Global Controls on the Carbon Isotopic Composition of Carbonate Platforms: Unrelated to the Glocal Carbon Cycle

对碳酸盐台地碳同位素组成的全球控制：与全球本地碳循环无关

• 批准号: 0825577
• 负责人: Peter Swart
• 金额: $ 30.79万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0825577&HistoricalAwards=false
• 关键词: Global; Controls; Carbon; Isotopic; Composition

The PI will test the hypothesis that over the past 25 yrs the variations in the carbon isotopic composition of marginal platform carbonates are not related to changes in the global carbon cycle as widely believed, but are instead related to the variations in global sea-level fluctuations and reflect the relative input of isotopically enriched carbonate produced in shallow water on the adjacent platforms. This hypothesis will be tested by analyzing the ä13C in bulk carbonate material sampled from DSDP and ODP sites cored adjacent to modern carbonate platforms. PI?s preliminary data has shown that (i) the ä13C of bulk carbonate sediments retrieved from such sequences cored at a number of sites adjacent to carbonate platforms such as the Bahamas can be correlated with each other, but that these variations are unrelated to changes in the global carbon cycle, and (ii) similar change can be recognized at locations in the Maldives and Australia over the past 10myrs. The PI will further investigate this phenomenon, by (i) extending the study to additional sites, (ii) extending the time range of samples back to 25 Ma, (iii) investigating the phenomenon over high amplitude glacio-eustatic changes in sea level, (iv) adding variations in the ä13C of organic material as a proxy of production from shallow-water carbonate platforms, and (v) developing a model combining the notion that input from shallow marine carbonate platforms alters the ä13C with changes in calcite-aragonite seas, and the varying burial of organic material. Broader Impacts: Recognition that other factors than the carbon cycle can control the ä13C of carbonates will improve the understanding of the history of the burial of organic carbon, but also lead to understanding of how such records relate to the present anthropogenic experiment of increasing the pCO2 of the atmosphere and transferring carbon from the organic to inorganic reservoirs. The project will support a Ph.D. thesis as well as the interaction of undergraduates, high-school students, and high-school teachers in the geochemical laboratories at RSMAS.

PI将检验以下假设：在过去的25年中，边缘平台碳酸盐的碳同位素组成的变化与全球碳循环的变化无关，而是广泛认为的，而是与全球海平面波动的变化有关，并且反映出同位素富集的含量富含碳纤维平台的相对输入。该假设将通过分析从DSDP和与现代碳酸盐平台相邻的DSDP和ODP所采样的大块碳酸盐材料中进行测试。 PI的初步数据表明，（i）从碳酸盐平台（例如巴哈马）邻近的许多地点检索到的序列中检索到的序列中的大量碳酸盐沉积物的ä13c可以彼此相关，但是这些变化与全球碳周期的变化无关，并且（ii）与澳大利亚相似的变化相似。 PI将通过（i）将研究扩展到其他地点，（ii）将样品的时间范围扩展到25 ma，（iii），调查了海平面高振幅变化的现象，（iii）将研究的时间范围扩展到25 ma，（iii），（iv）在ä13c添加了一种模型的生产（iv），则添加了一种模型的生产。从浅水碳酸盐平台的输入的观点会随着钙 - 阿拉贡海洋的变化和有机材料的不同埋葬而改变了ä13c。更广泛的影响：认识到，除碳周期以外的其他因素可以控制碳酸盐的ä13c将改善对有机碳埋葬历史的理解，同时也导致人们了解了此类记录与当前人类学的实验如何相关的人类学实验，以增加大气中的PCO2，并从有机碳转移到有机碳到无机储存库中。该项目将支持博士学位。在RSMAS的地球化学实验室中，本科生，高中生和高中老师的论文以及互动。