Previous work performed as part of the USGS Holocene Synthesis project illuminated complex centennial-scale patterns of drought and wetter-than-average conditions across the North American continent interior during the past two millennia, where paleorecord data coverage is sparse. In order to explain the patterns of naturally-occurring drought, floods, and storms for the past, identified by the Holocene Synthesis project, this project develops new, well-dated, high-resolution reconstructions from lake sediment archives from the continent interior. Using a combination of new and existing sediment cores, this project utilizes geophysical, geochemical, and biological proxy data in concert with novel 14C, 210Pb, and 137Cs-based statistical approaches for quantifying age-depth relationships to expand paleoflood and drought data coverage across the Upper Midwest and central U.S. during the Holocene.
Paleoclimate Science
Biological proxies such as diatoms, foraminifers, ostracodes, and pollen allow scientists to make inferences about climate conditions in the past.
Holocene Synthesis Project
The Holocene Synthesis Project integrates a variety of information about past climate variability across the North American continent for the past ~12,000 years.
Florence Bascom Geoscience Center
Learn more about this project and its role in the Florence Bascom Geoscience Center.
Statement of Problem: Heavy rainfall, flooding, and drought frequently devastate North American populations and are predicted to continue posing serious threats over the next century. These hydrologic extremes and regional hydrology at centennial and millennial timescales are not well understood. Paleoclimate records capture this low-frequency variability that instrumental records are too short to capture, yet the hydrology of the central U.S. is highly complex and paleorecords from the region are exceedingly sparse.
This project aims to expand existing data with additional paleorecords, which are needed to disentangle the complex patterns of and controls on interior continental hydrologic variability during the past ~12,000 years (i.e. the Holocene). Clarifying the spatial patterns of drought and moisture trends is fundamental for comparison with other datasets to understand the mechanisms that drive natural, low-frequency variability and for improving computer models that predict future changes. Data produced for this project is directly useful for local, state, and federal governments for mitigation planning, disaster relief, wildlife conservation, and resource management. Climate model researchers will benefit from data produced during this project, which provides an independent dataset to test model performance and improve prediction of future patterns and trends.
Why this Research is Important: This project performs research that is vital to guiding decision-making and policy for preserving our nation’s resources, specifically water resources and wildlife habitat. By characterizing the history and controls of drought across the landscape, this project assists in the management of the water resources that are vital for drinking water supplies, agriculture, and industry. This project advances understanding of the drivers of change and improves predictability of natural hazards, including floods and tropical cyclones, that threaten the safety and economic prosperity of the nation’s populations.
Objective(s):
- Develop paleorecords from the North American continent and surrounding landmasses, focusing on regions with substantial spatial gaps and/or complex spatial patterns of paleohydrologic extremes.
- Determine the natural, baseline variability of floods and droughts to assist resource managers, improve computer models, and improve natural disaster mitigation.
- Synthesize paleorecords to explain spatial patterns of paleohydrologic extremes across the North American continent and better understand the mechanisms of change during the Holocene.
Methods: Preliminary study site research will include searching the literature for previous work performed in the region, searching online databases for site information and data from previous studies, using historic maps and imagery to characterize the quality of proposed sites for flood and lake level reconstructions, and performing site visits to obtain basic water depth and geophysical (e.g. ground penetrating radar/seismic reflection) data as well as water and surface sediment samples. Sites determined to have high potential for archiving a continuous, high-resolution record of environmental changes with known historical flooding/drought will be prioritized to improve proxy validation.
Sediment cores will be split and imaged with classic sedimentology observations described in detail. Sediment sub-samples will be analyzed for bulk mineralogy, grain size, and organic content. These basic analyses will guide more specialized lab measurements for each site based on the presence and variability in abundance/types of geochemical, geophysical, and/or biological sediment components downcore. Sediment-based records will be dated using radiometric dating techniques (e.g. radiocarbon), and statistical age modeling will be performed to produce age-depth relationships with uncertainty approximations.
Interpretations of flood histories will be based upon multi-proxy evidence for high energy event deposition (e.g. coarse grain abundance, stratigraphic evidence for event deposition and/or slumping, geochemical evidence of sediment delivery from land surrounding the lake during periods of higher runoff) paired with elevation-based flood modeling, where possible. Where the sediment record overlaps with instrumental data, proxy validation will be performed to strengthen downcore proxy interpretations.
