کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6446031 | 1640790 | 2016 | 17 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Fluctuations of vegetation and climate over the last 75Â 000Â years in the Savanna Biome, South Africa: Tswaing Crater and Wonderkrater pollen sequences reviewed
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Quaternary palynological information from the Savanna Biome of South Africa is limited due to the scarcity of suitable pollen traps and new extensive pollen records of palaeoenvironments in the region are unlikely to be obtained easily. Those that are available, including the Tswaing Crater and the Wonderkrater spring sequences, can, however, be reassessed and their data optimised. These two pollen records are relevant to palaeo-environmental research in the area, although they have chronologies beyond the radiocarbon dating range that complicate interpretations. The Tswaing sequence in this study focuses on the upper 34Â m of pollen-rich layers out of a total of 90Â m of lake deposits. A new chronology is experimented with for this upper part of the sequence. It differs slightly from the previous one in that it does not rely on adjustments of the ages according to the precession cycle. Accordingly the age at 34Â m is estimated to be c. 75Â ka based on interpolation of the radiocarbon sequence and a basal fission track date of c. 200Â ka at 90Â m. In the case of the second site, Wonderkrater, recently published excavation and dating of the deposits and comparisons with the Tswaing pollen sequence provide new clues for the age of the lowermost deposit of the original borehole sequence of peats, sands and clay, which is estimated at c. 60Â 000Â years. The new results better situate the two pollen sequences in a wider regional and global palaeoenvironmental framework.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Quaternary Science Reviews - Volume 145, 1 August 2016, Pages 117-133
Journal: Quaternary Science Reviews - Volume 145, 1 August 2016, Pages 117-133
نویسندگان
L. Scott,