|
| The Kanosh (lower) Formation carbonate is Lower Ordovician in age and is exposed in Millard, Utah along with other locations. The fresh surface of the hand specimen has a gray color with visible shell fragments and some quartz crystals present. The weathered side of the specimen is gray to brown with visible shell fragments, quartz crystals, and an oxidation layer on the surface. The visible matrix is a micritic matrix with visible biological life. Some other visible features include a variation in grain size from medium sands to very fine silts and muds. The thin section of the Kanosh Formation hardground also has a mictric matrix like the hand sample. It is composed of many forms of biologic life not seen in the hand sample. Bryozoans, Eocriniods, Intraclasts, Bivalve shell fragments with iron oxidation effects, Brachipods that have undergone calcite replacement from their once possible aragonite shell, and a micritic matrix. Also in the thin section some calcite twinning can be found, along with a few examples of psuedouniaxial crosses. Under the Folk classification name the Kanosh hardground is a intrabiomicrite. Under the Dunham classification the Kanosh hardground is a packstone. The depostitional environment is shallow to deep marine, above wave base, in the photic zone, in a high energy area. |
|
 |
|
Figure 1. This photograph of a thin section of the Kanosh Formation shows several poorly rounded intraclasts. There are some replaced calcite shell fragments and a large oxidized intraclast at the top of the photo. In the center is a segment of a crinoid left behind. Width of view = 3.0 mm (40x).
|
 |
|
Figure 2. This photograph has an excellent bivalve shell fragment in the upper right corner. Other shell fragments are scattered around the section along with an oxidized clast on the left side of the photo. Width of view = 3.0 mm (40x).
|
 |
|
Figure 3. The photograph above shows some well rounded oxidized intraclasts. There are small shell fragments and a large biologic boring starting in the lower left corner and working into the center. There is also some micirtic matrix within the photo along with bivalve shell fragments. Width of view = 3.0 mm (40x).
|
 |
|
Figure 4. This photograph shows a ferruginous moderately well rounded intraclast with bivalve shell fragments. The large oxidized bivalve shell in the lower left corner shows the depositional environment as shallow to deep marine. Width of view = 3.0 mm (40x).
|