COLLABORATIVE RESEARCH: Taconic vs. Acadian Tectonothermal Record in the Blue Ridge: Rb-Sr and 40 Ar/39 Ar Mineral Age Constraints

最近在阿巴拉契亚山脉南部西部蓝岭省变质碎屑岩中发现的志留纪/早泥盆世化石，对蓝岭构造演化的主流观点提出了质疑。化石岩石表明变质作用一定是泥盆纪或更早的，而一些已发表的放射性年龄表明奥陶纪变质作用。这项研究将解决塔克期(奥陶系)与阿卡迪期(泥盆纪)变质作用的范围和作用，从而解决古生物和放射性数据之间的差异。40Ar/39Ar和Rb/Sr年代学将在两个研究较好的地区应用，以限制变质作用、糜棱岩化和逆冲作用的时间。这项研究的结果将解决目前围绕阿巴拉契亚山脉南部蓝岭结晶岩构造演化的争议。

Recent discoveries of Silurian/early Devonian fossils in metamorphosed clastic rocks of the western Blue Ridge province, southern Appalachians have called into question the prevailing views of Blue Ridge tectonic evolution. The fossiliferous rocks indicate that metamorphism must be Devonian or younger, whereas a number of published radiometric ages indicate Ordovician metamorphism. This study will resolve the extent and role of Taconic (Ordovician) versus Acadian (Devonian) metamorphism and thus the discrepancies between the paleontologic and radiometric data. 40Ar/39Ar and Rb/Sr geochronology will be used in two well- studied areas to constrain the timing of metamorphism, mylonitization and thrusting. The results of this study will resolve the current controversy surrounding the tectonic evolution of the Blue Ridge crystalline rocks of the southern Appalachians.