PALEOMAGNETISM OF THE NEWARK TREND IGNEOUS ROCKS OF THE NORTH CENTRAL APPALACHIANS AND THE OPENING OF THE CENTRAL ATLANTIC OCEAN

Paleomagnetic results from 28 sites on the Early Mesozoic Barndoor, East Rock, Mt. Carnmel, and West Rock intrusives of the Hartford Basin, central Connecticut, yield VGPs in an area bounded by 52.1o to 116.8oE, 57.6 to 80.0oN. These results, along with previously published paleomagnetic data from Connecticut, suggest two periods of igneous activity, dated by radiometric and biostratigraphic methods at about 190 and 175 m.y. Paleomagnetic pole positions and ages of Newark trend igneous rocks elsewhere in the north central Appalachians suggest that the two igneous pulses were of regional extent, represented by mean pole positions (including the Connecticut results) located at 83.2oE, 63.0oN (190 m.y. age group) and at 103.2oE, 65.3oN (175 m.y. age group). These pole positions show about 9o of eastward apparent polar wander, in good agreement with results from paleomagnetic studies of Late Triassic-Middle Jurassic rocks in the western United States. -Authors