The Appalachian peri-Gondwanan realm: a palaeogeographical perspective from the south
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The Appalachian peri-Gondwanan realm (APGR) is an extensive tract of exotic Neoproterozoic-early Palaeozoic crustal blocks that occupies the eastern flank of the orogen. Traditionally, southern APGR elements have been correlated with those of the northern Appalachians on the basis of gross geological similarities. Most palaeogeographical reconstructions of the APGR are based on data from the northern Appalachians; consequently in these reconstructions, southern APGR elements are viewed commonly either as being affiliated spatially with those of the north or ignored. However, emerging data from two southern Appalachian crustal blocks give new insights into the palaeogeography of the APGR. The Smith River allochthon may be a part of the APGR on the basis of recently obtained U-Pb monazite and staurolite ages that are apparently incompatible with a Laurentian origin. The allochthon and possibly adjacent terranes, appear to have followed a palaeogeographical track independent of other APGR elements. The Carolina zone is recognized as peri-Gondwanan in origin on the basis of its (i) gross geological evolution, (ii) fossil fauna and (iii) tectonic history. Mid-Palaeozoic regional kinematic patterns suggest that Carolina and its commonly held northern counterpart, the Avalon zone, travelled together on the same lithospberic plate, but their contrasting tectonic histories suggest that they formed along different margins of this plate. These interpretations lead to a new model for middle Palaeozoic interactions of the APGR with Laurentia. The Geological Society of London 2005.
