PALEOMAGNETISM OF MESOZOIC BASALTS IN THE POMPERAUG BASIN, CONNECTICUT

The Pomperaug Basin is a small Mesozoic basin in west-central Connecticut, filled with sedimentary rocks separated by three lava flows: South Brook, Orenaug, and East Hill. These lava flows are generally considered to be of the same age as the three lava flows in the Hartford/Deerfield Basin and the Newark Basin.

Paleomagnetic work in the Hartford/Deerfield, Newark, and Culpeper Basins indicates that one of the lava flows (middle flow in the Hartford and Newark Basins, only flow in the Deerfield Basin, and upper flow in the Culpeper Basin) has a magnetic inclination that is shallower than that of the other flows. They also have a corresponding paleomagnetic pole at a lower latitude than those for the other units. These data suggest a magnetic excursion event during the short interval of time when these flows were cooling.

Preliminary data from the lava flows in the Pomperaug Basin show a similar relationship, supporting the hypothesis that the Pomperaug Basin flows are correlative with the lava flows in the other basins, and adds weight to the suggestion of a magnetic excursion in the early Jurassic.