Seismostratigraphy of the Eastern Makarov Basin and Adjacent Lomonosov Ridge and Mendeleev Ridge

• Main Authors: Weigelt, Estella, Jokat, Wilfried
• Format: Conference Object
• Language: unknown
• Published: 2015
• Subjects: Arctic; Arctic Ocean; canada basin; laptev; Lomonosov Ridge; makarov basin
• Online Access: https://epic.awi.de/id/eprint/37220/; https://hdl.handle.net/10013/epic.44948

The contribution presents a high-resolution seismic reflection section collected along a transect at 81°N from the Mendeleev Ridge, across the Makarov Basin onto the Lomonosov Ridge. The slopes of both ridges bordering the Makarov Basin are compared concerning their surface of acoustic basement and configuration of seismic units to research tectonic and depositional processes. Age control for the sedimentary units was acquired via links to seismic lines and drill site data of the Canada Basin, the Lomonosov Ridge, and the adjacent Laptev Shelf. A tie point for dating is a pronounced sequence of high-amplitude reflectors, which is the most striking feature in the Siberian part of the Arctic Ocean. The top of the reflector band is suggested to mark the end of Oligocene, and its base likely corresponds to the base of Eocene (56 Ma). Seismic units below the high-amplitude reflector sequence show a similar configuration on the slopes of the Lomonosov and Mendeleev Ridges. The layers onlap on the slopes of the ridges and fill the basement topography in the center of the Makarov Basin. That indicates a sedimentary transport from the ridges and also the Laptev Shelf into the Makarov Basin formed before Eocene times. In contrast, seismic units above high-amplitude reflector sequence, and consequently younger than 23 Ma show distinct differences in reflector configuration between the Lomonosov and Mendeleev Ridges. The basement surface of the Mendeleev Ridge rises in several steps from the Makarov Basin with an angle of slope between 0.2 and 1.4 °. Here, sedimentary layers onlap or merge on the western slope of the Ridge and show numerous traces of slumping. Further the layers slightly downgrade from the Mendeleev Ridge westwards towards a basement heigth in the center of the Makarov Basin. In contrast the slopes of the Lomonosov Ridge towards the Makarov Basin are less steep (< 0.5°) and the sedimentary layers drape with almost constant thickness the flanks and crest of the ridge indicating a pelagic deposition realm ...