Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

2 Geological Quarterly

2 2013

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

A ground-penetrating radar study of the Vaidasoo bog (Estonia) : no crater structure exists

100%

Mustasaar M. , Plado J. , Jõeleht A.

Geological Quarterly

2013

tom Vol. 57, No. 2

357–-360

Ground-penetrating radar (GPR) was used to analyse the circular Vaidasoo bog in northern Estonia. This was done to better understand its structure and origin, and to test the suggestion that Vaidasoo represents a meteorite impact structure. The combination of GPR with LIDAR data suggests that Vaidasoo bog is developed in a NW–SE oriented glacial tunnel valley where post-glacial hydrology is affected by glaciofluvial deposits. As no clear impact-modified bedrock features were identified and the circular bog does not mirror the topography of the bedrock, we conclude that the Vaidasoo structure does not represent a meteorite impact structure.

Development of the Holocene foredune plain in the Narva-Jõesuu area, eastern Gulf of Finland

75%

Rosentau A. , Jõeleht A. , Plado J. , Aunap R. , Muru M. , Eskola K. O.

Geological Quarterly

2013

tom Vol. 57, No. 1

89--100

The morphogenesis and inner structure of the Holocene foredune plain in the Narva-Joesuu area, eastern Gulf of Finland, were studied using optically stimulated luminescence (OSL) dating, ground-penetrating radar (GPR) study and interpretation of airborne LIDAR elevation data. The results show that the Narva-Joesuu foredune plain consists of ca. 100 parallel coastal foredune ridges built of well-sorted fine sand underlain by gently (~7°) seaward-dipping sandy beach deposits. The distal part of the plain, which consists of at least 15 ridges, formed during the regressive phase of the Ancylus Lake/Early Litorina Sea, serving as a barrier for the lagoon behind it. A larger portion of ridges, with an average progradation rate of 0.26 m a-1, formed under conditions of falling relative sea level during the Litorina regression and was separated from the older foredune succession by a hiatus related to the Litorina transgression at 8.5-7.3 cal. ka BP. In the highest central part of the plain the foredune growth was interrupted by foredune instability and a re-blowing episode dated to 5.4 ± 0.9 ka BP which may correlate with a larger regional cooling at 5.8-5.1 cal. ka BP in the North Atlantic and central Europe. During the last 3000 years, the foredune progradation rate decreased to 0.19 m a-1, most probably because of decelerated land-uplift and increased human impact due to coastal protection.