Digital Products | Grand Canyon

Grand Canyon Animation

The Grand Canyon is truly one of the natural splendors of the world and the perfect place to demonstrate some of the key concepts of geology. Due to the long and diverse geologic history found there, we plan to create a series of short 3-5 minute animations that show "chapters" in the area's long geologic history. These animations could be viewed back to back or individualy. A condensed 3-5 minute version will also be produced from the more detailed chapters to give a quick overview of the areas geology. This introduction and overview of Grand Canyon's geology will be displayed in the Yavapai Science Center (to be finished spring 2005), at the Grand Canyon.

These animations will be produced jointly with University of New Mexico professors, Laura Crossey and Karl Karlstrom, to complent their "trail of time." The "trail of time" project involves a scaled walking trail at the South Rim where one meter of the trail represents one million years of Earth history. Through trail markers and exhibits visitors learn about geologic time and Earth processes in the context of spectacular vistas that provide inspiration and motivation for understanding Earth science and the scientific method.

The following lists the key geologic concepts that will be detailed in each chapter. Images taken from initial work into this project are shown when possible to give an idea of what the final animated movies will look like.

Chapter 1: Introduction and Overview

3-5 animation to be shown at Yavapai Observation station. The goal of this animation is to introduce the geologic themes of the Yavapai Observation Station and the Trail of Time.

1) Establish Location - Grand Canyon in the context of other parks, Colorado Plateau, Visitor Center, Yavapai Observation Station, and Trail of Time locations

	Shows the location of the Grand Canyon relative to the western United States and the Colorado Plateau. Lands managed by the Park Service are shown in purple.
	Shows the location of the South Rim visitor center relative to the canyon.

2) Zoom in on DEM to see the Canyon - visitor gets a sense of its depth, width, ruggedness

3) Fly from Lake Powell to Lake Mead, observe variation of Canyon along its length, point out localities that are especially important for later geologic discussions such as: Lees Ferry, Little Colorado River, Chuar Valley, Bright Angel creek and Phantom Ranch, Crystal Canyon, Elves Chasm, Havasu Canyon, Lava Falls, Diamond Creek, Grand Wash Cliffs.

A "fly-through" of the park will then show key geologic features (that will be animated) and the location of commonly know landmarks (visitor centers, etc.). The narration will give a brief overview of the geology of the area.

4) Highlight one rock unit as an introduction to the geologic map concept, for example the Tapeats sandstone or Kaibab Limestone

5) Briefly show geologic map itself to illustrate complexity of rock units preserved in the Canyon

Geologic map of the Grand Canyon drapped over Topography

6) "Open the Earth" and show a cross section to illustrate that rocks extend below the surface and their distribution can be interpreted from the geologic map

Geologic map of the Grand Canyon drapped over Topography with a cross section showing the rocks present below the surface.

Chapter 2: Precambrian formation of North America

The rocks that record the Precambrian formation of the southwestern part of the North American continent are well- exposed in Grand Canyon, along the river corridor and at lowest erosional levels in the Canyon (law of superposition).

1) The Archean nucleus was in Wyoming, North America grew southwards from 1.8 to 1.1 billion years ago.

2) Crust in the Southwest was added by island arc collisions similar to presentday Australia that is colliding with Indonesia (Plate Tectonics primer)

3) Rocks of Grand Canyon Metamorphic suite record the deformation and metamorphism associated with this orogeny (Mountain building)

4) Rocks in Zoroaster plutonic complex represent the arc plutons and crustal melting associated with collisions.

5) Grenville collision at 1.1 billion years ago (in Texas) was the end of this cycle of continental growth (supercontinent of Rodinia assembly).

6) The Unkar Group of Grand Canyon represent basins developed within the continent (at great distance from the plate margin) during Rodinia assembly

7) Likewise, faulting and tilting of the Unkar Group was an inboard expression of this Grenville collision

8) The Chuar Group of Grand canyon records the early stages of breakup of the Rodina supercontinents and prelude to one of the coldest periods on Earth ("snowball earth")

9) The Great Unconformity represents a beveled land surface (angular unconformity) that, by Cambrian time, had exposed deep crustal rocks from the previous orogenic cycles.

10) Early life in Grand Canyon is found in both the Unkar Group (algal colonies) and in Chuar Group (first heterotrophs on Earth)

Chapter 3: The Paleozoic layer cake and evolution of life

Rocks of the Paleozoic "Layer Cake" in Grand Canyon are a world-classic reference section for the Paleozoic Era. These rocks record the Cambrian record explosion in diversity of life in environments of advancing and retreating oceans. In spite of the exceptional record, there is more time missing (along disconformities) than recorded by these rocks. They remain horizontal because they have not been deformed by orogeny.

1) Continued breakup of Rodinia resulted in subsidence of the area west of Grand Canyon and a westward thickening sedimentary basin fill (Cordilleran Miogeocline), with thinner (~ 3 km) cratonal strata in Grand Canyon region.