Interpretations of drought histories will be based upon multiproxy evidence, mainly proxies for lake salinity, runoff, stratigraphic evidence for desiccation, and lake water elevation changes. Supporting information from vegetation proxies, diatom assemblages, evidence of fires, and isotopes of precipitation will be included when possible. Where the sediment record overlaps with instrumental data, proxy validation will be performed to strengthen downcore proxy interpretations.
Below are other science projects associated with this project.
Natural Drought and Flood Histories from Lacustrine Archives Project
Holocene Synthesis Project
Geological Investigations of the Neogene
Land-Sea Linkages in the Arctic
Wetlands in the Quaternary Project
Climate and Environmental Change in the Gulf of Mexico and Caribbean
Terrestrial Records of Holocene Climate Change: Fire, climate and humans
- Overview
Previous work performed as part of the USGS Holocene Synthesis project illuminated complex centennial-scale patterns of drought and wetter-than-average conditions across the North American continent interior during the past two millennia, where paleorecord data coverage is sparse. In order to explain the patterns of naturally-occurring drought, floods, and storms for the past, identified by the Holocene Synthesis project, this project develops new, well-dated, high-resolution reconstructions from lake sediment archives from the continent interior. Using a combination of new and existing sediment cores, this project utilizes geophysical, geochemical, and biological proxy data in concert with novel 14C, 210Pb, and 137Cs-based statistical approaches for quantifying age-depth relationships to expand paleoflood and drought data coverage across the Upper Midwest and central U.S. during the Holocene.
Paleoclimate Science
Biological proxies such as diatoms, foraminifers, ostracodes, and pollen allow scientists to make inferences about climate conditions in the past.
Holocene Synthesis Project
The Holocene Synthesis Project integrates a variety of information about past climate variability across the North American continent for the past ~12,000 years.
Florence Bascom Geoscience Center
Learn more about this project and its role in the Florence Bascom Geoscience Center.
Statement of Problem: Heavy rainfall, flooding, and drought frequently devastate North American populations and are predicted to continue posing serious threats over the next century. These hydrologic extremes and regional hydrology at centennial and millennial timescales are not well understood. Paleoclimate records capture this low-frequency variability that instrumental records are too short to capture, yet the hydrology of the central U.S. is highly complex and paleorecords from the region are exceedingly sparse.
This project aims to expand existing data with additional paleorecords, which are needed to disentangle the complex patterns of and controls on interior continental hydrologic variability during the past ~12,000 years (i.e. the Holocene). Clarifying the spatial patterns of drought and moisture trends is fundamental for comparison with other datasets to understand the mechanisms that drive natural, low-frequency variability and for improving computer models that predict future changes. Data produced for this project is directly useful for local, state, and federal governments for mitigation planning, disaster relief, wildlife conservation, and resource management. Climate model researchers will benefit from data produced during this project, which provides an independent dataset to test model performance and improve prediction of future patterns and trends.
Why this Research is Important: This project performs research that is vital to guiding decision-making and policy for preserving our nation’s resources, specifically water resources and wildlife habitat. By characterizing the history and controls of drought across the landscape, this project assists in the management of the water resources that are vital for drinking water supplies, agriculture, and industry. This project advances understanding of the drivers of change and improves predictability of natural hazards, including floods and tropical cyclones, that threaten the safety and economic prosperity of the nation’s populations.
Objective(s):
- Develop paleorecords from the North American continent and surrounding landmasses, focusing on regions with substantial spatial gaps and/or complex spatial patterns of paleohydrologic extremes.
- Determine the natural, baseline variability of floods and droughts to assist resource managers, improve computer models, and improve natural disaster mitigation.
- Synthesize paleorecords to explain spatial patterns of paleohydrologic extremes across the North American continent and better understand the mechanisms of change during the Holocene.
