GEODYNAMIC MODELING OF EDGE-DRIVEN CONVECTION IMAGED BY SIEDCAR (SEISMIC INVESTIGATION OF EDGE DRIVEN CONVECTION ASSOCIATED WITH THE RIO GRANDE RIFT)

SIEDCAR（与格兰德河裂谷相关的边缘驱动对流的地震调查）是一个由75个宽带地震仪组成的二维阵列，沿着大平原的西部边缘部署。SIEDCAR的目的是确定是否小规模的，边缘驱动的对流发生沿着边缘的大平原，东部的格兰德河裂谷带，如果是这样的话，它的横向尺寸是什么。SIEDCAR提案没有包括为地球动力学建模组件提供资金的请求，以解决其另外两个问题：1）什么条件导致边缘驱动对流，以及2）边缘驱动对流的构造（表面）效应是什么（如果有的话），以及它们如何与地质观测相匹配。虽然没有要求为地球动力学建模提供资金，但PI认为这是SIEDCAR提案的关键组成部分。s，由评审员和项目官员。目前的建议是为了追求资金的SIEDCAR的地球动力学建模组件，并与SIEDCAR的PIS Pulliam和Grand.Numerical实验合作开发的，岩石圈厚度的突然变化可能会对上地幔流动产生深远的影响。在岩石圈不连续面处存在下降流，在较薄的岩石圈之下存在上升流。地幔中的这种小规模对流（边缘驱动对流）是否是一种重要的、真实的世界现象，如果是的话，对地表地质的影响是什么，还不得而知。SIEDCAR将提供沿大平原边缘沿着上地幔的断层图像，边缘驱动对流发生在那里。我们的目标是回答以下问题：1）关于边缘驱动对流的过程：边缘驱动对流何时发生？什么流变学或其他参数影响这个过程？边缘驱动对流在3D中看起来如何？岩石圈的哪一部分可能脱离并沉入软流圈（只有地幔岩石圈还是下地壳？）什么是表面效应？在哪里（如果有的话）预计会部分融化？2)关于SIEDCAR拍摄的快速结构：这种快速结构与边缘驱动的对流有关吗？快速异常的性质是什么？3)关于地壳和地表效应：边缘驱动的对流与构造、地表过程（垂直运动）和新墨西哥州东南部的火山活动有什么关系？我们将使用数值软件Citcom进行边缘驱动对流的地球动力学模拟研究。此外，我们的博士生将做波形建模，以验证和校准以前产生的断层扫描。我们的研究计划将与SIEDCAR重叠一年。十名高中教师参加了SIEDCAR现场和数据分析工作和研讨会。SIEDCAR项目包括一个组成部分，为德克萨斯州和新墨西哥州的少数民族教师提供实地和数据分析经验，并与旨在增加地球科学多样性的独立E O项目合作。 通过与UT奥斯汀的GeoFORCE得克萨斯州公共/私人财团和题为通过专业发展为少数民族服务的K-12科学教育工作者加强多样性的途径项目（由美国国家科学基金会的机会资助增强地球科学的多样性（OEDG）计划）合作，我们访问了德克萨斯州地区合作卓越的科学教育招募高中教师。SIEDCAR项目汇集了一支热情和敬业的强大教师队伍。我们建议将该计划再延长一个夏天，以便在教师研讨会上增加地球动力学部分，并确保最终产品得到最终确定：有组织和有据可查。因此，我们建议在该项目的第一年为10名教师举办一次为期10天的讲习班，这是SIEDCAR讲习班的后续活动。这些课程将组织良好，记录良好，自成一体，并将广泛分发给感兴趣的教师。 将与SIEDCAR PI合作进行。

SIEDCAR (Seismic Investigation of Edge driven Convection Associated with the Rio Grande Rift) is a 2D array of 75 broadband seismographs deployed along the western edge of the Great Plains. SIEDCAR was designed to determine whether small-scale, edge-driven convection is occurring along the edge of the Great Plains, east of the Rio Grande rift zone, and if so, what its lateral dimensions are. The SIEDCAR proposal did not include a request for funding for a geodynamic modeling component to address its two other questions: 1) what conditions lead to edge-driven convection, and 2) what (if any) are tectonic (surface) effects of edge-driven convection and how do they match geologic observations. Although no funding was requested for the Geodynamic Modeling, it was considered a critical component of the SIEDCAR proposal by the PI?s, by the reviewers, and by the Program Officer. The present proposal serves to pursue funding for the geodynamic modeling component of SIEDCAR, and was developed in collaboration with SIEDCAR PIs Pulliam and Grand.Numerical experiments show that an abrupt change in the thickness of the lithosphere can have a profound effect on upper mantle flow. There is a downwelling at the lithospheric discontinuity, and upwelling below the thinner lithosphere. Whether such small-scale convective flow (edge-driven convection) in the mantle is a significant, real world phenomenon and, if so, what the effects on surface geology are, is unknown. SIEDCAR will provide tomographic images of the upper mantle along the edge of the Great Plains, where edge-driven convection supposedly occurs.Our goal of this proposal is to answer the following questions: 1) Regarding the process of edge-driven convection: When does edge-driven convection occur? What rheological or other parameters influence this process? How does edge-driven convection look like in 3D? Which part of the lithosphere may detach and sink into the asthenosphere (only mantle lithosphere or also lower crust?) What are surface effects? Where (if any) is partial melting expected? 2) Regarding the fast-velocity structure imaged by SIEDCAR: Is this fast-velocity structure related to edge driven convection? What is the nature of the fast-velocity anomaly? 3) Regarding crustal and surface effects: How does edge-driven convection relate to tectonics, surface processes (vertical movements), and volcanism in southeastern New Mexico?We will use the numerical software Citcom for a Geodynamic Modeling study of edge-driven convection. In addition, our PhD student will do waveform modeling to validate and calibrate the tomography produced previously. Our proposed research would overlap one year with SIEDCAR.Ten High-school teachers have participated in SIEDCAR field and data analysis efforts and workshops. The SIEDCAR project includes a component that provides field and data analysis experiences for minority-serving teachers in Texas and New Mexico in collaboration with separate E&O projects that aim to increase diversity in the geosciences. By partnering with UT Austin's GeoFORCE Texas public/private consortium and the project entitled Strengthening Pathways to Diversity Through Professional Development for Minority-Serving K-12 Science Educators (funded by NSF's Opportunities for Enhancing Diversity in the Geosciences (OEDG) Program), we accessed the Texas Regional Collaboratives for Excellence in Science Education to recruit the high school teachers. The SIEDCAR project has assembled a strong cadre of teachers who are enthusiastic and engaged. We propose to extend the program by one more summer, in order to add a geodynamic component to the teacher workshops and to ensure that final products are finalized: organized and well-documented. We thus propose to conduct a single, ten-days workshop for ten teachers in year one of this project which follows up on a SIEDCAR workshop. These lessons will be well-organized, well-documented, and self-contained and will be broadly distributed to interested teachers. They will be performed in collaboration with the SIEDCAR PIs.