Optical Dating of a Late Quaternary Sediment Sequence from Sokli, Northern Finland

Abstract

Interstadial and non-glacial stadial sediments collected in boreholes from Sokli in northeastern Finland have been dated by optically stimulated luminescence on quartz and feldspar grains. The quartz OSL ages follow stratigraphic order, with one exception, and support the litho-and biostratigraphical correlation with the NW European mainland climate-stratigraphy and the marine oxygen-isotope stages. Feldspar IRSL dates generally overestimate the age, probably due to incomplete bleaching. The data show that during the last glacial cycle north-eastern Finland was not glaciated until MIS 5b, around 90 ka. Interstadial conditions occurred around ~94 ka (MIS 5c), ~74-80 ka (MIS 5a) and 42-54 ka (MIS 3). The OSL ages have large standard errors mainly due to small sample sizes, relatively poor luminescence characteristics and uncertainties in dose-rate determinations.

A compilation of Western European terrestrial records 60–8 ka BP: towards an understanding of latitudinal climatic gradients

“…The entire sediment column has been dated using a combination of radiocarbon dating, OSL dating, lithostratigraphic correlation and palynostratigraphy (Helmens et al, 2007a,b;Alexanderson et al, 2008). The MIS3 sediments of the Sokli sequence have been analysed for pollen (Bos et al, 2009), chironomids (Engels et al, 2008a), diatoms , botanical macrofossils (Bos et al, 2009) and sedimentological properties (Helmens et al, 2007a,b;Alexanderson et al, 2008).…”

“…The entire sediment column has been dated using a combination of radiocarbon dating, OSL dating, lithostratigraphic correlation and palynostratigraphy (Helmens et al, 2007a,b;Alexanderson et al, 2008). The MIS3 sediments of the Sokli sequence have been analysed for pollen (Bos et al, 2009), chironomids (Engels et al, 2008a), diatoms , botanical macrofossils (Bos et al, 2009) and sedimentological properties (Helmens et al, 2007a,b;Alexanderson et al, 2008). Mean July air temperatures have been derived from pollen and chironomids (Helmens et al, 2007a;Engels et al, 2008a;Bos et al, 2009) while minimum mean July air temperatures have been reconstructed from aquatic plant remains using the indicator species approach.…”

Lithostratigraphy and Optically Stimulated Luminescence age determinations of pre‐Late Weichselian deposits in the Suupohja area, western Finland

“…Ukkonen et al 1999Ukkonen et al , 2007Lunkka et al 2001Lunkka et al , 2004Lunkka et al , 2008Arnold et al 2002;Raunholm et al 2002;Houmark-Nielsen & Kjaer 2003;Kalm 2006;Kjaer et al 2006;Helmens et al 2007;Alexanderson et al 2008;Auri et al 2008;Salonen et al 2008;Väliranta et al 2009;Wohlfarth 2010;Wohlfarth et al 2011). Ukkonen et al 1999Ukkonen et al , 2007Lunkka et al 2001Lunkka et al , 2004Lunkka et al , 2008Arnold et al 2002;Raunholm et al 2002;Houmark-Nielsen & Kjaer 2003;Kalm 2006;Kjaer et al 2006;Helmens et al 2007;Alexanderson et al 2008;Auri et al 2008;Salonen et al 2008;Väliranta et al 2009;Wohlfarth 2010;Wohlfarth et al 2011).…”

Major cooling intersecting peak Eemian Interglacial warmth in northern Europe

“…150e180 kyr (Helmens et al, 2000), and OSL dating on quartz (using SAR dose protocol) to > ca. 95 kyr (Helmens et al, 2007;Alexanderson et al, 2008). Furthermore, multi-proxy analysis on the fossil-rich lacustrine and fluvial sediments of Weichselian and Holocene age have earlier shown the potential of the Sokli record in providing detailed paleo-environmental and -climatic data for northern Europe (Helmens, 2014).…”