TY - Generic T1 - Subtle modification of glacially derived materials along Massachusetts’ southern coast by passing summer storms T2 - Abstracts with Programs - Geological Society of America Y1 - 2015 A1 - Nicholas L Venti A1 - Sabina Gessay A1 - Paul Southard A1 - Douglass Beach A1 - Margot Mansfield A1 - Stephen B Mabee A1 - Jonathan D Woodruff KW - #StaffPubs KW - Barges Beach KW - beach KW - beach erosion KW - beach profile KW - BOEM KW - Buzzard's Bay KW - climate change KW - coast KW - coastal KW - cobble KW - Cuttyhunk Island KW - dune KW - East beach KW - Edgartown KW - erosion KW - Falmouth KW - grain-size KW - Horseneck beach KW - intertidal KW - Low beach KW - Martha's Vineyard KW - Miacomet beach KW - Nantucket KW - nourishment KW - Oak Bluffs KW - offshore KW - onshore KW - Plum Island KW - profiles KW - sand KW - sea level rise KW - storm KW - Surf Beach KW - Sylvia State beaches KW - Town beach KW - Westport KW - winter storm AB - Engineered resupply of sand to coastal environments, i.e. nourishment, offers an attractive short-term strategy to address beach erosion in Massachusetts. For efficient nourishment, site-specific knowledge of seasonal grain size and sediment volume variability at eroding beaches is essential. We have begun measuring grain size and profile at 22 eroding Massachusetts beaches, capturing summer and winter conditions at each site through four to nine representative transects perpendicular to the shore and spaced 100-500 meters apart. Our recently completed first summer field season (August/September 2014) visited eight beaches along Massachusetts’ south coast from Rhode Island to Nantucket. These environments should reflect regional glacial history and a summer interval of reduced storm activity. Where unstratified surficial materials characterize the coast, erosion of glacial till (Horseneck and East beaches, Westport) and end moraine (Barges Beach, Cuttyhunk Island; Town and Sylvia State beaches, Oak Bluffs/Edgartown) can yield cobble berms capping steep intertidal zones. We noted that increased wave activity during storms strips a thin (inches-thick) layer of intertidal sand to reveal gravel and cobble below, while leaving beach profile essentially unchanged. In contrast, where (cobble-free) glacial outwash intersects the coast (Surf Beach, Falmouth; Miacomet and Low beaches, Nantucket) sand and gravel are distributed more evenly across beach facies. Here passing summer storms modify beach profile but not grain size: high surf cuts sandy berms, shifting steepened intertidal zones landward. We will reoccupy south coast sites at the end of winter in 2015 to examine effects of seasonally related increase in storm (and wave) activity. Survey of Massachusetts’ east coast (Sandwich to New Hampshire) is planned for summer of 2015 and winter of 2016. Additionally, overwash sequences recovered through backbarrier basin coring at selected sites complement our beach survey by providing depositional records of particularly strong storms. Study results will allow identification of suitably matched nourishment sources onshore, or offshore, as described in Massachusetts’ Office of Coastal Zone Management’s extensive grain-size database. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - Northeastern Section - 50th Annual Meeting (23–25 March 2015), Bretton Woods, NH VL - 47 UR - https://gsa.confex.com/gsa/2015NE/webprogram/Paper252510.html ER - TY - RPRT T1 - Field Investigation of the Geology and Possible Pisolitic Bauxite Occurrence at Menemsha Hills Reservation, Martha’s Vineyard, Massachusetts Y1 - 2008 A1 - Stephen B Mabee A1 - Panish, P. KW - #MGSPub KW - #MGSPubs KW - #Minerals KW - #Reports KW - aluminum KW - bauxite KW - ferricrete KW - glacial KW - hematite KW - Holocene KW - Martha's Vineyard KW - Menemsha Hills KW - minerals KW - ore KW - oxides KW - pisolite KW - pisolitic KW - precipitation KW - reservation KW - thrust faults KW - Trustees KW - Vineyard AB - The Office of the Massachusetts State Geologist was asked by The Trustees of Reservations to make an assessment of an unusual deposit of what appears to be pisolitic bauxite or iron hardpan exposed on the beach at Menemsha Hills Reservation in Chilmark, Massachusetts. The formation occurs as thin 10-20 cm wide lenses extending from 0.5 to 6 meters in length. They are found most commonly along a 200 to 250 meter section of the shore in the intertidal zone. The intact lenses trend northeast at about 25° to 35° and dip at 61° to 75°. The material occurs in a variety of forms. These include hematite and clay rich botyoidal (grape-like) surfaces, as iron hardpan cementing together gravel and pebble-sized stones, and as 1-2 cm wide pisolites (concentrically layered round structures). Prepared for the Trustees of Reservations PB - Office of the Massachusetts State Geologist CY - Amherst, MA UR - http://www.geo.umass.edu/stategeologist/Products/reports/FinalReport.pdf ER -