Rahul Sharma (Editor)

Tapeats Sandstone

Updated on
Edit
Like
Comment
Share on FacebookTweet on TwitterShare on LinkedInShare on Reddit
Type
  
Geological formation

Named by
  
Noble (1914)

Underlies
  
Bright Angel Shale

Primary
  
Sandstone, Conglomerate

Named for
  
Tapeats Creek

Thickness
  
70 m

Unit of
  
Tonto Group

Tapeats Sandstone Tapeats sandstone Hermit Trail Grand Canyon National Park Arizona

Other
  
conglomeratic sandstone

Region
  
northern Arizona (Grand Canyon), central Arizona, southeast California, southern Nevada, and southeast Utah

Country
  
United States of America

Overlies
  
Vishnu Basement Rocks, Unkar Group, Nankoweap Formation, Chuar Group, Sixtymile Formation

Features of the tapeats sandstone a sedimentary rock


The Cambrian Tapeats Sandstone is the lower geologic unit, about 230 feet (70 m) thick, at its maximum, of the 3-member Tonto Group.

Contents

Tapeats Sandstone Geotripper Into the Great Unknown The Aftermath of ChaosFinding

The Tapeats Sandstone is the highly erosion-resistant unit laid upon the Vishnu Basement Rocks in the central, parts of east, and parts of west Grand Canyon, Arizona. The unit comprises the 'base horizontal unit' of the platform around Granite Gorge (Inner Gorge) on the Colorado River, and because of its hardness, creates the Tonto Platform upon which the two slope-forming, highly erodable units, the Muav Limestone, and Bright Angel Shale lie.

Tapeats Sandstone httpsuploadwikimediaorgwikipediacommonsthu

The Tapeats Sandstone and the Tonto Platform follow the Colorado River, and surrounding tributary canyons, creeks, watercourses, or washes, in a dendritic fashion, much like the branches of a tree.

Tapeats Sandstone Geology of National Parks

The Tapeats unit is the bottom member of the Tonto Group, a typical marine transgression series of sandstone-(conglomerate)-shale-limestone, all part of a paleo sea, initially adjacent to land, the source of the Tapeats rocks-(conglomerates) and sand; (a regressing sequence has the reverse order). The Tapeats Sea at the early Devonian ceased to deposit more Muav Limestone, and a period of erosion ensued, a deposition unconformity.

Tapeats Sandstone Grand Canyon Panorama Project Tapeats Sandstone

The Tapeats Sandstone was laid upon the Vishnu Basement Rocks, after an unconformity of erosion, the Great Unconformity, of 1,000 million years (1.0 billion). Besides the erosion unconformity, the Unkar Group of the basement rocks are also at an angular unconformity, being an 8-member sequence tilted at 45 degrees.

Tapeats Sandstone Tapeats Sandstone Grand Canyon

The horizontal Tonto Platform has hiking trails that cross it from the South Rim to North Rim, Grand Canyon for instance. The extensive Tonto Trail lies on parts of the Tapeats Sandstone, and the platform on the south side of Granite Gorge.

Tapeats Sandstone Depositional Environment of the Tapeats Sandstone

The formation of crossbedding in the tapeats sandstone


Geologic sequence

The units of the Tonto Group:

  • 3--Muav Limestone
  • 2--Bright Angel Shale
  • 1--Tapeats Sandstone (start of transgression series)
    • Tapeats Sandstone Grand Canyon Panorama Project Tapeats Sandstone

  • Blakey, Ron and Wayne Ranney, Ancient Landscapes of the Colorado Plateau, Grand Canyon Association (publisher), 2008, 176 pages, ISBN 978-1934656037
  • Chronic, Halka. Roadside Geology of Arizona, Mountain Press Publishing Co., 1983, 23rd printing, pp. 229–232, ISBN 978-0-87842-147-3
  • Lucchitta, Ivo, Hiking Arizona's Geology, 2001, Mountaineers's Books, ISBN 0-89886-730-4

    • Gallery--Tapeats Sandstone

    Examples of the deposition unconformity of time (550-800 million yrs), the Great Unconformity. The Tapeats approximately 200 ft thick.

    Gallery—Great Unconformity and angular unconformity

    Examples of the angular unconformity below the Tapeats Sandstone, (approx. 15 degrees).

    Tapeats Sandstone Grand Canyon Geology

    References

    Tapeats Sandstone Wikipedia
    (Text) CC BY-SA