Astronomic timescale for the Pliocene Atlantic δ18O and dust flux records of Ocean Drilling Program Site 659
Astronomic timescale for the Pliocene Atlantic δ18O and dust flux records of Ocean Drilling Program Site 659
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DOI：
10.1029/94pa00208
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发表时间：
1994-08
期刊：
影响因子：
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通讯作者：
R. Tiedemann;M. Sarnthein;N. Shackleton
中科院分区：
文献类型：
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作者：
R. Tiedemann;M. Sarnthein;N. Shackleton
高分辨率的海底氧同位素和尘埃通量记录从大洋钻探计划网站659进行了分析，延长大西洋的天文校准的同位素时间尺度从2.85马回到5马。δ 18O记录的光谱分析表明，地球轨道周期的41 kyr占主导地位的上新世记录。这被证明是真实的，无论在上新世地球气候的根本变化。然而，萨赫勒干旱波动的周期表明在光谱特征的转变近3马。从上新世早期到3 Ma，周期性主要是岁差（19和23 kyr），并保持强劲，直到1.5 Ma。在3 Ma之后，演化期（41 kyr）的方差增加。调整到岁差的时间尺度表明上新世比以前估计的要长50多万年。
High-resolution benthic oxygen isotope and dust flux records from Ocean Drilling Program site 659 have been analyzed to extend the astronomically calibrated isotope timescale for the Atlantic from 2.85 Ma back to 5 Ma. Spectral analysis of the δ18O record indicates that the 41-kyr period of Earth's orbital obliquity dominates the Pliocene record. This is shown to be true regardless of fundamental changes in the Earth's climate during the Pliocene. However, the cycles of Sahelian aridity fluctuations indicate a shift in spectral character near 3 Ma. From the early Pliocene to 3 Ma, the periodicities were dominantly precessional (19 and 23 kyr) and remained strong until 1.5 Ma. Subsequent to 3 Ma, the variance at the obliquity period (41 kyr) increased. The timescale tuned to precession suggests that the Pliocene was longer than previously estimated by more than 0.5 m.y.