Geomorphology and Quaternary History of the Mackenzie River Valley near Fort Good Hope, N.W.T., Canada

1973 ◽  
Vol 10 (1) ◽  
pp. 26-41 ◽  
Author(s):  
J. Ross Mackay ◽  
W. H. Mathews
Keyword(s):  
Late Glacial ◽  
Sharp Change ◽  
Radiocarbon Dates ◽  
Plunge Pool ◽  
Free Drainage ◽  
History Of ◽  
Quaternary History ◽  
Abandoned Channels ◽  
Floodplain Sediments ◽  
Mackenzie River

The Mackenzie River displays a sharp change in geomorphic character at The Ramparts, a postglacially-developed rock-walled canyon near Fort Good Hope, N.W.T. Upstream for at least 70 km the river is cut into late-glacial and early postglacial lacustrine, deltaic, and floodplain sediments with radiocarbon dates of 11 000 to 11 500 years. These sediments are overlain by peat dating back 6120 radiocarbon years. Downstream the river reoccupies, for more than 350 km, a Pleistocene channel containing glacial and fluvial sediments yielding only dates beyond the range of carbon dating. Abandoned channels west of The Ramparts record the overflow, in early postglacial time, from a rock-rimmed lake athwart the newly developed Mackenzie drainage. The deepest of the channels, believed to have been abandoned in mid-postglacial time, contained a major waterfall with its plunge-pool floor close to present sea level. Free drainage from the foot of the falls to the ocean at the time it operated is indicated. Erosion continues along the Mackenzie River above The Ramparts but some aggradation occurs below it. Permafrost thaw and heavy rainfall contribute to landsliding along the river banks in both segments.

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.

scholarly journals Evaluation of Amino Acid Composition as a Geochronometer in Buried Soils on Mount Kenya, East Africa

2007 ◽  
Vol 40 (2) ◽  
pp. 171-183 ◽  
Author(s):  
William C. Mahaney ◽  
Michael G. Boyer ◽  
Nathaniel W. Rutter
Keyword(s):  
Amino Acid ◽  
East Africa ◽  
Aspartic Acid ◽  
Age Dating ◽  
Buried Soils ◽  
Radiocarbon Dates ◽  
Radiocarbon Age ◽  
Acid Ratio ◽  
History Of ◽  
Quaternary History

ABSTRACT A sequence of surface and buried paleosols from the slopes of Mount Kenya, East Africa, has been identified and dated by radiocarbon and amino acid dating techniques in order to elucidate the Quaternary history of the area. Buried paleosols vary in radiocarbon age from 900 to > 40,000 yrs BP. They have developed in glacial and periglacial deposits of variable texture, consisting of a high percentage of clasts of phonolite, basalt and syenite. All but two paleosols are located in the Afroalpine zone (above 3200 m). D/L ratios of amino acids in Ab horizons were determined in order to establish their reliability for relative age dating. Alanine, aspartic acid, glutamic acid, leucine, valine, and phenylalanine were routinely analyzed. Aspartic acid, as in other cases, proved reliable yielding remarkably consistent results, with higher ratios corresponding to increasing age. Other acids analyzed showed distinct trends, although not as convincing as aspartic acid. In most cases, the aspartic acid ratio/ age relationships were supported by radiocarbon dates. D/L ratios of aspartic acid varied from approximately 0.07 for modern samples, to approximately 0.45 in samples > 40,000 years old.

Radiocarbon Dates on Deglaciation, Cordillera Central, Northern Peruvian Andes

1989 ◽  
Vol 32 (1) ◽  
pp. 111-113 ◽  
Author(s):  
P.W. Birkeland ◽  
D.T. Rodbell ◽  
S.K. Short
Keyword(s):  
Late Glacial ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Cordillera Central ◽  
Peruvian Andes ◽  
Relative Dating ◽  
History Of ◽  
Ice Retreat ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractThree radiocarbon dates along with relative-dating criteria place limits on the deglaciation history of Manachaque Valley, Cordillera Central. Ice retreated from the late-glacial maximum by at least 12,100 yr B.P. During ice retreat numerous moraines were deposited throughout the valley. Glacier cover was reduced to about half that of the last glacial maximum by at least 9700 yr B.P. and to less than a tenth by at least 6450 yr B.P. Because all dates are minimum, the dates and field data are consistent with little or no ice remaining by early Holocene. No unambiguous Younger Dryas moraines are present.

