Collaborative Research: The marine Os isotope record of extreme Cenozoic climates

摘要（0526559/0525880）Ravizza/Peucker-Escherbrink的智力功绩人们普遍认为，全球化学风化速率对全球气候变化做出了反应，充当了地球的天然恒温器。这项研究的目的是利用沉积物中的海洋锇（Os）同位素记录来监测气候突然变暖和变冷的异常事件期间的化学风化，看看是否可以找到气候变化自我调节的证据。 为了实现这一目标，将检查沉积物中的海洋Os同位素记录，以确定始新世的变暖事件是否与海水187 Os/188 Os比值上升（表明风化速率增加）有关，以及渐新世和中新世的冷却事件是否与海水187 Os/188 Os比值下降（表明风化速率降低）有关。将分析来自大洋钻探计划和深海钻探项目岩心的存档沉积材料。 对于每个气候事件，将测量来自不同岩心位置的至少两个Os同位素记录。这将有助于检验海洋Os同位素记录的全球一致性。 通过将Os同位素数据与现有的古气候/古海洋学记录进行比较，将能够确定重要代用记录变化的相对时间。 例如，全球冰量减少与187 Os/188 Os上升之间的密切时间关联将支持与冰川作用相关的物理风化正在推动海洋Os记录的变化。另外，如果Os同位素的变化导致冰量的变化，这将意味着海洋Os同位素记录更强烈地受到广泛的气候制度，而不是严格意义上的冰川风化。 更广泛的影响这项研究的更广泛的影响包括公众宣传，学生教育和培训，并将数据归档到随时可访问的公共数据库。 这项工作将为夏威夷大学的研究生和本科生提供两年的支持，为他们提供实际工作经验，帮助他们做出有关继续教育或就业的明智决定。该研究还支持与欧洲科学家在古气候代理方面的国际合作，并为夏威夷和伍兹霍尔的女性技术人员提供工资支持。 此外，还将培训一名伍兹霍尔海洋学研究所本科生暑期实习生。研究成果将纳入夏威夷大学的必修课程。

ABSTRACT (0526559/0525880) Ravizza/ Peucker-Ehrenbrink Intellectual MeritIt is widely believed that global chemical weathering rates respond to global climate change, acting as natural thermostat for the Earth. The goal of this research is to use the marine osmium (Os) isotope record in sediments to monitor chemical weathering during unusual episodes of abrupt climatic warming and cooling to see if evidence can be found for self-regulating of climate change. To accomplish this goal, the marine Os isotope record in sediments will be examined to see if warming events in the Eocene are associated with rising seawater 187Os/188Os ratios (indicative of increased weathering rates), and if cooling events in the Oligocene and Miocene are associated with falling seawater 187Os/188Os ratios (indicative of decreased weathering rates). Archived sedimentary material from Ocean Drilling Program and Deep Sea Drilling Project cores will be analyzed. For each climate event at least two Os isotope records from different core locations will be measured. This will allow a test of the global coherence of the marine Os isotope record. By comparing the Os isotope data to existing paleo-climate/ paleoceanographic records the relative timing of changes in important proxy records will be able to be determined. For example, a close temporal association between decreasing global ice volume and rising 187Os/188Os will support the notion that physical weathering associated with glaciation is driving the changes in the marine Os record. Alternatively, if Os isotope shifts lead ice volume changes this will imply that the marine Os isotope record is more strongly influenced by the broad climate regime than by glacial weathering in the strict sense. Broader ImpactsThe broader impacts of this research include public outreach, student education and training, and archiving of data into readily accessible public databases. The work will support a graduate student and undergraduate at the University of Hawaii for two years, providing them with practical work experience that will help them make informed decisions about pursuing additional education or employment. The research also supports international collaboration with European scientists working on paleoclimate proxies and provides salary support for female technicians at Hawaii and Woods Hole. In addition, a Woods Hole Oceanographic Institution undergraduate summer intern will be trained. Research results will be incorporated into required courses at the University of Hawaii.