Blocks of acid sulfate altered rock ejected from Halema`uma`u crater in the March 2008 eruption provide evidence of deeper processes that are driving the shallow hydrothermal alteration in this area. Previous work shows that the surficial alteration is dominated by remnant opal (SiO2) and anatase (TiO2), which are compositionally similar to materials found at Home Plate on Mars. The opal deposi...

A detailed review was made of chemical indicators used to identify impacts from septic tanks on groundwater quality. Potential impacts from septic tank leachate on groundwater quality were assessed using the mass ratio of chloride–bromide (Cl/Br), concentrations of selected chemical constituents, and ancillary information (land use, census data, well depth, soil characteristics) for wells in pr...

Peat deposits occur in areas where water logging is common. Large areas of blanket mire occur throughout the temperate and cold regions of the Northern and Southern Hemispheres and are particularly extensive in the UK Uplands. Mass movements of peat, reported usually as peat slides and bog bursts, have been well documented for over 150 years. However, the fundamental controls of this form of sh...

Tillage intensities largely affect soil compaction dynamics in agro-ecosystems. However, the contribution of tillage intensities on compaction changes in underground peanut (Arachis hypogaea) fields has not been quantified. We thus aimed to better understand the role of soil tillage intensities in mitigation of compaction stress for peanuts. Using three field tillage experiments in major Chines...

A large reservoir of soil nitrate in desert subsoil zones has been demonstrated in previous studies; however, information on the subsoil nitrate reservoir and its distribution characteristics in the deserts of China is still limited. This study investigated the distribution patterns of soil total nitrogen (N), nitrate, ammonium, and stable isotopic ratios of (15)N (δ(15)N) in shallow (1 m) and ...

Permafrost is tightly coupled to the organic soil layer, an interaction that mediates permafrost degradation in response to regional warming. We analyzed changes in permafrost occurrence and organic layer thickness (OLT) using more than 3000 soil pedons across a mean annual temperature (MAT) gradient. Cause and effect relationships between permafrost probability (PF), OLT, and other topographic...

The Wells G and H Superfund site, located in the Aberjona watershed in Woburn, Massachusetts, has been studied by a number of MIT research groups since 1987. Initial research conducted to characterize the hydraulic properties of the wetland deposits, did not indicate the classical trend linking changes in hydraulic conductivity to changes in total porosity. It was hypothesized, therefore, that ...

Our goal was to describe stomatal conductance (gs) and the site-scale environmental parameters that best predict gs in Kruger National Park (KNP), South Africa. Dominant grass and woody species were measured over two growing seasons in each of four study sites that represented the natural factorial combination of mean annual precipitation [wet (750 mm) or dry (450 mm)] and soil type (clay or sa...

Kerman and its surrounding towns consist of a flat alluvial plain of fine silt and clay materials. In morphological aspects, these sediments have a very gentle slope with the main infrastructure of the city build on them. Generally, the structure of undisturbed soils is developed over time due to the influence of environmental factors. Geological factors in Kerman fine-grained alluviums have ca...