scholarly journals Evidence of Mid-Holocene (Northgrippian Age) Dry Climate Recorded in Organic Soil Profiles in the Central Appalachian Mountains of the Eastern United States

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 477
Author(s):  
Mitzy L. Schaney ◽  
James S. Kite ◽  
Christopher R. Schaney ◽  
James A. Thompson
Keyword(s):  
United States ◽  
Appalachian Mountains ◽  
Organic Soil ◽  
Field Investigation ◽  
Soil Profiles ◽  
Eastern United States ◽  
Accumulation Rates ◽  
Peat Accumulation ◽  
Climatic Fluctuations ◽  
Radiocarbon Dates

Peatlands in Canaan Valley National Wildlife Refuge hold a pedomemory of Pleistocene and Holocene climatic fluctuations in the central Appalachian Mountains of the eastern United States. A field investigation profiling 88 organic soil profiles, coupled with 52 radiocarbon dates and peat accumulation rates, revealed a distinct sequence of organic soil horizons throughout five study areas. The dominantly anaerobic lower portions of the organic soil profiles consist of varied thicknesses of hemic and sapric soil materials, typically layered as an upper hemic horizon, underlain by a sapric horizon, underlain by another hemic horizon. Peat deposition began after the Last Glacial Maximum with relatively high Heinrich Stadial 1 accumulation rates to form the lowest hemic horizon. Peat accumulated at significantly slower rates as the climate continued to warm in the early Holocene Greenlandian Age. However, between 10,000 and 4200 cal yr BP peat accumulation decreased further and the decomposition of previously deposited peat prevailed, forming the sapric horizon. This interval of greater decomposition indicates a drier climatic with dates spanning the late Greenlandian Age through the Northgrippian Age. The upper hemic horizon within the anaerobic portion of the soil profile formed from high peat accumulation rates during the wetter late Holocene Meghalayan Age.

A Study of Paleosols in the Saskatoon Area of Saskatchewan

1974 ◽  
Vol 11 (7) ◽  
pp. 905-915 ◽  
Author(s):  
L. W. Turchenek ◽  
R. J. St. Arnaud ◽  
E. A. Christiansen
Keyword(s):  
Classification Criteria ◽  
Soil Profiles ◽  
Climatic Fluctuations ◽  
Radiocarbon Dates ◽  
Dune Sands ◽  
Aeolian Sediments ◽  
Alteration Processes ◽  
Buried Soil ◽  
Aeolian Sands

Postglacial paleosols developed in lacustrine and aeolian sediments occur on terraces and in banks of the South Saskatchewan River near Saskatoon. At each of three sites a sequence of two paleosols was studied: a lower soil of immediate postglacial age as indicated by radiocarbon dates, that is buried by aeolian sands, and an upper one, located within the dune sands, that marks a period of stability of the dunes. Climatic fluctuations are inferred to be the cause of aeolian activity.One paleosol met the classification criteria for an Orthic Black Chernozemic soil. The other soils, particularly those developed in the dune sands, were weakly developed, Regosolic types of soils.Pedogenic interpretations were based on macro- and micromorphological observations as well as chemical characteristics. Micromorphology and the determination of calcite and dolomite distribution were particularly useful in differentiating sedimentary, pedogenic, and postburial alteration processes in the buried soil profiles. Studies of the organic matter suggest that it had changed markedly after burial.

Archaeological Potential of the Atlantic Continental Shelf

1966 ◽  
Vol 31 (5Part1) ◽  
pp. 733-737 ◽  
Author(s):  
K.O. Emery ◽  
R.L. Edwards
Keyword(s):  
United States ◽  
Continental Shelf ◽  
Sea Level ◽  
Marine Fish ◽  
Eastern United States ◽  
Radiocarbon Dates ◽  
Glacial Epoch

AbstractEarly man lived in eastern United States 11,000 years ago when most of the now-submerged continental shelf was exposed. The shelf almost certainly was ranged by nomadic hunters and possibly by marine fish- and mollusk- eaters. As the sea level rose at the end of the latest glacial epoch, the advancing water disrupted and submerged any habitation sites.The oldest radiocarbon dates for kitchen middens of marine refuse along the present shore appear to be younger than the oldest dates for kitchen middens of non-marine content. Older marine middens may be deeply submerged far out on the continental shelf. Greatest success in future exploration for these sites is likely in areas of the shelf which have received little or no cover of postglacial sediment and where rivers formerly crossed the shelf.

Carabodes of the eastern United States and adjacent Canada (Acari: Oribatida: Carabodidae)

1992 ◽  
Vol 70 (10) ◽  
pp. 2042-2058 ◽  
Author(s):  
R. Marcel Reeves
Keyword(s):  
United States ◽  
North America ◽  
Coastal Plain ◽  
Forest Floor ◽  
Appalachian Mountains ◽  
Atlantic Coastal Plain ◽  
Eastern North America ◽  
Eastern United States ◽  
Thelytokous Parthenogenesis ◽  
Atlantic Coastal

Adults of four new species of Carabodes, C. chandleri, C. erectus, C. interruptus, and C. pentasetosus, and the immatures of C. erectus, are described. All have been collected from a variety of forest-floor habitats, with C. chandleri, C. interruptus, and C. pentasetosus more common in leaf litter, and C. erectus preferring polyporous fungi. All four species are widely distributed in eastern North America, with C. chandleri, C. erectus, and C. interruptus more abundant in samples from the Appalachian Mountains and C. pentasetosus in those from the Atlantic coastal plain. Thelytokous parthenogenesis is suspected to occur in C. pentasetosus n.sp. and Carabodes granulatus Banks. A key to the 19 species of Carabodes found in North America is provided.

