TY - JOUR T1 - Holocene sedimentation in a blue hole surrounded by carbonate tidal flats in The Bahamas: Autogenic versus allogenic processes JF - Marine Geology Y1 - 2020 A1 - van Hengstum, Peter J. A1 - Winkler, Tyler S. A1 - Tamalavage, Anne E. A1 - Sullivan, Richard M. A1 - Little, Shawna N. A1 - MacDonald, Dana A1 - Donnelly, Jeffrey P. A1 - Albury, Nancy A. KW - Carbonate tidal flats KW - carbonates KW - North Atlantic Bahamas KW - sinkhole AB - The sediment in North Atlantic blue holes preserves paleoclimate records. However, accurate paleoclimate reconstructions require an improved understanding of allogenic versus autogenic processes controlling blue hole sedimentation. Here we provide a detailed case study of the Holocene stratigraphy within Freshwater River Blue Hole, which is currently surrounded by carbonate tidal flats in the northern Bahamas (Abaco Island). During the Holocene, concomitant coastal aquifer elevation and relative sea-level rise controlled internal blue hole depositional environments. The general Holocene facies succession observed is: (i) basal detrital and freshwater peat, (ii) palustrine to lacustrine marl, (iii) algal sapropel, and finally (iv) bedded carbonate mud. During the middle Holocene when groundwater levels were lower, small changes in accommodation space that were inherited from the bedrock surface below (<1 m) were able to promote significant lateral facies changes. Multiple cores are needed to characterize these lateral facies changes. Hydrographic characteristics of the coastal aquifer (e.g., vertical position, stratification, salinity) relative to the blue hole benthos exert a fundamental control on (a) benthic flora and meiofauna (e.g., charophytes, ostracodes, foraminifera, gastropods) and (b) organic matter production and preservation from pelagic productivity. Over the last 5000 years, water column stratification in Freshwater River Blue Hole was interrupted on millennial to sub-decadal timescales , which are potentially linked to changing aquifer recharge and rainfall. Lastly, historical intense hurricanes passing closely to the west of the site may have promoted deposition of coarse beds at the site. However, the lack of carbonate tidal flat microfaunal remains (foraminifera: Peneroplis) within these coarse intervals indicates that Freshwater River Blue Hole does not preserve a reliable record of hurricane-induced overwash deposition from the carbonate tidal flats during the last 2300 years. VL - 419 UR - https://linkinghub.elsevier.com/retrieve/pii/S0025322719301811 ER - TY - JOUR T1 - Drought in the northern Bahamas from 3300 to 2500 years ago JF - Quaternary Science Reviews Y1 - 2018 A1 - van Hengstum, Peter J. A1 - Maale, Gerhard A1 - Donnelly, Jeffrey P. A1 - Albury, Nancy A. A1 - Onac, Bogdan P. A1 - Sullivan, Richard M. A1 - Winkler, Tyler S. A1 - Tamalavage, Anne E. A1 - MacDonald, Dana AB - Intensification and western displacement of the North Atlantic Subtropical High (NASH) is projected for this century, which can decrease Caribbean and southeastern American rainfall on seasonal and annual timescales. However, additional hydroclimate records are needed from the northern Caribbean to understand the long-term behavior of the NASH, and better forecast its future behavior. Here we present a multi-proxy sinkhole lake reconstruction from a carbonate island that is proximal to the NASH (Abaco Island, The Bahamas). The reconstruction indicates the northern Bahamas experienced a drought from ∼3300 to ∼2500 Cal yrs BP, which coincides with evidence from other hydroclimate and oceanographic records (e.g., Africa, Caribbean, and South America) for a synchronous southern displacement of the Intertropical Convergence Zone and North Atlantic Hadley Cell. The specific cause of the hydroclimate change in the northeastern Caribbean region from ∼3300 to 2500 Cal yrs BP was probably coeval southern or western displacement of the NASH, which would have increased northeastern Caribbean exposure to subsiding air from higher altitudes. VL - 186 UR - https://linkinghub.elsevier.com/retrieve/pii/S0277379117306273 ER - TY - JOUR T1 - Local and regional wildfire activity in central Maine (USA) during the past 900 years JF - Journal of Paleolimnology Y1 - 2017 A1 - Miller, Daniel R. A1 - Castañeda, Isla S. A1 - Bradley, Raymond S. A1 - MacDonald, Dana AB - Climatic and environmental change has a direct effect on wildfire frequencies and distributions throughout many regions of the world. Reconstructions from natural archives such as lake sediments can extend temporally limited historical records of regional wildfire activity over longer timescales through sedimentary charcoal analysis or examining polycyclic aromatic hydrocarbon (PAH) concentrations. To date, little work has been completed on sedimentary PAH distributions from lacustrine records in the Northeastern United States, making it difficult to assess how accurately PAHs trace fire activity