DOI: 10.1016/j.palaeo.2017.02.037
论文题名: Reduction of oceanic temperature gradients in the early Eocene Southwest Pacific Ocean
作者: Hines B.R. ; Hollis C.J. ; Atkins C.B. ; Baker J.A. ; Morgans H.E.G. ; Strong P.C.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2017
卷: 475 起始页码: 41
结束页码: 54
语种: 英语
英文关键词: Early Eocene Climatic Optimum
; East Coast Basin
; LA-ICP-MS
; Mg/Ca paleothermometry
; New Zealand
; Paleoclimate
英文摘要: We present a Southwest Pacific Ocean paleothermometry transect using new and existing foraminiferal Mg/Ca data from six Eocene locations from eastern New Zealand to southwestern Campbell Plateau, spanning 10° of paleolatitude (43° to 53°S). Sea surface and seafloor temperatures (SST and SFT) have been calculated taking into account the partition coefficients of calcite and Paleogene Mg/Casw ratios, and used to determine values for the power component (H) of this relationship in foraminiferal calcite from paired proxy (δ18O and Mg/Ca) records from Canterbury Basin. This study presents the first Eocene paleotemperature record for the East Coast Basin and, in so doing, shows the absence of a meridional temperature gradient over 10° of latitude during the Early Eocene Climatic Optimum (EECO) and provides evidence for a very weak to absent gradient from the equatorial Pacific to 53°S at this time of extreme global warmth. The application of a new subsurface TEX86 calibration correlates remarkably well with Mg/Ca seafloor temperature trends from the continental slope setting (< 1000 m paleodepth) of the sites sampled in this study, suggesting that TEX86 is recording an upper ocean subsurface temperature record, rather than simply SST values. SST-SFT gradients demonstrate a notable reduction, decreasing to 3–5 °C across the EECO. The comparable ocean temperatures of the East Coast Basin, Canterbury Basin and DSDP Site 277 during this time support the intensification of a proto-East Australian Current (EAC), explaining the distribution of tropical sea temperatures extending into the high-latitude Southwest Pacific Ocean during the EECO. Seafloor temperatures (~ 1000 m paleodepth) likely correspond to a northern, intermediate water source during the early Eocene, before switching to a cooler southern-derived source in the middle to late Eocene. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/67856
Appears in Collections: 过去全球变化的重建
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作者单位: School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand; School of Environment, The University of Auckland, New Zealand
Recommended Citation:
Hines B.R.,Hollis C.J.,Atkins C.B.,et al. Reduction of oceanic temperature gradients in the early Eocene Southwest Pacific Ocean[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2017-01-01,475