NEW GEOLOGIC MAP AND GEOCHRONOLOGY OF THE GREAT SMOKY MOUNTAINS NATIONAL PARK REGION, TN/NC
The new studies have revealed that the rocks of the region were affected by multiple tectonic events from the Mesoproterozoic through the Paleozoic. Geochronologic analyses of zircon, sphene, monazite, and xenotime using U-Pb SHRIMP, 40Ar/39Ar analysis of hornblende and muscovite, fission-track analysis of zircon and apatite, and 10Be techniques document the following tectonic history:
1) Mesoproterozoic plutonism and tectonism from ca. 1195 to 1030 Ma associated with Grenvillian orogenesis;
2) Neoproterozoic uplift, cooling, erosion, extension, and sedimentation from ca. 870 to 700 Ma;
3) metamorphism at lower greenschist-facies from 685 to 560 Ma, amphibolite-facies at ca. 440 Ma (Taconian), and greenschist-facies accompanied by deformation at ca. 350 to 340 Ma (Neoacadian) and ca. 280 Ma (Alleghanian); and
4) post-Triassic unroofing, uplift, and erosion at rates between 28 and 18 m/m.y.