Parks Formed by Stream Parks Formed by Stream Erosion and WeatheringErosion and Weathering

(part 1)(part 1)

GRAND CANYON NATIONAL GRAND CANYON NATIONAL PARKPARK

ZION NATIONAL PARKZION NATIONAL PARK

Colorado PlateauColorado Plateau relatively undeformed rocks surrounded by the highly deformed Rocky

Mountains, and Basin and Range Provinces. The margins of the Colorado Plateau are

marked by major volcanic accumulations The major structures of the plateau include:

– broad flexures, – monoclines, – vertical faults,– igneous laccoliths and volcanics– Salt tectonic features.

Stratigraphy of Stratigraphy of Colorado PlateauColorado Plateau

From Geology of the Colorado From Geology of the Colorado Plateau, 1999, Annabelle Plateau, 1999, Annabelle Foos, Geology Department, Foos, Geology Department, University of AkronUniversity of Akron

Grand Canyon NP - Vital Grand Canyon NP - Vital StatisticsStatistics

Northwest ArizonaNorthwest Arizona Western Colorado PlateauWestern Colorado Plateau ~1,200,000 acres or 1,900 square ~1,200,000 acres or 1,900 square

milesmiles

Native American HistoryNative American History ~1000 BC Evidence of ~1000 BC Evidence of

Native American Native American Hunters in caves, Hunters in caves, artifactsartifacts

Basket Making Native Basket Making Native AmericansAmericans

AD 1350 Pueblo culture AD 1350 Pueblo culture (~500 sites)(~500 sites)

Up to today, still home Up to today, still home of three tribesof three tribes– Navajo (east)Navajo (east)– Hopi (east) Hopi (east) – Havasupai (west)Havasupai (west) Photo: NPS

Human History (con’t)Human History (con’t)

1540, Don Lopez de Cardenas1540, Don Lopez de Cardenas 1869, John Wesley Powell lead 1869, John Wesley Powell lead

expedition of 4 wooden boats & 9 expedition of 4 wooden boats & 9 men down the Colorado River (again men down the Colorado River (again in 1871)in 1871)

1893 protected as a Forest Reserve 1893 protected as a Forest Reserve 1908 TR proclaimed the area a NM1908 TR proclaimed the area a NM 1919 established as Park1919 established as Park

Geologic FeaturesGeologic Features

Stream ErosionStream ErosionMass WastingMass WastingDifferential ErosionDifferential ErosionUnconformitiesUnconformities

Stream ErosionStream Erosion Colorado River is 2Colorado River is 2ndnd longest river in US longest river in US Colorado River eroded Grand CanyonColorado River eroded Grand Canyon Canyon is 217 miles long, 1 mile deep, up to 18 miles Canyon is 217 miles long, 1 mile deep, up to 18 miles

widewide Erosion began between ~5 million years agoErosion began between ~5 million years ago PANORAMIC VIEW OF THE GRAND CANYON FROM PIMA POINT ON THE WEST RIM DRIVE, GRAND CANYON N.P. NPS PHOTO. PANORAMIC VIEW OF THE GRAND CANYON FROM PIMA POINT ON THE WEST RIM DRIVE, GRAND CANYON N.P. NPS PHOTO.

Stream Stream ErosionErosion

Colorado RiverColorado River

Erosion mainly Erosion mainly verticalvertical

VIEW DOWN THE COLORADO RIVER IN GRAND CANYON N.P. FROM NANKOWEAP IN MARBLE CANYON. MIKE QUINN, NPS

Mass WastingMass Wasting Movement of material downward due to Movement of material downward due to

gravitygravity Main process involved in widening canyonMain process involved in widening canyon Climate is arid; mechanical weathering; Climate is arid; mechanical weathering;

talustalus

Photo: Mirsky

Differential ErosionDifferential Erosion Responsible for rugged nature of cliffsResponsible for rugged nature of cliffs Caused by different degree of resistance Caused by different degree of resistance

to erosionto erosion– Resistant – cliffs – limestone, sandstoneResistant – cliffs – limestone, sandstone– Less resistant – slopes – shales Less resistant – slopes – shales

Unconformity: Buried erosion surfaceUnconformity: Buried erosion surface

Differential ErosionDifferential Erosion

Kaibab SSKaibab SS

Coconino SSCoconino SS

Hermit ShHermit Sh

Supai GroupSupai Group

Redwall LsRedwall Ls

Bright Angel Bright Angel ShSh

Tapeats SSTapeats SS

Photo: CD, HTT

Unconformities – PC/C Unconformities – PC/C nonconformitynonconformity

Vishnu Schist

Tapeats Sandstone

Unconformities – PC/C angular Unconformities – PC/C angular unconf.unconf.

