Timing of submarine canyon incision on the east Australian continental margin
Presented by Ms. Phyllis YU on 23 Sep 2013 from 17:15 to 19:15
Type: Poster presentation
Session: Poster session
Track: Poster presentations
Sediment composition and biostratigraphic age data are reported for nine dredge samples collected from submarine scarps located on the middle continental slope portion of the eastern Australian continental margin. These data are used to confirm the depositional origins of these materials and constrain the timing of the onset of submarine erosion and canyon incision. Sediments dredged from canyon walls and landslide scarps in this region are primarily comprised of calcareous sandy-silts, and present terrestrial plant macrofossils in addition to marine microfossils. Biostratigraphic dating of foraminifera indicates the sediments were deposited between Early Oligocene and Late Pliocene, with the majority of samples of Middle to Late Miocene age. These ages have a number of implications for the geological history of the margin, most importantly, enabling a likely maximum age to be determined for the onset of pronounced canyon incision into the margin. The geological events that formed slump scars and canyon incision cannot be older than the sediments in which these features are presented; it is therefore inferred that the eastern Australian margin underwent a change in character from a dominantly stable depositional system in which sediments gradually accumulated on the slope, to a less stable erosional system characterised by canyon incision and frequent submarine landsliding at some time after the Middle Miocene.
Location: GEOMAR East shore
Address: Wischhofstr. 1-3 / D-24148 Kiel