scholarly journals Deglaciation of the northwestern White Mountains, New Hampshire

2002 ◽  
Vol 53 (1) ◽  
pp. 59-77 ◽  
Author(s):  
Woodrow B. Thompson ◽  
Brian K. Fowler ◽  
Christopher C. Dorion
Keyword(s):  
New England ◽  
New Hampshire ◽  
Ice Sheet ◽  
White Mountains ◽  
Radiocarbon Dates ◽  
Drainage Channels ◽  
Connecticut Valley ◽  
Late Wisconsinan ◽  
Climatic Cooling ◽  
Original Interpretation

Abstract The mode of deglaciation in the northwestern White Mountains of New Hampshire has been controversial since the mid 1800's. Early workers believed that active ice deposited the Bethlehem Moraine complex in the Ammonoosuc River basin during recession of the last ice sheet. In the 1930's this deglaciation model was replaced by the concept of widespread simultaneous stagnation and downwastage of Late Wisconsinan ice. The present authors reexamined the Bethlehem Moraine complex and support the original interpretation of a series of moraines deposited by active ice. We found other moraine clusters of similar age to the northeast in the Johns River and Israel River basins. Ice-marginal deposits that probably correlate with the Bethlehem Moraine also occur west of Littleton. The Bethlehem Moraine complex and equivalent deposits in adjacent areas were formed by readvance and oscillatory retreat of the Connecticut Valley lobe of the Laurentide Ice Sheet. This event is called the Littleton-Bethlehem Readvance. Throughout the study area, sequences of glaciolacustrine deposits and meltwater drainage channels indicate progressive northward recession of the glacier margin. Radiocarbon dates from nearby New England and Québec suggest that the ice sheet withdrew from this part of the White Mountains between about 12 500 and 12 000 14 C yr BP. We attribute the Littleton- Bethlehem Readvance to a brief climatic cooling during Older Dyas time, close to 12,000 BP.

scholarly journals Pre-Late Wisconsinan age for part of the glaciolacustrine stratigraphy, lower Peabody valley, northern White Mountains, Gorham, New Hampshire

2002 ◽  
Vol 53 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Brian K. Fowler
Keyword(s):  
New England ◽  
New Hampshire ◽  
Ice Sheet ◽  
River Valley ◽  
White Mountains ◽  
Southern New England ◽  
Stratigraphic Position ◽  
Late Wisconsinan

Abstract Interbedded till and glaciolacustrine deposits in the lower Peabody River Valley near Gorham, New Hampshire suggest multiple glacial advances occurred in the northern White Mountains. Previous workers disagreed on whether these advances were local or regional in nature, but thought they all occurred during the recessional phase of the Late Wisconsinan ice sheet. New stratigraphic and geomorphic reconnaissance, however, shows that a thick and regionally extensive till overlies this stratigraphy and that this till was emplaced by the last full-glacial episode to affect the region, the Late Wisconsinan glaciation. The stratigraphic position of this till makes the age of the underlying till and glaciolacustrine deposits pre-Late Wisconsinan and much older than previously assumed. This change in age assignment for part of the Peabody Valley stratigraphy supports the extension of the Illinoian-Late Wisconsinan "two-till" stratigraphy of central and southern New England into the region north of the White Mountain Highlands.

Age of the Berlin moraine complex, New Hampshire, USA, and implications for ice sheet dynamics and climate during Termination 1

2019 ◽  
Vol 94 ◽  
pp. 80-93
Author(s):  
Gordon R.M. Bromley ◽  
Brenda L. Hall ◽  
Woodrow B. Thompson ◽  
Thomas V. Lowell
Keyword(s):  
New England ◽  
New Hampshire ◽  
Global Climate ◽  
Ice Sheet ◽  
Atmospheric Temperature ◽  
Laurentide Ice Sheet ◽  
White Mountains ◽  
Southern New England ◽  
Ice Sheet Dynamics ◽  
St Lawrence River

AbstractAt its late Pleistocene maximum, the Laurentide Ice Sheet was the largest ice mass on Earth and a key player in the modulation of global climate and sea level. At the same time, this temperate ice sheet was itself sensitive to climate, and high-magnitude fluctuations in ice extent, reconstructed from relict glacial deposits, reflect past changes in atmospheric temperature. Here, we present a cosmogenic 10Be surface-exposure chronology for the Berlin moraines in the White Mountains of northern New Hampshire, USA, which supports the model that deglaciation of New England was interrupted by a pronounced advance of ice during the Bølling-Allerød. Together with recalculated 10Be ages from the southern New England coast, the expanded White Mountains moraine chronology also brackets the timing of ice sheet retreat in this sector of the Laurentide. In conjunction with existing chronological data, the moraine ages presented here suggest that deglaciation was widespread during Heinrich Stadial 1 event (~18–14.7 ka) despite apparently cold marine conditions in the adjacent North Atlantic. As part of the White Mountains moraine system, the Berlin chronology also places a new terrestrial constraint on the former glacial configuration during the marine incursion of the St. Lawrence River valley north of the White Mountains.