Sources/Usage: Public Domain.Photo shows sediment cores resting in a canoe coring platform. Researchers Jess Rodysill and Michael Toomey (Reston) are investigating the history of large river floods along the Potomac River using sediment proxies from Black Pond cores. Methods: Preliminary study site research will include searching the literature for previous work performed in the region, searching online databases for site information and data from previous studies, using historic maps and imagery to characterize the quality of proposed sites for flood and lake level reconstructions, and performing site visits to obtain basic water depth and geophysical (e.g. ground penetrating radar/seismic reflection) data as well as water and surface sediment samples. Sites determined to have high potential for archiving a continuous, high-resolution record of environmental changes with known historical flooding/drought will be prioritized to improve proxy validation.
Sediment cores will be split and imaged with classic sedimentology observations described in detail. Sediment sub-samples will be analyzed for bulk mineralogy, grain size, and organic content. These basic analyses will guide more specialized lab measurements for each site based on the presence and variability in abundance/types of geochemical, geophysical, and/or biological sediment components downcore. Sediment-based records will be dated using radiometric dating techniques (e.g. radiocarbon), and statistical age modeling will be performed to produce age-depth relationships with uncertainty approximations.
Interpretations of flood histories will be based upon multi-proxy evidence for high energy event deposition (e.g. coarse grain abundance, stratigraphic evidence for event deposition and/or slumping, geochemical evidence of sediment delivery from land surrounding the lake during periods of higher runoff) paired with elevation-based flood modeling, where possible. Where the sediment record overlaps with instrumental data, proxy validation will be performed to strengthen downcore proxy interpretations.
Interpretations of drought histories will be based upon multiproxy evidence, mainly proxies for lake salinity, runoff, stratigraphic evidence for desiccation, and lake water elevation changes. Supporting information from vegetation proxies, diatom assemblages, evidence of fires, and isotopes of precipitation will be included when possible. Where the sediment record overlaps with instrumental data, proxy validation will be performed to strengthen downcore proxy interpretations.
- Science
Below are other science projects associated with this project.
Natural Drought and Flood Histories from Lacustrine Archives Project
Heavy rainfall, flooding, and drought frequently devastate North American populations and are predicted to continue posing serious threats over the next century. The nature of these phenomena at centennial and millennial timescales is not well constrained. Clarifying the spatial patterns of drought and moisture trends is fundamental for comparison with other datasets for the purposes of...Holocene Synthesis Project
The Holocene Synthesis Project integrates a variety of information about past climate variability across the North American continent for the past ~12,000 years to characterize the spatial patterns of previous climate states, advance our understanding about mechanisms that drive natural climate variability, and improve the quality of climate models that are used to predict future climate patterns...Geological Investigations of the Neogene
More than a third of the United States population lives in counties directly on the shoreline, making them vulnerable to hazards associated with changing sea level and storm surges associated with hurricanes and severe storms. The geologic record contains many examples of past intervals of warm climate and high sea level. "Geological Investigation of the Neogene" is examining proxy records of...Land-Sea Linkages in the Arctic
The Arctic is undergoing historically unprecedented changes in weather, sea ice, temperature and ecosystems. These changes have led to greater coastal erosion, greater export of freshwater, and changes to marine and terrestrial ecosystems, habitats, and productivity, among other trends. Meanwhile, many believe the Arctic “amplifies” large climate changes during both warm periods and ice ages and...Wetlands in the Quaternary Project
Wetlands accumulate organic-rich sediment or peat stratigraphically, making them great archives of past environmental change. Wetlands also act as hydrologic buffers on the landscape and are important to global biogeochemical cycling. This project uses wetland archives from a range of environments to better understand how vegetation, hydrology, and hydroclimate has changed on decadal to multi...Climate and Environmental Change in the Gulf of Mexico and Caribbean
This project documents paleoceanographic, climatic, and environmental changes in the Gulf of Mexico and adjacent land areas over the last 10,000 years. The paleoenvironmental data is used to determine rates of change in the past, and to better understand both the natural and anthropogenic factors that contribute to climate variability on inter-annual to millennial timescales.Terrestrial Records of Holocene Climate Change: Fire, climate and humans
Large wildfires have raged across the western Americas in the past decade including the Las Conchas, New Mexico fire that burned 44,000 acres in a single day in 2011 (Orem and Pelletier, 2015, Geomorphology 232: 224-238, and references therein), the 2016 Fort McMurray, Alberta fire that required evacuating an entire city, and the 2015 Alaskan fire season that burned more than 5 million acres... - Publications