Hydrochemistry, weathering and weathering rates on Madeira island

Bond Strength and the Relative Weathering Rates of Simple Orthosilicates

Common naturally occurring orthosilicates can be grouped into those in which the major non-tetrahedral cations are (1) FeII and/or Mg, plus or minus Al (olivine, pyralspite garnets, staurolite); (2) Al (Al2SiO5 polymorphs), or (3) Zr. Feand Mg-bearing orthosilicates have the weakest bonds between non-tetrahedral cations and structural oxygen (M-O bonds), and zircon the strongest, with Al-O bond...

Biota and Chemical Weathering

The Earth has an average surface temperature of about 15°C, which is, in terms of planetary conditions suitable for life, the equivalent of winning the cosmic lottery. Yet, without an atmosphere filled with biological waste gases capable of retaining heat (O2, N2O, CH4, CO2), the average temperature of the planet would be about −18°C (Smil 2002), making the present diversity and abundance of li...

Weathering profiles, mass-balance analysis, and rates of solute loss: Linkages between weathering and erosion in a small, steep catchment

In a headwater catchment in the Oregon Coast Range, we find that solid-phase mass losses due to chemical weathering are equivalent in the bedrock and the soil. However, the long-term rate of mass loss per unit volume of parent rock is greater in the soil than in the rock. We attribute this finding to the effects of biotic processes in the soil and to hydrologic conditions that maximize contact ...

Sunlight , UV , & Accelerated Weathering

Sunlight is an important cause of damage to plastics, textiles, paints, and other organic materials. Short wavelength ultraviolet light has long been recognized as being responsible for most of this damage2. Spectroradiometric measurements were made to quantify the wide variations in UV content of sunlight under the following conditions: direct summer sunlight, winter sunlight, sunlight filtere...

Modeling relative frost weathering rates at geomorphic scales