Geodynamic mechanisms of basin and plateau formation in subduction settings

作为地球科学的基础，板块构造范式描述了在洋中脊的岩石圈板块的形成，它们在地球表面的平移，以及在海沟的另一个板块下的俯冲而造成的破坏。俯冲带可以形成具有极端地形的高原，对大气环流和地球气候产生深远影响，并可能导致快速的进化变化和生物多样性热点。在岩浆弧与海沟相对的地区，弧后地壳的垂直运动是与俯冲有关的造山过程的敏感记录。因此，了解产生高原的过程可以为一系列学科提供信息。我将定量盆地分析、沉积物物源和古高程重建结合起来，建立垂直地壳运动，并将这些运动与引起盆地（向下运动）或与俯冲系统演化相关的高原形成（向上运动）的过程联系起来。我研究的长期目标是确定全球高原的原因和影响。短期目标是通过考察玻利维亚中部安第斯高原，了解俯冲系统中的高原形成。玻利维亚中部安第斯高原是低海拔、弧后前陆盆地向高海拔高原过渡的典型。玻利维亚和秘鲁中部安第斯高原的弧后演化模式强调盆地和隆升历史的统一。我最近在秘鲁的研究(1)通过提供盆地北段可能早被分割的证据来修正这一模型，并伴随着俯冲的变浅；(2)发展了一个时空变化的地表隆起的新范式，暗示了高原构造的多个过程。我将通过确定盆地形成的速率和轨迹来记录地壳向下运动，以及通过应用多元方法确定沉积盆地填充的来源和年龄来确定沉积物源区。我还将应用一种新的方法来评估该地区的古海拔历史，这将扩展和独立验证以前的古海拔研究。最后，我将在直观的开源软件中开发新的分析工具，以分析如上所述的多变量沉积物物源数据集。该研究将为至少3名博士、2名硕士和5名本科生以及潜在的哥伦比亚博士后（待额外资助）组成的多元化国际团队提供多学科领域和实验室培训。这两个硕士项目将由玻利维亚妇女领导，她们将于2020年秋季开始。我将建立一个支持性和包容性的研究环境，并将指导学生顺利完成学业并进入他们的职业生涯，从而增加传统上代表性不足的群体在地球科学领域的代表性和成功。

Underpinning the geosciences, the plate tectonic paradigm describes creation of lithospheric plates at mid-ocean ridges, their translation across Earth's surface, and destruction by subduction beneath another plate at oceanic trenches. Subduction zones can develop plateaus with extreme topography that have profound impacts on atmospheric circulation, the Earth's climate, and can lead to rapid evolutionary change and biodiversity hotspots. Vertical movement of the Earth's crust in the retroarc, the region on the opposite side of the magmatic arc from the trench, is a sensitive recorder of mountain-building processes related to subduction. Understanding the processes that produce plateaus therefore informs a range of disciplines. I integrate quantitative basin analysis, sediment provenance, and paleoelevation reconstructions to establish vertical crustal movements and link those to the processes that cause basin (downward movement) or plateau formation (upward movement) related to the evolution of subduction systems. The long-term objective of my research is to determine the causes and impacts of plateaus globally. The short-term objective is to understand plateau formation in subduction systems by examining the Bolivian Central Andean Plateau, which is archetypal of the transition from a low-elevation, retroarc foreland basin to a high-elevation plateau. Recent models of retroarc evolution in the Central Andean Plateau of Bolivia and Peru have emphasized a unified basin and uplift history. My recent research (1) revised this model in Peru by providing evidence that the northern segment of the basin may have been partitioned early, accompanying shallowing of subduction, and (2) developed a new paradigm of spatially and temporally variable surface uplift implicating multiple processes in plateau construction. I will document downward crustal movement by determining the rate and locus of basin formation, as well as identifying sediment source areas, through application of a multi-variate approach to determine the source and age of sedimentary basin fill. I will also apply a new method to assess the paleoelevation history of this region that will extend and independently verify previous paleoelevation research. Finally, I will develop new analytical tools in intuitive, open-source software to analyze multi-variate sediment provenance data sets such as the one described above. This study will provide multi-disciplinary field- and lab-based training to a diverse, international group of at least 3 PhD, 2 MSc, and 5 undergraduate students as well as potentially a Colombian post-doctoral fellow (pending additional funding). The 2 MSc projects will be led by Bolivian women who are starting in Fall 2020. I will establish a supportive and inclusive research environment, and will mentor students through successful completion and on into their careers thus increasing representation and success of traditionally underrepresented groups in the geosciences.