Radiocarbon Reservoir Effect and the Timing of the Late-Glacial/Early Holocene Humid Phase in the Atacama Desert (Northern Chile)

1999 ◽  
Vol 52 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Mebus A. Geyh ◽  
Martin Grosjean ◽  
Lautaro Núñez ◽  
Ulrich Schotterer
Keyword(s):  
Lake Level ◽  
Atacama Desert ◽  
Late Glacial ◽  
Early Holocene ◽  
Vegetation Changes ◽  
Northern Chile ◽  
Lake Levels ◽  
Human Occupation ◽  
Radiocarbon Dates ◽  
History Of

We revise substantially the regional chronology of lake-level fluctuations from the late-glacial/early Holocene humid phase along a high altitude transect (3500 to 4500 m) between 18°S and 28°S in the Southwestern Altiplano of Northern Chile. Radiocarbon dates and 210Pb profiles for limnic and terrestrial materials allow us to estimate and justify reservoir correction values for conventional 14C dates. Our chronology suggests that the latest Pleistocene/early Holocene humid phase started between 13,000 and 12,000 14C yr B.P., and that maximum lake levels were reached between 10,800 and 9200 14C yr B.P. This is significantly younger than what has been established so far for the Titicaca–Uyuni Basin in Bolivia. The paleolakes disappeared sometime between 8400 and 8000 14C yr B.P. Our revised chronology agrees with the regional history of human occupation, and is broadly synchronous with vegetation changes in subtropical continental South America, and with the onset of wetland expansion in the northern hemisphere tropics.

The Quaternary History of the Northern Cumberland Peninsula, Baffin Island, N.W.T. Part III: The Late Glacial Deposits of Sulung and Itidlirn Valleys and Adjacent Parts of the Maktak-Narpaing Trough

1972 ◽  
Vol 9 (4) ◽  
pp. 366-374 ◽  
Author(s):  
R. E. Dugdale
Keyword(s):  
Cross Correlation ◽  
Phase 1 ◽  
Late Glacial ◽  
Lateral Moraine ◽  
Baffin Island ◽  
Phase 3 ◽  
Outlet Glacier ◽  
Valley Glacier ◽  
History Of ◽  
Quaternary History

Four moraine systems are recognized within the area. The oldest was deposited at the margin of a major outlet glacier about 600 m a.s.1 Local corrie glaciers in the Sulung and Itidlirn Valleys show three and two moraine systems respectively, which in part have over-ridden the lateral moraine. Studies of the degree of boulder weathering and the rounding of pebble edges on the four units allows cross-correlation between Itidlirn and Sulung Valleys. Weathering ratios are used to tentatively date the moraines as follows: lateral moraine of the outlet valley glacier, 43 000± years old; Phase 1 corrie moraine in Sulung Valley 35 000± years old; Phase 2 corrie moraines 23 000± years old and the youngest corrie moraines (Phase 3) 12 500± years old, as determined from weathering studies in adjacent valleys.

scholarly journals Direct dating reveals the early history of opium poppy in western Europe

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aurélie Salavert ◽  
Antoine Zazzo ◽  
Lucie Martin ◽  
Ferran Antolín ◽  
Caroline Gauthier ◽  
...  
Keyword(s):  
Western Europe ◽  
Western Alps ◽  
Western Mediterranean ◽  
Opium Poppy ◽  
Radiocarbon Dates ◽  
Macrobotanical Remains ◽  
History Of ◽  
Temperate Europe ◽  
Radiocarbon Chronology ◽  
Botanical Remains

AbstractThis paper aims to define the first chrono-cultural framework on the domestication and early diffusion of the opium poppy using small-sized botanical remains from archaeological sites, opening the way to directly date minute short-lived botanical samples. We produced the initial set of radiocarbon dates directly from the opium poppy remains of eleven Neolithic sites (5900–3500 cal BCE) in the central and western Mediterranean, northwestern temperate Europe, and the western Alps. When possible, we also dated the macrobotanical remains originating from the same sediment sample. In total, 22 samples were taken into account, including 12 dates directly obtained from opium poppy remains. The radiocarbon chronology ranges from 5622 to 4050 cal BCE. The results show that opium poppy is present from at least the middle of the sixth millennium in the Mediterranean, where it possibly grew naturally and was cultivated by pioneer Neolithic communities. Its dispersal outside of its native area was early, being found west of the Rhine in 5300–5200 cal BCE. It was introduced to the western Alps around 5000–4800 cal BCE, becoming widespread from the second half of the fifth millennium. This research evidences different rhythms in the introduction of opium poppy in western Europe.

scholarly journals RADIOCARBON DATES FROM THE MONASTERY ON KOM H IN OLD DONGOLA (SUDAN) AND THE CHRONOLOGY OF MEDIEVAL NUBIAN POTTERY

Radiocarbon ◽  
2021 ◽  
pp. 1-21
Author(s):  
Dorota Dzierzbicka ◽  
Katarzyna Danys
Keyword(s):  
Historical Research ◽  
Crucial Importance ◽  
Radiocarbon Dates ◽  
14Th Century ◽  
15Th Century ◽  
History Of

