scholarly journals Evaluation of 14C Ages of Organic Fractions of Paleosols from Loess-Paleosol Sequences Near Xian, China

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 680-695 ◽  
Author(s):  
M J Head ◽  
Weijian Zhou ◽  
Mingfu Zhou
Keyword(s):  
Shaanxi Province ◽  
Agricultural Activity ◽  
Agricultural Activities ◽  
The Loess Plateau ◽  
Last Glacial Period ◽  
Period Analysis ◽  
History Of ◽  
Climatic History ◽  
Organic Fractions ◽  
The Last Glacial

The 14C dating of organic fractions from paleosol layers containing <2% carbon in loess-paleosol sequences from the loess plateau in China has yielded results that are quite often much younger than the true age of the sediments. Percolation of modern organic materials from agricultural activities, and binding of these materials within the weathered clays of the paleosols has meant that conventional pretreatment techniques for 14C dating would not isolate a reliable chemical fraction. The total sequence from Bei Zhuang Cun, in Shaanxi Province, reflects the climatic history of the area for ca 30,000 years, ranging from the interstadial of the last glacial period to the postglacial period. Analysis of solvent extracts of organic material from this site indicates that they are mainly composed of carbohydrate residues originating from the relatively recent agricultural activity. Validity of the humic components for dating will be discussed.

scholarly journals Palaeogeographical And Archaeological Records Of Natural Changes Of The Jordanowo-Niesulice Subglacial Channel Near Lubrza, The Lubusz Lakeland

2015 ◽  
Vol 34 (3) ◽  
pp. 101-116 ◽  
Author(s):  
Magdalena Ratajczak-Szczerba ◽  
Iwona Sobkowiak-Tabaka ◽  
Iwona Okuniewska-Nowaczyk
Keyword(s):  
Late Glacial ◽  
Last Glacial Period ◽  
Geochemical Composition ◽  
Palynological Analysis ◽  
The Holocene ◽  
Ams Radiocarbon Dating ◽  
History Of ◽  
Geomorphological Analysis ◽  
Geological Research ◽  
The Last Glacial

Abstract The region of the Lubusz Lakeland in western Poland where there are a lot of subglacial channels provides opportunity for multi-proxy palaeoenvironmental reconstructions. None of them has not been the object of a specific study. The developmental history of the palaeolakes and their vicinity in the subglacial trough Jordanowo-Niesulice, spanning the Late Glacial and beginning of the Holocene, was investigated using geological research, lithological and geomorphological analysis, geochemical composition, palynological and archaeological research, OSL and AMS-radiocarbon dating. Geological research shows varied morphology of subglacial channel where at least two different reservoirs functioned in the end of the Last Glacial period and at the beginning of the Holocene. Mostly during the Bølling-Allerød interval and at the beginning of the Younger Dryas there took place melting of buried ice-blocks which preserved the analysied course of the Jordanowo-Niesulice trough. The level of water, and especially depth of reservoirs underwent also changes. Palynological analysis shows very diversified course of the Allerød interval.

Pleistocene history of Betula with special reference to the British Isles

1984 ◽  
Vol 85 (1-2) ◽  
pp. 1-11 ◽  
Author(s):  
J. H. Dickson
Keyword(s):  
Special Reference ◽  
Glacial Period ◽  
British Isles ◽  
Last Glacial Period ◽  
Glacial Sediments ◽  
Last Glacial ◽  
History Of ◽  
The Last Glacial

SynopsisBetula is well represented in the Pleistocene deposits of the British Isles; B. nana is often recovered from glacial sediments and tree Betula flourished early and late in the interglacial periods. In western and northern Britain, tree Betula has remained important in the forests since the last glacial period.

scholarly journals A successful habitat reconstruction effort, the short history of the European Bee-eater (Merops apiaster) colony at Albertirsa (Hungary)

2013 ◽  
Vol 21 (2) ◽  
pp. 47-51
Author(s):  
Sándor Urbán ◽  
Katalin Túri ◽  
Zoltán Vas ◽  
Tibor István Fuisz
Keyword(s):  
Glacial Period ◽  
Short History ◽  
Last Glacial Period ◽  
Reconstruction Effort ◽  
Nesting Sites ◽  
History Of ◽  
Merops Apiaster ◽  
Vertical Walls ◽  
Construction Works ◽  
The Last Glacial

Abstract In the Golyófogó Valley near Albertirsa natural erosion created near vertical walls in the loess deposited in the last glacial period, offering natural nesting sites for the European Bee-eater. Later the deeply cut coach roads, the pits of loess extraction and the construction works of the motorway nearby created further man-made banks. Hence by the 1970-ies a well-established colony bred here, but by the beginning of the 21st century, disturbance and the demise of vertical banks led to a serious reduction in the number of breeding pairs. The purchase of 5-hectare loess grassland plot and the adjacent loess bank, and later its reconstruction led to an unprecedented growth in the number of Bee-eaters. From 2010 the number of breeding pairs exceeded 200 every year. Not only the Bee-eater colony, but also the natural vegetation and the botanical values of the area are managed to maintain the population of rare and protected element of the local flora and fauna.

