(GC) Grand Canyon Stratigraphic Suite -- Grand Canyon, Arizona

Title

(GC) Grand Canyon Stratigraphic Suite -- Grand Canyon, Arizona

Description

This collection contains 21 samples. They are a representation of samples of lithology from the early precambrian to the late permian. The stratigraphic sequence contains a variety of rocks including, but not limited to schist, limestone, and sandstone. These specimens are representative of the geologic section in the Grand Canyon, but no specimens were collected within the boundaries of the National Park.

Contributor

Western Minerals Inc.

Spatial Coverage

Peach Springs, Mohave Co., Arizona
Peach Springs, Coconino Co., Arizona
Seligman, Ysvupai Co., Arizona
Williams, Coconino Co., Arizona

Temporal Coverage

Samples range from Precambrian - Permian

Accrual Method

Purchased from Western Minerals Inc.

References

Start Here:
Blakey, R.C., and Middleton, L.T., 2012, Geologic history and paleogeography of paleozoic and early mesozoic sedimentary rocks, eastern Grand Canyon, Arizona: Geologic Society of America Bulletin, v. 489, pp. 81-92, doi: 10.1130/2012.2489(05)
  • This reference outlines the stratigraphy found in this suite. It specifically highlights the paleozoic era in which the samples represent. 

Additional Resources: 
Brown, E.H., Babcock, R.S., Clark, M.D., and Livingston, D.E., 1979, Geology of the older Precambrian rocks of the Grand Canyon Part I. Petrology and structure of the Vishnu Complex: Precambrian Research, v. 8, p. 219-241, doi: 10.1016/0301-9268(79)90030-5 
  • Brown et al. begins this series of 3 articles outlining the geologic timescale and discusses the Vishnu complex and how it fits into the geologic timescale. It provides an explaination for several of the samples in this collection. 
Brown, E.H., Babcock, R.S., Clark, M.D., and Livingston, D.E., 1979, Geology of the older Precambrian rocks of the Grand Canyon Part II. The Zoroaster Plutonic Complex and related rocks: Precambrian Research, v. 8, p. 243-275, doi: 10.1016/0301-9268(79)90031-7
  • In the second part of the article, the authors discuss the importance of the pluton and how it affected the formation of the stratigraphic profile of the grand canyon. 
Clark, M.D., 1979, Geology of the older Precambrian rocks of the Grand Canyon. Part III. Petrology of mafic schists and amphibolites: Precambrian Research, v. 8, p. 277-302, doi: 10.1016/0301-9268(79)90032-9
  • The final section of this discussion set provides insight into the mafic layers of the stratigraphic column. 
Ilg, B.R., Karlstrom, K.E., Hawkins, D.P., and Williams, M.L., 1996, Tectonic evolution of Paleoproterozoic rocks in the Grand Canyon: Insights into middle-crustal processes: Bulletin of the Geological Society of America, v. 108, p. 1149-1166, doi: 10.1130/0016-7606(1996)108
  • This is a general look into the formation of the stratigraphic layers. This article does a good job combining the above articles into one condensed summary. 

Collection Items

Grand Canyon Western Minerals Supplementary Information
OCR PDF of supplemental information for the Grand Canyon collection.

Vishnu Schist
Both thin section images were taken at a 400x magnification.

Vishnu Schist
Both cross polarized and plain polarized images were taken at a 400x magnification.

Brahma Schist
Part of the The Granite Gorge Metamorphic Suite, this is usually considered a metavolcanic, and its mineralogy is dominated by quartz and mica.

Both thin section images were taken at a 400x magnification.

Pegmatite
This sample is mis-labeled as a pegmatite. It is really a porphyritic dike material that cuts through the Zoroaster Granite. The phenocrysts are hornblende.

Tapeats Sandstone
Sandstone shows metamorphic overprinting with triple junctions between quartz grains common.

Both thin section images were taken at a 400x magnification.

Muav Limestone
Mottled lithology of the Muav Limestone.

Both thin section images were taken at a 400x magnification.

Bright Angel Shale
Green clay lithology of the Bright Angel Shale.

Both thin section images were taken at a 400x magnification.

Bright Angel Shale
Red siltstone lithology of the Bright Angel Shale.

Both thin section images were taken at a 400x magnification.

Muav Limestone
Limestone containing fossils of the alga, Girvanella.

Both thin section images were taken at a 400x magnification.

Bright Angel Shale
A silty-shale where the clasts are dominated by quartz. Sample collected from an area typified by interbedded limestones and shale.

Both thin section images were taken at a 400x magnification.

Redwall Limestone (Oblitic and Crinoidal Lithology)
Oblitic and Crinoidal Lithology.

Both thin section images were taken at a 400x magnification.

Redwall Limestone (green conglomerate lithology)
Fine-grained limestone with occasional fossil remains.

Both thin section images were taken at a 400x magnification.

Chert
Collected from the Redwall Formation, this is a highly silicious sample defined in the suite's documentation as chert, but the sample lacks the nano-crystalline appearance of a traditional chert. It appears to be more of a slightly metamorphosed…

Redwall Limestone (Conglomerate)
Though listed as a limestone, this sample is best described as a conglomerate with calcite present in the matrix. This sample was collected from a bed of conglomerate lithology just below contact with Supai formation.

Both thin section images…

Supai Sandstone
A classic red-bed sample typical of the sandstones from the Supai Formation.

Both thin section images were taken at a 400x magnification.

Supai Shale
Classic red-bed sample from the Supai Formation with silt-sized grains of mostly quartz. Some grains are semi-rounded.

Both thin section images were taken at a 400x magnification.

Hermit Shale
A ferruginous sample.

Both thin section images were taken at a 400x magnification.

Coconino Sandstone
A buff-colored siltstone/sandstone. The grains are angular and are quartz-dominated.

Thin section images were taken at a 400x magnification.

Toroweap Limestone
A sample from the gamma member of the Toroweap Formation. It is an orangish-brown sample.
Both thin section images were taken at a 400x magnification.
View all 22 items