Along-Strike Variation of the Uplift and Exhumation of the Pyrenean Orogen: Constraining the Evolution of an Intraplate Collisional Orogen

比利牛斯造山带隆升折返的沿走向变化：制约板内碰撞造山带的演化

• 批准号: 0538216
• 负责人: Paul Fitzgerald
• 金额: $ 31.51万
• 依托单位: Syracuse University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538216&HistoricalAwards=false
• 关键词: Along; Strike; Variation; Uplift; Exhumation

The Pyrenean Mountains of Spain and France provide an excellent natural laboratory to study fundamental tectonic processes involved in the formation of intraplate orogenic systems. The Pyrnenean Orogen formed as a result of continent-continent convergence between the Iberian plate and the European Plate, beginning ~80 million years ago. In the central Pyrenees, shortening due to convergence was initially accommodated on relict extensional structures, formed prior to convergence, when the region was an extensional basin. When relict extensional structures could no longer accommodate shortening, deformation was taken up by movement on thrust faults that led to the formation of stacked antiformal nappes. Plate reconstructions and balanced cross-sections indicate deformation youngs to the west, the amount of convergence decreases to the west and the structure of the mountain range varies considerably. This project uses low to medium temperature thermochronologic methods to constrain the variation in the time-temperature history of rocks within the Pyrenean mountain belt. The across-strike (north-south trend) and along-strike (east-west trend) variation in the thermal, and denudation history of the orogen are being constrained using apatite fission track thermochronology, apatite Uranium-Thorium-Helium dating and Argon-Argon analysis of potassium feldspars on selected granite massifs from the central and western Pyrenees. The variation in the denudation history is being used to assess whether the onset of convergence/thrusting is synchronous or diachronous with uplift and erosion, whether denudation youngs to the west, if the amount of denudation decreases westward, and if the across-strike denudation pattern is symmetric or asymmetric along the range. These results are being used to quantify the four dimensional evolution of the Pyrenean continental collisional orogen and to evaluate processes associated with the formation of intraplate orogenic systems. The outcome of this research is of interest to a wide range of earth scientists who study orogenic systems, including thermochronologists, tectonicians, geodynamicists, reflection seismologists, sedimentologists and basin analysts. Funding provides research training and education for a postdoctoral research associate and undergraduate students. Field and lab based components of this project promote integration of research with teaching activities. Collaboration with Spanish colleagues enhances international scientific cooperation and educational training, by facilitating visits that include fieldwork, project discussions, and shared use of analytical facilities.

西班牙和法国的比利牛斯山脉为研究板内造山系统形成过程中的基本构造过程提供了极好的天然实验室。 Pyrnenean造山带是伊比利亚板块和欧洲板块之间的大陆-大陆会聚的结果，开始于约8000万年前。 在比利牛斯山脉中部，由于收敛而缩短的长度最初是在收敛之前形成的残余伸展构造上进行调节的，当时该地区是一个伸展盆地。 当残余的伸展构造不能再容纳缩短时，变形被逆冲断层的运动所吸收，导致叠置的反形式推覆体的形成。 板块重建和平衡剖面表明，变形向西倾斜，会聚量向西减少，山脉的结构变化很大。 该项目使用中低温热年代学方法来限制比利牛斯山脉带内岩石的时间-温度历史变化。造山带的热历史和剥蚀历史的横向（南北走向）和纵向（东西走向）变化正在受到磷灰石裂变径迹热年代学、磷灰石铀-钍-氦定年和对比利牛斯山脉中部和西部选定花岗岩碎屑上钾长石的氩-氩分析的制约。剥蚀历史的变化被用来评估聚合/逆冲作用的开始是否与隆起和侵蚀同步或穿时，剥蚀是否向西倾斜，剥蚀量是否向西减少，以及跨走向剥蚀模式是否沿山脉沿着对称或不对称。 这些结果被用来量化的比利牛斯大陆碰撞造山带的四维演化，并评估与板内造山系统的形成过程。 这项研究的成果引起了研究造山系统的广大地球科学家的兴趣，包括热年代学家、构造学家、地球动力学家、反射地震学家、沉积学家和盆地分析师。资助为博士后研究助理和本科生提供研究培训和教育。该项目的实地和实验室组成部分促进了研究与教学活动的整合。与西班牙同事的合作通过促进包括实地考察、项目讨论和共享分析设施在内的访问，加强了国际科学合作和教育培训。