Holocene stable-isotope stratigraphy at Lough Gur, County Limerick, Western Ireland

After the pronounced fluictuation of 4‰ in δ 18 O during the Younger Dryas and the 1‰ dip during the Preboreal Oscillation, values for δ 18 O decreased very steadily from -2.5 to -5.3‰ from 9300 to about 8000 14 C yr BP (uncal.). This early-Holocene decrease of almost 3‰ is interpreted as a result o...

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Bibliographic Details
Published in:The Holocene
Main Authors: Ahlberg, Karin, Almgren, Elisabeth, Wright, H. E., Ito, Emi
Format: Article in Journal/Newspaper
Language:English
Published: SAGE Publications 2001
Subjects:
Paleontology
Earth-Surface Processes
Ecology
Archeology
Global and Planetary Change
Low Lake
Ice Sheet
Online Access:http://dx.doi.org/10.1191/095968301674434407
http://journals.sagepub.com/doi/pdf/10.1191/095968301674434407
Description
Summary:After the pronounced fluictuation of 4‰ in δ 18 O during the Younger Dryas and the 1‰ dip during the Preboreal Oscillation, values for δ 18 O decreased very steadily from -2.5 to -5.3‰ from 9300 to about 8000 14 C yr BP (uncal.). This early-Holocene decrease of almost 3‰ is interpreted as a result of a declinle of almost 6°C in the temperature of precipitation. The previous high temperature of much of the Lateglacial and the Preboreal (12000-9300 yr BP uncal.) may reflect warm summers related to greater insolation and warm winters caused by the influence of the Laurentide ice sheet on atmospheric circulation. After 8000 yr BP a disconformity interrupts the sequence, but after about 5000 yr BP the δ 18 O and δ 13 C are irregular because of a low lake level, as shown by the occurrence of littoral shells and woody detritus in the littoral core, and because of anthropogenic factors, as inferred from pollen indicators of forest disturbance and farming found in both the littoral and offshore cores.

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