ABSTRACT The paper presents and discusses a series of radiocarbon (14C) dates from a medieval Nubian monastery found on Kom H of Old Dongola, the capital of the kingdom of Makuria located in modern-day Sudan. The monastery was founded in the 6th–7th century AD and although it probably ceased to function in the 14th century, the site remained occupied until the beginning of the 15th century. The investigated courtyard of the monastery was in use from the 11th to the 14th century, as indicated by the ceramics and 14C analysis results presented here. The dates under consideration are the first published series of 14C dates from this site, which is of crucial importance for historical research on medieval Nubian Christianity and monasticism. They permit to begin building an absolute chronological framework for research on the archaeological finds from the site and region. A group of finds in particular need of such a framework are ceramics, and the implications of the 14C dates for pottery assemblages found in the dated contexts are discussed. The conclusions summarize the significance of the datings for the history of the site.

Late-glacial and Post-glacial history of the Chalk escarpment near Brook, Kent

1964 ◽  
Vol 248 (745) ◽  
pp. 135-204 ◽  
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Valley Floor ◽  
Glacial Period ◽  
Late Neolithic ◽  
Local Conditions ◽  
Arable Farming ◽  
History Of

This paper describes the morphology of a small piece of the Chalk escarpment near Brook in east Kent, and reconstructs its history since the end of the Last Glaciation. The escarpment contains a number of steep-sided valleys, or coombes, with which are associated deposits of chalk debris, filling their bottoms and extending as fans over the Gault Clay plain beyond. Here the fans overlie radiocarbon-dated marsh deposits of zone II (10 000 to 8800 B.C.) of the Late-glacial Period. The debris fans were formed and the coombes were cut very largely during the succeeding zone III (8800 to 8300 B.C.). The fans are the products of frost-shattering, probably transported by a combination of niveo-fluvial action and the release of spring waters; intercalated seams of loess also occur. The molluscs and plants preserved in the Late-glacial deposits give a fairly detailed picture of local conditions. The later history of one of the coombes, the Devil’s Kneadingtrough, is reconstructed. The springs have effected virtually no erosion and have probably always emerged more or less in their present position. In the floor of the coombe the periglacial chalk rubbles of zone III are covered by Postglacial deposits, mainly hillwashes. They are oxidized and yield no pollen, but contain rich faunas of land Mollusca, which are presented in the form of histograms revealing changing local ecological and climatic conditions. During most of the Post-glacial Period, from the end of zone III until about the beginning of zone VIII, very little accumulation took place on the coombe floor. But below the springs there are marsh deposits which span much of this interval. They yield faunas of considerable zoogeographical interest. The approximate beginning of zone VII a (Atlantic Period) is reflected by a calcareous tufa, which overlies a weathering horizon, and represents an increase in spring flow. Two clearance phases are deduced from the molluscan record. The first may have taken place at least as early as the Beaker Period (Late Neolithic/earliest Bronze Age); the second is probably of Iron Age ‘A’ date. In Iron Age times the subsoil was mobilized and a phase of rapid hillwashing began. As a result the valley floor became buried by humic chalk muds. The prime cause of this process was probably the beginning of intensive arable farming on the slopes above the coombe; a possible subsidiary factor may have been the Sub-Atlantic worsening of climate. The muds yield pottery ranging in date from Iron Age ‘Kentish first A’ ( ca . 500 to ca . 300 B.C.) to Romano-British ware of the first or second centuries A.D. Evidence is put forward for a possible climatic oscillation from dry to wet taking place at about the time of Christ. In the later stages of cultivation, possibly in the Roman Era, the valley floor was ploughed and given its present-day form.

scholarly journals XIX.—The Bone-Cave in the Valley of Allt nan Uamh (Burn of the Caves), near Inchnadamff, Assynt, Sutherlandshire

1918 ◽  
Vol 37 ◽  
pp. 327-349 ◽  
Author(s):  
B. N. Peach ◽  
J. Horne ◽  
E. T. Newton
Keyword(s):  
Characteristic Feature ◽  
Late Glacial ◽  
Early History ◽  
The Arctic ◽  
Geological History ◽  
Collateral Evidence ◽  
History Of ◽  
Glacial Time

A characteristic feature of the plateau of Cambrian Limestone in the neighbourhood of Inchnadamff is the occurrence in it of swallow-holes, caves, and subterranean channels which are intimately associated with the geological history of the region. The valley of Allt nan Uamh (Burn of the Caves), locally known as the Coldstream Burn, furnishes striking examples of these phenomena. One of the caves in this valley yielded an interesting succession of deposits, from which were collected abundant remains of mammals and birds. The discovery of bones of the Northern Lynx, the Arctic Lemming, and the Northern Vole among these relics, and the collateral evidence of the materials forming some of these layers, seem to link the early history of this bone-cave with late glacial time, or at least with a period before the final disappearance of local glaciers in that region.

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