SEDIMENTATION PROCESSES AND MORPHOLOGICAL BEHAVIOR OF LOVELLS ISLAND, BOSTON HARBOR MA

Lovells Island is located at the entrance to Boston Harbor, MA and is exposed to the dominant northeast wave climate of the region. The island consists of several drumlins connected by spits, which have evolved into salients along the southwest facing portion of the island and formed a lagoon at the northeast end. Lovells Island is unique because it contains the only robust dune system in Boston Harbor; the dune sand is well-sorted sand but mineralogically immature. The source of sand, mode of salient development, and present erosional-depositional shoreline trends are being studied using historical, sedimentologic, and geophysical data.

Sedimentological and mineralogical data suggest that sediment is moving westward around the southern tip of Lovells Island, and southward from the north end of the island. This is evident from fining grain sizes from the SE -0.26, to the NW 2.6 phi, and standard deviations that range from very poorly sorted 1.08 at the SE to very well sorted 0.167 in the NW. This trend is consistent with the relative mineralogical maturity of the shore where the percentage of quartz increases from the SE (35%) to the NW (42%).

A sediment budget of Lovells Island suggests that Rams Head contained ample sand to have provided a sediment source for the dune systems on the southwest shore. It is theorized that northeast storms transported sediment from Rams Head towards Lovells Island and that sediment was reworked west and southward along the shore by local wave energy. Volume calculations of the relict Rams Head are based on an estimated paleo-drumlin height of 10m, a diameter of 250m, and a 34% sand drumlin composition, yielding a sand volume of 167,000 m3, which is slightly less than the dune volume of 188,000 m3. Further investigation of hydrodynamics, and accretionary history with maps, nautical charts and GPR data will help to identify the evolution of accretionary structures and determine whether the volume of sand is stable/increasing or depleting.