@article {2503, title = {Quantifying overwash flux in barrier systems: An example from Martha{\textquoteright}s Vineyard, Massachusetts, USA}, journal = {Marine Geology}, volume = {343}, year = {2013}, month = {Jan-09-2013}, pages = {15 - 28}, abstract = {Coastal barriers are particularly susceptible to the effects of accelerated sea-level rise and intense storms. Over centennial scales, barriers are maintained via overtopping during storms, which causes deposition of washover fans on their landward sides. Understanding barrier evolution under modern conditions can help evaluate the likelihood of future barrier stability. This study examines three washover fans on the undeveloped south shore of Martha{\textquoteright}s Vineyard using a suite of vibracores, ground penetrating radar, high resolution dGPS, and LiDAR data. From these data, the volumes of the deposits were determined and range from 2.1 to 2.4 {\texttimes} 104 m3. Two of these overwash events occurred during Hurricane Bob in 1991. The water levels produced by this storm have a calculated return interval of ~ 28 years, implying an onshore sediment flux of 2.4{\textendash}3.4 m3/m/yr. The third washover was deposited by a nor{\textquoteright}easter in January 1997, which has a water level return interval of ~ 6 years, suggesting a flux of 8.5 m3/m/yr. These onshore fluxes are smaller than the erosional flux of sediment resulting from shoreline retreat, suggesting that the barrier is not in long-term equilibrium, a result supported by the thinning of the barrier in recent years.}, keywords = {barrier system, Coastal evolution, overwash flux, sea-level rise, storm impacts}, issn = {00253227}, doi = {10.1016/j.margeo.2013.05.013}, url = {http://linkinghub.elsevier.com/retrieve/pii/S002532271300114Xhttp://api.elsevier.com/content/article/PII:S002532271300114X?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S002532271300114X?httpAccept=text/plain}, author = {Carruthers, Emily A. and Lane, D. Philip and Evans, Rob L. and Donnelly, Jeffrey P. and Ashton, Andrew D.} } @article {2556, title = {Refining the model of barrier island formation along a paraglacial coast in the Gulf of Maine}, journal = {Marine Geology}, volume = {307-310}, year = {2012}, month = {Jan-04-2012}, pages = {40 - 57}, abstract = {Details of the internal architecture and local geochronology of Plum Island, the longest barrier in the Gulf of Maine, have refined our understanding of barrier island formation in paraglacial settings. Ground-penetrating radar and shallow-seismic profiles coupled with sediment cores and radiocarbon dates provide an 8000-year evolutionary history of this barrier system in response to changes in sediment sources and supply rates as well as variability in the rate of sea-level change. The barrier sequence overlies tills of Wisconsinan and Illinoian glaciations as well as late Pleistocene glaciomarine clay deposited during the post-glacial sea-level highstand at approximately 17 ka. Holocene sediment began accumulating at the site of Plum Island at 7{\textendash}8 ka, in the form of coarse fluvial channel-lag deposits related to the 50-m wide erosional channel of the Parker River that carved into underlying glaciomarine deposits during a lower stand of sea level. Plum Island had first developed in its modern location by ca. 3.6 ka through onshore migration and vertical accretion of reworked regressive and lowstand deposits. The prevalence of southerly, seaward-dipping layers indicates that greater than 60\% of the barrier lithosome developed in its modern location through southerly spit progradation, consistent with a dominantly longshore transport system driven by northeast storms. Thinner sequences of northerly, landward-dipping clinoforms represent the northern recurve of the prograding spit. A 5{\textendash}6-m-thick inlet-fill sequence was identified overlying the lower stand fluvial deposit; its stratigraphy captures events of channel migration, ebb-delta breaching, onshore bar migration, channel shoaling and inlet infilling associated with the migration and eventual closure of the inlet. This inlet had a maximum cross-sectional area of 2800 m2 and was active around 3.5{\textendash}3.6 ka. Discovery of this inlet suggests that the tidal prism was once larger than at present. Bay infilling, driven by the import of sediment into the backbarrier environment through tidal inlets, as well as minor sediment contribution from local rivers, led to a vast reduction in the bay tidal prism. This study demonstrates that, prior to about 3 ka, Plum Island and its associated marshes, tidal flats, and inlets were in a paraglacial environment; that is, their main source of sediment was derived from the erosion and reworking of glaciogenic deposits. Since that time, Plum Island has been in a state of dynamic equilibrium with its non-glacial sediment sources and therefore can be largely considered to be in a stable, {\textquotedblleft}post-paraglacial{\textquotedblright} state. This study is furthermore the first in the Gulf of Maine to show that spit accretion and inlet processes were the dominant mechanisms in barrier-island formation and thus serves as a foundation for future investigations of barrier development in response to backbarrier infilling.}, keywords = {barrier-island formation, ground-penetrating radar, inlet processes, inlet-fill sequence, paraglacial, spit accretion}, issn = {00253227}, doi = {10.1016/j.margeo.2012.03.001}, url = {https://doi.org/10.1016/j.margeo.2012.03.001}, author = {Hein, Christopher J. and FitzGerald, Duncan M. and Carruthers, Emily A. and Stone, Byron D. and Barnhardt, Walter A. and Gontz, Allen M.} }