Sediments

USGS scientists use marine geological archives to investigate how ocean temperature, salinity and circulation patterns changed over the past few centuries to millennia. This is done by analyzing the geochemical and physical clues about past environments that are preserved in fossil coral skeletons, clam shells, foraminifera and marine sediments.

Coastal environments are dynamic systems that provide high ecological, economical, recreational, and cultural value. Managing coastal systems requires a comprehensive understanding of the complex interactions between geological and ecological processes, as well as the ability to predict both the near-term and long-term impacts of storms and sea-level rise. The Coastal Resource Evaluation for...

Geologic proxies may shed light on long-term environmental trends and stability of the Louisiana coastal marsh. The combined processes of accretion, sea-level rise and subsidence influence wetland elevation and determine marsh stability.

The goal of the Estuarine and MaRsh Geology (EMRG) Research Project is to study how and where short- and long-term marsh and estuarine coastal processes interact, how they influence coastal accretion or erosion, and how they pre-condition a marsh’s resiliency to storms, sea-level change, and human alterations along the northern Gulf of America (Grand Bay and Point aux Chenes, Mississippi and St...

Sediments are the foundation of coastal systems, including barrier islands. Their behavior is driven by not only sediment availability, but also sediment exchanges between barrier island environments. We collect geophysical, remote sensing, and sediment data to estimate these parameters, which are integrated with models to improve prediction of coastal response to extreme storms and sea-level rise...

Fire Island is a 50-km long barrier island along the south shore of Long Island, New York. The island is comprised of seventeen year-round communities; federal, state, and county parks; and supports distinct ecosystems alongside areas of economic and cultural value. In addition to providing resources to its residents, the barrier island also protects the heavily-populated mainland from storm waves...

Sediment supply is a critical control on barrier island vulnerability and resilience over a variety of time scales (e.g., storms to sea level rise). Past work at Fire Island and elsewhere has demonstrated a link between inner shelf sediment availability and barrier island evolution over geologic and historical time scales. However, there have been few opportunities to explore nearshore sediment...

This project assesses the physical controls of sediment and material exchange between wetlands and estuarine environments along the northern Gulf of America (Grand Bay Alabama/Mississippi and Vermilion Bay, Louisiana) and the Atlantic coast (Chincoteague Bay, Virginia/Maryland).

Quantifying changes in morphology and sediment distribution over short time scales will demonstrate how geologic variability influences medium-term barrier island response and near-term barrier island trajectories and help to refine sedimentological boundary conditions for morphologic evolution models.

Video observations of Sand Key, Florida, are used to monitor a range of coastal processes, for example changes in the shoreline position, both seasonally and due to long-term effects such as sea-level rise, and instances of beach and dune erosion during extreme storm events.

This project integrated a wetland assessment with existing coastal-change hazard assessments for the adjacent dunes and beaches of Assateague Island, Maryland, to create a more comprehensive coastal vulnerability assessment.

A sediment trap time series in the northern Gulf of America is used to better assess the control of environmental variables (e.g., temperature and salinity) on the flux of both microfossils and molecular fossils to the sediments. The information gained from sediment trap studies is used to develop better proxy-based estimates of past oceanographic conditions from analyses of microfossils and...