Using the data of the CAMREX project (1982–1984) on the water geochemistry of the Amazon river and its main tributaries, it was possible to assess the silicate rock weathering processes and the associated consumption of atmospheric/soil CO2, taking into account seasonal and spatial variations. This study confirms the important role of the Andes in the fluvial transport of dissolved and particul...

Enhanced weathering of (ultra)basic silicate rocks such as olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine weathering is expected to increase seawater alkalinity, thus resulting in additional CO2 uptake from the atmosphere. However, the mechanisms of marine olivine weathering and its effect on seawater-carbon...

pedogenesis and clay mineralogy of soils and rock samples were studied in a transect of calcareous, gypsiferous, saline soils and sediments of bakhtegan lake bank in southern iran. the main objectives of study were to determine the occurrence of clay minerals and factors controlling their distribution pattern and relative abundance in soils and parent materials. the soil parent material is high...

Salt crystallization can severely damage anisotropic foliated rocks, therefore it is necessary to have an understanding of crystallization process. The present study was conducted to investigate the effect of salt crystallization on Arakʾs calcareous slates, as anisotropic rocks of Mesozoic. To compare salt crystallization weathering (EN 12370 norm was used up to 30 cycles) with natural weather...

Several weathering steels and a plain carbon steel exposed to atmosphere for 17 years at Yokkaichi (at a coastal and industrial region) and Mikuni Pass (at a rural region) in Japan were analyzed and compared to find effects of environments on the formed rusts. Specimens were examined with electron probe microanalysis (EPMA), X-ray diffraction (XRD) and transmission electron microscope (TEM). Th...

Estimation of the temperature dependence of natural feldspar weathering in two catchments at different elevations yields an apparent Arrhenius activation energy of 18.4 kcal/mol (77.0 kj/mol), much higher than most laboratory values. This finding supports recent suggestions that hydrolytic weathering of silicate minerals may consume carbonic acid and thereby remove atmospheric carbon dioxide mo...

The effect of watershed spatial scale on chemical weathering is inadequately known for subtropical environments. In order to determine the relationship between watershed scale and weathering chemistry, the Enoree River basin was sampled at seven different spatial scales ranging from second-order watersheds smaller than 2 km^2 to a sixth order watershed of 1840 km^2. The second-order watersheds ...

The weathering hypothesis suggests that early childbearing is an adaptive mechanism for disadvantaged young women, especially African Americans, who believe that their health status may decline as they move through adulthood. Implicitly, weathering assumes that these young women use contextual clues to formulate the likelihood of their own future adult health. We propose a simple yet, to date, ...

The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [(87Sr/86Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of (87Sr/86Sr...

Several operative limitations are involved in the quantitative evaluation of damage processes. To plan an intervention, the assessment of the state of conservation appears incomplete without a realistic estimation. Stone and brick and above all sculptured surfaces and paintings need characterization, quantification, interpretation and rating of the weathering. In this field the use of non destr...