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Abstract:
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Multiproxy temperature estimation requires careful attention to biological, chemical, physical, temporal,
and calibration differences of each proxy and paleothermometry method. We evaluated mid-Pliocene sea surface
temperature (SST) estimates from multiple proxies at Deep Sea Drilling Project Holes 552A, 609B, 607, and
606, transecting the North Atlantic Drift. SST estimates derived from faunal assemblages, foraminifer Mg/Ca,
and alkenone unsaturation indices showed strong agreement at Holes 552A, 607, and 606 once differences in
calibration, depth, and seasonality were addressed. Abundant extinct species and/or an unrecognized
productivity signal in the faunal assemblage at Hole 609B resulted in exaggerated faunal-based SST
estimates but did not affect alkenone-derived or Mg/Ca–derived estimates. Multiproxy mid-Pliocene North
Atlantic SST estimates corroborate previous studies documenting high-latitude mid-Pliocene warmth and refine
previous faunal-based estimates affected by environmental factors other than temperature. Multiproxy
investigations will aid SST estimation in high-latitude areas sensitive to climate change and currently
underrepresented in SST reconstructions. |