,000
5,000,000
height reached height
continues unitl present present unitl continues
Uplift of mountains of Uplift
25,000,000
Volcanic Activity Volcanic
38,000,000
Erosion
70,000,000
Rocky Mountain Uplift Mountain Rocky
park are advancing or retreating. or advancing are park
been done to verify whether glaciers in the the in glaciers whether verify to done been
and snowfields. No definitive research has has research definitive No snowfields. and
could have a significant impact on the glaciers glaciers the on impact significant a have could
melts back during dry years. Global warming warming Global years. dry during back melts
evidence of down-valley movement, but it it but movement, down-valley of evidence
Ice Age landscapes. Andrews Glacier shows shows Glacier Andrews landscapes. Age Ice
occupy the tops of glacial valleys only hint at at hint only valleys glacial of tops the occupy
and stationary snowfields in the park that that park the in snowfields stationary and
some bedrocks. Now, the few small glaciers glaciers small few the Now, bedrocks. some
striations, grooves, and polished surfaces on on surfaces polished and grooves, striations,
Road. Glacial erosion also left scratches or or scratches left also erosion Glacial Road.
Numerous cirques are visible from Trail Ridge Ridge Trail from visible are cirques Numerous
east face of Longs Peak, rests in such a cirque. cirque. a such in rests Peak, Longs of face east
glaciated valleys. Chasm Lake, below the the below Lake, Chasm valleys. glaciated
often snow-filled, form the tops of U-shaped, U-shaped, of tops the form snow-filled, often Steep-sided, semicircular scars (cirques), (cirques), scars semicircular Steep-sided,
75,000,000
retreat
Seas invade and and invade Seas
Erosion
Mesozoic
Rockies
Uplift of Ancestral of Uplift
retreat repeatedly retreat
Seas invade and and invade Seas
Paleozoic
boundary.
Mountains along the park's northwest northwest park's the along Mountains
volcanic formations of the Never Summer Summer Never the of formations volcanic
sedimentary rock are found among the the among found are rock sedimentary
sections of the park. A few remnants of of remnants few A park. the of sections
rocks dominate in the central and eastern eastern and central the in dominate rocks
Today, Precambrian granites and metamorphic metamorphic and granites Precambrian Today,
Present Landscape Present
Lake were formed by terminal moraines. terminal by formed were Lake
Kawuneeche Valley. Bear Lake and Grand Grand and Lake Bear Valley. Kawuneeche
called Glacier Basin, Horseshoe Park, and the the and Park, Horseshoe Basin, Glacier called
glaciers melted and left moraines in areas now now areas in moraines left and melted glaciers
Eagle Cliff Mountain to the east. Similar Similar east. the to Mountain Cliff Eagle
Moraine Park and a terminal moraine against against moraine terminal a and Park Moraine
that define the south and north sides of of sides north and south the define that
massive glacier left distinct lateral moraines moraines lateral distinct left glacier massive
in the area now called Moraine Park. This This Park. Moraine called now area the in
together to form a large glacier which melted melted which glacier large a form to together Gorge, and other tributary valleys all flowed flowed all valleys tributary other and Gorge,
Intrusion of Granite of Intrusion
created
Schist and Gneiss and Schist
Long Sedimentation Long Era Precambrian
years ago years
4,600,000,000
glaciers are terminal moraines. moraines. terminal are glaciers
Material left at the farthest extension of the the of extension farthest the at left Material
along valley sides are called lateral moraines. moraines. lateral called are sides valley along
the mountainsides above. Debris deposits deposits Debris above. mountainsides the
the ice melted and dropped debris scraped from from scraped debris dropped and melted ice the
rivers of ice flowed into lower elevations where where elevations lower into flowed ice of rivers
V-shaped cuts and widening streams. These These streams. widening and cuts V-shaped
formed, flowing downward, forming deep deep forming downward, flowing formed,
elevations. As snow compacted glaciers glaciers compacted snow As elevations.
snow accumulated on the lee side of the highest highest the of side lee the on accumulated snow
"ice age," began and the climate cooled. Deep Deep cooled. climate the and began age," "ice
About two million years ago, the Pleistocene Pleistocene the ago, years million two About
glaciers from Forest Canyon, Odessa Odessa Canyon, Forest from glaciers
glaciation, starting about 28,000 years ago, ago, years 28,000 about starting glaciation,
During the most recent time of major major of time recent most the During
sculpted today's marvelous landscapes. marvelous today's sculpted
geological building blocks of the park, glaciers glaciers park, the of blocks building geological
While uplifts and volcanoes provided the major major the provided volcanoes and uplifts While
Glaciation
Geologic Timeline for Rocky Mountain National Park National Mountain Rocky for Timeline Geologic
Rocks Don't Like to Travel to Like Don't Rocks
enjoy!
provide insights to our future. Leave the rocks for others to to others for rocks the Leave future. our to insights provide
Don't take samples or chips. These clues to the earth's past past earth's the to clues These chips. or samples take Don't
protected under United States law from theft and vandalism. vandalism. and theft from law States United under protected Rocky's geological resources, like the flora and fauna, are are fauna, and flora the like resources, geological Rocky's