Technical note: Late Pliocene age control and composite depths at ODP Site 982, revisited
2012
N. Khélifi | M. Sarnthein | B. D. A. Naafs
Ocean Drilling Program (ODP) Site 982 provided a key sediment section at Rockall Plateau for reconstructing northeast Atlantic paleoceanography and monitoring benthic &delta;<sup>18</sup>O stratigraphy over the late Pliocene to Quaternary onset of major Northern Hemisphere glaciation. A renewed hole-specific inspection of magnetostratigraphic reversals and the addition of epibenthic &delta;<sup>18</sup>O records for short Pliocene sections in holes 982A, B, and C, crossing core breaks in the &delta;<sup>18</sup>O record published for Hole 982B, now imply a major revision of composite core depths. After tuning to the orbitally tuned reference record LR04, the new composite &delta;<sup>18</sup>O record results in a hiatus, where the Kaena magnetic subchron might have been lost, and in a significant age reduction for all proxy records by 130 to 20 ky over the time span 3.2–2.7 million years ago (Ma). Our study demonstrates the general significance of reliable composite-depth scales and &delta;<sup>18</sup>O stratigraphies in ODP sediment records for generating ocean-wide correlations in paleoceanography. The new concept of age control makes the late Pliocene trends in SST (sea surface temperature) and atmospheric <i>p</i>CO<sub>2</sub> at Site 982 more consistent with various paleoclimate trends published from elsewhere in the North Atlantic.
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