Collaborative Research: High-resolution Cretaceous terrestrial climate records of temperature, weathering and hydrologic response to hyperthermals in Songliao Basin, China

摘要：白垩纪（145 - 66myr前）是地球经历异常温暖温度和高二氧化碳水平的时期。为了了解地球在温室条件下的表现，必须研究地球过去的这些独特时期。为了研究这一时期，国际大陆科学钻探计划启动了名为“松辽盆地白垩纪大陆科学钻探项目：连续高分辨率陆地档案与温室气候变化”的项目。该项目将提供约10公里的贯穿整个白垩纪的几乎连续的岩心，这些岩心作为古湖泊沉积物保存在中国东北。PIs将利用这一前所未有的机会，通过收集同位素和沉积学数据来研究白垩纪温室，特别是在白垩纪地球经历极端温暖和海洋缺氧的时间段（例如~93 myr以前）。他们组建了一个由斯坦福大学、威斯康星大学和西北大学的科学家组成的团队，他们拥有独特而互补的技能，来解决地球中纬度地区在极端温暖时期的行为问题。pi特别感兴趣的是研究地球水文和碳循环与这些循环运行的时间尺度之间的联系和反馈。他们的研究将为地球环境提供最详细和最有限的同位素数据集之一。这些数据将为他们的模拟研究提供基础，这些研究将给出与高温事件相关的温度和降水变化的定量界限。技术：这项为期一年的研究重点是中国东北松辽盆地白垩纪的陆地气候变化记录，松辽盆地是一个长期存在的内排水裂谷盆地。PIs对陆地对全球气候变化的反应的理解部分是通过对地球经历温室和温室条件时期的古气候研究得到的。他们有一个独特的机会，通过检查白垩纪松辽盆地ICDP取芯收集的核心材料，解决有关全球变暖、碳循环和陆地水文循环之间的联系和反馈的问题。他们对该盆地上白垩纪岩心（sk - 1）的初步研究表明，介形类的碳同位素值反映了海洋记录中观察到的全球碳循环扰动（Chamberlain et al., 2013）。随着SK-II（2014年5月）新钻井岩心的收集，石油公司将在下白垩纪延续这一记录。在白垩纪钻孔岩心的研究中，他们将提出两个相关的假设：1)SK-II岩心将记录下白垩纪在海洋环境中观测到的温度历史，特别是超热物及其碳同位素变化；2)松辽岩心包含了Cenomanian/Turonian边界的海洋缺氧事件（OAE） 2的碳同位素证据，该边界将记录可能导致OAE 2的化学和物理风化加剧的证据。为了验证这两个相关的假设，将需要在严格的沉积学和地质年代学框架内进行氧、碳和锶同位素和痕量/稀土元素研究。后者将得到在盆地边缘附近暴露的火山岩和沉积岩的实地调查的支持。在他们早期研究的推动下，pi认识到同位素值记录了全球气候变化和区域盆地演化。解开这些盆地的反应并非易事，因此他们聚集了具有独特而互补的专业知识的科学家，包括沉积学、地球化学和建模。由于这是一项为期一年的研究，pi将重点关注现有的核心材料（sk - 1）和计划核心的上部（SK-II），这些核心跨越Cenomanian/Turonian边界和OAE 2。

Abstract Non-technical: The Cretaceous period (145 to 66 myr ago) is characterized by an interval when the Earth experienced unusually warm temperatures and high carbon dioxide levels. To understand how the Earth might behave during greenhouse conditions it is imperative to study these unique times in the Earth's past. In an effort to examine this time period, the International Continental Scientific Drilling Program launched a project entitled 'Continental Scientific Drilling Project of Cretaceous Songliao Basin: Continuous High-resolution Terrestrial Archives and Greenhouse Climate Change,'. This project will provide ~10 km of nearly continuous core through the entire Cretaceous that is preserved as ancient lake sediments in northeast China. PIs will take advantage of this unprecedented opportunity to study the Cretaceous hothouse by collecting isotopic and sedimentologic data specifically focusing on intervals (e.g. ~93 myr ago) in the Cretaceous when the Earth experienced extreme warmth and the oceans became anoxic. They have assembled a team of scientists (Stanford Univ., Univ. of Wisconsin, and Northwestern Univ.) with unique and complimentary skill sets to address the problem of how Earth's mid-latitudes behave during extreme warmth. PIs are particularly interested in examining the links and feedbacks between the Earth's hydrologic and carbon cycles and time-scales that these cycles are operative over. Their study will provide one of the most detailed and constrained isotopic data sets for a terrestrial setting. These data will provide the basis for their modeling studies that will give quantitative bounds on the temperature and precipitation changes associated with hyperthermal events.Technical: This one-year study focuses on the Cretaceous terrestrial record of climate change in the Songliao Basin of northeastern China, a long-lived, internally drained rift basin. PIs understanding of the terrestrial responses to global climate change are informed in part, by paleoclimate studies of times when the Earth experienced greenhouse and hothouse conditions. They have a unique opportunity to address questions concerning the links and feedbacks between global warming, the carbon cycle and the hydrologic cycle in a terrestrial setting through the examination of core material collected in ICDP coring of the Cretaceous Songliao Basin. Their initial studies of the Upper Cretaceous core (SK-I) from this basin show that the carbon isotopic values of ostracods reflect the global perturbations of the carbon cycle as observed in marine records (Chamberlain et al., 2013). With the collection of the new drill core from SK-II (May 2014), PIs are positioned to extend this record through the Lower Cretaceous. In their study of the Cretaceous drill-core they will address two related hypotheses, which are: 1) SK-II core will record the temperature history of the Lower Cretaceous observed in marine settings, particularly the hyperthermals and their carbon isotopic changes; and 2) the Songliao drill core contains carbon isotopic evidence for the Ocean Anoxic Event (OAE) 2 at the Cenomanian/Turonian boundary, and this boundary will record evidence for the increased chemical and physical weathering that may be responsible for OAE 2. To test these two related hypotheses will require oxygen, carbon and strontium isotopic and trace/REE element studies set within a rigorous sedimentologic and geochronologic framework. The latter will be supported by field investigations of volcanic and sedimentary rocks exposed near the basin margins. Driven by their earlier studies, PIs recognize that the isotopic values record both global climate changes and regional basin evolution. Unraveling these basin responses is not trivial, thus they have assembled scientists with unique yet complimentary expertise involving sedimentology, geochemistry, and modeling. Since this is a one-year study PIs will focus on existing core material (SK-I) and the upper portion of planned core (SK-II) that span the Cenomanian/Turonian boundary and OAE 2.