RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 7, ES5004, doi:10.2205/2005ES000180, 2005
[40] The highlands and mountain ranges adjacent to the Sea of Okhotsk are commonly believed to have been glaciated by cirque and valley glaciers; a few bigger paleoglacier complexes are envisioned only in Verkhoyansk, Koryak and Kamchatka mountains [Velichko, 2002]. However, interpretation of space images of Northeast Siberia along with numerical modeling based on the 1000 m to 1200 m snowline depression led us to conclude that all the mountains, piedmonts and intramontane basins were virtually completely ice-covered in that region [Grosswald, 1998a; Grosswald and Hughes, 2002]. According to our model, a continuous chain of large glacier complexes extended from the Pamirs to Chukchi Peninsula and merged with the marine ice sheets of the Eurasian Arctic margins. Specifically, the northeastern link of that chain, the Cherski-Kolyman glacier complex of Cordilleran type, together with a local ice cap on Kamchatka Peninsula, semi-surrounded the Sea of Okhotsk and discharged their ice into the sea.
[41] Judging by the Okhotsk-Sea coastal geomorphology, the strongest ice inflow was focused in two sectors, first - on the concave southeastern side of Suntar Khayata Range, and second - in the sea's northeastern embayment where broad valleys of Penzhina and Belaya-Talovka-Kuyul occur. The first sector was fed by ice of the Suntar Khayata and Cherski Ranges centers, the second - by ice of the Kolyman and Koryak mountain complexes. A paleo-ice stream flowing along the huge submarine Shelikhov-TINRO trough is evidenced by the fjord-like Gulfs of Gizhiga and Penzhina, glacially-cut "corners" on their sides and on both sides of Shelikhov Bay (see, e.g., Cape Utkholoksky of western Kamchatka, and Cape Piyagina, east of Magadan), as well as by a linear system of elongated ridges, scarps and erosional furrows that extend along the western coastal plain of Kamchatka Peninsula. This system has not been recognized or studied previously, yet judging by its appearance on maps and air-photographs, and by its relation to the Okhotsk-Sea geomorphology, the system is an assemblage of lateral moraines, eskers, and meltwater drainage channels.
[42] This reconstruction of a glacial setting in the near-Okhotsk coastal zone is consistent with the at-or-near-sea-level paleo-snowline of the region. It is also consistent with the aforementioned modeling experiments. Our own modeling results [Grosswald and Hughes, 1998], yielded the shape, elevation, and thickness of the Okhotsk spillover ice sheet, based on these specific geomorphic and climatic constraints. An additional constraint, most favorable to inception, growth and stabilization of that ice sheet, was the fact that the Kurile Ice Sheet was buttressed by the Kurile Island Arc, i.e., by an extensive submarine ridge (see below).
Citation: 2005), "Back-arc" marine ice sheet in the Sea of Okhotsk, Russ. J. Earth Sci., 7, ES5004, doi:10.2205/2005ES000180.
Copyright 2005 by the Russian Journal of Earth Sciences (Powered by TeXWeb (Win32, v.2.0).