Abstract
We here suggest a glacial and climate history of the Taimyr Peninsula and Severnaya Zemlya archipelago
in arctic Siberia for the last about 150 000 years (ka). Primarily it is based on results from seven field
seasons between 1996 and 2012, to a large extent already published in papers referred to in the text e
and on data presented by Russian workers from the 1930s to our days and by German colleagues working
there since the 1990s.
Although glaciations even up here often started in the local mountains, their culminations in this
region invariably seems to have centred on the shallow Kara Sea continental shelf e most likely due to
expanding marine ice-shelves grounding there, as a combined effect of thickening ice and eustatically
lowered sea-levels.
The most extensive glaciation so far identified in this region (named the Taz glaciation) took place
during Marine Isotope Stage 6 (MIS 6), i.e. being an equivalent to the late Saale/Illinoian glaciations. It
reached c. 400 km southeast of the Kara Sea coast, across and well beyond the Byrranga Mountain range
and ended c. 130 ka. It was followed by the MIS 5e (Karginsky/Eemian) interglacial, with an extensive
marine transgression to 140 m above present sea level e facilitated by strong isostatic downloading
during the preceding glaciation. During the latest (Zyryankan/Weichselian/Wisconsinan) glacial cycle
followed a series of major glacial advances. The earliest and most extensive, culminating c. 110e100 ka
(MIS 5de5e), also reached south of the Byrranga mountains and its post-glacial marine limit there was c.
100 m a.s.l. The later glacial phases (around 70e60 ka and 20 ka) terminated at the North Taimyr Ice
Marginal Zone (NTZ), along or some distance inland from the present northwest coast of Taimyr. They
dammed glacial lakes, which caused the Taimyr River to flow southwards where to-day it flows
northwards into the Kara Sea. The c. 20 ka glacial phase, contemporary with the maximum (LGM)
glaciation in NW Europe, was this glacial cycle's least extensive one up here e probably an effect of
precipitation shadow caused by the major glaciations to the west. From the Kara Sea shelf this advance
only reached c. 100 km inland, over some limited parts of NW Taimyr. The Severnaya Zemlya islands
were only locally glaciated at this time.
The lowlands south of the Byrranga Mountains have been a terrestrial “Mammoth steppe” environment
during the last c. 50 ka and periglacial permafrosted sediments here have preserved excellent
information on its megafauna and vegetation. The latter, according to new DNA-data, had considerably
more (for grazing animals nourishing) flowering plants growing than earlier pollen-based (grass
dominated) spectra have suggested.
in arctic Siberia for the last about 150 000 years (ka). Primarily it is based on results from seven field
seasons between 1996 and 2012, to a large extent already published in papers referred to in the text e
and on data presented by Russian workers from the 1930s to our days and by German colleagues working
there since the 1990s.
Although glaciations even up here often started in the local mountains, their culminations in this
region invariably seems to have centred on the shallow Kara Sea continental shelf e most likely due to
expanding marine ice-shelves grounding there, as a combined effect of thickening ice and eustatically
lowered sea-levels.
The most extensive glaciation so far identified in this region (named the Taz glaciation) took place
during Marine Isotope Stage 6 (MIS 6), i.e. being an equivalent to the late Saale/Illinoian glaciations. It
reached c. 400 km southeast of the Kara Sea coast, across and well beyond the Byrranga Mountain range
and ended c. 130 ka. It was followed by the MIS 5e (Karginsky/Eemian) interglacial, with an extensive
marine transgression to 140 m above present sea level e facilitated by strong isostatic downloading
during the preceding glaciation. During the latest (Zyryankan/Weichselian/Wisconsinan) glacial cycle
followed a series of major glacial advances. The earliest and most extensive, culminating c. 110e100 ka
(MIS 5de5e), also reached south of the Byrranga mountains and its post-glacial marine limit there was c.
100 m a.s.l. The later glacial phases (around 70e60 ka and 20 ka) terminated at the North Taimyr Ice
Marginal Zone (NTZ), along or some distance inland from the present northwest coast of Taimyr. They
dammed glacial lakes, which caused the Taimyr River to flow southwards where to-day it flows
northwards into the Kara Sea. The c. 20 ka glacial phase, contemporary with the maximum (LGM)
glaciation in NW Europe, was this glacial cycle's least extensive one up here e probably an effect of
precipitation shadow caused by the major glaciations to the west. From the Kara Sea shelf this advance
only reached c. 100 km inland, over some limited parts of NW Taimyr. The Severnaya Zemlya islands
were only locally glaciated at this time.
The lowlands south of the Byrranga Mountains have been a terrestrial “Mammoth steppe” environment
during the last c. 50 ka and periglacial permafrosted sediments here have preserved excellent
information on its megafauna and vegetation. The latter, according to new DNA-data, had considerably
more (for grazing animals nourishing) flowering plants growing than earlier pollen-based (grass
dominated) spectra have suggested.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Quaternary Science Reviews |
| Vol/bind | 107 |
| Sider (fra-til) | 149-181 |
| Antal sider | 33 |
| ISSN | 0277-3791 |
| DOI | |
| Status | Udgivet - 1 jan. 2015 |
Emneord
- Det Natur- og Biovidenskabelige Fakultet
- Eurasian ice sheet Taimyr Glaciation history Palaeoenvironmental reconstruction Weichselian chronology
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