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Milankovitch type cycles in the Lower Carboniferous of NW Ireland
Author(s) -
Schwarzacher W.
Publication year - 1989
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1989.tb00412.x
Subject(s) - milankovitch cycles , carboniferous , eccentricity (behavior) , geology , paleontology , amplitude , geodesy , annual cycle , type (biology) , climatology , physics , structural basin , optics , glacial period , political science , law
A short description of the Lower Carboniferous near Sligo (NW Ireland) is given. Limestones and mark in four measured sections in the Glencar Limestone were numerically coded as plus and minus one, respectively. Such sequences show good and persistent cyclicity with a basic wave length of 200 cm. Filtered sections have been adjusted to give each cycle a constant length. Such records show a much longer cycle in the form of amplitude modulation of the basic cycle. The 200 cm cycle is very regular and its approximate duration is around 100 kyr. It could, therefore be the result of eccentricity variations in the earth's orbit. The longer cycle represents approximately 1–1.5 Myr and may be equivalent to the Yoredale cycles in the northern England.