Crayton J. 卷边装订

• 低温系统稳定同位素与微量元素地球化学
• 地球化学指标的古气候
• 水循环
• 含针铁矿矿床与古大气

课程

地球系统
GEOL 3353 -现代和古代气候
地质过程热力学
GEOL 6371 -同位素地球化学 

相关链接

刊物一览表[PDF]

研究声明

固体地球, 大气, 液态水 and living organisms interact in surface and near-surface environments termed the "critical zone". These interactions occur on time scales that range from fractions of a second to hundreds of thousands of years or more. Our research on the stable isotope geochemistry of the critical zone has included study of regolith minerals, 大陆古气候, 古代生物活动, 水文循环, 以及现代和古代的大气化学.

生锈的地球 
丰富的铁元素共存, 液态水, 和地球上的自由大气氧一样, 据我们所知, 在现代太阳系中独一无二. 在地表和近地表环境中, chemical weathering reactions that result from this remarkable association of materials commonly produce iron (III) oxide and oxyhydroxides minerals ("rusts"). 在地球上，两种最丰富的“铁锈”是针铁矿(a-FeOOH)和赤铁矿(a-Fe)₂O₃). Natural variations of the stable isotope ratios of structural oxygen and hydrogen in goethite indicate variations of ancient temperatures and isotopic compositions of waters, 从而提供有关古气候的信息. 此外，迄今为止分析的所有天然针铁矿都含有少量的铁(CO)₃)固溶体中的OH组分. 交换实验表明，该Fe(CO)₃)只要针铁矿结构保持完整，OH组分就保持一个封闭系统. 因此，Fe(CO₃)针铁矿中的OH可以保存CO的分压和碳同位素组成信息₂ 在古针铁矿结晶环境中.

Although goethite is extremely insoluble in oxidizing environments at values of pH characteristic of most low temperature terrestrial environments, 对现代系统的研究表明，它们具有明显的连续性, 生物介导的针铁矿的溶解和再沉淀是活跃的, 湿, 氧化土壤. 因此, 在活跃的土壤环境中, 成土针铁矿不断“更新”其土壤条件的同位素记录. 随后埋下的针铁矿可以锁定这一大陆温度记录, 降雨, 大气和土壤CO₂ 压力. 这些代用记录在显生宙的针铁矿中发现. 例如, data from a weathering system formed 440 million years ago indicate that the Earth's 大气 contained about 16 times more CO₂ 比今天更重要, 而温度至少在一个潮湿, 大陆, 热带地区约23°C. The inferred value of the oxygen isotope ratio of ancient tropical waters suggests intense seasonal, 也许monsoon-related, 降雨. 此外，铁(CO)的浓度₃)，该地区晚奥陶世土壤针铁矿的OH组分表明, 甚至在维管植物广泛出现之前, 大陆上有重要的生物活动. 成土针铁矿数据的垂直变化表明土壤CO的通量₂ 由生物活动(呼吸)引起的可能与现代测量的相似, 湿, 热带土壤.  

CO的混合₂ from different sources in oxidizing surface and near-surface environments occurs as a consequence of a number of processes. 铁(有限公司₃)OH component in goethite can serve as a recorder of these processes in both vadose and phreatic groundwater systems. 例如, formation of goethite as a consequence of pyrite oxidation in the presence of ambient limestone represents a circumstance in which mixing between the CO₂ 来自“上游土壤”和CO₂ 石灰石的局部溶解由铁(CO)记录₃)针铁矿中的OH成分. 原则上, evolution of the pH in the system may be deduced from the pattern of variation of 浓度 and carbon isotope ratios of the Fe(CO₃)OH. Such a pattern appears to be present in goethites that were crystallized during the Late Cretaceous or Earliest Tertiary in the Lucero Mountains of New Mexico. 因此, aspects of the history of local groundwater chemistry and mixing processes may be constrained using the special properties of a common iron (III) oxyhydroxides. 

古生代针铁矿资料, 中生代, 和新生代系统提出的问题, (1)地球过去气候的动态和能量平衡, (2)各种边界条件在形成这些气候中的作用, (3)当地的水和碳循环——包括生物活动的作用.

岩石圈与大气的界面 
在很大程度上, terrestrial gastropods spend the active portions of their lives immediately at the interface between the solid Earth and the troposphere. 因此, 它们可以作为这个临界边界层现在和过去条件的重要指标. Our research has shown that the oxygen isotope composition of land snail shells is controlled by temperature, 相对湿度, 环境水蒸气的氧同位素比值, 钉螺活动时的雨水氧同位素比值(i.e.(文石壳形成时代). The stable carbon isotope ratios of land snail shells reflect the carbon isotope composition of plants used by the snails for food as well as the flux of carbon associated with normal snail metabolism. 因此, the carbon isotope composition of these shells can record information on the relative importance of C₃ 与C₄环境中的光合作用. Oxygen and carbon isotope data from modern land snail populations calibrate these paleoenvironmental indicators, which have been used to deduce changes in climatic conditions and vegetation in the Pleistocene and Holocene epochs.

