Geology and Geological Oceanography
Paleoclimate, Planktonic foraminifera, Pacific
This study is designed as a step toward reconstructing the climate variability in the Northeast Pacific during the last ice age cycle, including the glacial and deglacial transitions. Reconstruction may also contribute to the regional picture of climate change and potentially provide new insights into the pattern of variability in the Northeast Pacific. Deep-sea sediment core AT26-19 09PC was collected west of the Juan de Fuca Ridge in the Northeast Pacific Ocean. Samples were analyzed in 1 cm intervals, representing approximately 300-year resolution. The abundance of mineral grains, planktonic foraminifera, and the polar foraminifera N.pachyderma was quantified using split aliquots of each sample. This data can then be related to deposition patterns of ice-rafted debris, preservation of foraminifera CaCO3, and the varying presence of polar and subpolar waters at the study site. Results indicate that the abundance of polar foraminifera N. pachyderma and overall planktonic foraminifera abundance are greater during the glacial interval, as indicated by benthic δ¹⁸O data, compared to interglacial periods or deglaciation, which suggests a varying presence of polar waters at the study site. There is no evidence of iceberg deposition at the site in the last 80,000 years. However, the current study is limited by its use of a sedimentation rate-based age model and a limited examination of specific foraminifera species. Future research may provide additional information about the pattern of climate variability in the region, which may then be compared to climatic and oceanographic patterns observed in the subpolar Northeast Atlantic to explore similarities in regional climate variations. In addition, there is potential through future research for differences in the climate variability in the Northeast Pacific to be revealed, offering insights into the regional onset, progression and end of ice-age climate.