scholarly journals Till Stratigraphy and Late Wisconsinan Deglaciation of Southern Maine: A Review

2007 ◽  
Vol 39 (2) ◽  
pp. 199-214 ◽  
Author(s):  
Woodrow B. Thompson ◽  
Harold W. Borns Jr.
Keyword(s):  
New England ◽  
New Hampshire ◽  
Ice Sheet ◽  
Ocean Floor ◽  
Laurentide Ice Sheet ◽  
Marine Transgression ◽  
Coastal Lowland ◽  
Southern New England ◽  
Clay Deposits ◽  
Late Wisconsinan

ABSTRACT At least two glaciations are recorded by the till stratigraphy of southern Maine. A more deeply weathered lower till is tentatively correlated with the early Wisconsinan (or older) Nash Stream Till in New Hampshire and its inferred equivalents in southern New England and Québec. The Laurentide Ice Sheet flowed south-southeastward across southern Maine in late Wisconsinan time and deposited the upper till. By about 14,000 years ago the ice sheet started to recede from the Maine coast, and the high peaks of the Mahoosuc Range emerged as nunataks in western Maine. Marine transgression accompanied déglaciation of lowland areas of southern Maine, with deposition of end moraines, deltas, and subaqueous outwash along the active ice margin, while thick clay deposits of the Presumpscot Formation accumulated on the ocean floor. The ice margin retreated quickly, reaching the marine limit in central Maine by 13,000 yr BP. The Pineo Ridge moraine system in eastern Maine, formerly thought to represent a major readvance, is reinterpreted as a glacial stillstand near the marine limit. Deglaciation inland from the marine limit in eastern and southwestern Maine occurred by recession of an active ice margin in some areas, and elsewhere by stagnation and downwasting of ice that was separated from the active ice sheet. Southern Maine was ice-free by 12,000 yr BP. but marine submergence persisted until about 11,000 years ago in the southwestern coastal lowland.

Late glacial fluctuations of the Laurentide Ice Sheet in the White Mountains of Maine and New Hampshire, U.S.A.

2015 ◽  
Vol 83 (3) ◽  
pp. 522-530 ◽  
Author(s):  
Gordon R.M. Bromley ◽  
Brenda L. Hall ◽  
Woodrow B. Thompson ◽  
Michael R. Kaplan ◽  
Juan Luis Garcia ◽  
...  
Keyword(s):  
New England ◽  
New Hampshire ◽  
Ice Sheet ◽  
Late Glacial ◽  
Laurentide Ice Sheet ◽  
White Mountains ◽  
Northern New England ◽  
The Mean ◽  
Ice Sheet Dynamics ◽  
Complex Relationships

Prominent moraines deposited by the Laurentide Ice Sheet in northern New England document readvances, or stillstands, of the ice margin during overall deglaciation. However, until now, the paucity of direct chronologies over much of the region has precluded meaningful assessment of the mechanisms that drove these events, or of the complex relationships between ice-sheet dynamics and climate. As a step towards addressing this problem, we present a cosmogenic 10Be surface-exposure chronology from the Androscoggin moraine complex, located in the White Mountains of western Maine and northern New Hampshire, as well as four recalculated ages from the nearby Littleton–Bethlehem moraine. Seven internally consistent 10Be ages from the Androscoggin terminal moraines indicate that advance culminated ~ 13.2 ± 0.8 ka, in close agreement with the mean age of the neighboring Littleton–Bethlehem complex. Together, these two datasets indicate stabilization or advance of the ice-sheet margin in northern New England, at ~ 14–13 ka, during the Allerød/Greenland Interstadial I.

Ice-free conditions in southwestern British Columbia at 16000 years BP

1988 ◽  
Vol 25 (6) ◽  
pp. 938-941 ◽  
Author(s):  
John J. Clague ◽  
Ian R. Saunders ◽  
Michael C. Roberts
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Radiocarbon Dates ◽  
Maximum Extent ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

New radiocarbon dates on wood from two exposures in Chilliwack valley, southwestern British Columbia, indicate that this area was ice free and locally forested 16 000 radiocarbon years ago. This suggests that the Late Wisconsinan Cordilleran Ice Sheet reached its maximum extent in this region after 16 000 years BP. The Chilliwack valley dates are the youngest in British Columbia that bear on the growth of the Cordilleran Ice Sheet.

