Seismic stratigraphy of late quaternary glacial to marine sediments offshore Bornholm, southern Baltic sea
Perini, L.; Missiaen, T.; Ori, G.G.; De Batist, M. (1996). Seismic stratigraphy of late quaternary glacial to marine sediments offshore Bornholm, southern Baltic sea. Sediment. Geol. 102(1-2): 3-21. https://dx.doi.org/10.1016/0037-0738(95)00056-9
In: Sedimentary Geology. Elsevier: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0037-0738; e-ISSN 1879-0968, more
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| Keywords |
Marine/Coastal; Brackish water; Fresh water |
| Authors | | Top |
- Perini, L.
- Missiaen, T., more
- Ori, G.G.
- De Batist, M., more
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| Abstract |
The Quaternary history of the southern Baltic is marked by a complex sequence of glacial, lacustrine and marine phases. Consequently, a large number of unconformities and erosional and depositional surfaces are present in the stratigraphic record. Over 600 km of high-resolution, single-channel reflection seismic profiles were collected offshore Bornholm. A sequence stratigraphic interpretation of the seismic data, in combination with some available core data, has led to the identification of two Quaternary depositional sequences unconformably overlying the late Mesozoic deposits. The sequences contain up to nine different seismic-stratigraphic units, and are separated by sharp boundaries representing strong erosional events.The lower depositional sequence contains five units (A-E) of glacial and late-glacial origin. The unconformity, at its base is marked by a southward flowing channel drainage pattern, which may be related to the mid-Weichselian Alnarp River system. Units A and B contain till and moraine deposits, probably of middle or early-late Weichselian age. Units C-E consist of glaciolacustrine clays, and most likely represent different Baltic Ice Lake phases of the late Weichselian. The upper depositional sequence contains four units (F-I) of postglacial lacustrine and marine origin. Its sharp erosional base possibly indicates subaerial exposure. Unit F consists of backstepping delta or beach deposits, which are partially interfingered with the lacustrine clays of unit G. Both units can most likely be correlated with the Ancylus Lake. The marine mud deposits of units H and I represent the widespread Litorina transgression. |
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