CAREER: Middle and Late Cenozoic Surface Uplift and Climate along the Strike of the Rocky Mountains: Refining the Development of an Intracontinental Mountain Belt

北美西部的落基山脉是大陆内山脉带的最好例子。厚的白垩纪海洋沉积物提供了明确的证据，表明该地区在大约80 Ma前接近海平面。然而，随后的垂直运动的历史，形成了现在的地形没有那么好的约束，但至关重要的了解构造过程和驱动力的山脉形成在大陆内部。该项目旨在限制落基山脉和西部大平原的地表隆起以及过去3500万年来相关的气候变化。国家的最先进的同位素方法将被用来估计古地形沿着样带在北方和南部落基山脉。研究结果将检验这一假设，即落基山脉隆起的时间和幅度沿其长度沿着变化，这些变化可以限制在这一时期形成落基山脉的复杂地球动力学过程。该职业奖的教育部分涉及协调一致的努力，让来自STEM中代表性不足的少数民族的学生参与进来，并为研究生提供教学培训，以更好地为他们的学术生涯做好准备。具体来说，该项目将通过为期两天的GEOCAMP，向德克萨斯州东部约100名代表性不足的少数民族高中生介绍地球科学家的专业活动和职业前景，让代表性不足的高中生和本科生参与研究，并培训博士生在教学中为不同的学习者实施最佳实践，作为成功职业生涯的一部分。典型陆内造山带的研究表明，落基山脉隆升的动力学驱动因素是复杂的，包括：（1）晚白垩世-早始新世地壳增厚缩短，或与低角度俯冲或洋坪移走有关的地幔动力学过程;（2）中新生代洋板拆离;（3）晚新生代地幔上涌和热均衡。发生的时间和每种机制所起的作用可能沿着山脉的走向而变化。这个项目探讨了这样一种观点，即落基山脉的隆起的时间和幅度沿沿着走向变化，这些变化是由新生代中期至晚期复杂但可解释的地球动力学过程造成的。具体而言，该项目将：（1）校准第四纪河流碳酸盐胶结物的块状同位素地质温度计，以评估其在古海拔和古气候重建中的应用;（2）通过使用碎屑和凝灰岩锆石U-Pb地质年代学确定沉积年龄，改进落基山脉和邻近的大平原以及东德克萨斯州中新生代和上新生代地层的年代地层学;（3）利用碳酸盐凝块同位素和火山玻璃氢同位素古高度计记录落基山脉及其邻近大平原沿着走向的古地形和古气候演化，以了解落基山脉形成的构造过程和新生代中晚期的气候变化。

The Rocky Mountains of the western North America is the premier example of intracontinental mountain belts. Thick Cretaceous marine deposits provide unambiguous evidence that the region was near sea level at about 80 Ma ago. However, the history of subsequent vertical movements that formed present topography are less well constrained, yet crucial for understanding the tectonic processes and driving forces by which mountains form in continental interiors. This project aims to constrain the surface uplift of the Rocky Mountains and western Great Plains and associated climate changes during the last 35 million years. State-of-the-art isotopic methods will be used to estimate the paleotopography along transects in the northern and southern Rocky Mountains. The results will test the hypothesis that the timing and magnitude of uplift of the Rockies varied along its length, variations that can constrain the complex geodynamic processes the formed the Rockies during the this time period. The educational component of this CAREER award involve concerted efforts to engage students from underrepresented minorities in STEM and to provide teaching training to graduate students to better prepare them for academic careers. Specifically, the project will introduce professional activities and career outlooks of geoscientists to about 100 underrepresented minority high-school students in east Texas through a two-day long GEOCAMP, involve underrepresented high-school and undergraduate students in research, and train doctoral students to implement best practices in teaching for diverse learners as part of successful professional careers.Recent geologic and geophysical observations of this classic intracontinental mountain belt demonstrate that the geodynamic drivers of Rocky Mountain uplift are complex and include: (1) late Cretaceous-early Eocene crustal thickening and shortening, or mantle dynamic processes related to low-angle subduction or the removal of an oceanic plateau; (2) middle Cenozoic detachment of oceanic slab; and/or (3) late Cenozoic mantle upwelling and thermal isostasy. The timing of occurrence and the role each mechanism played probably varied along the strike of the range. This project explores the idea that the timing and magnitude of the uplift of the Rockies varied along strike, and that these variations resulted from complex, but decipherable, geodynamic processes during the mid- to late Cenozoic. Specifically, the project will: (1) calibrate clumped isotope geothermometer of Quaternary fluvial carbonate cement in order to evaluate its application to paleoelevation and paleoclimate reconstructions; (2) improve the chronostratigraphy of the middle and upper Cenozoic strata in the Rockies and adjacent Great Plains as well as east Texas by determination depositional ages using detrital and tuff zircon U-Pb geochronology; and (3) document the paleotopographic and paleoclimatic evolution of the Rockies and the adjacent Great Plains along strike using carbonate clumped isotope and volcanic glass hydrogen isotope paleoaltimeters in order to understand the tectonic processes of the formation of the Rockies and associated climate changes during the middle and late Cenozoic.