Changing Patterns in the Holocene Pollen Record of Northeastern North America: A Mapped Summary

1977 ◽  
Vol 8 (1) ◽  
pp. 64-96 ◽  
Author(s):  
J. Christopher Bernabo ◽  
Thompson Webb
Keyword(s):  
North America ◽  
Large Scale ◽  
Deciduous Forest ◽  
Rapid Expansion ◽  
Early Holocene ◽  
Pollen Record ◽  
Data Set ◽  
Northeastern North America ◽  
The Holocene ◽  
Changing Patterns

By mapping the data from 62 radiocarbon-dated pollen diagrams, this paper illustrates the Holocene history of four major vegetational regions in northeastern North America. Isopoll maps, difference maps, and isochrone maps are used in order to examine the changing patterns within the data set and to study broad-scale and long-term vegetational dynamics. Isopoll maps show the distributions of spruce (Picea), pine (Pinus), oak (Quercus), herb (nonarboreal pollen groups excluding Cyperaceae), and birch + maple + beech + hemlock (Betula, Acer, Fagus, Tsuga) pollen at specified times from 11,000 BP to present. Difference maps were constructed by subtracting successive isopoll maps and illustrate the changing patterns of pollen abundances from one time to the next. The isochrone maps portray the movement of ecotones and range limits by showing their positions at a sequence of times during the Holocene. After 11,000 BP, the broad region over which spruce pollen had dominated progressively shrank as the boreal forest zone was compressed between the retreating ice margin and the rapidly westward and northward expanding region where pine was the predominant pollen type. Simultaneously, the oak-pollen-dominated deciduous forest moved up from the south and the prairie expanded eastward. By 7000 BP, the prairie had attained its maximum eastward extent with the period of its most rapid expansion evident between 10,000 and 9000 BP. Many of the trends of the early Holocene were reversed after 7000 BP with the prairie retreating westward and the boreal and other zones edging southward. In the last 500 years, man's impact on the vegetation is clearly visible, especially in the greatly expanded region dominated by herb pollen. The large scale changes before 7000 BP probably reflect shifts in the macroclimatic patterns that were themselves being modified by the retreat and disintegration of the Laurentide ice sheet. Subsequent changes in the pollen and vegetation were less dramatic than those of the early Holocene.

A radiocarbon chronology of Holocene climate change and sea-level rise at the Delmarva Peninsula, US Mid-Atlantic Coast

The Holocene ◽  
2021 ◽  
pp. 095968362110482
Author(s):  
Kelvin W Ramsey ◽  
Jaime L. Tomlinson ◽  
C. Robin Mattheus
Keyword(s):  
Climate Change ◽  
North America ◽  
Sea Level Rise ◽  
Sea Level ◽  
Early Holocene ◽  
Eastern North America ◽  
Delmarva Peninsula ◽  
The Holocene ◽  
Cool Climate ◽  
And Sea Level

Radiocarbon dates from 176 sites along the Delmarva Peninsula record the timing of deposition and sea-level rise, and non-marine wetland deposition. The dates provide confirmation of the boundaries of the Holocene subepochs (e.g. “early-middle-late” of Walker et al.) in the mid-Atlantic of eastern North America. These data record initial sea-level rise in the early Holocene, followed by a high rate of rise at the transition to the middle Holocene at 8.2 ka, and a leveling off and decrease in the late-Holocene. The dates, coupled to local and regional climate (pollen) records and fluvial activity, allow regional subdivision of the Holocene into six depositional and climate phases. Phase A (>10 ka) is the end of periglacial activity and transition of cold/cool climate to a warmer early Holocene. Phase B (10.2–8.2 ka) records rise of sea level in the region, a transition to Pinus-dominated forest, and decreased non-marine deposition on the uplands. Phase C (8.2–5.6 ka) shows rapid rates of sea-level rise, expansion of estuaries, and a decrease in non-marine deposition with cool and dry climate. Phase D (5.6–4.2 ka) is a time of high rates of sea-level rise, expanding estuaries, and dry and cool climate; the Atlantic shoreline transgressed rapidly and there was little to no deposition on the uplands. Phase E (4.2–1.1 ka) is a time of lowering sea-level rise rates, Atlantic shorelines nearing their present position, and marine shoal deposition; widespread non-marine deposition resumed with a wetter and warmer climate. Phase F (1.1 ka-present) incorporates the Medieval Climate Anomaly and European settlement on the Delmarva Peninsula. Chronology of depositional phases and coastal changes related to sea-level rise is useful for archeological studies of human occupation in relation to climate change in eastern North America, and provides an important dataset for future regional and global sea-level reconstructions.

