Transported by wind and water,the relatively old sediments can deposit in the terminal lake of an inland drainage basin.The reworking effect can affect the lake sediments 14 C dating and explanations for proxies.The Z...Transported by wind and water,the relatively old sediments can deposit in the terminal lake of an inland drainage basin.The reworking effect can affect the lake sediments 14 C dating and explanations for proxies.The Zhuye Lake is the terminal lake of the Shiyang River Basin.Previous studies indicated that sediments in different locations of the lake basin showed different climatic change patterns.And then,some radiocarbon dates were inverted for some Late Pleistocene sections.Whether this phenomenon is related with the reworking effect? The pollen concentrates 14 C dating can avoid the reservoir effect,which is an ideal method for studying the reworking effect.In this study,we used the pollen concentrates as dating materials and dated five Holocene sections in the Zhuye Lake Basin.Based on the 14 C dates comparison between the pollen concentrates,organic matter,and shells,the pollen concentrates dates are relatively older than other dating materials.Based on the result,the reworking effect worked in the Zhuye Lake Basin during the Holocene;however,in different locations of the lake basin the reworking effects were in different levels.Furthermore,the Holocene lacustrine deposits were formed mostly during the early and middle Holocene.This study provided clues for reworking effect studies of other lakes in arid China.展开更多
Peat in boreholes is the most important ^(14)C dating material used for constructing age framework. 20 bulk peat samples were collected from five boreholes, the ^(14)C ages of two fractions(organic sediment fraction a...Peat in boreholes is the most important ^(14)C dating material used for constructing age framework. 20 bulk peat samples were collected from five boreholes, the ^(14)C ages of two fractions(organic sediment fraction and peat fraction) of the bulk peat samples were investigated by AMS-dating and which fraction is better to help construct an age framework for the boreholes were compared and discussed. The results indicated that the peat fraction give a good dating results sequence in the boreholes, compared with the corresponding organic sediment fraction. And the dating results of organic sediment fraction show 161-6 702 years older than corresponding peat fraction, which was caused by marine influence. Then, we suggest an experience formula as y =0.99 x-466.5 by the correlation analysis for correcting the marine influenced organic sediment ages within the conventional ages between 4 000 to 9 000 yrs BP, and more study should be carried out for the AMS ^(14)C dating of the bulk organic sediments.展开更多
A small sample of human bone from Tomb BSII of the Chalcolithic cemetery of RemedelloSotto (Brescia, Northern Italy) was processed with the AMS technique. It gave a date of 4070 ± 70BP (Beta-35224; ETH-6196) corr...A small sample of human bone from Tomb BSII of the Chalcolithic cemetery of RemedelloSotto (Brescia, Northern Italy) was processed with the AMS technique. It gave a date of 4070 ± 70BP (Beta-35224; ETH-6196) corresponding to 2711 (2609) 2512 cal BC yrs (1 sigma). Una datazione radiometrica per la Tomba BSII del cimitero Calcolitico di RemedelloSotto (Brescia). Viene presentata la datazione radiometrica eseguita con il metodo dell’acceleratore sudi un frammento di osso di calcagno del piede destro dello scheletro di inumato della Tomba BSII delsepolcreto di Remedello Sotto. L’analisi ha fornito il risultato di 4070 ± 70 BP (Beta-35224; ETH-6196)corrispondente a 2711 (2609) 2512 cal BC (1 sigma).展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 41001116 and J1030519)the Fundamental Research Fund for the Central Universities (Grant No. LZUJBKY-2010-99)
文摘Transported by wind and water,the relatively old sediments can deposit in the terminal lake of an inland drainage basin.The reworking effect can affect the lake sediments 14 C dating and explanations for proxies.The Zhuye Lake is the terminal lake of the Shiyang River Basin.Previous studies indicated that sediments in different locations of the lake basin showed different climatic change patterns.And then,some radiocarbon dates were inverted for some Late Pleistocene sections.Whether this phenomenon is related with the reworking effect? The pollen concentrates 14 C dating can avoid the reservoir effect,which is an ideal method for studying the reworking effect.In this study,we used the pollen concentrates as dating materials and dated five Holocene sections in the Zhuye Lake Basin.Based on the 14 C dates comparison between the pollen concentrates,organic matter,and shells,the pollen concentrates dates are relatively older than other dating materials.Based on the result,the reworking effect worked in the Zhuye Lake Basin during the Holocene;however,in different locations of the lake basin the reworking effects were in different levels.Furthermore,the Holocene lacustrine deposits were formed mostly during the early and middle Holocene.This study provided clues for reworking effect studies of other lakes in arid China.
基金Supported by the China Geological Survey(No.121201006000182401)the National Natural Science Foundation of China(Nos.41476074,41372173)
文摘Peat in boreholes is the most important ^(14)C dating material used for constructing age framework. 20 bulk peat samples were collected from five boreholes, the ^(14)C ages of two fractions(organic sediment fraction and peat fraction) of the bulk peat samples were investigated by AMS-dating and which fraction is better to help construct an age framework for the boreholes were compared and discussed. The results indicated that the peat fraction give a good dating results sequence in the boreholes, compared with the corresponding organic sediment fraction. And the dating results of organic sediment fraction show 161-6 702 years older than corresponding peat fraction, which was caused by marine influence. Then, we suggest an experience formula as y =0.99 x-466.5 by the correlation analysis for correcting the marine influenced organic sediment ages within the conventional ages between 4 000 to 9 000 yrs BP, and more study should be carried out for the AMS ^(14)C dating of the bulk organic sediments.
文摘A small sample of human bone from Tomb BSII of the Chalcolithic cemetery of RemedelloSotto (Brescia, Northern Italy) was processed with the AMS technique. It gave a date of 4070 ± 70BP (Beta-35224; ETH-6196) corresponding to 2711 (2609) 2512 cal BC yrs (1 sigma). Una datazione radiometrica per la Tomba BSII del cimitero Calcolitico di RemedelloSotto (Brescia). Viene presentata la datazione radiometrica eseguita con il metodo dell’acceleratore sudi un frammento di osso di calcagno del piede destro dello scheletro di inumato della Tomba BSII delsepolcreto di Remedello Sotto. L’analisi ha fornito il risultato di 4070 ± 70 BP (Beta-35224; ETH-6196)corrispondente a 2711 (2609) 2512 cal BC (1 sigma).
