@article {2744, title = {Holocene sea-level variability from Chesapeake Bay Tidal Marshes, USA}, journal = {The Holocene}, volume = {29}, year = {2019}, month = {Dec-11-2020}, pages = {1679 - 1693}, abstract = {We reconstructed the last 10,000 years of Holocene relative sea-level rise (RSLR) from sediment core records near Chesapeake Bay, eastern United States, including new marsh records from the Potomac and Rappahannock Rivers, Virginia. Results show mean RSLR rates of 2.6 mm yr-1 from 10 to 8 kilo-annum (ka) due to combined final ice-sheet melting during deglaciation and glacio-isostatic adjustment (GIA subsidence). Mean RSLR rates from ~6 ka to present were 1.4 mm yr-1 due mainly to GIA, consistent with other East Coast marsh records and geophysical models. However, a progressively slower mean rate (<1.0 mm yr-1) characterized the last 1000 years when a multi-century-long period of tidal marsh development occurred during the {\textquoteleft}Medieval Climate Anomaly{\textquoteright} (MCA) and {\textquoteleft}Little Ice Age{\textquoteright} (LIA) in the Chesapeake Bay region and other East Coast marshes. This decrease was most likely due to climatic and glaciological processes and, correcting for GIA, represents a fall in global mean sea level (GMSL) near the end of Holocene Neoglacial cooling. These pre-historical climate- and GIA-driven Chesapeake Bay sea-level changes contrast sharply with those based on Chesapeake Bay tide-gauge rates (3.1{\textendash}4.5 mm yr-1) (back to 1903). After subtracting the GIA subsidence component, these rates can be attributed to long-term (millennial) global factors of accelerated ocean thermal expansion (~1.0 mm yr-1) and mass loss from alpine glaciers and Greenland and Antarctic Ice Sheets (1.5{\textendash}2.0 mm yr-1).}, keywords = {chesapeake bay, Foraminifera, Holocene, sea level, tidal marsh, US East Coast}, issn = {0959-6836}, doi = {10.1177/0959683619862028}, url = {http://journals.sagepub.com/doi/10.1177/0959683619862028}, author = {Cronin, Thomas M and Clevenger, Megan K and Tibert, Neil E and Prescott, Tammy and Toomey, Michael and Hubeny, J Bradford and Abbott, Mark B and Seidenstein, Julia and Whitworth, Hannah and Fisher, Sam and Wondolowski, Nick and Ruefer, Anna} } @article {2743, title = {The Mighty Susquehanna{\textemdash}Extreme Floods in Eastern North America During the Past Two Millennia}, journal = {Geophysical Research Letters}, volume = {46}, year = {2019}, month = {Apr-03-2021}, pages = {3398 - 3407}, abstract = {The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high-flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99-2209, a sediment core recovered in 26 m of water from Chesapeake Bay near Annapolis, Maryland, United States. We identify coarse-grained deposits left by Hurricane Agnes (1972) and the Great Flood of 1936, as well as during three intervals that predate instrumental flood records (~1800{\textendash}1500, 1300{\textendash}1100, and 400{\textendash}0 CE). Comparison to sedimentary proxy data (pollen and ostracode Mg/Ca ratios) from the same core site indicates that prehistoric flooding on the Susquehanna often accompanied cooler-than-usual winter/spring temperatures near Chesapeake Bay{\textemdash}typical of negative phases of the North Atlantic Oscillation and conditions thought to foster hurricane landfalls along the East Coast.}, issn = {0094-8276}, doi = {10.1029/2018GL080890}, url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL080890}, author = {Toomey, Michael and Cantwell, Meagan and Colman, Steven and Cronin, Thomas and Donnelly, Jeffrey and Giosan, Liviu and Heil, Clifford and Korty, Robert and Marot, Marci and Willard, Debra} } @article {2739, title = {Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins}, journal = {Climate of the Past}, volume = {13}, year = {2017}, month = {Jan-01-2017}, pages = {1097 - 1110}, abstract = {Deglacial (12.8{\textendash}10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM; \~{} 24 kiloannum or ka) minimum sea level of \~{} 125{\textendash}130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( \~{} 400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42{\textendash}47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.}, doi = {10.5194/cp-13-1097-2017}, url = {https://cp.copernicus.org/articles/13/1097/2017/}, author = {Cronin, Thomas M. and O{\textquoteright}Regan, Matt and Pearce, Christof and Gemery, Laura and Toomey, Michael and Semiletov, Igor and Jakobsson, Martin} }