The relative influence of local, extra-local, and regional factors on organic sedimentation in the Vällamäe kettle hole, Estonia     

JAAN-MATI PUNNING  THU KOFF  MATI ILOMETS  JAAN JOTGI 《Boreas: An International Journal of Quaternary Research》1995,24(1):65-80

This paper examines the data obtained during a complex study of a 17 m deep peat sequence in a small glaciokarstic kettle hole mire in SE Estonia. The pollen and macrofossil analysis and the ¹⁴C data were used for the spatio-temporal reconstruction of the development of the mire, including its vegetation and microclimatic conditions during the Holocene. The comparative analysis of the data gained allows us to estimate the relative influence of various local, extra-local, and regional natural processes on the dynamics of the ecosystems.  相似文献   

The isotopic composition of oxygen and carbon in the subfossil mollusc shells of the Baltic Sea as an indicator of palaeosalinity     

JAAN-MATI PUNNING  TÖNU MARTMA  HELGI KESSEL  REIN VAIKMÄE 《Boreas: An International Journal of Quaternary Research》1988,17(1):27-31

The carbon (δ¹³ C) and oxygen (δ¹⁸O) isotopic composistion in mollusc shells in mainly determined by the isotopic composition of water and dissolved bicarbonate. The δ¹⁸O values of water show a good correlation with the salinity of the Baltic. This correlation served as a basis for reconstructing palaeosalinity and for stratifying the marine sediments according to the δ¹⁸O values of the carbonate skeletons of subfossil shells. The δ¹³C values in shells are mainly determined by the isotopic composition of land-originating bicarbonate, especially in the carbonate skeleton of Lymnaea balthica , which inhabits the immediate coastal zone. According to the δ¹⁸O data, salinity in the investigated area (the coastal area of W and NW Estonia) was highest (about 9–11%) during the Littorina stage. The Limnae a stage had, in general, a salinity similar to the contemporary one, but during some phases possibly exceeding it by 2–3%.  相似文献   

Pleistocene glaciation chronology of Spitsbergen     

LEONID TROITSKY  JAAN-MATI PUNNING  GALINA HÜTT  RAIVO RAJAMÄ 《Boreas: An International Journal of Quaternary Research》1979,8(4):401-407

Troitsky, Leonid, Punning, Jaan-Mati, HÜtt, Galina & Rajamäe, Raivo 1979 12 01: Pleistocene glaciation chronology of Spitsbergen. Boreas , Vol. 8, pp. 401–407. Oslo. ISSN 0300–9483.
Geomorphological and geochronological studies of Pleistocene deposits were carried out in sections along Billefjorden and Bellsund as well as on Bröggerhalvöya and Prins Karls Forland. For purposes of correlation and development of a time scale, radiocarbon (¹⁴C) and thermoluminescent (TL) dating methods were used. The dates obtained indicate the presence of older Pleistocene deposits on Spitsbergen and also provide information on the distribution of Middle Pleistocene glacial deposits. A correlation scheme of Pleistocene deposits of Spitsbergen with stratigraphic units of the Alps and northwestern Europe is presented.  相似文献   

Thermoluminescence dating of the Eemian-Early Weichselian sequence at Fjøsanger, western Norway     

GALINA HÜTT  JAAN-MATI PUNNING  JAN MANGERUD 《Boreas: An International Journal of Quaternary Research》1983,12(4):227-231

Thermoluminescence (TL) dating of shallow marine sediments from the well studied interglacial-carly glacial sequence at Fjtfsangcr, western Norway has yielded ages that with few exceptions become progressively older with depth. For Ecmian samples the TL method yielded a mean of 111,000 ± 23,000 years, close to the often postulated age of 125,000 years. For the Early Weichselian the TL dates were younger than suggested by the amino-acid method.  相似文献   

Stable isotope and pollen stratigraphy of a Holocene lake marl section from NE Finland     

HANNU HYVÅINEN  TÖNU MARTMA  JAAN-MATI PUNNING 《Boreas: An International Journal of Quaternary Research》1990,19(1):17-24

Oxygen and carbon isotope analyses are described from a marl series of Lake Vanhalampi, NE Finland, covering the time interval between about 9,000 and 4,000 to 3,000 years B.P. Both oxygen and carbon isotope ratios show consistent trends through time, apparently in response to significant environmental changes. Maximum 6^lsO levels of -12.0 on average are found in the Boreal Chronozone and minimum levels of –13.3 on average in the Subboreal Chronozone, with intermediate values during Atlantic time. A sharp decline occurs at the Atlantic/Subboreal transition between 5,000 and 4,000 years B.P. The δ15O trends are primarily believed to reflect trends in summer temperatures. The results from Lake Vanhalampi are compared with those from Lake Narotch in northwestern Belorussia.  相似文献