Age determination of hornblende in ODP Site 188-1165 and DSDP Hole 28-268 ...

• Main Authors: Williams, Trevor J, van de Flierdt, Tina, Hemming, Sidney R, Chung, Elena, Roy, Martin, Goldstein, Steven L
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2010
• Subjects: Deep Sea Drilling Project DSDP; Ocean Drilling Program ODP; Antarctic; Southern Ocean; East Antarctica; Prydz Bay; East Antarctic Ice Sheet; Indian; Wilkes Land; Antarc*; Antarctica; Ice Sheet; Iceberg*
• Online Access: https://dx.doi.org/10.1594/pangaea.786664; https://doi.pangaea.de/10.1594/PANGAEA.786664

Sediments from Ocean Drilling Program Site 1165 in the Indian Ocean sector of the Southern Ocean (off Prydz Bay) contain a series of layers that are rich in ice-rafted debris (IRD). Here we present evidence that IRD-rich layers at Site 1165 at 7, 4.8, and 3.5 Ma record short-lived, massive discharges of icebergs from Wilkes Land and Adélie Land, more than 1500 kilometers to the east of the depositional site. This distant source of icebergs is clearly defined by the presence of IRD hornblende grains with 40Ar/39Ar ages of 1200-1100 Ma and 1550-1500 Ma, ages that are not found on the East Antarctic continent in locations closer to Site 1165. This observation requires enormous amounts of detritus-carrying drifting icebergs, most likely in the form of large icebergs. These events probably reflect destabilization, surge, and break-up of ice streams on the Wilkes Land and Adélie Land margins of the East Antarctic Ice Sheet, in the vicinity of the low-lying Aurora and Wilkes Basins. They occurred under warming ... : Supplement to: Williams, Trevor J; van de Flierdt, Tina; Hemming, Sidney R; Chung, Elena; Roy, Martin; Goldstein, Steven L (2010): Evidence for iceberg armadas from East Antarctica in the Southern Ocean during the late Miocene and early Pliocene. Earth and Planetary Science Letters, 290(3-4), 351-361 ...