Controls on aeolian sand sheet formation exemplified by the Lower Triassic of Helgoland
The basal part of the Middle Buntsandstein (Lower Triassic) on Helgoland in the southern North Sea is composed of lacustrine redbeds with thin white beds of aeolian sand sheet origin. The aeolian deposits formed during lake low-stands, and sand sheet formation was caused by a restricted sand supply perhaps in combination with frequent wind changes and high-speed wind events. With time aeolian sedimentation was progressively influenced by brief flood events or by minor lake transgressions. Ultimately the sand sheets were covered by fine-grained lake deposits during a new phase of lake high-stand. Preservation of the aeolian deposits records the overall low-energy of the littoral processes, and early cementation. The aeolian deposits define sedimentary cycles of various thickness, and it is suggested that the cyclicity records Early Triassic orbital climatic forcing.
KeywordsLake Level Aeolian Sand Lower Triassic Aeolian Deposit Lake Deposit
Unable to display preview. Download preview PDF.
- Berthelsen, F.: Lithostratigraphy and depositional history of the Danish Triassic. Danm. Geol. Unders. (Ser. B) 4, 59 pp. (1980).Google Scholar
- Binot, F., Rohling, H.-G.: Lithostratigrafie und natx00FC;rliche Gammastrahlung des Mittleren Buntsandsteins von Helgoland.-Ein Vergleich mit del’ Nordseebohl’ung J/18-1. 2. Dt. Geol. Ges. 139, 33–49 (1988).Google Scholar
- Fine, S.: The diagenesis of the Lower Triassic Bunter Sandstone Formation, onshore Denmark. Danm. Geol. Unders. (Ser. A) 15, 51 pp. (1986).Google Scholar
- Folk, R. L., Ward, C.: Brazos River Bar: a study in the significance of grain size parameters. J. Sedim. Petrol. 27, 3–26 (1957).Google Scholar
- Kocurek, G., Townsley, M., Yeh, M., Sweet, M., Havholm, K.: Dune and dune-field development stages on Padre Island, Texas: effects of lee airflow and sand-saturation levels and implications for interdune deposition. (1990) Extended abstracts. Nato advanced research workshop on sand, dust and soil in their relation to aeolian and littoral processes.Google Scholar
- Wurster, P.: Kreuzschichtung in Buntsandstein von Helgoland. Mitt. Geol. Staatsinst. Hamburg 29, 61–65 (1960).Google Scholar