Seismic reflection surveys on the Lomonosov Ridge in regard to IODP Leg 377

• Main Authors: Weigelt, Estella, Gebhardt, Catalina, Stein, Rüdiger
• Format: Conference Object
• Language: unknown
• Published: Geological Survey of Canada 2022
• Subjects: Arctic; Arctic Ocean; Amundsen Basin; amundsen basin; Fram Strait; Lomonosov Ridge; North Atlantic
• Online Access: https://epic.awi.de/id/eprint/55852/; https://hdl.handle.net/10013/epic.2fe1958b-58ea-4b9a-80d6-cc3fe8f8696b

We present a regional seismic data set across the southeastern Lomonosov Ridge (LR) serving as pre-site survey for the upcoming drilling project IODP-377 (ArcOP). The overall goal of this drilling campaign is to recover a com¬plete stratigraphic sedimentary record of the southern ridge to meet the highest priority paleoceanographic objective, the continuous long-term Cenozoic climate history of the central Arctic Ocean. The seismic surveys provide basic information for the drilling, as the identification of undisturbed strata, location of slumps or hiatuses, depth-calculations of target reflectors, age estimations, and suggestions on the type of sedimentary rocks inferred from interval velocities of seismic units. On the LR the seismic lines confirm the presence of 1600 m thick, undisturbed, parallel sedimentary layers. 10 drilling locations can be proposed to recover the entire Miocene sedimentary sequence or even down to sediments of Lower Eocene age at about 900 mbsf. A prominent high-amplitude-reflector sequence (HARS) within the strata can be used to directly correlate to previous seismostratigraphic models for the eastern Arctic Ocean. Four major seismic units were identified which provide constraints on the coupled evolution of tectonic processes, palaeoceanography, and glaciation history of the Arctic Ocean. First, Mesozoic strata on the LR, its faulted flanks and the initial Amundsen Basin were covered with syn-rift sediments of Paleocene to early Eocene age. Numerous vertical faults indicate differential compaction of possibly anoxic sediments deposited in the young, still isolated Eurasian Basin. The second stage, as indicated by a prominent high-amplitude-reflector sequence covering the ridge, was a time of widespread changes in deposition conditions, likely controlled by the ongoing subsidence of the LR and gradual opening of the Fram Strait. Episodic incursions of water masses from the North Atlantic probably were the consequences and led to the deposition of thin sedimentary layers of different ...