Skip to main content
×
Home
    • Aa
    • Aa

Postglacial Vegetation and Climate in the Northwestern Great Plains of Montana

  • Cathy W. Barnosky (a1)
Abstract
Abstract

Two pollen records from the northern Great Plains of Montana portray vegetational and climatic changes during the last 12,200 yr in a region where few other data are available. A 6.4-m core from Guardipee Lake, east of the Rocky Mountains in the area formerly covered by the Two Medicine glacial lobe, contains the Glacier Peak G and Mt. St. Helens Jy volcanic ashes. Pollen percentage data are dominated by Pinus, Poaceae, Artemisia, and Chenopodiaceae/Amaranthaceae. High nonarboreal percentages and small amounts of Juniperus, Alnus, Salix, and Populus pollen in sediments deposited between ca. 12,200 and ca. 9300 yr B.P. suggest a temperate grassland with shrubs growing locally in mesic settings. After ca. 9300 yr B.P. an increase in Chenopodiaceae/Amaranthaceae pollen and a concomitant decline in Artemisia indicate the development of more xerophytic grassland and the beginning of the altithermal period. The lake probably was intermittently dry thoughout the Holocene. A high sedimentation rate and the presence of cereal taxa characterize the last ca. 100 yr of Euroamerican settlement. Lost Lake at the northern margin of the Highwood Mountains yielded a 16.94-m core with no volcanic ashes that spans the last 9400 yr. High amounts of Chenopodiaceae/Amaranthaceae, Artemisia, and Poaceae pollen, from ca. 9400 to ca. 6000 yr B.P., suggest the presence of xeric grassland and a climate drier than at present. After ca. 6000 yr B.P. Chenopodiaceae/Amaranthaceae values declined and Artemisia, Poaceae, Pinus, Picea, Salix, Alnus, and Betula increased. The inferred spread of shrubs in wet habitats at this time and the expansion of forest in nearby mountain ranges indicate the end of the altithermal period and the onset of cooler/moister conditions.

Copyright
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

C.W. Barnosky Late Quaternary vegetation in the southwestern Columbia Basin, Washington Quaternary Research 23 1985 109 122

P.E. Carrara R.E. Wilcox S.K. Short Deglaciation of the mountainous region of northwestern Montana east of the Continental Divide Arctic and Alpine Research 18 1986 317 325

A.M. Cvancara L. Clayton W.B. Bickley Jr. A.F. Jacob A.C. Ashworth J.A. Brophy C.T. Shay L.D. Delorme G.E. Lammers Paleolimnology of late Quaternary deposits: Seibold Site, North Dakota Science 171 1971 172 174

L.C. Cwynar E. Burden J.H. McAndrews An inexpensive sieving method for concentrating pollen and spores from fine-grained sediments Canadian Journal of Earth Sciences 16 1979 1115 1120

O.K. Davis J.C. Sheppard S. Robertson Contrasting climatic histories for the Snake River Plain, Idaho, resulting from multiple thermal maxima Quaternary Research 26 1986 321 339

D.S. Fullerton R.B. Colton Stratigraphy and correlation of the glacial deposits on the Montana Plains V. Sibrava D.Q. Bowen G.M. Richmond Quaternary Glaciations in the Northern Hemisphere Quaternary Science Reviews 5 1986 69 82

J.E. Kutzbach P.J. Guetter The influence of changing orbital parameters and surface boundary conditions on climatic simulations for the past 18,000 years Journal of the Atmospheric Sciences 43 1986 1726 1759

J. Lichti-Federovich The pollen stratigraphy of a dated section of late Pleistocene lake sediment from Central Alberta Canadian Journal of Earth Sciences 7 1970 938 945

G.M. MacDonald Late Quaternary paleoenvironments of the Morley Flats and Kananaskis Valley of southwestern Alberta Canadian Journal of Earth Sciences 19 1982 23 25

G.M. MacDonald Postglacial development of the subalpine-boreal transition forest of western Canada Journal of Ecology 75 1987 303 320

G.M. MacDonald L. Cwynar A fossil pollen based reconstruction of the late Quaternary history of lodgepole pine (Pinus contorta ssp. latifolia) in the Western interior of Canada Canadian Journal of Forestry Research 15 1985 1039 1044

R.N. Mack N.W. Rutter S. Valastro Holocene vegetation history of the Kootenai River Valley, Montana Quaternary Research 20 1983 177 193

J.H. McAndrews A.A. Berti G. Norris Key to the Quaternary Pollen and Spores of the Great Lakes Region 1973 Royal Ontario Museum Toronto, Canada Life Sciences Miscellaneous Publication

P.J. Mehringer Jr. S.F. Arno K.L. Peterson Postglacial history of Lost Trail Pass Bog, Bitterroot Mountains, Montana Arctic and Alpine Research 9 1977 345 368

P.J. Mehringer Jr. J.C. Sheppard F.F. Foit Jr. The age of Glacier Peak tephra in westcentral Montana Quaternary Research 21 1984 36 41

G.M. Richmond Tentative correlation of deposits of the Cordilleran ice-sheet in the northern Rocky Mountains V. Sibrava D.Q. Bowen G.M. Richmond Quaternary Glaciations in the Northern Hemisphere Quaternary Science Reviews 5 1986 129 134

W.A. Watts R.C. Bright Pollen, seed, and mollusk analysis of a sediment core from Pickerel Lake, northeastern South Dakota Geological Society of America Bulletin 79 1968 855 876

H.E. Wright Jr. D.H. Mann P.H. Glaser Piston corers for peat and lake sediments Ecology 65 1983 657 659

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Quaternary Research
  • ISSN: 0033-5894
  • EISSN: 1096-0287
  • URL: /core/journals/quaternary-research
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Abstract views

Total abstract views: 13 *
Loading metrics...

* Views captured on Cambridge Core between 20th January 2017 - 24th July 2017. This data will be updated every 24 hours.