scholarly journals Late Quaternary Pollen Records and Vegetation History of the Southwest Yukon Territory: A Review

2007 ◽  
Vol 45 (2) ◽  
pp. 175-193 ◽  
Author(s):  
Xia-Cheng Wang ◽  
Marie-Anne Geurts
Keyword(s):  
Vegetation History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Yukon Territory ◽  
Circulation System ◽  
Spruce Forest ◽  
Migration Routes ◽  
Shrub Tundra ◽  
History Of ◽  
Pollen Records

ABSTRACTThis paper is a summary of all known late Quaternary palynostratigraphic records from the southwest Yukon Territory. Thirty two pollen sites available by the end of 1988 are reviewed. Most pollen records in the region are of Holocene age. During the late-glacial to early Holocene, the southwest Yukon supported a herb-dominated tundra vegetation which was replaced by a birch-dominated shrub-tundra at about 10,000 yr BP. Spruce invaded the area between 9000 and 8600 yr BP at different localities, and a southward time transgression is visible in the Aishihik Basin. The current regional vegetation has been stable since 7600-8000 yr BP when dense spruce forest and/or spruce forest-tundra was established in most localities. In the Snag area, however, dense spruce forest developed only around 5700 yr BP, which is about 2000 years later than in the Aishihik Basin. The exotic pine pollen records in the region exhibit an interesting pattern, suggesting a frequent shift of the atmospheric circulation system. Anomalous records of alder pollen from the Aishihik Basin and adjacent regions suggest that alder has never been widespread in these areas due to aridity, and alder pollen is greatly overrepresented in pollen spectra. Spruce arrival dates suggest that further investigations in the Tintina Valley, Yukon River Valley, and Car-macks region might provide useful information concerning the spruce migration routes.

A revised late-Quaternary vegetation history of the unglaciated southwestern Yukon Territory, Canada, from Antifreeze and Eikland ponds

2010 ◽  
Vol 47 (1) ◽  
pp. 75-88 ◽  
Author(s):  
Jesse C. Vermaire ◽  
Les C. Cwynar
Keyword(s):  
Vegetation Change ◽  
Vegetation History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Yukon Territory ◽  
Early Holocene ◽  
Glacial Period ◽  
Vegetation Shifts ◽  
History Of ◽  
New Interpretation

Antifreeze Pond was thought to contain the oldest record of continuous environmental change in the southwestern Yukon. We have revised the original interpretation of the vegetation history of Antifreeze Pond and this region based on new pollen, stomate, and macrofossil analysis, along with 38 new accelerator mass spectrometry (AMS) 14C dates from Antifreeze Pond and nearby Eikland Pond. Although the overall pattern of vegetation change is similar to the previously published Antifreeze Pond record, our new analysis indicates that the timing of the major vegetation shifts is substantially different, particularly during the late-glacial and early Holocene periods (from ∼17 000 – 9000 cal years BP). The original Antifreeze Pond record was thought to span a mid-Wisconsinan interstadial (>30 000 cal years BP) and the full-glacial period. Our results, however, indicate that the material of mid-Wisconsinan age was likely deposited by slumping around the pond making interpretation of the paleoenvironment difficult. Furthermore, our AMS 14C dates show that what was thought to be a full-glacial vegetation record is actually the vegetation history of the late-glacial period (ca. 17 000 – 11 000 cal years BP), which was a time of rapid sediment deposition into the ponds. The Eikland Pond record has an early Holocene Populus rise between ca. 11 000 – 8000 cal years BP that is not present in either the new or original Antifreeze Pond records. This new interpretation of the vegetation history should aid comparisons to other regional paleoenvironmental records.

scholarly journals Late-Glacial and Postglacial Vegetation and Climate of Jackson Hole and the Pinyon Peak Highlands, Wyoming

1985 ◽  
Vol 9 ◽  
pp. 44-49
Author(s):  
Cathy Barnosky
Keyword(s):  
Rocky Mountains ◽  
National Park ◽  
Vegetation History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Glacial Refugia ◽  
Northern Rocky Mountains ◽  
Jackson Hole ◽  
History Of ◽  
Vegetation And Climate

The late-Quaternary vegetation history of the northern Rocky Mountains has thus far been inferred largely from isolated records. These data suggest that conifer forests were established early in postglacial time and were little modified thereafter. The similarity of early postglacial vegetation to modern communities over broad areas gives rise to two hypotheses: (1) that glacial refugia were close to the ice margin, and (2) that vegetation soon colonized the deglaciated areas and has been only subtly affected by climatic perturbations since that time. It is the goal of this project to test these two hypotheses in the region of Grand Teton National Park.

