CAROLINIAN TECTONICS (Invited Presentation)
1) Building and amalgamation of arc terranes, metamorphic fabric development. In the Carolina slate t this is evinced by a post-537 Ma/ pre-Middle Cambrian angular unconformity. Sedimentary rocks above the unconf contain a diverse peri-Gondwanan fauna. In the Charlotte t, metamorphic fabric is cut by a 535±4 Ma pluton. Eclogite-Hi-P granulite Silverstreet t may record an Eocambrian event but must have formed before 415 Ma.
2) Rift-drift sequence of the Middle Cambrian opening of the Rheic Ocean is recorded by epiclastic and carbonate rocks of the Kings Mountain t.
3) Late Ordovician accretion of Carolinia to Laurentia is supported by paleomagnetic studies and Ar/Ar dating of phyllites in the Carolina Slate t, as well as structural and geochonologic studies along the Gold Hill fault zone.
4) Deposition of the Cat Square Salinic successor basin south of the New York Promontory. The Cat Square basin accepted detritus from Laurentia and Carolinia after 430 Ma. The basin is intruded by plutons as old as 415 Ma. Basin development was accompanied by lithospheric thinning, with Ludlow-Pridoli crustally derived melts, followed by Lower Devonian alkalic-subalkalkic mantle-derived gabbros and syenites.
5) Famennian collapse of this basin against Laurentia and beneath Carolinia occurred south of the New York Promontory resulting in upper amphibolite –granulite facies metamorphism and extensive anatexis within the Cat Square terrane. Erosion of these highlands yielded the Catskill clastic wedge capped by the Spechty Kopf-Rockwell Formations.
6) ≥ 500 km dextral transport along the Brevard zone during the Mississippian.
7) Final juxtaposition of terranes during Serpukhovian through Upper Pennsylvanian emplacement of the Blue Ridge-Piedmont composite crystalline thrust sheet, including movement along central Piedmont shear zone and Modoc zone.
8) Minor dextral strike terrane dispersal and gravitational collapse of the orogen complete by Guadalupian time.
9) Upper Triassic K-metasomatic alteration of Late Paleozoic mylonites is locally observed. Aspects of pre-Devonian development of Carolinia are comparable to Ganderia in the northern Appalachians.