Grand Canyon Series

Tapeats Sandstone

Geologic History - Geologic History - StratigraphyStratigraphy

Geologic History – Pre-Geologic History – Pre-CambrianCambrian

2,000 mya marine sediments and 2,000 mya marine sediments and volcanic rocks (since metamorphosed volcanic rocks (since metamorphosed into Vishnu Schist) and into Vishnu Schist) and

1,700 mya folding, faulting, intrusions1,700 mya folding, faulting, intrusions(Zoroaster Granite)(Zoroaster Granite)

1,000 mya sea transgressed and 1,000 mya sea transgressed and deposited Grand Canyon Seriesdeposited Grand Canyon Series

Mountain building, then erosion to low Mountain building, then erosion to low hillshills

Geologic History – PaleozoicGeologic History – Paleozoic

Cambrian – Sea transgresses againCambrian – Sea transgresses again– Tapeats SandstoneTapeats Sandstone– Bright Angel ShaleBright Angel Shale

Ordovician, Silurian – no rock recordOrdovician, Silurian – no rock record Devonian Temple Butte LimestoneDevonian Temple Butte Limestone

Geologic History – PaleozoicGeologic History – Paleozoic

MississippianMississippian– Redwall limestone - marineRedwall limestone - marine

PennsylvanianPennsylvanian– Supai formation – lower part marineSupai formation – lower part marine

upper part non marine, with reptile tracksupper part non marine, with reptile tracks Permian – near shore alternatingPermian – near shore alternating

– Hermit Shale – non-marine, more tracksHermit Shale – non-marine, more tracks– Coconino sandstone – dune sand, x-bedsCoconino sandstone – dune sand, x-beds– Toroweap formation – marineToroweap formation – marine– Kaibab limestone – top cliff, marineKaibab limestone – top cliff, marine

Geologic History – MesozoicGeologic History – Mesozoic

Thousands of feet of sediment Thousands of feet of sediment deposited, but mostly eroded away deposited, but mostly eroded away from GC areafrom GC area

Rock of this age to north (Zion, Rock of this age to north (Zion, Bryce), east (Painted Desert, Black Bryce), east (Painted Desert, Black Mesa) and remnants near Grand Mesa) and remnants near Grand Canyon at Cedar Mt.Canyon at Cedar Mt.

Geologic History - CenozoicGeologic History - Cenozoic

Miocene – Ancestral Colorado River Miocene – Ancestral Colorado River flowed over lowlands with little flowed over lowlands with little elevationelevation

Pliocene – beginning of uplift of Pliocene – beginning of uplift of Colorado Plateau (continues to Colorado Plateau (continues to present)present)

Mid-Pliocene – Colorado River Mid-Pliocene – Colorado River entrenchment begins ~4-6 myaentrenchment begins ~4-6 mya

Geologic History – Pleistocene to Geologic History – Pleistocene to TodayToday

Colorado River cut quickly through Pz Colorado River cut quickly through Pz sedsed

Inner Gorge cut more slowlyInner Gorge cut more slowly River only removes material in its River only removes material in its

channelchannel Mass wasting delivers sediment to Mass wasting delivers sediment to

riverriver Faulted areas form tributary valleysFaulted areas form tributary valleys

Zion National ParkZion National Park

Cliffs of Navajo Sandstone

Vital StatisticsVital Statistics

Southwest UtahSouthwest Utah Western Colorado PlateauWestern Colorado Plateau 147,000 acres or 230 square miles 147,000 acres or 230 square miles 1909 Monument (by TR)1909 Monument (by TR) 1919 National Park1919 National Park Expanded in 1937 & 1956Expanded in 1937 & 1956

Later Human HistoryLater Human History

~ AD 500 Basket Maker Culture Native Americans

Later, Piute tribe 1776, Don Lopez de Cardenas1776, Don Lopez de Cardenas 1872, John Wesley Powell lead expedition 1872, John Wesley Powell lead expedition

and named the area Mukuntuweapand named the area Mukuntuweap 1909 TR proclaimed the area a NM as 1909 TR proclaimed the area a NM as

Mukuntuweap NMMukuntuweap NM 1918 name changed to Zion NM1918 name changed to Zion NM 1919 established as Park1919 established as Park

Geologic FeaturesGeologic Features

Stream Erosion & Mass Stream Erosion & Mass WastingWasting

Structural ControlStructural ControlWeatheringWeatheringArchesArches

Stream Erosion & Mass Stream Erosion & Mass WastingWasting

Virgin River has gradient of ~60 ft/miVirgin River has gradient of ~60 ft/mi Mass wasting widens Zion CanyonMass wasting widens Zion Canyon Sapping by springs creates Sapping by springs creates

overhangsoverhangs Tributaries – less water, left hangingTributaries – less water, left hanging

