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Important slides for PBL. 2705 m. Composite Stratigraphic Section. 77.2 ka. MIS 5a. MIS 5b-a. MIS 5c-b. ~60 kyr of lake and wetland history. MIS 5c. MIS 5d-c. MIS 5e-d. Late MIS 6-5e. 138.5 ka. Elevational Ranges of Modern and Fossil Plant Taxa. Elevation (m). - PowerPoint PPT Presentation
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Important slides for PBL
2705 m
Present-Day Plant Elevation Ranges
Data from Hartmann et al., 2002. Rocky Mountain Herbarium
Ziegler Plant Macrofossil Record
90 Taxa, 54 Genera, 36 FamiliesAquatic and wetland plants
Deciduous trees and shrubsConiferous trees
Herbaceous plants
138.5 ka
77.2 ka
MIS 5a
MIS 5b-a
MIS 5c-b
MIS 5c
MIS 5d-c
MIS 5e-d
Late MIS 6-5e
~60 kyr of lake and wetland history
Composite Stratigraphic Section
Elevational Ranges of Modern and Fossil Plant Taxa
Modern and Fossil Taxa
(in veg surveys)
Modern and Fossil Taxa(not in veg. surveys but
likely living nearby)Fossil Only
Extra-local taxaat lower elevations
Within CO Outside CO
Elev
ation
(m)
Montane mixed-conifer forestWarm like the present, or warmer
late MIS 6 to 5c
No trees, cooler than present during MIS 5b
Alpine peatland (fen), conifers only, cooler than present MIS 5a
Conclusions
• Shallow water environments with alkaline and hardwater conditions existed in Ziegler Reservoir throughout the history of the lake, suggesting that groundwater percolating through calcareous bedrock or soil was an important water source.
• MIS 6 - 5c: Macrofossils suggest a mixed montane forest environment was present, similar to today, but including some lower elevation plant taxa (Abies concolor and many herbs) suggesting that the climate was as warm or warmer than today.
• MIS 5d: There is a treeless period, with a climate cooler than today.
• MIS 5a: A peatland (fen) occupied the basin, and conifer taxa Picea sp. and Pinus flexilis were present, deciduous trees were absent, and the climate may have been cooler than today.
• Overall, the climate and vegetation of the Last Interglacial were not largely different from today, even though these two interglacials are separated in time by a glacial period with very different climate and vegetation.
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