(Table 1) Stable isotopic record of Neogloboquadrina pachyderma s of ODP Site 152-919A

Stable isotopic records based on the planktonic foraminifer Neogloboquadrina pachyderma (sinistrally coiling) from Holes 919A and 919B from the western Irminger Basin (62°40'N, 37°28'W) provide records of surface water environments of the mid- to late Quaternary in the Irminger Sea. The 147-m sequence clearly shows oxygen isotope Stages 1 through 20 (possibly to 25). Assignment of oxygen isotope stages is supported by calcareous nannofossil biostratigraphy, magnetic polarity stratigraphy, and strontium isotope stratigraphy. Sedimentation rates average ~17.9 cm/k.y. for the 960-420 ka interval and ~13.4 cm/k.y. for the 420-0 ka interval. Significantly, interglacial d18O in Stages 21 through 15 is 0.5 per mil to 0.8 per mil lower than in succeeding interglacials, suggesting warmer sea surface temperatures and/or lower salinity in this interval. The magnitude and rapidity of these low-d18O events suggest large variations in salinity of the Irminger Sea during the 860-600 ka interval, perhaps reflecting […]

采自伊尔明格海盆（Irminger Basin）西部（62°40′N，37°28′W）919A与919B钻孔的浮游有孔虫（planktonic foraminifer）——左旋盘绕厚壳新抱球虫（Neogloboquadrina pachyderma, sinistrally coiling）的稳定同位素记录，可为伊尔明格海（Irminger Sea）中晚第四纪的表层水体环境演化提供可靠数据记录。该147米的沉积序列清晰识别出氧同位素阶段（oxygen isotope Stages）1至20（或可延伸至25）。氧同位素阶段的划分得到了钙质超微化石生物地层学（calcareous nannofossil biostratigraphy）、磁极性地层学（magnetic polarity stratigraphy）以及锶同位素地层学（strontium isotope stratigraphy）的联合佐证。960-420 ka时段的平均沉积速率（sedimentation rates）约为17.9厘米/千年，420-0 ka时段的平均沉积速率则约为13.4厘米/千年。值得注意的是，氧同位素阶段21至15的间冰期δ¹⁸O值较其后的间冰期低0.5‰至0.8‰，指示该时段内表层海水温度更高或盐度更低。此类低δ¹⁸O事件的幅度与发生速率表明，860-600 ka时段内伊尔明格海的盐度存在大幅波动，这或许反映了[...]