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

摘要(0526559/0525880)Ravizza/Peucker-Ehrenbrink的学术价值人们普遍认为，全球化学风化速率对全球气候变化做出反应，起到了地球自然恒温器的作用。这项研究的目的是利用沉积物中的海洋Os(Os)同位素记录来监测气候突然变暖和变冷不寻常时期的化学风化，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，以确定始新世变暖事件是否与海水187Os/188Os比值上升(指示风化速率增加)有关，以及渐新世和中新世的冷却事件是否与海水187Os/188Os比值下降(指示风化速率下降)有关。将对大洋钻探项目和深海钻探项目岩心的沉积资料进行分析。对于每个气候事件，将测量来自不同核心位置的至少两个Os同位素记录。这将使测试海洋Os同位素记录的全球一致性成为可能。通过将Os同位素数据与现有的古气候/古海洋记录进行比较，将能够确定重要替代记录变化的相对时间。例如，全球冰量减少和187Os/188os上升之间的密切时间关联将支持与冰川有关的物理风化正在推动海洋Os记录变化的概念。或者，如果Os同位素漂移导致冰量变化，这将意味着海洋Os同位素记录受到广泛气候制度的影响比严格意义上的冰川风化影响更大。更广泛的影响这项研究的更广泛的影响包括公共宣传、学生教育和培训，以及将数据归档到易于访问的公共数据库中。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，帮助他们做出关于继续深造或就业的明智决定。这项研究还支持与研究古气候指标的欧洲科学家进行国际合作，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，伍兹霍尔海洋研究所的一名本科生暑期实习生将接受培训。研究成果将被纳入夏威夷大学的必修课。

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.