The Village District in New Hampshire

1946 ◽  
Vol 40 (5) ◽  
pp. 962-965
Author(s):  
Lashley G. Harvey
Keyword(s):  
New England ◽  
New Hampshire ◽  
The State ◽  
State Governments ◽  
Outward Appearance ◽  
White Mountains ◽  
State Tax ◽  
The Village ◽  
The Town ◽  
Railroad Station

Although legally buried since 1891, the “precinct” in New Hampshire, like Banquo's ghost, continually arises to baffle students of New England local government. To the lawmakers, it is known as the village district; while in its annual report the state tax commission lists village districts as precincts, only adding to the confusion.In making a count of governmental areas in New Hampshire, one finds the state divided into ten counties. Within these, there are eleven municipalities classed as cities and 224 towns. The cities were once towns, but have been incorporated as cities by the legislature, not in accordance with a population prerequisite, but upon application. The first city to be incorporated was Manchester in 1846.All New Hampshire cities and towns include within their limits a great deal of rural land. Clusters of houses or settlements are sprinkled over these areas. Frequently, a settlement has several stores, a post office, and a railroad station and has the outward appearance of a village. Legally, however, such a settlement is not a village. It is administered entirely as a part of the town or city in which it is located, although it may be several miles from the principal urban center. New Hampshire has 639 such settlements, none of which is incorporated. Villages are not incorporated in New Hampshire as they are in Connecticut, Vermont, and Maine. Frequently they are referred to as places, but they should not be confused with the 23 so-called “unincorporated places” (found principally in the White Mountains), which are administered by the county and state governments almost completely. However, there are a few of the “villagelike” settlements within unincorporated places.

scholarly journals Late-Quaternary history of the alpine flora of the New Hampshire White Mountains

2002 ◽  
Vol 53 (1) ◽  
pp. 137-157 ◽  
Author(s):  
Norton G. Miller ◽  
Ray W. Spear
Keyword(s):  
New England ◽  
New Hampshire ◽  
Vascular Plants ◽  
Late Quaternary ◽  
Late Glacial ◽  
Plant Macrofossils ◽  
Cold Climate ◽  
Alpine Tundra ◽  
White Mountains ◽  
Alpine Zone

Abstract A distinctive flora of 73 species of vascular plants and numerous bryophytes occurs in the ca. 20 km 2 of alpine tundra in the White Mountains, New Hampshire. The late- Quaternary distribution of these plants, many of which are disjuncts, was investigated by studies of pollen and plant macrofossils from lower Lakes of the Clouds (1 542 m) in the alpine zone of Mount Washington. Results were compared with pollen and macrofossils from lowland late-glacial deposits in western New England. Lowland paleofloras contained fossils of 43 species of vascular plants, 13 of which occur in the contemporary alpine flora of the White Mountains. A majority of species in the paleoflora has geographic affinities to Labrador, northern Québec, and Greenland, a pattern also apparent for mosses in the lowland deposits. The first macrofossils in lower Lakes of the Clouds were arctic-alpine mosses of acid soils. Although open-ground mosses and vascular plants continued to occur throughout the Holocene, indicating that alpine tundra persisted, fossils of a low-elevation moss Hylocomiastrum umbratum are evidence that forest (perhaps as krummholz) covered a greater area near the basin from 7 500 to 3 500 yBP. No calcicolous plants were recovered from sediments at lower Lakes of the Clouds. Climatic constraints on the alpine flora during the Younger Dryas oscillation and perhaps during other cold-climate events and intervening periods of higher temperature may have led to the loss of plant species in the White Mountain alpine zone. Late-glacial floras of lowland western New England were much richer than floras of areas above treeline during late-glacial time and at the present.

scholarly journals Modeling the Cordilleran Ice Sheet

2007 ◽  
Vol 45 (3) ◽  
pp. 287-299 ◽  
Author(s):  
Barry L. Robert
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Time Dependent ◽  
Balance Function ◽  
Ice Flow ◽  
Radiocarbon Dates ◽  
Ice Growth ◽  
Flow Directions ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

ABSTRACT A time-dependent ice flow model is used to provide detailed reconstructions of ice growth and retreat for the southern portion of the Late Wisconsinan Cordilleran Ice Sheet. The two-dimensional, time-dependent model provides ice surface elevations and flow directions at a grid spacing of 15 km. Input to the model includes subglacial topography, a net mass balance function, and two ice flow parameters. The net mass balance function uses a polynomial equation to estimate equilibrium line altitude (ELA) across the study area. A quadratic equation is then used to provide net mass balance values as a function of elevation relative to the ELA. Late Wisconsinan glacial conditions are simulated by systematically lowering the ELA. The general timing of the model ice advance and retreat is tested against radiocarbon dated localities which place limits on the ice sheet's areal extent for different times during the Late Wisconsinan glaciation. In addition, glacial-geologic evidence directly attributable to the latest Cordilleran Ice Sheet is used in assessing the model reconstructions. Results from these experiments show that an ice growth and retreat chronology consistent with the limiting radiocarbon dates can be generated using the model, and provide information on flow directions and ice growth and retreat patterns.

scholarly journals Varve, paleomagnetic, and 14 C Chronologies for late Pleistocene events in New Hampshire and Vermont (U.S.A.)

