An unusually long and continuous Late Quaternary sedimentary sequence has been preserved in a sedimentary basin formed in the Sokli Carbonatite Massif in eastern-central Finnish Lapland. A nearly complete sediment recovery from the central Sokli basin combined with palynological results from sediments not earlier recovered and an independent OSL/AMS 14 C chronology allow us here to define the Late Quaternary climate-stratigraphy at Sokli and describe in detail the environmental record. Three interstadial intervals of Weichselian age are distinguished that correlate with MIS 5c, 5a and part of MIS 3 in the marine oxygen-isotope record. The interstadials of MIS 5c and 3 age are here defined as the Sokli and Tulppio Interstadials, respectively. The MIS 5a interstadial is correlated with the Maaselkä/Peräpohjola Interstadials of Finnish Lapland, which previously have been tentatively assigned a MIS 5c age. Till beds in the Sokli sequence (deposited during stadials 3-1) correlate to MIS 5b, 4 and 3/2, respectively. Depositional environments and vegetational changes during the ice-free intervals at Sokli are discussed. The Sokli sedimentary sequence indicates significantly less extensive and more variable ice-cover over Finnish Lapland during the Weichselian than has been earlier suggested based on the long-distance correlation of litho-and bio-stratigraphic fragmentary evidence.
The Hitura open pit exposes a sedimentary sequence up to 50 m thick representing Late Saalian to Holocene glacial and non‐glacial sediments. The sequence was investigated using sedimentological methods, OSL‐dating and pollen and diatom analyses to reconstruct the Middle Weichselian (MWG) glacial event in the central part of the Scandinavian Ice Sheet (SIS). The results indicate that the sediment succession represents two entire glacial advance and retreat cycles. The lowermost deposits are Late Saalian esker and delta sediments overlain by sediments that correlate with the early Eemian lacustrine phase. Remnants of the Eemian soil post‐dating the lacustrine phase were also observed. The area was ice‐free during the entire Early Weichselian (EWG). The first glacial advance recorded in the sediments is related to the MWG. It started 79 kyr ago, deformed underlying sediments and deposited an immature till, including large detached sediment pods containing remains of organic material, soils and fluvial sediments representing allochthonous material from EWG ice‐free stadials and interstadials. The glacial deposits are conformably overlain by glaciolacustrine and littoral accumulations, indicating MWG deglaciation between 62 and 55 kyr ago. Based on the fabric measurements from the till unit overlying the MWG sediments, ice advance during the Late Weichselian (LWG) was initially from the west and later from a north‐northwesterly direction. The Hitura strata provide the first dating of the MWG deglaciation (55 to 62 kyr ago) from central parts of the SIS. It can be considered as a key site for studying the growth and decay of SIS during the poorly known early parts of the glaciation.
Compared to the other islands in the Svalbard archipelago, Nordaustlandet offers only limited stratigraphical or sedimentological information on its Quaternary deposits. This article aims to fill the gap by presenting new results from glacial geological, sedimentological and chronological studies in the southern Murchisonfjorden area. Field data include reconnaissance mapping and detailed logging of vertical sections along cliff-face outcrops a few metres high adjacent to the present-day shoreline. Combined with OSL and AMS age determinations, these data provide evidence of three successive Weichselian sequences, each represented by the deposition of till followed by the accumulation of shallow marine deposits. Contrary to earlier conclusions, this study demonstrates that the area was occupied by a Late Weichselian glacier (LWG), although the LWG till is thin and discontinuous. Interstadial sublittoral sand related to the Mid-Weichselian interstadial was dated to 38-40 kyr, and an Early Weichselian interstadial to 76-80 kyr. The preservation of older sediments, multiple striae generations and abundant observations of weathered local bedrock material indicate weak glacial erosion within the study area. We suggest that the Late Weichselian glacier was relatively inactive and remained mainly cold-based until the deglaciation. The Isvika sections can be considered a new key site that offers further potential to improve our understanding of the Weichselian stage within the northwestern sector of the Barents-Kara Ice Sheet.
In 1603, the Italian shoemaker Vincenzo Cascariolo found that a stone (baryte) from the outskirts of Bologna emitted light in the dark without any external excitation source. However, the calcination of the baryte was needed prior to this observation. The stone later named as the Bologna Stone was among the first luminescent materials and the first documented material to show persistent luminescence. The mechanism behind the persistent emission in this material has remained a mystery ever since. In this work, the Bologna Stone (BaS) was prepared from the natural baryte (Bologna, Italy) used by Cascariolo. Its properties, e.g. impurities (dopants) and their valences, luminescence, persistent luminescence and trap structure, were compared to those of the pure BaS materials doped with different (transition) metals (Cu, Ag, Pb) known to yield strong luminescence. The work was carried out by using different methods (XANES, TL, VUV-UV-vis luminescence, TGA-DTA, XPD). A plausible mechanism for the persistent luminescence from the Bologna Stone with Cu þ as the emitting species was constructed based on the results obtained. The puzzle of the Bologna Stone can thus be considered as resolved after some 400 years of studies.
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.
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