The MLg(F) Magnitude Scale: A Proposal for its use for Northeastern North America

1994 ◽  
Vol 65 (2) ◽  
pp. 157-166 ◽  
Author(s):  
John E. Ebel
Keyword(s):  
Standard Deviation ◽  
North America ◽  
Magnitude Scale ◽  
Data Set ◽  
Study Region ◽  
Northeastern North America ◽  
Spatial Attenuation ◽  
Magnitude Estimates

Abstract The mLg(f) magnitude scale of Herrmann and Kijko (1983b), computed with appropriate Lg spatial attenuation functions and calibrated to mb, is proposed for routine use in northeastern North America. The Herrmann and Kijko (1983b) formula yields consistent magnitudes for different forms of Lg attenuation, and it shows little or no distance or period dependence for a data set of ten earthquakes from the northeastern U.S. and southeastern Canada. The standard deviation of the mLg(f) magnitude estimates relative to mb is about .32 magnitude units. Also, since on average mbLg=mb for the ten earthquakes in the data set, the mLg(f) formula proposed here is also calibrated to mbLg in the study region.

scholarly journals Application of Nonnegative Tensor Factorization for Intercity Rail–Air Transport Supply Configuration Pattern Recognition

2019 ◽  
Vol 11 (6) ◽  
pp. 1803
Author(s):  
Han Zhong ◽  
Geqi Qi ◽  
Wei Guan ◽  
Xiaochen Hua
Keyword(s):  
Pattern Recognition ◽  
High Speed ◽  
Large Scale ◽  
Rapid Expansion ◽  
Air Transport ◽  
Tensor Factorization ◽  
Nonnegative Tensor ◽  
Data Set ◽  
Nonnegative Tensor Factorization ◽  
Supply Level

With the rapid expansion of the railway represented by high-speed rail (HSR) in China, competition between railway and aviation will become increasingly common on a large scale. Beijing, Shanghai, and Guangzhou are the busiest cities and the hubs of railway and aviation transportation in China. Obtaining their supply configuration patterns can help identify defects in planning. To achieve that, supply level is proposed, which is a weighted supply traffic volume that takes population and distance factors into account. Then supply configuration can be expressed as the distribution of supply level over time periods with different railway stations, airports, and city categories. Furthermore, nonnegative tensor factorization (NTF) is applied to pattern recognition by introducing CP (CANDECOMP/PARAFAC) decomposition and the block coordinate descent (BCD) algorithm for the selected data set. Numerical experiments show that the designed method has good performance in terms of computation speed and solution quality. Recognition results indicate the significant pattern characteristics of rail–air transport for Beijing, Shanghai, and Guangzhou are extracted, which can provide some theoretical references for practical policymakers.

An n-alkane-based Holocene climate reconstruction in the Altai Mountains, northern Xinjiang, China

2020 ◽  
Author(s):  
Min Ran
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Time Lag ◽  
Geographic Location ◽  
Early Holocene ◽  
Altai Mountains ◽  
Temperature Changes ◽  
The Holocene ◽  
The North ◽  
Highly Sensitive

<p>The climate in the Altai Mountains is highly sensitive to large-scale forcing factors because of its special geographic location. Based on n-alkane data of 150 samples and with a chronologic support of 15 accelerator mass spectrometry (AMS) dates from a 600-cm core at GHZ Peat, the Holocene climatic changes in the Altai Mountains were reconstructed. The reconstruction revealed a warming and drying early Holocene (~10,750-~8500 cal. yr BP), a cooling and persistent dry middle Holocene (~8500-~4500 cal. yr BP), and a cooling and wetting late Holocene (~4500-~700 cal. yr BP). The Holocene temperature changes were primarily controlled by the summer solar radiation with a certain time lag in the early Holocene and also modulated by solar activity, and the time lag in the early Holocene was probably resulted from ice and permafrost melting. The Holocene moisture in the southern Altai Mountains was likely modulated by the North Atlantic Oscillations (NAO) or by the Atlantic Multi-centennial Oscillations (i.e., AMO-like) or by temperature, and or by any combination of the three (NAO, AMO-like, and temperature).</p>

scholarly journals The Holocene history of the NE Black Sea and surrounding areas: An integrated record of marine and terrestrial palaeoenvironmental change

The Holocene ◽  
2019 ◽  
Vol 29 (4) ◽  
pp. 648-661 ◽  
Author(s):  
Fabienne Marret ◽  
Lee R Bradley ◽  
Pavel E Tarasov ◽  
Elena V Ivanova ◽  
Maria A Zenina ◽  
...  
Keyword(s):  
Black Sea ◽  
Deciduous Forest ◽  
Land Use Changes ◽  
Water Environment ◽  
Early Holocene ◽  
The Black Sea ◽  
Pollen Record ◽  
Temperate Deciduous Forest ◽  
Black Sea Region ◽  
Palaeoenvironmental Change