2002 ◽  
Vol 53 (1) ◽  
pp. 79-107 ◽  
Author(s):  
John C. Ridge ◽  
Mark R. Bensonen ◽  
Marc Brochu ◽  
Sarah L. Brown ◽  
Jamie W. Callahan ◽  
...  
Keyword(s):  
New England ◽  
New Hampshire ◽  
Late Pleistocene ◽  
Aquatic Plants ◽  
Varve Chronology ◽  
Northern New England ◽  
Connecticut Valley

Abstract A deglacial chronology for northern New England has been formulated using an atmospheric 14 C calibration of the New England Varve Chronology and paleomagnetic records. This 14 C chronology is based on 14 C ages from macrofossils of non-aquatic plants and is about 1 500 yr younger than existing chronologies that are based primarily on 14 C ages of bulk organic samples. The lower and upper Connecticut Valley varve sequences of Ernst Antevs (NE varves 2 701-6 352 and 6 601-8 500) overlap (lower 6 012 = upper 6 601) based on their crudely matching varve records and their similar paleomagnetic records. Three 14 C ages at Canoe Brook, Vermont (NE varve 6 150 = 12.3 14C ka) calibrate the lower Con necticut Valley sequence. New AMS and con ventional 14 C ages on woody twigs from Newbury, Vermont calibrate the upper se quence from 11.6-10.4 14 C ka (NE varves 7 440-8 660) and are consistent with the over lapping varve and paleomagnetic records, and the Canoe Brook 14 C ages. Deglaciation of the Connecticut Valley in southern Vermont began at 12.6 14 C ka (15.2 cal ka) and the Littleton-Bethlehem Readvance in northern New Hampshire and Vermont reached its maximum at11.9-11.8 14 C ka (14.0-13.9 cal ka) followed by recession of ice into Québec at about 11.5 14 C ka (13.4 cal ka). A lake persisted in the upper Connecticut Valley until at least 10.4 14 C ka (12.3 cal ka) and may have been seen by the first humans in the area.

The Land, the River, and the People : The Connecticut Valley, 1790-1830

2001 ◽  
Author(s):  
John T. Cumbler
Keyword(s):  
Nineteenth Century ◽  
New Hampshire ◽  
Central Valley ◽  
River Valley ◽  
Connecticut River ◽  
The West ◽  
White Mountains ◽  
Yale College ◽  
Connecticut River Valley ◽  
Connecticut Valley

On Wednesday morning September 21, 1795, only a year after he was appointed president of Yale College, forty-four-year-old Timothy Dwight began the first of his thirteen excursions through New England and upstate New York. On six of his thirteen trips, he traveled through the Connecticut Valley, a valley he was familiar with since childhood and was linked to by both family and sentiment. The Connecticut River Valley was changing, as Dwight made his several trips through it. It was transformed under the impact of human activity. Increasingly, mill dams and factory villages were being built along the river and its tributaries. Technology, science, and the market were restructuring the way people were interacting with their environment. The land became less wild. That “civilizing” of nature, as Dwight called it, began first on the alluvial soils of the lower and central valley in the eighteenth century and then spread north and up into the hill country in the early years of the nineteenth century. By the end of the fifth decade of the nineteenth century, this new world had pretty much taken shape, and valley residents began to take stock of the changes that had occurred. Dwight began this process of accounting at the beginning stages of that transformation. And it was in the Connecticut River Valley that the changes made the biggest impact on him. At the center of the Connecticut Valley runs New England’s largest waterway. The Connecticut River flows south some four hundred miles from a series of small lakes in the swampy district of northern New Hampshire on the Canadian border. It eventually spills into Long Island Sound at Saybrook, Connecticut. To the west and east of the river are mountain ranges, the Housatonic and Green Mountains to the west and the White Mountains to the east. In northern New Hampshire and Vermont, the river travels through a narrow and rough mountain valley. As the river moves south into central Vermont and New Hampshire, the valley widens, particularly on the river’s western shore, and is intersected with tributary rivers and valleys.

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