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Mid-Holocene climate in Northern Minnesota

R. M. Forester·L.D. Delorme·J.P. Bradbury
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Abstract

Study of Holocene ostracodes and diatoms from Elk Lake, in North-Central Minnesota, indicates that the local climate of the mid-Holocene can be subdivided into three intervals. Throughout interval 1 (ca. 7800 to 6700 yr B.P.), climate was colder and much drier than today. During intervals 2 and 3 (ca. 6700 to 4000 yr B.P.) average mean-annual air temperatures approached the modern mean (3.7??C), but warm summers persisted throughout interval 2, whereas during interval 3 warm summers fell into discrete episodes. Furthermore, average mean-annual precipitation was about 85 and 90% of modern during intervals 2 and 3, respectively. Transition times between the principal intervals were less than 50 yr. The expected effects of a retreating Laurentide Ice Sheet that initially maintained a winter-style circulation, followed by transitional climate states, and finally a near-modern circulation pattern may explain these local climatic events. ?? 1987.

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R. M. Forester, L.D. Delorme, J.P. Bradbury. 2017-01-20. Mid-Holocene climate in Northern Minnesota. https://doi.org/10.1016/0033-5894(87)90064-0

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