Collaborative Research: Paleohydrology of the Paleocene-Eocene Thermal Maximum: A Multiple Proxy Reconstruction

这项合作赠款将开发古新世-始新世热最大期（PETM）期间陆地水文的多代理记录，这是一个发生在约5580万年前的突然，短暂和大规模全球变暖的时期。PETM是新生代最温暖的时期，与大量的碳释放到大气中有关，并且与陆生脊椎动物和植物的戏剧性反应正好吻合。了解古东印度晚更新世时期水文循环的响应和反馈对模拟未来气候对人为CO2水平增加的响应具有直接意义。该项目将使用四个替代指标来重建古东印度晚更新世时期的古水文学：1）植物脂类化合物特异性氢同位素比值，2）哺乳动物牙齿和雀鳝鱼鳞化石釉质的氧同位素比值，3）化石叶片的外貌特征，（4）古土壤的形态和化学。这些替代方法将被应用到最近公认的PETM部分在东南部大角盆地，怀俄明州，在那里一个40米厚的间隔代表PETM已被确定，并在那里的团队已经表明，露头有丰富的化石脊椎动物，树叶，植物脂质和古土壤。由此产生的降水，相对湿度，季节性，土壤湿度，温度和降水水分来源的记录将具有约10 ky的时间分辨率，这将使团队能够检测PETM期间水文循环的变化。以高时间分辨率重建水文循环将产生更准确的古水文重建，更好地了解PETM内的气候波动如何与大气环流变化相关，并更好地了解PETM气候变化对陆地生态系统的环境后果。科学家在户外教室，”与提顿科学学校在杰克逊霍尔，怀俄明州。学校与K-12日校相连，并为所有年龄段的自然科学和自然科学教育学生提供住宿计划，每年为11，000多名学生提供服务。拟议的计划将涉及专业人员和研究生在教师培训课程的目标1）说明我们如何了解气候和生命从岩石记录和2）介绍教师地球科学及其从业者。该项目将与每年在学校举行的合作者年会一起进行。为了接触更广泛的受众，该团队将开发一个关于“重建古代森林生态系统”的网站，该网站将设在佛罗里达自然历史博物馆，并与史密森学会网站链接。该网站将探索如何重建古生态系统，使用古新世和始新世森林作为案例研究。

This collaborative grant will develop a multiple-proxy record of terrestrial hydrology during the Paleocene-Eocene Thermal Maximum (PETM), a period of abrupt, short lived and large-scale global warming that occurred ~55.8 million years ago. The PETM was the warmest period of the Cenozoic, is associated with a massive release of carbon to the atmosphere, and precisely coincided with a dramatic response in terrestrial vertebrates and plants. Understanding the response and feedbacks of the hydrologic cycle during the PETM has direct implications for modeling future climate responses to increasing levels of anthropogenic CO2.The project will use four proxies to reconstruct the paleohydrology of the PETM: 1) compound-specific hydrogen isotope ratios of plant lipids, 2) oxygen isotope ratios of fossil enamel from mammal teeth and gar fish scales, 3) physiognomy of fossil leaves, and 4) morphology and chemistry of paleosols. These proxy methods will be applied to the recently recognized PETM sections in the Cabin Fork area of the southeastern Bighorn Basin, Wyoming, where a 40 m-thick interval representing the PETM has been identified, and where the team has already shown that the outcrops have abundant fossil vertebrates, leaves, plant lipids, and paleosols. The resulting record of precipitation, relative humidity, seasonality, soil moisture, temperature, and precipitation moisture source will have a temporal resolution of ~10 ky, which will allow the team to detect variations in the hydrologic cycle during the PETM. Reconstructing the hydrological cycle at high temporal resolution will yield more accurate paleohydrological reconstructions, better knowledge of how climatic fluctuations within the PETM relate to changes in atmospheric circulation, and a refined understanding of the environmental consequences of PETM climate change for terrestrial ecosystems.The proposed research includes the development of a teacher training program, "Climate and Life Through Time: Scientists in the Outdoor Classroom," in conjunction with the Teton Science School in Jackson Hole, Wyoming. The school is connected to a K-12 day school and hosts residential programs for students of all ages in natural science and natural science education, serving over 11,000 students a year. The proposed program will involve PIs and graduate students in a teacher training course with the goals of 1) illustrating how we learn about climate and life from the rock record and 2) introducing teachers to Earth science and its practitioners. This outreach program will be conducted in conjunction with an annual meeting of collaborators to be held at the school.To reach an even broader audience, the team will develop a web site on "Reconstructing Ancient Forest Ecosystems" that will be hosted at the Florida Museum of Natural History and linked to Smithsonian Institution websites. The site will explore how to reconstruct ancient ecosystems by using the Paleocene and Eocene forests as a case study.