Gs. Wilson et al., Late Neogene Sirius Group strata in Reedy Valley, Antarctica: a multiple-resolution record of climate, ice-sheet and sea-level events, J GLACIOL, 44(148), 1998, pp. 437-447
Late Neogene Sirius Group strata from Tillite Spur and Quartz Hills in the
Reedy Glacier area, Antarctica, demonstrate the variability in Sirius Group
facies and contrasts Sirius Group strata deposited at high and low palco-e
levation, respectively. The Tillite Spur and Quartz Hills Formations (Plioc
ene) are formally defined here. The Tillite Spur Formation type section cro
ps out on the edge of the Wisconsin Plateau overlooking Tillite Spur. It co
mprises 32 m of alternating coarse gray conglomerate and muddy olive-brown
diamictites. The Quartz Hills Formation type section crops out above the we
stern margin of Reedy Glacier in a pre-existing cirque towards the southern
end of the Quartz Hills. It comprises c. 100 m of alternating massive diam
ictites and rhythmically interbedded sandstone and laminated mudstones whic
h were deposited close to sea level and subsequently rapidly uplifted (>500
m Myr(-1)) to their present elevation at c. 1500 m. Three orders of paleoc
limatic variability are recorded in the Sirius Group strata from Reedy Vall
ey: (1) recycled marine microfloras in glacial diamictites indicate interva
ls of marine incursion into the Antarctic cratonic interior co-occurring wi
th reductions in the East Antarctic ice sheet; (2) an advancing and retreat
ing paleo-Reedy Glacier deposited a glacial/interglacial sequence alternati
ng on a 10-100 kyr scale; (3) Centimeter and millimeter stratification in s
trata of the Quartz Hills Formation record annual kyr scale variability.