کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7817011 | 1502245 | 2018 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The last forests on Antarctica: Reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The last forests on Antarctica: Reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains The last forests on Antarctica: Reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains](/preview/png/7817011.png)
چکیده انگلیسی
Fossil-bearing deposits in the Transantarctic Mountains, Antarctica indicate that, despite the cold nature of the continent's climate, a tundra ecosystem grew during periods of ice sheet retreat in the mid to late Neogene (17-2.5â¯Ma), 480â¯km from the South Pole. To date, palaeotemperature reconstruction has been based only on biological ranges, thereby calling for a geochemical approach to understanding continental climate and environment. There is contradictory evidence in the fossil record as to whether this flora was mixed angiosperm-conifer vegetation, or whether by this point conifers had disappeared from the continent. In order to address these questions, we have analysed, for the first time in sediments of this age, plant and bacterial biomarkers in terrestrial sediments from the Transantarctic Mountains to reconstruct past temperature and vegetation during a period of East Antarctic Ice Sheet retreat. From tetraether lipids (MBTâ²/CBT palaeothermometer), we conclude that the mean continental summer temperature was ca. 5â¯Â°C, in agreement with previous reconstructions. This was warm enough to have allowed woody vegetation to survive and reproduce even during the austral winter. Biomarkers from vascular plants indicate a low diversity and spatially variable flora consisting of higher plants, moss and algal mats growing in microenvironments in a glacial outwash system. Abietane-type compounds were abundant in some samples, indicating that conifers, most likely Podocarpaceae, grew on the Antarctic continent well into the Neogene. This is supported by the palynological record, but not the macrofossil record for the continent, and has implications for the evolution of vegetation on Antarctica.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Organic Geochemistry - Volume 118, April 2018, Pages 4-14
Journal: Organic Geochemistry - Volume 118, April 2018, Pages 4-14
نویسندگان
Rhian L. Rees-Owen, Fiona L. Gill, Robert J. Newton, Ruza F. IvanoviÄ, Jane E. Francis, James B. Riding, Christopher H. Vane, Raquel A. Lopes dos Santos,