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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751311
• 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.

作为地球科学的基础，板块构造范式描述了在大洋中脊产生的岩石圈板块，它们穿过地球表面的移动，以及通过俯冲到大洋海沟另一个板块之下而造成的破坏。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，并可能导致快速进化变化和生物多样性热点。地球地壳在弧后区域的垂直运动是与俯冲有关的造山过程的灵敏记录。因此，了解产生高原的过程有助于一系列学科的发展。我结合了定量的盆地分析、沉积物来源和古海拔重建来建立垂直地壳运动，并将这些运动与引起盆地(向下运动)或高原形成(向上运动)的过程联系起来，这些过程与俯冲系统的演化有关。我的研究的长期目标是确定全球高原的原因和影响。短期目标是通过研究玻利维亚中央安第斯高原来了解俯冲系统中的高原形成，该高原是从低海拔的弧后前陆盆地向高海拔高原过渡的原型。玻利维亚和秘鲁中安第斯高原最近的弧后演化模式强调了统一的盆地和隆起史。我最近的研究(1)在秘鲁修正了这一模型，提供了盆地北段可能被早期分割的证据，并伴随着俯冲变浅，以及(2)发展了一个新的时空可变的地表隆起范例，涉及高原建设的多个过程。我将通过确定盆地形成的速度和地点记录地壳向下运动，并通过应用多变量方法确定沉积盆地充填的来源和年龄来确定沉积源区。我还将应用一种新的方法来评估该地区的古海拔历史，这将扩展并独立验证先前的古海拔研究。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来源数据集。这项研究将为至少3名博士、2名硕士和5名本科生以及可能还有一名哥伦比亚博士后研究员(等待额外资金)的多样化的国际群体提供基于现场和实验室的多学科培训。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，并将通过成功完成学业和进入他们的职业生涯来指导学生，从而增加传统上代表性不足的群体在地球科学中的代表性和成功。