کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8912802 | 1639829 | 2018 | 43 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Multiple varve chronologies for the last 2000 years from the sediments of Lake Å»abiÅskie (northeastern Poland) - Comparison of strategies for varve counting and uncertainty estimations
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Multiple varve chronologies for the last 2000 years from the sediments of Lake Å»abiÅskie (northeastern Poland) - Comparison of strategies for varve counting and uncertainty estimations Multiple varve chronologies for the last 2000 years from the sediments of Lake Å»abiÅskie (northeastern Poland) - Comparison of strategies for varve counting and uncertainty estimations](/preview/png/8912802.png)
چکیده انگلیسی
This study compares different methods to count biogenic varves in Lake Å»abiÅskie in northeastern Poland. To perform this comparison, we used 2000 years-long varved sediment record from this lake because of the well-preserved laminations as well as the independent age controls, i.e. 29 AMS14C dates, 137Cs activity peaks and volcanic glass shards (1875 AD Askja cryptotephra). Microscopic investigations of thin sections allowed us to identify six major varve microfacies along the sediment profile. Using these microfacies, we tested three counting methods and different approaches of counting uncertainty estimation. These methods provided comparable numbers of varves (1943â¯Â±â¯30, 2034â¯Â±â¯34, 2028 +34/-53) and similar shapes in the age-depth relations. However, in two methods, we found possible disadvantages in arbitrary assumptions and subjective decisions in the process of chronology building, procedures leading to age underestimation as well as problems with reliable and objective estimations of counting uncertainty. Based on these results, we propose the counting method which include analyses of major varve microfacies and three independent countings without the need for varve-by-varve microscopic investigations. This method provided acceptable results (<5% uncertainty) and was more objective and less time-consuming. Semi-automatic counting using μXRF Ca record in the sediments was also tested and provided results that can serve as a first approximation of the number of varves. Our study also indicates that different counting strategies may lead to different uncertainty estimations, which may be important in the reliable interpretation of proxy data.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Quaternary Geochronology - Volume 47, August 2018, Pages 107-119
Journal: Quaternary Geochronology - Volume 47, August 2018, Pages 107-119
نویسندگان
Maurycy Å»arczyÅski, Wojciech Tylmann, Tomasz Goslar,