Early Ordovician gastropod opercula and epicontinental seas
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Abstract
Collections made for some years from Lower Ordovician rocks by many geologists have established that the heavy calcareous operculum of the gastropod Ceratopea is almost never found associated with a shell and that commonly this operculum is secondarily silicified. Ceratopea may have lived in a stressed habitat and may have been essentially the only shelled invertebrate present. Presumably these animals grazed on algal mats and mounds growing in areas of water slightly more saline than open marine water and were killed by an influx of hypersaline water. Subsequent decay of soft parts would permit the operculum to rot off and would also lighten the shell so that it could float away. Pene-contemporaneous silicification of calcareous opercula on the Ordovician sea bottom is postulated.
Some Middle Ordovician opercula of the Middle to Late Ordovician genus Maclurites serve to test this speculation. These opercula also occur in geologic settings which may be interpreted in terms of kill of animal, wafting away of shell, and secondary silicification of operculum.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Early Ordovician gastropod opercula and epicontinental seas |
| Series title | Journal of Research of the U.S. Geological Survey |
| Volume | 3 |
| Issue | 4 |
| Year Published | 1975 |
| Language | English |
| Publisher | U. S. Geological Survey |
| Description | 4 p. |
| First page | 447 |
| Last page | 450 |
| Country | Greenland, Norway, United States |
| State | Alabama, Arkansas, Colorado, Georgia, Maryland, Newfoundland and Labrador, New Mexico, New York, Oklahoma, Pennsylvania, Tennessee, Texas, Virginia |
| Other Geospatial | Spitsbergen, Svalbard |
| Google Analytic Metrics | Metrics page |