Title
The Eemian stratotype locality at Amersfoort in the central Netherlands: A re-evaluation of old and new data
Author
Nederlands Instituut voor Toegepaste Geowetenschappen TNO
Cleveringa, P.
Meijer, T.
van Leeuwen, R.J.W.
de Wolf, H.
Pouwer, R.
Lissenberg, T.
Burger, A.W.
Publication year
2000
Abstract
In order to obtain a better understanding of the infilling of the Saalian glacial basins during the Eemian, particularly following the recent research in the Amsterdam Basin (Terminal borehole), it was necessary to re-investigate the type locality of the Eemian at Amersfoort. Both published and unpublished data from various biota (diatoms, foraminifers, molluscs, ostracods, pollen) provide new information on the changing sedimentary environments during the Eemian. Although the organic and clastic sediments of the infilling represent nearly all the pollen zones, the sedimentary sequence at Amersfoort is discontinuous: four breaks at least are recognised at the type locality. The successive sedimentary environments and the breaks in the record are linked with the transgression of the Eemian sea, the topographic position at the margin of an ice-pushed ridge, and the changes in hydrodynamic conditions. Local conditions, such as a sandy sea bed, shallow water and a reduced water exchange near the North Sea margin, influenced the salinity of the basin. Rib counts of Cerastoderma edule shells indicate a higher salinity at the end of the Taxus (E4b) and the beginning of the Carpinus (E5) zones than that present in the modern North Sea. Local conditions were responsible for the higher salinity following the climate optimum. During the Abies phase (the later part of regional pollen zone E5), the sea level had already fallen. The change from eutrophic peat growth (with Alnus and Salix) to an oligotrophic Ericaceae/Sphagnum community at the end of the Eemian resulted from the change from a marine to a fresh-water environment, probably coherent with a deterioration of the climate.
Subject
Energy / Geological Survey Netherlands
Geological Survey Netherlands
Biostratigraphy
Climate
Eemian stratotype
Fauna
Flora
Lithology
Palaeoenvironment
Sea level
basin fill
Eemian
Last Interglacial
Pleistocene
stratotype
Netherlands
To reference this document use:
http://resolver.tudelft.nl/uuid:cb4a2bbd-27ee-48ac-8951-7bc7f898a5b2
TNO identifier
235681
ISSN
0016-7746
Source
Geologie en Mijnbouw/Netherlands Journal of Geosciences, 79 (79), 197-216
Document type
article