城市大气二氧化碳 
户外有限公司₂
人为的CO输入₂ to the 大气 are superimposed on natural cyclical inputs and outputs associated with soil/plant respiration, 光合作用, 以及海洋-大气交换. The effects of all of these processes must be evaluated on large spatial scales to understand the overall global evolution of CO₂ 在现代地球大气中的浓度. 然而，在较小的CO空间尺度上₂ 工厂”(我.e., 城市环境), 可以预期，人为输入将主导当地大气CO₂ 以相对简单的方式进行预算. 然而，室外CO的测量₂ 发生在达拉斯市区中心的事件表明, 在温暖的月份, 光合作用具有可测量的影响，并且可能, 有时, 本地主导的CO₂ 通量平衡. The local effects of this photosynthetic "complication" can be taken into account and separated from anthropogenic effects with combined measurements of the 浓度 and stable carbon isotope ratios of atmospheric CO₂. 然而, the complexities highlight the need for careful assessment of net photosynthetic carbon isotope fractionation factors in urban settings to enable more accurate assessments of relative magnitudes of natural and anthropogenic CO₂ 通量.
室内有限公司₂
对室内空气也进行了研究, 其中CO的浓度和稳定碳同位素组成₂ 是否受到室内空间居住者呼吸的显著影响. 研究表明, 即使在有通风系统的室内空间, CO的稳态浓度和碳同位素比值₂ 从单个室内环境空气样本和单个一氧化碳样本中提取₂ 远离室外空气, can be used to obtain a reasonable mass balance estimate of the average carbon isotope ratio of the respired CO₂ 在房间里. 因此，这些室内空间可以作为测定C的比例的“样品容器”₄在采样时，房间里的人的平均饮食中的碳来源.

选定的出版物

Clark-Thorne,年代.T. 和卷边装订,C.J. (2003)稳定碳同位素对CO混合和质量平衡的约束₂ 在城市氛围中:美国德克萨斯州的达拉斯市区， 应用地球化学18， 75-95.

卷边装订,C.J. (2004)铁(有限公司₃)来自北美中纬度奥西索尔的针铁矿中的OH:大气CO的估计₂ 早始新世“气候最佳”浓度.  Geochim. Cosmochim. 68年学报, 935-947.

他泊,N.J.C.J.，和Montañez，我.P. (2004)针铁矿, 方解石, 二叠纪和三叠纪土壤中的有机质:碳同位素和CO₂浓度.  Geochim. Cosmochim. 68年学报, 1503-1517.

Balakrishnan, M. 和卷边装订,C.J. (2004)陆地蜗牛壳氧和碳同位素组成的通量平衡模型.  Geochim. Cosmochim. 学报 68, 2007-2024. 

Balakrishnan米.C.J.泰勒·J.L.卡特·B.J.Wyckoff D.G. (2005) Environmental significance of 13C/12C and 18O/16O ratios of modern land snail shells from the southern Great Plains of North America.  第四纪研究63, 15-30. 

Balakrishnan米.， 卷边装订C.J.， Meltzer D.J.泰勒·J.L. (2005)新墨西哥州Folsom考古遗址的古环境，~ 10500 14C年B.P. 根据陆地蜗牛壳化石的稳定同位素组成推断.  第四纪研究63, 31-44. 

他泊,N.J. 和卷边装订,C.J. (2005) Coexisting goethite and gibbsite from a high paleolatitude (55°N) Late Paleocene laterite: concentration and 13C/12C ratios of occluded CO₂ 以及伴生有机物.  Geochim. Cosmochim. 69年学报, 5495-5510.  

卷边装订,C.J. (2007) Oxygen isotopes in synthetic goethite and a model for the apparent pH dependence of goethite-water 18O/16O fractionation. Geochim. Cosmochim. 71年学报, 1115-1129. 

卷边装订,C.J. (2008) 18O/16O and D/H in goethite from a North American Oxisol of the Early Eocene climatic optimum.  Geochim. Cosmochim. 72年学报, 5838-5851.

冯,W. 和卷边装订,C.J. (2009) 18O/16O and D/H ratios of pedogenic kaolinite in a North American Cenomanian laterite: paleoclimatic implications.  Geochim. Cosmochim. 学报 73, 6249-6263.

燕Y. 和卷边装订C.J. (2010)城市室内和室外大气CO₂稳定碳同位素对混合和质量平衡的约束. 应用地球化学25， 1339-1349.

燕Y.， 卷边装订C.J.，德尔加多.， Ibáñez M.阿隆索·M.R.De-la-Nuez J.卡斯蒂略C.， Quesada M.L. (2011) Pleistocene-Holocene environmental change in the Canary Archipelago: a land snail isotopic record. 第四纪研究 75, 658 - 669.

卷边装订C.J. 和Shuster D.L. (2011) Environmental memory and a possible seasonal bias in the stable isotope composition of (U-Th)/He-dated goethite from the Canadian Arctic.  Geochim. Cosmochim. 学报 75, 4194 - 4215.

卷边装订C.J. (2015) ¹⁸O/¹⁶CO中的O₂ 在一些异常快速的固态a-FeOOH到a-Fe的过程中从针铁矿演化而来₂O₃ phase transitions: Test of an exchange model for possible use in oxygen isotope analyses of goethite.  地球化学与宇宙化学学报[j], 1-16.