What is the “age” of the Grand Canyon of the Colorado River?

Kip Ault, Ph.D.Lewis & Clark College

Laurasia and Gondwana

North America

Pangea

Rodinia

The WilsonCycle

Grand Canyon

250-40 Million Years Ago“Mezozoic and Cenozoic”

Age of Reptiles toPrimitive Mammals:

Bryce CanyonDinosaur

MonumentGlen CanyonZion Canyon

What happened to the “Andes and Amazon” landscape in Arizona?

299 to 251 MYA “Permian”90% of marine species extinct by end

Kaibab Limestone Cliffs: Tropical tidal flats Toroweap Layers: Warm shallow seas Coconino Sandstone Cliffs:Coastal dunesHermit Shales (slope): River floodplains

318 to 299 MYA “Pennsylvanian”Supai Group: Esplanade Sandstone CliffsGondwana Collides with Laurasia to formSupercontinent PangeaIce Ages raise and lower seas

Redwall Formation 400 feet thick

416 to 318 Million Years Ago “Mississippian”Carbonate Seas deposit limestoneCliffs and caves from the Tetons to Tucson!

525 to 318 MYA “Cambrian”Seas expanding calmly onto land

Muav LimestoneBright Angel Shale

Tapeats Sandstone

1.25 to .75 Billion Years Ago“Late Proterozoic”Rodinia rifts apartGrand Canyon Supergroup: Chuar-Cardenas-Nankoweap-Unkar 12,000 feet thick!

1.75 Billion Years Ago“Early Proterozoic”Island Arcs added to North American CratonOnce 15 miles below the surface of the earth!

Vishnu Schist and Zoroaster Granite

The Great Unconformity

740-1255 mya

525 mya

1750 mya

Angular Unconformity

525 mya

The Great Nonconformity

https://www.flickr.com/photos/grand_canyon_nps/sets/72157624999234563/

Atlantic rifting PangeaGrand Canyoncarving

Pre and Post Rodinia

Focus QuestionThinking Doing

Concepts

Principles

Events and Objects

Vee Diagram of Inquiry from D. B. Gowin

Records

Claims

(Prior Knowledge) (New Knowledge))

When did the Colorado River begin to carve the Grand Canyon?

(Focus Question)

How did the San Andreas fault help the Colorado River leave the Colorado Plateau?

Implications of the Miocene(?) Crooked Ridge River of Northern Arizona for the Evolution of the Colorado River and Grand Canyon

Ivo Lucchitta

(New Knowledge Claims)

Origin and Evolution of the Colorado River System

Karl E. Karlstrom

(New Knowledge Claims)

The mystery of the pre–Grand Canyon Colorado River—Results from the Muddy Creek Formation

Joel L. Pederson

(New Knowledge Claims)

Age of the Grand Canyon: 80 million or 6 millions years?

80 mya ago the Cretaceous seas withdrew. Rivers drained to the Northeast for 50 million years.

Laramide orogeny uplifted the Colorado Plateau—North American crumpled and the Farallon Plate subducted shallowly from 70 to 40 mya.

Rivers “disappear” from view on the Colorado Plateau between 30 and 16 mya

(Principles and Prior Knowledge)

http://cpgeosystems.com/index.html

Basins formed to the West (Muddy Creek Formation) and to the East (Bidahochi Formation)

16 mya the Mogollan Highlands to the Southwest begin to rift apart and collapse.

At this time the spreading zone in the Pacific collided with the North American plate to create the San Andreas fault.

Instead of compressing, the North American plate began to pull apart. The Basin and Range Province forms to the West and Southwest of the Colorado Plateau.

(Claims from prior inquiries)

How and when did the Colorado River find its way through the Colorado Plateau and to the Sea of Cortez?

(Focus Question restated)

How and when did the Colorado River find its way through the Colorado Plateau and to the Sea of Cortez?

Or, how and when did the sections of the Colorado River above and below the Grand Canyon join together?

(Additional Focus Question)

Headward erosion and stream capture of the Little Colorado?

Reversal of drainage in Marble Canyon?

Catastrophic spillover of lakes?

(Competing hypotheses with key concepts)

Where did the Colorado River flow before 6 mya?

To the Northwest after going around the Kaibab Plateau?

To the Southwest through Peachtree Canyon?

To the Southeast down the Little Colorado to the Rio Grande and the Gulf of Mexico?

Or underground and emerge to deposit the Hulapai Limestone?

(Competing claims dependent upon Records of Events)

16 mya: Muddy Creek Formation at the mouth of the Grand Canyon has no sediments from up the Colorado drainage..

Interestingly, above the Muddy Creek lies the Hualapai Limestone.

(Objects and Events; Records of Events)

The distribution of sedimentary rocks and the timing of tectonic and climatic events are the keysto solving the puzzle.

(Objects of Interest—key records)

(Principle: order events in time on different scales)

Focus QuestionThinking Doing

Concepts

Principles

Events and Objects

Vee Diagram of Inquiry from D. B. Gowin

Records

Claims

(Prior Knowledge) (New Knowledge))