CONTINUATION OF NORTHERN APPALACHIAN BROMPTON-CAMERON,CENTRAL MAINE, AND AVALON TERRANES UNDER THE NEW JERSEY COASTAL PLAIN

A regional terrane map of the New Jersey Coastal Plain basement was constructed using seismic, drilling, gravity and magnetic data. The Brompton-Cameron (BC) and Central Maine (CM) terranes were coalesced as one volcanic island arc terrane before obducting onto Laurentian, Grenville age, continental crust in the Taconic Orogeny. Volcanic island arc rocks of the Avalon (AV) terrane are in contact with Central Maine terrane rocks in southern Connecticut where the latter are overthrust onto Brompton-Cameron, which is thrust over Laurentian basement. Similarities of these allochthonous island arc terranes (BC, CM, AV) in lithology, fauna and age suggest that they are faulted segments of the margin of one major late Precambrian to early Paleozoic, high latitude, peri-Gondwanan island arc plate designated as "Avalonia", which collided with Laurentia in the early to middle Paleozoic. The BC/AV terranes are projected as the basement under the eastern New Jersey Coastal Plain based on drill core samples of metamorphic rocks of active margin/magmatic arc origin. A seismic reflection profile across the New York Bight traces the gently dipping (~ 20 degrees ) Cameron's Line Taconic suture southeast beneath allochthonous Avalon and other terranes to a 4s TWTT depth (~ 9km) where the Avalonian rocks are over Laurentian crust. Gentle up-pluge (~ 5 degrees) projections to the southwest bring the Laurentian Grenville age basement and the drift-stage early Paleozoic cover rocks to windows in Burlington Co. at ~ 1 km and Cape May Co. at ~ 2 km depths. The antiformal Chester/Shellburne Falls dome and Chain Lakes/Pelham dome/Bronson Hill structural trends, and the synformal Connecticut Valley/Gaspe structural trend can be traced southwest into the New Jersey Coastal Plain basement.