in the region, the spatial scope of the signal (local vs. regional), or if certain compounds do a more adequate job of tracking fire than others. In this study, we examine PAHs and macrocharcoal from a varved sedimentary record from Basin Pond, Fayette, Maine (USA). We find that a drastic increase in the concentrations of 12 measured PAHs occurred during the nineteenth to twentieth centuries due to industrialization of the region. Additionally, elevated concentrations of the PAH retene were found to be coeval with known large-scale regional wildfire events that occurred in 1761–1762, 1825, and 1947 (A.D.). We used the ratio of the PAHs retene and chrysene to infer differences in biomass burning versus anthropogenic combustion sources because retene is associated with conifer resin whereas chrysene is associated with fossil fuel burning. Our new Basin Pond PAH records, along with a local signal of fire occurrence from charcoal analysis, offers the prospect of using this multi-proxy approach as a method for examining long-term wildfire frequency at both the local and regional scale in the Northeastern US. VL - 58 UR - https://link.springer.com/article/10.1007/s10933-017-0002-z IS - 4 ER - TY - JOUR T1 - Climate forcing of unprecedented intense-hurricane activity in the last 2000 years JF - EARTHS FUTURE Y1 - 2015 A1 - Donnelly, Jeffrey P. A1 - Hawkes, Andrea D. A1 - Lane, Philip A1 - MacDonald, Dana A1 - Shuman, Bryan N. A1 - Toomey, Michael R. A1 - van Hengstum, Peter J. A1 - Woodruff, Jonathan D. KW - Climate change KW - common era KW - Holocene KW - sea surface temperature KW - tropical cyclones AB - How climate controls hurricane variability has critical implications for society is not well understood. In part, our understanding is hampered by the short and incomplete observational hurricane record. Here we present a synthesis of intense-hurricane activity from the western North Atlantic over the past two millennia, which is supported by a new, exceptionally well-resolved record from Salt Pond, Massachusetts (USA). At Salt Pond, three coarse grained event beds deposited in the historical interval are consistent with severe hurricanes in 1991 (Bob), 1675, and 1635 C.E., and provide modern analogs for 32 other prehistoric event beds. Two intervals of heightened frequency of event bed deposition between 1400 and 1675 C.E. (10 events) and 150 and 1150 C.E. (23 events), represent the local expression of coherent regional patterns in intense-hurricane-induced event beds. Our synthesis indicates that much of the western North Atlantic appears to have been active between 250 and 1150 C.E., with high levels of activity persisting in the Caribbean and Gulf of Mexico until 1400 C.E. This interval was one with relatively warm sea surface temperatures (SSTs) in the main development region (MDR). A shift in activity to the North American east coast occurred ca. 1400 C.E., with more frequent severe hurricane strikes recorded from The Bahamas to New England between 1400 and 1675 C.E. A warm SST anomaly along the western North Atlantic, rather than within the MDR, likely contributed to the later active interval being restricted to the east coast. VL - 3 ER - TY - JOUR T1 - Repeated century-scale droughts over the past 13,000 yr near the Hudson River watershed, USA JF - Quaternary Research Y1 - 2011 A1 - Newby, Paige E. A1 - Shuman, Bryan N. A1 - Donnelly, Jeffrey P. A1 - MacDonald, Dana AB - Long-term sediment and ground-penetrating radar data from Davis Pond, a small lake near the Hudson River valley, reveal past droughts in a historically humid region that presently supplies water to millions of people in and around New York City. A minimum of eleven sandy paleoshoreline deposits in the lake date from 13.4 to 0.6 cal ka BP. The deposits span 1500 to 200 yr between bracketing radiocarbon ages, and intrude into lacustrine silts up to 9.0 m below the modern lake surface in a transect of six sediment cores. Three low stands, ca. 13.4–10.9, 9.2 and 8.2 cal ka BP indicate low regional moisture balance when low temperatures affected the North Atlantic region. Consistent with insolation trends, water levels rose from ca. 8.0 cal ka BP to present, but five low stands interrupted the rise and are likely associated with ocean–atmosphere interactions. Similar to evidence from other studies, the data from Davis Pond indicate repeated multi-century periods of prolonged or frequent droughts super-imposed on long-term regional trends toward high water levels. The patterns indicate that water supplies in this heavily populated region have continuously varied at multiple time scales and confirm that humid regions such as the northeastern United States are more prone to severe drought than historically expected. VL - 75 UR - http://www.sciencedirect.com/science/article/pii/S0033589411000172 IS - 3 N1 - id: 2183 JO - Repeated century-scale droughts over the past 13,000 yr near the Hudson River watershed, USA ER -