Sl. Forman et al., HOLOCENE RELATIVE SEA-LEVEL HISTORY OF FRANZ-JOSEF-LAND, RUSSIA, Geological Society of America bulletin, 109(9), 1997, pp. 1116-1133
One of the largest uncertainties in ice-volume changes during the late
Quaternary Period is the extent of ice sheets over the Barents and Ka
ra seas, Field research on central and eastern Franz Josef Land, Russi
a, provide new observations on postglacial emergence and deglaciation
that further constrain the magnitude and timing of late Weichselian gl
aciations, Radiocarbon dating of driftage from raised-marine sequences
place deglacial unloading prior to 9.4 ka. At a number of localities
within 1 to 2 km of the present glacier margin, in situ shells from ra
ised-marine sediments yield C-14 ages between 9.7 and 8.4 yr B.P., evi
dence that outlet glaciers were at or behind present margins by the ea
rly Holocene Period. The altitude of the marine limit on Franz Josef L
and ranges from 49 to 20 m above sea level (asl) and is low compared t
o eastern Svalbard (110 to 60 m asl), The age of the marine limit rang
es from greater than or equal to 10.4 ka to ca, 6.0 ka and exhibits gr
eater diachrony where emergence is <35 m, A low initial rate of emerge
nce reflects glacio-isostatic compensation offset by a eustatic rise i
n sea level, and perhaps an additional component from renewed water lo
ading of the Barents Sea after deglaciation. The presence of raised be
aches at 1 to 4 m asl that are 1 to 2 ka indicates that uplift is inco
mplete, Are exponential extrapolation of uplift data for Franz Josef L
and and eastern Svalbard yields current maximum uplift estimates of 0.
7 to 1.6 mm/yr, an inferred <5.5 m of uplift remaining, These values a
re at least 50% to 80% lower than the inferred uplift residual for a m
odeled ice sheet in the Barents and Kara seas, The discrepancy indicat
es that further refinement is needed for this ice-sheet model. The com
pilation of emergence data from Franz Josef Land, Svalbard, and Novoya
Zemyla confine maximum glacio-isostatic compensation to the Barents S
ea; comparatively minor ice sheet loads were over Novaga Zemlya and th
e southeastern Parents Sea, Emergence isobases since 5 and 9 ka descen
d northward across Franz Josef Land, indicating a diminishing glacio-i
sostatic response into the Arctic Ocean.