Age and weathering status of granite tors in Arctic Finland (~68° N)

The first stages of erosion by ice sheets: Evidence from central Europe

“…This is consistent with cosmogenic exposure ages of 10 5 yr obtained for tor summits in other glaciated areas in Europe (Stroeven et al, 2002;Ballantyne et al, 2006, Ballantyne and Hall, 2008, Darmody et al, 2008 and in North America (Briner et al, 2003). Some small tors may have emerged, however, since MIS 12 glaciation.…”

The impact of Quaternary glaciations on inselbergs in northern Sweden

“…However, the glacial effect on the north Swedish preglacial landscape has been shown to be highly heterogeneous as a result of a patchy distribution of warm-based erosional/depositional zones and cold-based nonerosive zones under the ice sheets (Kleman, 1992;. Some areas have been heavily eroded throughout numerous glaciations, as witnessed by bedrock hills being integrated in glacial erosional and depositional streamlined features such as drumlins and crag-and-tails (Hättestrand et al, , 2004, while other areas display what appears to be an essentially unmodified landscape including tors and other relict weathering remnants (Lagerbäck, 1988;Hättestrand and Stroeven, 2002;André, 2004;Darmody et al, 2008).…”

Late Cenozoic deep weathering patterns on the Fennoscandian shield in northern Finland: A window on ice sheet bed conditions at the onset of Northern Hemisphere glaciation

“…Exposed, glacially polished rock surfaces of different rock types have been lowered by 1-25 mm in the last 10 ka (André, 2002). Development of podzolic soils during the Holocene has been weak and soil depths are b1 m (Räisänen et al, 1997;Land et al, 1999;Darmody et al, 2008). Postglacial weathering of till has affected only the most mobile minerals (Öhlander et al, 1996;Land et al, 1999), and till clasts remain largely fresh.…”

“…Periglacial forms include tors that rise up to 10 m above inselberg summits (Fig. 5A), including examples with exposure histories of up to~1 My (Darmody et al, 2008). Tors and tor stumps occur locally even on low ground in the Vuotso area and the survival of these old, delicate features indicates very limited glacial erosion through the middle and late Pleistocene.…”

“…Despite multiple phases of glaciation by the Fennoscandian Ice Sheet (FIS) over the last 2.7 Myr (Kleman and Stroeven, 1997), the Archaean and Precambrian shield of the Vuotso area of northern Finland retains many preglacial and periglacial relief elements (Darmody et al, 2008;Ebert et al, 2015). Significantly, deep weathering is known to exist extensively beneath till (Hirvas, 1991;Islam et al, 2002;Johansson et al, 2011), but the regional distribution and geochemistry of these weathering mantles has not been analysed systematically.…”