Progress in Estonian Quaternary stratigraphy the last decade
Aasta | 2003 |
---|---|
Kirjastus | Lietuvos mokslu akademija |
Kirjastuse koht | Vilnius |
Ajakiri | Geologija |
Köide | 41 |
Leheküljed | 36-43 |
Tüüp | artikkel ajakirjas |
Eesti autor | |
Keel | inglise |
Id | 19115 |
Abstrakt
Raukas A. Progress in Estonian Quaternary stratigraphy during the last decade. Geologija. Vilnius. 2003. No. 41. P. 3643. ISSN 1392110X. Based on medium-and large-scale mapping and special scientific projects, rather well--grounded stratigraphical schemes of the Pleistocene, Holocene and Late-glacial deposits were compiled and published in Estonia in the mid-nineties. As the number of new drillings is very scanty, not a single new interglacial or interstadial has been recognised in Estonia during the last decade. Therefore, much attention has been paid to methodical problems and improve-ment of dating methods (ESR, OSL, varvochronology, etc.). In the official stratigraphical sche-me of the Quaternary deposits in Estonia lithostratigraphic terms are used as basic units. Formation, as a fundamental unit, is used in the sense of glacial and interglacial episodes in event stratigraphy. Big stadial episodes in the sense of event stratigraphy are comparable with subformations. Although interglacial sediments are differentiated on the basis of spore and pollen and other fossil evidence, and pollen assemblage zones underlie their description, for the unity of the scheme even here lithostratigraphical terms Prangli (=Eemian Interglacial) and Karuküala (=Holsteinian Interglacial) formations were preferred. All stratigraphical units (for-mations and subformations) are based on well-investigated stratotypes. For the interglacials, there are composite stratotypes, i. e. the localities where both boundary and unit stratotypes are recognized. For the tills, areal stratotypes are used. In Holocene stratigraphy we have adopted the chronozone boundaries of the Nordic countries and differentiated eleven pollen assamblage zones which are time-transgressive. Stratotype sections for the Holocene deposits have not yet been officially accepted. This work is still in progress.