Notes on Late Wisconsin and Early Holocene History of Vegetation in Canada

1973 ◽  
Vol 5 (3) ◽  
pp. 201-222 ◽  
Author(s):  
J. Terasmae
Baltica ◽  
2015 ◽  
Vol 28 (2) ◽  
pp. 121-134 ◽  
Author(s):  
Olga Druzhinina ◽  
Dmitry Subetto ◽  
Miglė Stančikaitė ◽  
Giedrė Vaikutienė ◽  
Jury Kublitsky ◽  
...  

Newly obtained pollen and diatom data from the Kamyshovoe Lake (germ. Dobauen, Vishtynets Highland, Baltic Uplands) controlled by radiocarbon dating allowed to reconstruct the history of local vegetation during late Pleistocene – early Holocene. Pollen records show the formation of birch-predominating forest at ca. 13.4 ka cal. BP and the flourishing of pine towards the second half of the chronozone since about 13.2 ka cal. BP. The transition to the Younger Dryas around 12.7 ka cal. BP led to the development of sparse shrub tundra with Juniperus and communities of steppe herbs. Amelioration of the environmental regime enabled birch and pine woods to spread during the second part of GS-1 event and the Preboreal. The late Preboreal time is marked by the appearance of Populus and an increase in the role of grasses in the vegetation cover, which can be correlated to similar open vegetation phases deduced from other pollen records in Europe (11.3–11.1 ka cal. BP). During the Boreal (since ca. 10.0 ka cal. BP) Corylus had its maximum value, Alnus, Tilia and Quercus appeared and spread while the birch-pine forests retreated.


1999 ◽  
Vol 77 (4) ◽  
pp. 570-581 ◽  
Author(s):  
W Wyatt Oswald ◽  
Linda B Brubaker ◽  
Patricia M Anderson

Palynological records from Tukuto and Etivlik Lakes contribute to an improved understanding of the late Quaternary history of vegetation in the Howard Pass area of northern Alaska. During the Itkillik II glaciation (24-14 ka BP), the vegetation of the western Arctic Foothills was sparse, xeric tundra, as evidenced by taxa indicative of dry, rocky substrates (e.g., Selaginella rupestris (L.) Spring, Chenopodiaceae, and Encalypta cf. rhaptocarpa) and very low pollen accumulation rates in this interval of the 30-ka-old Tukuto Lake record. Mesic tundra dominated by non-Sphagnum (Bryidae) mosses, Cyperaceae, and Salix species expanded near Tukuto Lake during the late-glacial period, followed by the establishment of Sphagnum moss and increased shrub cover at ca. 10 ka BP. Landscapes around both lakes supported stands of Populus cf. balsamifera during the early Holocene, and Alnus crispa expanded in the Howard Pass area during the middle Holocene. Local variation in plant communities is illustrated by the comparison of the Tukuto and Etivlik pollen records. During the early Holocene, Populus cf. balsamifera was more common near Etivlik Lake than Tukuto Lake, and Juniperus cf. communis was present only in the vicinity of Etivlik Lake. Throughout the middle to late Holocene, Sphagnum, mesic tundra shrubs (Betula nana L., Salix, and Ericaceae species), and minor herbaceous taxa (e.g., Rubus chamaemorus L., Thalictrum, and Caryophyllaceae) were more prevalent at Tukuto Lake than at Etivlik Lake. These differences are likely related to the influence of local landform and soil characteristics near the two sites.Key words: Alaska, Arctic Foothills, Brooks Range, pollen analysis, Quaternary.


Author(s):  
E V Volchatova ◽  
E V Bezrukova ◽  
N V Kulagina ◽  
O V Levina ◽  
A A Shchetnikov ◽  
...  

2021 ◽  
Vol 48 (10) ◽  
pp. 1733-1739
Author(s):  
N. V. Blagoveshchenskaya ◽  
Ch. T. Zamaldinova ◽  
G. V. Funk

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengli Yang ◽  
Xiaojing Liu ◽  
Ting Cheng ◽  
Yuanlong Luo ◽  
Qiong Li ◽  
...  

Aeolian sediments hold key information on aeolian history and past environmental changes. Aeolian desertification and extensive land degradation have seriously affected the eco-environment in the Gannan region on the eastern Tibetan Plateau. Understanding the history of aeolian activities can deepen our understanding of the impacts of climatic changes on aeolian activities in the future. This study uses a detailed chronology and multiple proxy analyses of a typical aeolian section in Maqu to reconstruct aeolian activities in the region during the Holocene. Our results showed that aeolian activities have occurred in the eastern Tibetan Plateau since the early Holocene. Magnetic susceptibility, grain size records, and paleosols formation indicated a trend of stepwise weakening in aeolian activities from the early Holocene to the present. The weakening of aeolian activities was divided into three stages: ∼10.0–8.0 ka BP, ∼8.0–4.0 ka BP, and ∼4.0 ka BP to the present. Paleosols were primarily formed after ∼8.0 ka BP, and episodically interrupted aeolian activities processes in the Gannan region. Aeolian activity may increase in the Gannan region as the climate gradually warms. Climatic changes and local hydrological conditions have jointly affected the history of aeolian activities in this region.


1975 ◽  
Vol 12 (5) ◽  
pp. 745-756 ◽  
Author(s):  
R. W. Mathewes ◽  
G. E. Rouse

The postglacial history of vegetation in the Yale area of the lower Fraser River Canyon is described from sediments of two lakes using percentage pollen analysis supplemented with macrofossil evidence and radiocarbon dating. Deposition of postglacial sediments, ranging from basal clays to gyttjas, began about 11 500 y B.P. Three distinct pollen assemblage zones are distinguished, reflecting in part the main climatic conditions for the intervals. The oldest zone, with high percentages of pine (Pinus) and alder (Alnus) pollen, suggests cool and moist conditions following withdrawal of glacial ice. This is followed by marked increases in Douglas-fir (Pseudotsuga), grasses and other nonarboreal pollen, suggesting in part, warmer and drier conditions. The third zone, ranging from about the Mt. Mazama ash at 6600 y B.P. to the present, is marked by high alder and Douglas-fir, and increasing cedar (Thuja-Chamaecyparis type), western hemlock (Tsuga heterophylla), fir (Abies) and birch; an assemblage indicating a return to wetter conditions. This sequence contrasts with previously described successions that recognized the classical Hypsithermal in adjacent areas. The sequence of inferred vegetational changes, although similar to those described for the Haney area to the west, suggests that the Yale area has been a biogeoclimatically transitional area for much of postglacial time.


2007 ◽  
Vol 2 (2) ◽  
pp. 161-175 ◽  
Author(s):  
Kristian Kristiansen

In this article I examine how long-term economic strategies in the Bronze Age of northern Europe between 2300 and 500 BCE transformed the environment and thus created and imposed new ecological constraints that finally led to a major social transformation and a "dark age" that became the start of the new long-term cycle of the Iron Age. During the last 30 years hundreds of well-excavated farmsteads and houses from south Scandinavia have made it possible to reconstruct the size and the structure of settlement and individual households through time. During the same period numerous pollen diagrams have established the history of vegetation and environmental changes. I will therefore use the size of individual households or farmsteads as a parameter of economic strength, and to this I add the role of metal as a triggering factor in the economy, especially after 1700 BCE when a full-scale bronze technology was adopted and after 500 BCE when it was replaced by iron as the dominant metal. A major theoretical concern is the relationships between micro- and macroeconomic changes and how they articulated in economic practices. Finally the nature of the "dark age" during the beginning of the Iron Age will be discussed, referring to Sing Chew's use of the concept (Chew 2006).


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