Collaborative research: Quantifying weathering rind formation rates using U-series isotopes along steep gradients of precipitation, bedrock ages, and topography in Guadeloupe

合作研究：利用U系列同位素沿着瓜德罗普岛陡峭的降水梯度、基岩年龄和地形量化风化皮的形成速率

• 批准号: 1251875
• 负责人: Susan Brantley
• 金额: $ 5.22万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1251875&HistoricalAwards=false
• 关键词: Collaborative; research; Quantifying; weathering; rind

The process of mechanical and chemical decomposition of volcanic rocks at the Earth's surface (i.e., weathering) regulates the global carbon cycle, releases nutrients to ecosystems, and sculpts landscapes. Despite its fundamental importance, we still lack effective tools and key observations to quantify the weathering rates of volcanic rocks and to understand how they respond to changes in climate and tectonic regime. During weathering, rock fragments in soils commonly form weathering rinds. These rinds can provide an ideal long-term record to help understand the controls of chemical weathering. Investigators propose to combine a novel U-series isotopic technique with bulk chemical, petrographic, and electron microprobe analyses to quantify formation rates of weathering rinds on the tropical volcanic Basse-Terre Island of French Guadeloupe. By comparing weathering rinds from a single watershed, they will understand the controls on weathering rind formation at the micro-scale through processes including dissolution, formation of new phases, and development of porosity. In addition, the field setting at Basse-Terre Island provides a superb natural laboratory with large environmental variables, allowing them to study rind formation along steep gradients of precipitation, bedrock ages and relief at large watershed scale. The combined analysis of weathering rinds will provide a novel and fundamental method to directly determine chemical weathering rates. This will be of broad interests to scientists worldwide studying the Critical Zone or Earth's surface layer extending from the top of the vegetative canopy to the base of groundwater. For example, such an approach provides a direct means to understand the controls on chemical weathering across different spatial scales. The gained insights will also help to understand how changes in precipitation affect mineral dissolution and reaction surfaces in rinds and soils, and how these processes control river chemistry over long time scales. This project brings together resources and expertise from the U.S., France, and UK. Graduate and undergraduate students at Univ. of Texas at El Paso (UTEP), one of the largest Ph.D.-granting Hispanic Serving Institutes in the U.S., and Dickinson College, an undergraduate-only liberal arts college in Pennsylvania will conduct research at an international Critical Zone research site (Guadeloupe, France) and in research facilities at Pennsylvania State University, Institut de Physique du Globe de Paris, Univ. of Strasbourg, and Univ. of Bristol. This importance is highlighted for UTEP and Dickinson College where the students are rarely exposed to such opportunities at international levels. This project will also support one early career faculty (PI Ma) at UTEP. Educational and outreach activities at UTEP and Dickson College, in collaboration with the NSF funded Pathways and STEP Scholars, as well as Earth Science Day at UTEP, will expose local high school students and general public in the rapidly growing and diverse El Paso region to cutting edge Critical Zone research topics (water, soils, and environments). The project will attract future STEM students who wish to study and solve emerging environmental problems facing the local community.

火山岩在地面表面（即风化）的机械和化学分解过程可调节全球碳循环，将营养释放到生态系统中，并雕刻景观。尽管它具有根本的重要性，但我们仍然缺乏有效的工具和关键观察，无法量化火山岩的风化速率，并了解它们如何应对气候和构造制度的变化。在风化过程中，土壤中的岩石碎片通常形成风化的果皮。这些皮肤可以提供理想的长期记录，以帮助了解化学风化的控制。研究人员建议将一种新型的U系列同位素技术与散装化学，岩石学和电子微探针分析相结合，以量化法国瓜德罗普（Grench Guadelupe）热带火山山地岛上风化果皮的形成速率。通过比较单个流域的风化果皮，他们将通过包括溶解，新阶段的形成和孔隙率的过程（包括溶解，形成新阶段的形成以及孔隙率的发展）来理解微型覆盖地层的控制。此外，Basse-Terre Island的田间设置提供了一个具有较大环境变量的出色自然实验室，使它们可以沿着陡峭的降水，基岩年龄和大型分水岭量表的陡峭梯度研究果皮形成。风化果皮的组合分析将提供一种新颖的基本方法，以直接确定化学风化速率。这对于全球研究临界区域或地球表面层从营养冠层的顶部到地下水的底部的科学家来说将具有广泛的兴趣。例如，这种方法提供了一种直接的手段，可以理解不同空间尺度上化学风化的控制。获得的见解还将有助于了解降水的变化如何影响矿物质溶解和土壤中的反应表面，以及这些过程如何在长期尺度上控制河流化学。该项目汇集了美国，法国和英国的资源和专业知识。大学的研究生和本科生。 of Texas at El Paso (UTEP), one of the largest Ph.D.-granting Hispanic Serving Institutes in the U.S., and Dickinson College, an undergraduate-only liberal arts college in Pennsylvania will conduct research at an international Critical Zone research site (Guadeloupe, France) and in research facilities at Pennsylvania State University, Institut de Physique du Globe de Paris, Univ.斯特拉斯堡和大学。布里斯托尔。对于UTEP和Dickinson College，强调了这一重要性，在那里，学生很少在国际水平上接触过此类机会。该项目还将支持UTEP的一个早期职业教师（PI MA）。 UTEP和Dickson College的教育和外展活动与NSF资助的途径和Step学者以及UTEP的Earth Science Day合作，将使当地的高中学生和公众在快速成长且多样化的El Paso地区与削减关键区域研究主题（水，土壤和环境）的削减边缘重要区域。该项目将吸引未来的STEM学生，他们希望学习和解决当地社区面临的新兴环境问题。