Climate Change in North Dakota Since the Last Glaciation
By Allan Ashworth
Department of Geosciences, North Dakota State University


Introduction

The Last Glaciation

The Late Glacial

The Holocene

Conclusions

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Conclusions

Studies in Quaternary paleontology have contributed significantly to our knowledge of climate change on the northern Great Plains. Future studies will be directed at filling gaps in the knowledge base and in "fine tuning" methods to improve the quality of interpretation. The climate along the ice margin during the last glacial is still poorly known. The semi-arid climate of the southwestern part of the state, and the depth of oxidation, is not conducive to the preservation of organic sediments. Nevertheless, the sediments of shallow basins should continue to be examined for pollen. Future fossil discoveries will probably continue to be vertebrate remains. Radiocarbon dating of bone has been unreliable but new techniques promise to change that situation. Also, it may be possible to infer vegetation from isotopic studies of tooth enamel.

Late-glacial and early Holocene sediments on the Missouri Coteau need to be more completely examined. The Seibold site, with its incredible preservation, is probably not unique. Ancient DNA could well be preserved in these fossils. Future studies in molecular genetics could provide a real link between populations of the past and those of today that would enable detailed reconstructions of dispersal routes of organisms in response to climate change.

Micropaleontological studies of lacustrine sediments during the last 10 years have made a significant contribution to our knowledge of Holocene climate. Historically, the terms altithermal and hysithermal were used to describe a peak of warmth in the mid-Holocene. The high resolution records of pollen, diatoms, ostracods and geochemistry that are now being studied indicate that that classical concept was an oversimplification. The latest records indicate much more complexity. The modal changes which seem to be part of the Holocene record are especially intriguing, as they imply major reorganizations of the Pacific oceanic-atmospheric circulation.

The opportunities for future paleontological research in lacustrine sediments are great. There is a need to find out more about the relationships between specific organisms and their responses to climate parameters and water chemistry. There is also a need to resolve the complex relationships between climatic parameters and hydrology in such a way that it can be taken into account in paleoclimatic interpretation. In a vicious pun, paleontology has been referred to as the "dead science". Nothing could be further from the truth. Quaternary paleontology, with its links to global change and climate change, is very much alive.


This report first appeared in the Proceedings of the North Dakota Academy of Science, Vol. 53, 1999.

Dr. Allan Ashworth, Chairman
Geology Department
130 Stevens Hall
North Dakota State University
Fargo, ND 58105
Phone: 701-231-7919
E-mail: ashworth@plains.nodak.edu


NDSU Central Grasslands Research Extension Center

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