Late Quaternary Vegetation of Southern Isla Grande De Chiloé, Chile

1988 ◽  
Vol 29 (3) ◽  
pp. 294-306 ◽  
Author(s):  
Carolina Villagran
Keyword(s):  
Climatic Change ◽  
Pollen Analysis ◽  
Tree Species ◽  
Late Quaternary ◽  
Late Glacial ◽  
Pollen Diagrams ◽  
History Of ◽  
Valdivian Forest ◽  
Nothofagus Dombeyi ◽  
Pollen Records

Late-glacial-Holocene forest history of southern Isla Chiloé (latitude 43°10′ S) was reconstructed on the basis of pollen analysis in three profiles (Laguna Soledad, Laguna Chaiguata, Puerto Carmen). Prior to 12,500 yr B.P. pollen records are dominated by plant taxa characteristic of open habitats (Zone I). From 12,500 yr B.P. to the present, tree species predominate in the pollen records (Zones II–V). Between 12,500 and 9500 yr B.P. ombrophyllous taxa (Nothofagus, Podocarpus nubigena. Myrtaceae, Fitzroya/Pilgerodendron, and Drimys) are frequent in all pollen diagrams, suggesting a wetter and colder climate than the present. Between 9000 and 5500 yr B.P. Valdivian forest elements, such as Nothofagus dombeyi type, Weinmannia, and Eucryphia/Caldcluvia, dominate, indicating a period of drier and warmer climate. From 5500 yr B.P. onward, the expansion of mixed North Patagonian-Subantarctic forest elements and the increased frequence of Tepualia suggest increased rainfall and temperatures oscillating around the modern values.The change from open to forest vegetation (ca. 12,500 yr B.P.) probably represents the most pronounced climatic change in the record and can be interpreted as the glacial-postglacial transition in the study area.

Late Quaternary glacial and interglacial environments of the Nechako River - Cheslatta Lake area, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 719-731 ◽  
Author(s):  
A Plouffe ◽  
V M Levson
Keyword(s):  
British Columbia ◽  
Late Quaternary ◽  
Late Glacial ◽  
Lake Area ◽  
Glacial Lakes ◽  
Ice Flow ◽  
Coast Mountains ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Quaternary History

The Quaternary stratigraphy of the Nechako River – Cheslatta Lake area of central British Columbia is described and interpreted to reconstruct the late Quaternary history of the region. Exposures of glacial and nonglacial sediments deposited prior to the last glaciation (Fraser) are limited to three sites. Pollen assemblages from pre-Fraser nonglacial sediments at two of these sites reveal forested conditions around 39 000 BP. During the advance phase of the Fraser Glaciation, glacial lakes were ponded when trunk glaciers blocked some tributary valleys. Early in the glaciation, the drainage was free in easterly draining valleys. Subsequently, the easterly drainage was blocked either locally by sediments and ice or as a result of impoundment of the Fraser River and its tributaries east of the study area. Ice generally moved east and northeast from accumulation zones in the Coast Mountains. Ice flow was influenced by topography. Major late-glacial lakes developed in the Nechako River valley and the Knewstubb Lake region because potential drainage routes were blocked by ice.

Late Quaternary vegetation, climate, and fire history of the Southeast Atlantic Coastal Plain based on a 30,000-yr multi-proxy record from White Pond, South Carolina, USA

2019 ◽  
Vol 91 (2) ◽  
pp. 861-880 ◽  
Author(s):  
Teresa R. Krause ◽  
James M. Russell ◽  
Rui Zhang ◽  
John W. Williams ◽  
Stephen T. Jackson
Keyword(s):  
South Carolina ◽  
Vegetation Change ◽  
Fire History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Atlantic Coastal Plain ◽  
Proxy Records ◽  
Dry Conditions ◽  
History Of ◽  
Mississippian Culture

AbstractThe patterns and drivers of late Quaternary vegetation dynamics in the southeastern United States are poorly understood due to low site density, problematic chronologies, and a paucity of independent paleoclimate proxy records. We present a well-dated (15 accelerator mass spectrometry14C dates) 30,000-yr record from White Pond, South Carolina that consists of high-resolution analyses of fossil pollen, macroscopic charcoal, andSporormiellaspores, and an independent paleotemperature reconstruction based on branched glycerol dialkyl tetraethers. Between 30,000 and 20,000 cal yr BP, openPinus-Piceaforest grew under cold and dry conditions; elevatedQuercusbefore 26,000 cal yr BP, however, suggest warmer conditions in the Southeast before the last glacial maximum, possibly corresponding to regionally warmer conditions associated with Heinrich event H2. Warming between 19,700 and 10,400 cal yr BP was accompanied by a transition from conifer-dominated to mesic hardwood forest.Sporormiellaspores were not detected and charcoal was low during the late glacial period, suggesting megaherbivore grazers and fire were not locally important agents of vegetation change.Pinusreturned to dominance during the Holocene, with step-like increases inPinusat 10,400 and 6400 cal yr BP, while charcoal abundance increased tenfold, likely due to increased biomass burning associated with warmer conditions. Low-intensity surface fires increased after 1200 cal yr BP, possibly related to the establishment of the Mississippian culture in the Southeast.

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