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

西班牙和法国的比利牛斯山脉为研究与板内造山系统形成有关的基本构造过程提供了一个极好的天然实验室。皮尔涅斯造山带是伊比利亚板块和欧洲板块之间大陆-大陆汇聚的结果，始于约8000万年前。在比利牛斯山脉中部，由于汇聚而导致的缩短最初是在会聚之前形成的残余伸展构造上进行的，当时该地区是一个伸展盆地。当残留的伸展构造不再适应缩短时，变形被逆冲断层上的运动所吸收，从而形成了堆叠的不规则推覆构造。板块重建和平衡剖面表明，变形年轻向西，会聚量向西减少，山脉结构变化较大。该项目使用中低温度热年代学方法来限制比利牛斯山脉带内岩石的时间-温度历史的变化。利用磷灰石裂变径迹热年代学、磷灰石U-Th-He定年和Ar-Ar分析对比利牛斯山中西部花岗岩地块钾长石进行定年，约束了造山带热史和剥蚀史的跨走向(南北走向)和沿走向(东西走向)变化。剥蚀史的变化被用来评估会聚/逆冲的开始是与抬升和剥蚀同步还是历时的，剥蚀是否向西延伸，剥蚀量是否向西减少，以及跨走向剥蚀模式是对称的还是不对称的。这些结果正被用来量化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形成有关的过程。这项研究的结果引起了研究造山系统的广泛地球科学家的兴趣，其中包括热年代学家、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家。Funding为博士后研究助理和本科生提供研究培训和教育。该项目以实地和实验室为基础的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访问，包括实地考察、项目讨论和共享使用分析设施，加强了国际科学合作和教育培训。

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.