The geologic history of the Post-Croatan (Pleistocene) sediments at the Lee Creek Mine, Beaufort County, North Carolina / by Sarah Ann Roberts.
| Author/creator | Roberts, Sarah Ann author. |
| Other author | Riggs, Stanley R., degree supervisor. |
| Other author | East Carolina University. Department of Geology. |
| Format | Theses and dissertations |
| Production | 1981. |
| Description | 76 leaves, 10 unnumbered leaves : illustrations, maps ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The study area is located on the outer coastal plain, at the Lee Creek phosphate mine, near Aurora, Beaufort County, North Carolina. The purpose of the study was to map the distribution of the Pleistocene overburden units within a 4.6 square kilometer area of the mine site. Six post-Croatan units and sixteen subunits were delineated. Sediments of these units were deposited in fluvial, estuarine, or marine environments during the Late Pleistocene epoch in response to glacially induced sea level changes. Marine regression resulted in the establishment of streams far out onto the continental shelf; marine transgression resulted in inundation of the stream valleys, and deposition of fluvial, estuarine and marine sediments that sequentially filled the topographic lows, and systemically spread upward upon and across the interstream divides. This interpretation of the geologic history of the post-Croatan sediments in the Lee Creek area indicate three regressive and two transgressive sequences. Regression of the sea to -0.3 m resulted in deposition of fluvial sediments in unit 1. The estuarine sediments of unit 2 were then deposited during the next transgressive stage which formed an extensive estuarine system. During the subsequent regression, the Lee Creek fluvial system deposited fluvial sediments of unit 3. Sea level rose again producing an estuarine system in which the sediments of unit 4 were deposited. The sea continued to transgress and deposited the marine sediments of unit 5. During the last regression of the Late Wisconsin glacial stage, the unit 6 fluvial sediments were deposited and the soil profile was developed on unit 5 sediments. Fluvial sediments of unit 6 are iii still forming today in the topographic lows, and the soil profile continues to develop in the interstream upland areas. Thus, unit 6 is still both forming and actively being modified today. If the present slow but steady world wide rise in sea level (15-46 cm/100 years) continues, unit 6 would become submerged and estuarine sediments similar to those in units 2 and 4 would be deposited above it. |
| General note | "Presented to the graduate faculty of the Department of Geology ... in partial fulfillment of the requirements for the degree Master of Science in Geology." |
| General note | Advisor: Stanley R. Riggs |
| Dissertation note | M.S. East Carolina University 1981 |
| Bibliography note | Includes bibliographical references (leaves 67-73). |
| Genre/form | dissertations. |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
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|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Joyner | NC Microforms | MICROFILM | ✔ Available | |
| Electronic Resources | Access Content Online | ✔ Available |