Sedimentology and Palynology of Middle Wisconsinan Deposits in the Pecatonica River Valley, Wisconsin and Illinois

1982 ◽  
Vol 17 (2) ◽  
pp. 228-240 ◽  
Author(s):  
G. Richard Whittecar ◽  
Anthony M. Davis
Keyword(s):  
Pollen Record ◽  
Peat Accumulation ◽  
Climatic Fluctuations ◽  
Radiocarbon Dates ◽  
Forest Tundra ◽  
Valley Fill ◽  
Vegetation Zones ◽  
Zone Ii ◽  
Sediment Data ◽  
Channel Deposits

AbstractThe bedrock valley of the Pecatonica River north of Freeport, Illinois, contains a thick valley-fill complex of alluvium and drift. Within the valley, loess-capped benches surround hills of silty Illinoian drift. Beneath these benches lie thick deposits of poorly sorted stony silt interbedded with thin lenses of silt, sand, and organic-rich loam. Channel deposits and peat cap the diamicton in places. We interpret the stony silts as solifluction debris shed from silty slopes within the valley-fill during the Early or Middle Wisconsinan (Altonian). Top and bottom radiocarbon dates from a 2.5-m section of peat overlying the diamicton are 26,820 ± 200 and 40,500 ± 1700 yr B.P., respectively. We informally refer to the stony silts, channel sediments, and peat as the “Martintown unit.” Geomorphic position, sediment input, and macrofossils suggest that the dated peat was deposited in a floodplain pond (oxbow?). The pollen record from the peat indicates that a boreal forest dominated this area during the Middle Wisconsinan (late Altonian and Farmdalian). Two pollen zones are recognized: a basal Zone I with Pinus slightly more abundant than Picea and with few herbs and shrubs, and an upper Zone II dominated by Picea and with a larger representation of herbaceous and shrub taxa. Little displacement of vegetation zones is indicated, even though ice advanced to within 100 km of the site during the time of peat accumulation. Because of the problems involved in clearly defining Middle Wisconsinan forest-tundra in mid-latitudes by using analogs of Holocene forest-tundra in high latitudes, caution is required in making geomorphic inferences solely from vegetation data. Together, though, pollen and sediment data indicate that during the Middle Wisconsinan, Pecatonica hillslopes progressed through a sequence of instability-stability-instability related to climatic fluctuations.

scholarly journals Convective Episodes in the East-Central United States

2007 ◽  
Vol 135 (11) ◽  
pp. 3707-3727 ◽  
Author(s):  
Matthew D. Parker ◽  
David A. Ahijevych
Keyword(s):  
United States ◽  
Coastal Plain ◽  
Appalachian Mountains ◽  
Vertical Wind Shear ◽  
Radar Data ◽  
Daily Maximum ◽  
Eastern United States ◽  
East Central ◽  
Convective Systems ◽  
Central United States

Abstract Nine years of composited radar data are investigated to assess the presence of organized convective episodes in the east-central United States. In the eastern United States, the afternoon maximum in thunderstorms is ubiquitous over land. However, after removing this principal diurnal peak from the radar data, the presence and motion of organized convective systems becomes apparent in both temporally averaged fields and in the statistics of convective episodes identified by an objective algorithm. Convective echoes are diurnally maximized over the Appalachian chain, and are repeatedly observed to move toward the east. Partly as a result of this, the daily maximum in storms is delayed over the Piedmont and coastal plain relative to the Appalachian Mountains and the Atlantic coast. During the 9 yr studied, the objective algorithm identified 2128 total convective episodes (236 yr−1), with several recurring behaviors. Many systems developed over the elevated terrain during the afternoon and moved eastward, often to the coastline and even offshore. In addition, numerous systems formed to the west of the Appalachian Mountains and moved into and across the eastern U.S. study domain. In particular, many nocturnal convective systems from the central United States entered the western side of the study domain, frequently arriving at the eastern mountains around the next day’s afternoon maximum in storm frequency. A fraction of such well-timed systems succeeded in crossing the Appalachians and continuing across the Piedmont and coastal plain. Convective episodes were most frequent during the high-instability, low-shear months of summer, which dominate the year-round statistics. Even so, an important result is that the episodes still occurred almost exclusively in above-average vertical wind shear. Despite the overall dominance of the diurnal cycle, the data show that adequate shear in the region frequently leads to long-lived convective episodes with mesoscale organization.

Cloud chemistry in the eastern United States, as sampled from three high-elevation sites along the Appalachian Mountains

1999 ◽  
Vol 33 (30) ◽  
pp. 5105-5114 ◽  
Author(s):  
James B. Anderson ◽  
Ralph E. Baumgardner ◽  
Volker A. Mohnen ◽  
Jon J. Bowser
Keyword(s):  
United States ◽  
Appalachian Mountains ◽  
High Elevation ◽  
Eastern United States ◽  
Cloud Chemistry
Sign in / Sign up

Export Citation Format

Share Document