COLLABORATIVE RESEARCH: Paleoventilation of the Southwest Pacific and Southern Ocean in the Holocene and late Quaternary

根据该奖项，PI将构建冰川和冰消期几个时间片的14 C年龄剖面，以更好地限制西南太平洋和南大洋过去的深水年龄。 为此，研究员将在新西兰北部和东部的亚热带和亚热带沃茨进行沉积物取样考察。 这次航行将在新西兰北岛陶波火山区六个已知含有广泛火山灰层的地点中的每一个地点采集多个岩心。 这些灰烬在陆地上的年代测定很好，提供了地层联系点，也是确定过去海洋和陆地（大气）碳库相对年代的一种手段。 先前的工作与这些灰烬已经表明，在末次冰期和冰消期的地表和深水质量可能比以前想象的和有争议的世纪，因为地表水水库年龄在亚热带地区超过1900年被认为是不可能的，即使在冰期。 解决这些问题的持续工作受到了阻碍，因为来自亚热带地区的岩心要么没有足够的材料和/或深度覆盖，无法继续进行14 C的工作，而且火山灰的识别也有问题。 该项目将收集巨大的活塞岩心，以提供足够的沉积物，从而从灰烬周围的狭窄沉积带中获得足够的有孔虫，以正确识别火山灰并确定其年代，从而对海洋沉积物中与灰烬层相关的有孔虫进行14 C AMS放射性碳测年。

Under this award the PIs will construct a profile of 14C ages for several time slices in the glaciation and deglaciation in order to better constrain past deep water age of the southwest Pacific and Southern Oceans. To do this, the PIs will perform a sediment coring expedition to the subtropical and subantarctic waters to the north and east New Zealand. The cruise will recover multiple cores at each of six locations that are known to contain widespread tephra layers from the from the Taupo volcanic zone on the North Island of New Zealand. These ashes have been well dated on land and provide stratigraphic tie points and a means to establish the relative ages of marine and terrestrial (atmospheric) carbon reservoirs in the past. Previous work on preexisting cores with these ashes has demonstrated that surface and deep water masses in the last glaciation and deglaciation could be centuries older than previously imagined and controversial because surface water reservoir ages in subtropical locations of more than 1900 yrs are considered unlikely even in the glaciation. Continued work to resolve these issues has been hampered because cores from subtropical locations have either insufficient material and/or depth coverage for continued work on 14C and have problematic ash identification. This project will collect giant piston cores to provide sufficient sediment to obtain enough foraminifera from a narrow sediment band surrounding the ashes to properly identify and date the tephras in order to conduct 14C AMS radiocarbon dating foraminifera associated with ash layers in the marine sediment.