Rectangular stream Rectangular stream pattern – fracturespattern – fractures

Columns and PyramidsColumns and Pyramids Vertical fractures Vertical fractures

encourage vertical cliffsencourage vertical cliffs Rapid downcutting Rapid downcutting

through soft sandstone through soft sandstone leaves deep, narrow leaves deep, narrow canyonscanyons

Bedding planes also act Bedding planes also act as plane of weaknessas plane of weakness

Structural Structural ControlControl

Rectangular stream pattern – fracturesRectangular stream pattern – fractures Columns and PyramidsColumns and Pyramids Vertical fractures encourage vertical Vertical fractures encourage vertical

cliffscliffs Rapid downcutting through soft Rapid downcutting through soft

sandstone leaves deep, narrow canyonssandstone leaves deep, narrow canyons Bedding planes also act as plane of Bedding planes also act as plane of

weaknessweakness

Structural ControlStructural Control

Rectangular stream pattern – fracturesRectangular stream pattern – fractures Columns and PyramidsColumns and Pyramids Vertical fractures encourage vertical Vertical fractures encourage vertical

cliffscliffs Rapid downcutting through soft Rapid downcutting through soft

sandstone leaves deep, narrow canyonssandstone leaves deep, narrow canyons Bedding planes also act as plane of Bedding planes also act as plane of

weaknessweakness

Structural Control - Columns and Structural Control - Columns and PyramidsPyramids

Great White Throne

Cliffs of Navajo Sandstone

Rectangular stream Rectangular stream pattern – fracturespattern – fractures

Columns and PyramidsColumns and Pyramids Vertical fractures Vertical fractures

encourage vertical encourage vertical cliffscliffs

Rapid downcutting Rapid downcutting through soft sandstone through soft sandstone leaves deep, narrow leaves deep, narrow canyonscanyons

Bedding planes also act Bedding planes also act as plane of weaknessas plane of weakness

Structural Structural ControlControl

Rectangular stream pattern – fracturesRectangular stream pattern – fractures Columns and PyramidsColumns and Pyramids Vertical fractures encourage vertical Vertical fractures encourage vertical

cliffscliffs Rapid downcutting through soft Rapid downcutting through soft

sandstone leaves deep, narrow canyonssandstone leaves deep, narrow canyons Bedding planes also act as plane of Bedding planes also act as plane of

weaknessweakness

Structural Control - Bedding planes Structural Control - Bedding planes also act as plane of weaknessalso act as plane of weakness

Checkerboard Mesa Navajo Sandstone

Rock color from iron oxideRock color from iron oxide Frost wedgingFrost wedging Acid dissolves calcium carbonate Acid dissolves calcium carbonate

cementcement Arches – example Kolab ArchArches – example Kolab Arch

Kolab Arch

WeatheringWeathering

Stratigraphy of Stratigraphy of Colorado PlateauColorado Plateau

From Geology of the Colorado From Geology of the Colorado Plateau, 1999, Annabelle Plateau, 1999, Annabelle Foos, Geology Department, Foos, Geology Department, University of AkronUniversity of Akron

Geologic HistoryGeologic History

Permian – Kaibab Permian – Kaibab limestone – shallow limestone – shallow seasea

Triassic – Triassic – – arid near-shorearid near-shore– Uplift and some Uplift and some

volcanic ashvolcanic ash– Fossils fresh water fish, Fossils fresh water fish,

clams, snails, clams, snails, amphibians, wood, amphibians, wood, dinosaur tracksdinosaur tracks

Geologic History – JurassicGeologic History – Jurassic

Navajo Sandstone – Navajo Sandstone – arid climate with sand arid climate with sand dunes (up to 2000 ft dunes (up to 2000 ft thick)thick)

Forms the White CliffsForms the White Cliffs Frosted, fine-grained, Frosted, fine-grained,

quartz sandstonequartz sandstone Cross-beddedCross-bedded Capped by marine Capped by marine

Carmel FormationCarmel Formation

Navajo Sandstone

Geologic History - JurrasicGeologic History - Jurrasic

Geologic History – Cretaceous Geologic History – Cretaceous and Cenezoicand Cenezoic

Cretaceous (End of Mz) – erosionCretaceous (End of Mz) – erosion Lt. Miocene (~13mya) block faultingLt. Miocene (~13mya) block faulting

– TiltedTilted– Uplifted – increased river gradient, Uplifted – increased river gradient,

rejuvenated stream erosion, carved Zion rejuvenated stream erosion, carved Zion CanyonCanyon