Geodynamic mechanisms of basin and plateau formation in subduction settings

俯冲背景下盆地和高原形成的地球动力学机制

• 批准号: RGPIN-2020-04691
• 负责人: Saylor, Joel
• 金额: $ 2.19万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716660
• 关键词: Geodynamic; mechanisms; basin; plateau; formation

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.

板块构造范式是地球科学的基础，它描述了大洋中脊岩石圈板块的产生，它们在地球表面的平移，以及在海沟另一个板块之下俯冲而造成的破坏。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，并可能导致迅速的进化变化和生物多样性热点。弧后地壳的垂直运动，即岩浆弧与海沟相对的区域，是与俯冲有关的造山过程的敏感记录器。因此，了解产生高原的过程可以为一系列学科提供信息。我整合定量盆地分析，沉积物来源，和古高程重建，建立垂直地壳运动和链接的过程，导致盆地（向下运动）或高原形成（向上运动）有关的俯冲系统的演变。 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来了解俯冲系统中高原的形成，该高原是从低海拔弧后前陆盆地向高海拔高原过渡的典型。玻利维亚和秘鲁的中安第斯高原弧后演化的最新模式强调了一个统一的盆地和隆起历史。我最近的研究（1）在秘鲁修正了这一模型，提供了盆地北方段可能已被早期分割的证据，伴随着俯冲的变浅，（2）开发了一个时空可变的地表隆起的新范例，暗示了高原建设的多个过程。 我将通过确定盆地形成的速率和轨迹，以及确定沉积物源区，通过应用多变量方法来确定沉积盆地填充的来源和年龄，来记录地壳向下运动。我还将采用一种新的方法来评估这一地区的古高程历史，这将扩展和独立验证以前的古高程研究。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来源数据集。 这项研究将提供多学科领域和实验室为基础的培训，至少有3个博士，2个硕士，和5个本科生，以及潜在的哥伦比亚博士后研究员（等待额外的资金）的多元化，国际组。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，并将指导学生通过成功完成并进入他们的职业生涯，从而增加在地球科学传统上代表性不足的群体的代表性和成功。