A compilation of new airborne magnetic and gravity data across Dronning Maud Land, Antarctica.

The evolution of the South Atlantic region including the Weddell Sea and its adjacent areas is of crucialimportance for understanding the processes of the structure and tectonics of the Antarctic lithosphere, its relation to geodynamic processes, especially to the timing and geometry of the initial stages of the Mesozoic break-up between Africa, Antarctica and South America. For unravelling the geological evolution of Antarctica prior to the break-up of Gondwana, the sub-glacial geology is of utmost importance. Understanding the sub-ice geology allows reconstruction of ancient mountain chains (collision zones) across continents, which are separated by large ocean basins in the presentworld. Since only the peaks of the Dronning Maud Land (DML) mountains can be geologically sampled, geophysical methods are required to uncover the geological structure beneath the ice. Therefore, extensive airborne surveys were conducted across DML between 2001 to 2005 to close data gaps and to improve existing data sets

Paleo-Current Activity in the Eastern Arctic Ocean - Evidence from Seismic

Four stages of deposition regime have been detected on high-resolution seismic reflection profiles. First, in strata of Paleocene-Eocene age small vertical faults indicate differential compaction of probably anoxic sediments deposited in the still isolated Eurasian Basin. Than, a high-amplitude-reflector sequence indicates a time of widespread changes in deposition realm associated with the gradual opening of the Fram Strait and ongoing subsidence of the Lomonosov Ridge (LR) in Eocene and Oligocene. Episodical incursions of water masses from the North Atlantic were the consequences and led to the deposition of sediments of strongly different lithology. The third stage marks widespread and pelagic sedimentation since earliest Miocene. Sediment waves are evidence for paleo-bottom current activity and the onset of an ocean circulation system. The slope of the LR is structured into terraces, indicating fault-controlled sediment drifts arisen due to the onset and intensification of current circulation. Advanced deepening of the Fram Strait likely enabled an effective exchange of water masses between the North Atlantic and Arctic Ocean. Continuous sagging of the LR, reactivation of former faults and bottom currents passing along the ridge may shape the steep sediment free flanks of the terraces in addition. At least, a continuous regional drape of reflectors marks the transition to glaciation of the northern hemisphere in early Pliocene

Crustal variability along the rifted/sheared East African margin

The East African margin between the Somali Basin in the north and the Natal Basin in the south formed as a result of the Jurassic/ Cretaceous dispersal of Gondwana. While the initial movements between East and West Gondwana left (oblique) rifted margins behind, the subsequent southward drift of East Gondwana from 157 Ma onwards created a major shear zone, the Davie Fracture Zone (DFZ), along East Africa. To document the structural variability of the DFZ, several deep seismic lines were acquired off northern Mozambique. The profiles clearly indicate the structural changes along the shear zone from an elevated continental block in the south (14°–20°S) to non-elevated basement covered by up to 6-km-thick sediments in the north (9°–13°S). Here, we compile the geological/geophysical knowledge of five profiles along East Africa and interpret them in the context of one of the latest kinematic reconstructions. A pre-rift position of the detached continental sliver of the Davie Ridge between Tanzania/ Kenya and southeastern Madagascar fits to this kinematic reconstruction without general changes of the rotation pole