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The Bornholm Basin, southern Scandinavia: a complex history from Late Cretaceous structural developments to recent sedimentation

Citation

Jensen, JB and Moros, M and Endler, R, IODP Expedition 347 Scientific Party, The Bornholm Basin, southern Scandinavia: a complex history from Late Cretaceous structural developments to recent sedimentation, Boreas, 46, (1) pp. 3-17. ISSN 0300-9483 (2017) [Refereed Article]

Copyright Statement

Copyright 2016 Collegium Boreas

DOI: doi:10.1111/bor.12194

Abstract

The Bornholm Basin has experienced a complex history linked closely to the structural development of the Tornquist Zone strike-slip fault system. The latest major tectonic development was late Cretaceous and early Tertiary Rønne Graben inversion caused by dextral transpressional strike-slip movements focused around rigid blocks such as Bornholm. By applying the strike-slip concept, it is possible to show that the Rønne Graben inversion push-up structure was created by restraining left step-over. The fault system continues northwest and north of Bornholm where the strike-slip movement resulted in right step-over and the formation of a pull-apart basin: the northern part of the Bornholm Basin. Detailed seismo-acoustic and sediment core studies show that, despite a rather uniform present bathymetry in the central part of the Bornholm Basin, the Quaternary deposits mirror the pull-apart basin synsedimentary depositional pattern with depocentres close to the major normal faults, bounding the Christiansø Ridge. IODP Site M0065 penetrated a secondary fault zone and provided detailed information on neotectonic events and on environmental changes during the Holocene. The generally rather homogeneous sediments in the cores indicate a dominance of oxic conditions in the Bornholm Basin during the Holocene. However, strong internal seismic reflectors, indirectly reflecting variations in the sediment density and the reflection coefficient, were caused by a shift to stronger laminated, organic-rich sediments that were deposited during the Medieval Warm Period (MwP). The variable depth positions of the MwP-related strong reflectors indicate large differences in the spatial and temporal sedimentation pattern in the Bornholm Basin. These differences in the depositional environment may have been caused by local neotectonic events in the basin.

Item Details

Item Type:Refereed Article
Keywords:Bornholm Basin, Baltic Sea, IODP 347
Research Division:Earth Sciences
Research Group:Geology
Research Field:Sedimentology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
ID Code:115499
Year Published:2017
Web of Science® Times Cited:2
Deposited By:CODES ARC
Deposited On:2017-03-28
Last Modified:2017-11-21
Downloads:0

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