Post-Glacial Fossil Mollusca in Western Canada

1934 ◽  
Vol 71 (8) ◽  
pp. 370-382 ◽  
Author(s):  
Alan Mozley
Keyword(s):  
Ice Sheets ◽  
Field Work ◽  
General Nature ◽  
Western Canada ◽  
Glacial Retreat ◽  
Last Glacial Period ◽  
History Of ◽  
Molluscan Fauna ◽  
Made In ◽  
The Last Glacial

From the standpoint of biological geography, the most significant event in the recent history of Canada has been the occurrence of widespread severe glaciation. This resulted in the whole of the previously existing fauna being either exterminated or driven southward. When the ice sheets receded northwards at the end of the last glacial period, this region was once more populated by animals, including both fresh water and terrestrial mollusca, the remains of which are to be found in various post-glacial deposits. The migration of animals into this new territory did not take place all at once, and it is noteworthy that no fossil mollusca have been found in the deposits laid down during the early stages of the glacial retreat. The purpose of this paper is to give in concise form the history of the present molluscan fauna of this region in so far as it is evidenced by the post-glacial fossils found in the region. The series of fossil-bearing deposits herein described is far from complete, and many additional finds will doubtless be made in the course offuture field work. Nevertheless, a sufficient number of observations has been made to indicate the general nature and duration of the molluscan immigration into the area.

scholarly journals Chromosome-Scale Genome Assembly for Chinese Sour Jujube and Insights Into Its Genome Evolution and Domestication Signature

2021 ◽  
Vol 12 ◽  
Author(s):  
Lian-Ying Shen ◽  
Hang Luo ◽  
Xiao-Ling Wang ◽  
Xue-Meng Wang ◽  
Xiao-Jing Qiu ◽  
...  
Keyword(s):  
Population Structure ◽  
Genome Assembly ◽  
Effective Population ◽  
Last Glacial Period ◽  
Population Structure Analysis ◽  
History Of ◽  
Ziziphus Jujuba ◽  
Fruit Flavor ◽  
High Quality Genome ◽  
The Last Glacial

Sour or wild jujube fruits and dried seeds are popular food all over the world. In this study, we reported a high-quality genome assembly of sour jujube (Ziziphus jujuba Mill. var. spinosa), with a size of 406 Mbp and scaffold N50 of 30.3 Mbp, which experienced only γ hexaploidization event, without recent genome duplication. Population structure analysis identified four jujube subgroups (two domesticated ones, i.e., D1 in West China and D2 in East/SouthEast China, semi-wild, and wild), which underwent an evolutionary history of a significant decline of effective population size during the Last Glacial Period. The respective selection signatures of three subgroups were discovered, such as strong peaks on chromosomes #3 in D1, #1 in D2, and #4 in wild. Genes under the most significant selection on chromosomes #4 in wild were confirmed to be involved in fruit variations among jujube accessions, in transcriptomic analysis. Our study offered novel insights into the jujube population structure and domestication and provided valuable genomic resources for jujube improvement in stress response and fruit flavor in the future.

Middle and Upper Palaeolithic environments and the calibration of 14C dates beyond 10,000 BP

Antiquity ◽  
1998 ◽  
Vol 72 (275) ◽  
pp. 26-33 ◽  
Author(s):  
Tjeerd H. van Andel
Keyword(s):  
Magnetic Field ◽  
Time Scale ◽  
Archaeological Sites ◽  
Upper Palaeolithic ◽  
Upper Limit ◽  
History Of ◽  
Climatic History ◽  
Quaternary History ◽  
The Last Glacial

Advances in our understanding of the Quaternary history of the earth's magnetic field provide the means to correct the radiocarbon time-scale for long-term (millennia) deviations from the calendrical one beyond the upper limit of the tree-ring-based calibration. The conversion is essential when Middle and Upper Palaeolithic archaeological sites are to be placed within the context of the complex climatic history of the last glacial interval and following deglaciation.

Paleontology and stratigraphy of Middle Eocene rock units in the southern Green River and Uinta Basins, Wyoming and Utah

2017 ◽  
Vol 4 ◽  
pp. 1-53 ◽  
Author(s):  
Paul Murphey ◽  
K.E. Townsend ◽  
Anthony Friscia ◽  
James Westgate ◽  
Emmett Evanoff ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Middle Eocene ◽  
Green River Basin ◽  
Green River ◽  
Scientific Exploration ◽  
History Of ◽  
Climatic History ◽  
Field Excursion ◽  
Land Mammal ◽  
Bridger Formation

The Bridger Formation is restricted to the Green River Basin in southwest Wyoming, and the Uinta and Duchesne River Formations are located in the Uinta Basin in Utah. These three rock units and their diverse fossil assemblages are of great scientific importance and historic interest to vertebrate paleontologists. Notably, they are also the stratotypes from oldest to youngest for the three middle Eocene North American Land Mammal Ages—the Bridgerian, Uintan, and Duchesnean. The fossils and sediments of these formations provide a critically important record of biotic, environmental, and climatic history spanning approximately 10 million years (49 to 39 Ma). This article provides a detailed field excursion through portions of the Green River and Uinta Basins that focuses on locations of geologic, paleontologic, and historical interest. In support of the field excursion, we also provide a review of current knowledge of these formations with emphasis on lithostratigraphy, biochronology, depositional, and paleoenvironmental history, and the history of scientific exploration.

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