2) Cambrian Tonto Group records west-to-east transgression (advance) of seas across the beveled Great Unconformity surface.

	The lowest and oldest of the Paleozoic rocks in the Grand Canyon are called the Tonto Group. These rocks are highlighted in yellow here.
	When the Tonto Group was being deposited, complex life was evolving on earth. As sea-level rose an ocean covered the area depositing three rock units called the Tapeats Sandstone, the Bright Angel Shale, and the Muav Limestone. These rocks make up the Tonto Group.

3) Walthers Law allows us to use the preserved vertical stacking of sedimentary facies at a given place (sandstone, shale, limestone) as a proxy for horizontal distribution of sedimentary environments at any given time (beach, off shore muds, reef, respectively).

4) Cambrian marine depostional environments of the Tonto Group were host for a rich diversity of organisms (trilobites, etc) that appeared fairly suddenly in the fossil record and evolved and diversified.

5) A major time break (disconformity) is present at the top of the Tonto Group, where remnants of Devonian rivers (Temple Butte Formation) occur between the Tonto Group and overlying Redwall Limestone.

6) Mississippian through Pennsylvanian rocks involved both marine and terrestrial environments, including cave systems in the Redwall. Life evolved to include fish and large ammonites, etc

7) Permian rocks that now cap the canyon represented shallow oceans and adjacent land areas; life evolved to include land plants. At the end of the Permian, 90% of species went extinct.

8) Mesozoic rocks, now eroded at Grand Canyon but present in the Grand Staircase, Zion and Bryce National Parks, include ~ 2 km thick section of mainly terrestrial deposits. Reptiles became the dominant animals.

9) Cretaceous seaway was an inland sea that covered North America during one of the warmest periods on Earth (Greenhouse Earth). Grand Canyon was on the WEST coast!

Chapter 4: Late Mesozoic (Laramide) uplift of the western U.S. and Colorado Plateau

1) Rocks of the Grand Canyon region were near sea level from 1000-65 million years ago, then got uplifted to their present position over a mile above sea level.

2) Uplift took place in response to flat slab subduction of the Farallon plate at the Pacific plate margin; this uplift also resulted in uplift of the Rocky Mountains

3) Old faults (Unkar- and Chuar- age) got reactivated by compression to form monoclines in the Grand Canyon region.

4) The Colorado Plateau became defined as a tectonic entity separate from deforming areas to the east (Rocky Mountains) and thrust belt to the west (Sevier highlands). Reasons remain controversial, but suggest that the Colorado Plateau was a stronger part of the plate.

5) The ignimbrite flare up resulted from delamination of the Farallon slab and resulted in collapse of the Sevier highlands, voluminous volcanics, and early stages of development of the Basin and Range. Volcanism (becoming less explosive in character) continued to development (for example) of the San Francisco volcanic field, Ship Rock, and Uinkaret volcanic fields.

6) By ~10 Ma, the western U.S. looked much as it does today, with collapsed but still high western U.S. orogenic plateau, but Grand Canyon had not yet been carved.

Chapter 5: Cenozoic incision of Grand Canyon chapter - and the scientific method

1) The Colorado River system is the main river system that drains the west side of the Rocky Mountains(essentially only river in SW); it flows across numerous tectonic provinces and, for much of its, course, is a desert river (water in the desert).

2) The longitudinal profile shows steep sections (rapids) and flat sections that represent a river still trying to reach equilibrium with the actively deforming western U.S.

3) Grand Canyon did not exist in present form until ~ 6 M.Y. ago - evidence comes from an absence of Colorado river deposits in Grand Wash basin, in western Grand Canyon.

4) J.W. Powell thought the river shape was old (meanders and bends), but the land was uplifted (East Kaibab uplift) after its course was established (layer cake raised up through the knife model). This "Old river, young uplift" model still has its proponents.

5) W. M. Davis thought the river shape was established at a higher stratigraphic level and was "let down" by erosion to cut across the previously developed Kaibab uplift - (knife lowered through layer cake). This "old uplift, young river") model has many proponents (present consensus).

6) Grand canyon incision began after deposition of the 5.5 million years Hualapai Limestone

7) Hunt proposed that that headward erosion of a small stream captured the river system that, at that time, flowed south out Little Colorado. Capture caused reversal of flow in Little Colorado and carving of canyon.

8) The "Buzz saw" model for modern incision is for a river cutting at ~ 150 m/my with differential incision caused by faulting in western Canyon.

9) Glacial/Interglacial cycles deposited terrace gravels that are now at various heights above the river but record past wet and dry climates.

11) Lavas flowed into the Canyon from 600 ka to present. Hamblin proposes that lavas formed massive lava dams that created lakes with water backed up to Moab Utah. Or were the dams leaky??

12) Gravity and Mass Wasting act to carry debris to the river for transport out of the canyon. This is why the Canyon is so wide.

13) What will Canyon look like in the future?

14) The Dam has changed flows in the river (eliminated spring floods and high discharges) - how long will it last??