24. THE LATE MIOCENE STABLE ISOTOPE RECORD, SITE 926 1
24. THE LATE MIOCENE STABLE ISOTOPE RECORD, SITE 926 1
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24. 中新世晚期稳定同位素记录，站点 926 1
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
M. Hall
中科院分区：
文献类型：
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作者：
N. Shackleton;M. Hall
在晚中新世和中中新世晚期（5 - 14 Ma），获得了块状碳酸盐岩中δ ~（18）O和δ ~（13）C的连续记录，记录间隔为10 cm（相当于平均6k.y）。提供了5 ~ 7.3 Ma以及~9.5 ~ 9.8 Ma和11 ~ 13 Ma期间底栖有孔虫的连续数据。有限的数据也可用于浮游有孔虫在相同的时间间隔。大量CO2的δ 13 C与底栖有孔虫的δ 13 C之间存在很强的轨道-频率协方差，表明这两个参数都能反映海洋溶解CO2的δ 13 C的变化。对整个δ ~（13）C记录的光谱分析表明，在400-k. y范围内，δ ~（13）C记录具有很强的能量。100-k.y.偏心带底栖δ 18 O显示的变化，可能切除深（3.6公里）大西洋海水的温度。大量的煤岩组分δ 18 O显示出非常小的高频变异性，这可能是由于原始信号通过与孔隙水的同位素平衡而降低。块状片麻岩组分δ 18 O的长期变化，显然意味着以9.5Ma为中心的冷却，其来源是个谜，因为这一特征在G的δ 18 O数据中不明显。囊虫
A continuous δ 18 O and δ 13 C record in bulk Þne-fraction carbonate has been obtained for the late Miocene and late middle Miocene (5 - 14 Ma) at 10-cm intervals (corresponding to an average 6 k.y.). Continuous data are presented for benthic foraminifers over the interval 5Ð7.3 Ma as well as over intervals from ~9.5 to 9.8 Ma and 11 to 13 Ma. Limited data are also available for planktonic foraminifers over the same intervals. There is strong orbital-frequency covariance between δ 13 C in bulk Þne fraction and δ 13 C in benthic foraminifers, suggesting that both parameters resect variability in the δ 13 C of dissolved CO 2 in the ocean. Spectral analysis of the whole δ 13 C record for bulk Þne fraction shows strong power in the 400-k.y. and 100-k.y. eccentricity bands. Benthic δ 18 O shows variability that probably resects the temperature of the deep (3.6 km) Atlantic Ocean water. Bulk Þne-fraction δ 18 O displays very little high-frequency variability, possibly due to an original signal having been reduced through isotopic equilibration with pore water. The origin of the long-term variability in bulk Þne-fraction δ 18 O, which apparently implies a cooling centered on about 9.5 Ma, is enigmatic, since this feature is not evident in the δ 18 O data for G. sacculifer.