Sedimentation and potential venting on the rifted continental margin of Dronning Maud Land

Abstract

The relief of Dronning Maud Land (DML), formed by Middle and Late Mesozoic tectonic activity, had a strong spatial control on the early fluvial and subsequent glacial erosion and deposition. The sources, processes, and products of sedimentation along the DML margin and in the Lazarev Sea in front of the DML mountains have been barely studied. The onshore mountain belt parallel to the coast of the DML margin acts as a barrier to the transport of terrigenous sediments from the east Antarctic interior to the margin and into the Lazarev Sea. Only the Jutul-Penck Graben system allows a localized ice stream controlled transport of material from the interior of DML across its old mountain belt. Offshore, we attribute repeated largescale debris flow deposits to instability of sediments deposited locally on the steep gradient of the DML margin by high sediment flux. Two types of canyons are defined based on their axial dimensions and originated from turbidity currents and slope failures during glacial/fluvial transport. For the first time, we report pipe-like seismic structures in this region and suggest that they occurred as consequences of volcanic processes. Sedimentary processes on the DML margin were studied using seismic reflection data and we restricted the seismic interpretation to the identification of major seismic sequences and their basal unconformities.

Bathymetry Beneath Ice Shelves of Western Dronning Maud Land, East Antarctica, and Implications on Ice Shelf Stability

“…The repetition of this pattern throughout wDML suggests a link to former glacial extents, most likely via the formation of end moraines by ice sheets that advanced to the continental shelf edges during the Last Glacial Maximum (LGM, at 23–19 kyr BP; Grobe & Mackensen, 1992; Hillenbrand et al, 2014). Subglacial sediments deposited at shelf edges might be displaced downslope or be remobilized by currents to form contourites, as observed in seismic data close to the ice shelves of Dronning Maud Land by Huang and Jokat (2016).…”

Impact of Weddell Sea shelf progradation on Antarctic bottom water formation during the Miocene

“…We argue that the intensified AABW originating in the Weddell Sea as well as the Weddell Gyre influenced the morphology of the continental rise by developing sediment drifts or contourites [ Rebesco et al ., ; Hernández‐Molina et al ., ; Maldonado et al ., ; Huang and Jokat , , ]. The dense and cold AABW, strong bottom currents, and intensified supply of glacially transported sediment to the continental rise are the prerequisites of developing these sediment drifts.…”

“…Herein, we focus on an alternative modeling approach that investigates the long‐term impact of shelf progradation due to massive glacial sediment deposition. Such a progressive shelf expansion of the outer shelves is well observed from seismic data and stratigraphy around the Antarctic margins [e.g., Cooper et al ., ; Gohl et al ., ; Huang et al ., ], leading to large‐scale geomorphic features (trough fans and contourite drifts) on the continental rise that point to massive sediment transport processes by ice sheet advances on the shelf with intensified bottom current activities in the Miocene [e.g., Rebesco et al ., ; Uenzelmann‐Neben and Gohl , ; Huang and Jokat , , ]. On the southern Weddell Sea continental rise, about two thirds of the sediment thickness were already in place by the latest Miocene [ Huang et al ., ].…”

The Weddell Gyre, Southern Ocean: Present Knowledge and Future Challenges

“…Geographically, the present‐day sedimentation pattern in the WG can be split into three geomorphological regions (Jerosch et al, ): (i) a southern and eastern region, influenced by downslope transport of sediments near the glaciated continental margin with channel‐levee deposits and contourites (Michels et al, ); (ii) the central and northern WG, dominated by slowly accumulating sediments of mostly terrigenous origin (Geibert et al, ; Howe et al, ); and (iii) a northwestern part with contourites and hemipelagites (Gilbert et al, ; Pudsey et al, ). In addition, Maud Rise in the eastern part of the gyre (Huang & Jokat, ) and the Polarstern Bank in the southern Weddell Sea (Bart et al, ) stand out from the surrounding abyssal plain with a cover of biogenic sediments (Abelmann et al, ; Figure ).…”