Browse Items (22 total)

A light tan limestone with weathered surfaces

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

Sample from the beta member of the Toroweap formation. Sample is light tan-orangish with weathered surfaces.

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

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.

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

Thin section images were taken at a 400x magnification.

A ferruginous sample.

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

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.

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

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

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…

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…

Fine-grained limestone with occasional fossil remains.

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

Oblitic and Crinoidal Lithology.

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

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.

Limestone containing fossils of the alga, Girvanella.

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

Red siltstone lithology of the Bright Angel Shale.

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

Green clay lithology of the Bright Angel Shale.

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

Mottled lithology of the Muav Limestone.

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

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

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

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.

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.

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