Early Pliocene deep water circulation in the western equatorial Atlantic: Implications for high‐latitude climate change
Early Pliocene deep water circulation in the western equatorial Atlantic: Implications for high‐latitude climate change
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上新世早期赤道大西洋西部深水环流：对高纬度气候变化的影响
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
J. Zachos
中科院分区：
文献类型：
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作者：
K. Billups;A. Ravelo;J. Zachos
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High-resolution (-3-4 kyr) stable isotope stratigraphies from sites drilled along a depth transect on Ceara Rise (Ocean Drilling Program Leg 154, Sites 925 and 929) are used to reconstruct the deep water circulation response to the long- and short-term climate changes of the early Pliocene (3.2-4.7 Ma). Over the long term, benthic foraminiferal carbon isotope records show that the vertical fil3c gradient in this region was similar to that of the late Holocene, implying a steady flux of Northern Component Deep Water (NCDW) into the deep Atlantic during most of the early Pliocene. The vertical benthic foraminiferal oxygen isotope gradient is reversed with respect to that of the late Holocene. On the basis of density constraints imposed by seawater stability along this depth transect we attribute the reversed gradient to warmer and more saline NCDW (5oC and 35.1). On orbital timescales we find that the phase relationship between fi180 and fil3c values at the deeper Site 929 differs from the late Pliocene/Pleistocene, while that at the shallower Site 925 was essentially the same.