The effectiveness of lichens in degrading their rock substrates, leading to the first stages in the formation of soil, has long been discussed and opinions have varied widely (Jones, 1988; Syers & lskandar, 1973). Nevertheless, it is generally recognized that lichen encrusted rocks provide an ideal environment for studying the biological weathering of minerals since, unlike the situation in soi...

We present models of the spectral reflectances of groups of outer Solar System objects defined primarily by their colors in the spectral region 0.4 -1.2pm , and which have geometric albedo 0.04 at wavelength 0.55pm . Our models of the groups with the strongest reflectance gradients (reddest colors) use combinations of organic tholins. We test the hypothesis that metal-reddened igneous rock-form...

The composition of the silicate portion of Martian regolith fines indicates derivation of the fines from mafic to ultramafic igneous rocks, probably rich in pyroxene. Rock types similar in chemical and mineralogical composition include terrestrial Archean basalts and certain achondrite meteorites. If these igneous rocks weathered nearly isochemically, the nontronitic clays proposed earlier as a...

The observation that “old” water dominates storm runoff suggests that release of low-solute water from soils rather than rainwater must cause storm runoff dilution. This inference is supported by sprinkling experiments in an 860-m catchment in the Oregon Coast Range, in which .200 mm of both high and low ionic strength precipitation produced similar concentration-discharge trends. Rainwater che...

Dyella jiangningensis strain SBZ3-12 can weather biotite and release Al and Fe from biotite under nutrient-poor conditions. Here, we report the first complete genome sequence of D. jiangningensis strain SBZ3-12, which may facilitate a better understanding of the molecular mechanism behind mineral weathering.

This paper presents a micromechanics-based elastoplastic damage model for quasi-brittle rocks in compression stress state. The plastic strain is considered to be related to frictional sliding along microcracks and inherently coupled with damage evolution. By following a homogenization procedure, we first determine the free energy for the matrix-cracks system. The thermodynamic force associated ...

Introduction: Lichen dominated cryptoendolithic communities from the Dry Valleys of Antarctica have been the subject of much research over recent years owing to their potential as analogues of Martian lifeforms. This is primarily owing to the stress tolerant nature of the microorganisms, remarkable adaptive achievements and the similarities between the Antarctic Dry Valley ecosystems and condit...

Investigations over two major tectonic zones in the Hallandsås Horst, Southern Sweden were carried out in connection with a railway tunnelling project. A combination of resistivity imaging, core drilling and geophysical logging was found to provide a good overview of the variation in rock quality and detailed information on the engineering geological characteristics and genesis of the strata. R...

In this paper an attempt is made to offer insights into local slope failure mechanisms from the perspective of hydrogeology. The hypothesis examined envisages that the hydraulic conductivity distribution in a weathered profile includes a relatively high hydraulic conductivity zone associated with the jointed rock mass near rockhead. There is evidence locally for such a condition. The groundwate...

The aim of this paper is to investigate landslide prone areas in Nilgiri hills which have caused damage to people and properties and to devise preventive steps to be taken in the events of future landslides. Our study area was situated at Ooty region, Nilgiri District, Tamilnadu. In this study we use the seismic refraction survey carried out across landslides located near the villages in Allanc...