United States Geological Survey

About: United States Geological Survey is a government organization based out in Reston, Virginia, United States. It is known for research contribution in the topics: Population & Groundwater. The organization has 17899 authors who have published 51097 publications receiving 2479125 citations. The organization is also known as: USGS & US Geological Survey.

Gas-water-rock interactions in Frio Formation following CO2 injection: Implications for the storage of greenhouse gases in sedimentary basins

Abstract: To investigate the potential for the geologic storage of CO2 in saline sedimentary aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick sandstone section of the Frio Formation, a regional brine and oil reservoir in the U.S. Gulf Coast. Fluid samples obtained from the injection and observation wells before CO2 injection showed a Na-CaCl‐type brine with 93,000 mg/L total dissolved solids (TDS) at near saturation with CH4 at reservoir conditions. Following CO2 breakthrough, samples showed sharp drops in pH (6.5‐5.7), pronounced increases in alkalinity (100‐3000 mg/L as HCO3) and Fe (30‐1100 mg/L), and significant shifts in the isotopic compositions of H2O, dissolved inorganic carbon (DIC), and CH4. Geochemical modeling indicates that brine pH would have dropped lower but for the buffering by dissolution of carbonate and iron oxyhydroxides. This rapid dissolution of carbonate and other minerals could ultimately create pathways in the rock seals or well cements for CO2 and brine leakage. Dissolution of minerals, especially iron oxyhydroxides, could mobilize toxic trace metals and, where residual oil or suitable organics are present, the injected CO2 could also mobilize toxic organic compounds. Environmental impacts could be major if large brine volumes with mobilized toxic metals and organics migrated into potable groundwater. The d 18 O values for brine and CO2 samples indicate that supercritical CO2 comprises ;50% of pore-fluid volume ;6 mo after the end of injection. Postinjection sampling, coupled with geochemical modeling, indicates that the brine gradually will return to its preinjection composition.

The Surface of Mars

Abstract: Our knowledge of Mars has grown enormously over the last decade as a result of the Mars Global Surveyor, Mars Odyssey, Mars Express, and the two Mars Rover missions. This book is a systematic summary of what we have learnt about the geological evolution of Mars as a result of these missions. It describes the diverse Martian surface features and summarizes current ideas as to how, when, and under what conditions they formed, and explores how Earth and Mars differ and why the two planets evolved so differently. The author also discusses possible implications of the geologic history for the origin and survival of indigenous Martian life. Up-to-date and highly illustrated, this book will be a principal reference for researchers and graduate students in planetary science. The comprehensive list of references will also assist readers in pursuing further information on the subject. Colour images can be found at www.cambridge.org/9780521872010.

Overestimation of marsh vulnerability to sea level rise

Abstract: In this Perspective it is argued that coastal marsh vulnerability is often overstated because assessments generally neglect feedback processes known to accelerate soil building with sea level rise, as well as the potential for marshes to migrate inland. Coastal marshes are considered to be among the most valuable and vulnerable ecosystems on Earth, where the imminent loss of ecosystem services is a feared consequence of sea level rise. However, we show with a meta-analysis that global measurements of marsh elevation change indicate that marshes are generally building at rates similar to or exceeding historical sea level rise, and that process-based models predict survival under a wide range of future sea level scenarios. We argue that marsh vulnerability tends to be overstated because assessment methods often fail to consider biophysical feedback processes known to accelerate soil building with sea level rise, and the potential for marshes to migrate inland.

Increased groundwater to stream discharge from permafrost thawing in the Yukon River basin: Potential impacts on lateral export of carbon and nitrogen

Abstract: [1] Arctic and subarctic watersheds are undergoing climate warming, permafrost thawing, and thermokarst formation resulting in quantitative shifts in surface water –groundwater interaction at the basin scale. Groundwater currently comprises almost one fourth of Yukon River water discharged to the Bering Sea and contributes 5–10% of the dissolved organic carbon (DOC) and nitrogen (DON) and 35–45% of the dissolved inorganic carbon (DIC) and nitrogen (DIN) loads. Long-term streamflow records (>30 yrs) of the Yukon River basin indicate a general upward trend in groundwater contribution to streamflow of 0.7–0.9%/yr and no pervasive change in annual flow. We propose that the increases in groundwater contributions were caused predominately by climate warming and permafrost thawing that enhances infiltration and supports deeper flowpaths. The increased groundwater fraction may result in decreased DOC and DON and increased DIC and DIN export when annual flow remains unchanged.