|
| Specimen Number C/W-38 is a fossiliferous micritic carbonate hardground from the Richmond Formation, and was collected in Adams County, Ohio. The hardground is Upper Ordovician in age. The fresh surface on the hand specimen is medium gray (5 N5) in color, while the weathered surface is light olive gray (5Y 5/2). Bryozoans, brachiopods, and other invertebrate fossils can be seen with the naked eye when viewing the hand specimen. Many of the larger peloids can be seen by using a handlens. While viewed in thin section the grains are moderately well sorted and are surrounded by a micritic matrix. The depositional environment was most likely shallow marine and below the wave base. The Folk classification name given to this hardground is Biopelmicrite and is a Wackestone under the Dunham classification system. |
|
 |
|
Figure 1. This thin section photograph of the Richmondian Upper Ordovician Hardground shows both valves of an ostracode. Other shell fragments and moderately well rounded peloids can also be seen within the image. Width of view = 3.00mm (40x).
|
 |
|
Figure 2. Image of the biopelmicrite hardground specimen with a longitudinal section of a bryozoan in the center. Width of view = 3.00mm (40x)
|
 |
|
Figure 3. This photograph shows the typical micritic matrix of the sample containing shell fragments and moderalty well rounded peloids. The majority of the sample has a similar appearance to this photograph, which thus lends to the classification names of biopelmicrite and wackestone. Width of view = 3.00mm (40x).
|
 |
| Figure 4. Image of a large void, of unknown origin, which is now filled in with a sparry calcite matrix, and thus disrupting the normal micritic sediment texture. There were no other voids of the same appearance within the thin section. Width of view = 3.00mm (40x). |