Here we present an almost complete and integrated Holocene record of marine and terrestrial palaeoenvironmental change from the NE shelf of the Black Sea. A dinoflagellate cyst record used to reconstruct Holocene sea-surface conditions highlights that the NE shelf was a brackish water environment, with a minimum salinity of 7 psu in the early-Holocene before changing at a gradual rate to a more saline environment with maximum salinities of ~18 psu being reached around 3 cal. ka. A warming phase was detected from 6 cal. ka BP, with warmest conditions between 3 and 2.5 cal. ka BP. A pollen record is used to examine the major climate and land-use changes in the eastern Black Sea region. Biome reconstructions show that the temperate deciduous forest dominates throughout the record, although with an overall decline. From early-Holocene to the first hiatus around ~9 cal. ka BP, Pinus pollen dominates, while taxa representing a mixed oak-hornbeam-beech forest are less abundant, indicating relatively cool and dry conditions. Between ~7.9 and ~6.1 cal. ka BP, a thermophilous deciduous forest established, suggesting an overall warming trend and humid conditions. From 4 cal. ka BP, Pinus dominates the pollen record, accompanied by an increase of herbs, implying an opening of the landscape, which would coincide with the beginning of the Meghalayan Age. The integrated record of the marine and terrestrial climate indicators supports the notion that this change in landscape may have been triggered by a combination of warmer and drier conditions and human activities in this region.

Stability of Holocene Climate Regimes in the Yellowstone Region

1995 ◽  
Vol 43 (3) ◽  
pp. 433-436 ◽  
Author(s):  
Cathy Whitlock ◽  
Patrick J. Bartlein ◽  
Kelli J. Van Norman
Keyword(s):  
Early Holocene ◽  
Summer Drought ◽  
Pollen Record ◽  
Holocene Climate ◽  
Pressure System ◽  
Climate History ◽  
The Holocene ◽  
Mountainous Regions ◽  
History Of ◽  
Wet Climate

AbstractA 12,500-yr pollen record from Loon Lake, Wyoming provides information on the climate history of the southwestern margin of Yellowstone National Park. The environmental reconstruction was used to evaluate hypotheses that address spatial variations in the Holocene climate of mountainous regions. Loon Lake lies within the summer-dry/winter-wet climate regime. An increase in xerophytic pollen taxa suggests drier-than-present conditions between ca. 9500 and 5500 14C yr B.P. This response is consistent with the hypothesis that increased summer radiation and the expansion of the east Pacific subtropical high-pressure system in the early Holocene intensified summer drought at locations within the summer-dry/winter-wet regime. This climate history contrasts with that of nearby sites in the summer-wet/winter-dry region, which were under the influence of stronger summer monsoonal circulation in the early Holocene. The Loon Lake record implies that the location of contrasting climate regimes did not change in the Yellowstone region during the Holocene. The amplitude of the regimes, however, was determined by the intensity of circulation features and these varied with temporal changes in the seasonal distribution of solar radiation.

Exposure matters: Forest dynamics reveal an early Holocene conifer refugium on a north facing slope in Central Europe

The Holocene ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 1833-1848
Author(s):  
Zsuzsanna Anna Pató ◽  
Tibor Standovár ◽  
Mariusz Gałka ◽  
Gusztáv Jakab ◽  
Mihály Molnár ◽  
...  
Keyword(s):  
Forest Cover ◽  
Deciduous Forest ◽  
Vegetation Type ◽  
Early Holocene ◽  
Primary Forest ◽  
Vegetation Changes ◽  
Pinus Cembra ◽  
The Holocene ◽  
The North ◽  
Recent Climate

Although several studies provide a broad overview of vegetation changes in the Carpathian Basin during the Holocene, stand-scale vegetation changes are lesser known because of the rarity of suitable sampling sites. In this study we investigated the sediment of a small closed-canopy site (Nagy-forrás forest hollow, 685 m a.s.l., 0.1 ha), located in the Mátra Mountains, on the north facing slope of Kékes (1014 m a.s.l.). We carried out detailed pollen, conifer stomata and plant macrofossil analyses, as well as radiocarbon dating to examine Late Glacial and Holocene dynamics of vegetation development. The site dates back to ca. 15,500 cal yr BP, when open boreal forests and wet tundra-like habitats occurred around the hollow. Closed forest cover developed around 14,600 cal yr BP, when a boreal European larch-Swiss stone pine ( Larix decidua-Pinus cembra) forest surrounded the hollow. This vegetation type remained stable up to 7700 cal yr BP. We observed a hiatus between 7700 and 2710 cal yr BP, followed by a beech ( Fagus sylvatica) dominated mixed temperate deciduous forest. Our results confirmed that the area was covered by a primary forest, as human influence was visible only from 175 cal yr BP. The relatively long lasting persistence of Pinus cembra in the Holocene at relatively low altitude was documented, which has never been found in Holocene sediments in the Pre-Carpathians before. We hypothesize that the north facing slope acted as a cold-stage refugium in the Early Holocene and could play the same role for the present-day beech forest that is threatened by recent climate change.

A tree-ring chronology and paleoclimate record for the Younger Dryas-Early Holocene transition from northeastern North America

2017 ◽  
Vol 32 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Carol Griggs ◽  
Dorothy Peteet ◽  
Bernd Kromer ◽  
Todd Grote ◽  
John Southon
Keyword(s):  
North America ◽  
Tree Ring ◽  
Younger Dryas ◽  
Early Holocene ◽  
Tree Ring Chronology ◽  
Northeastern North America
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