Cracking up a story about erosion pdf

The first continental-scale mineral maps generated from an imaging satellite with spectral bands designed to measure clays, quartz and other minerals were released in for Australia. Here we show how these satellite mineral maps improve our understanding of weathering, erosional and depositional processes in the context of changing weather, climate and tectonics. The same clay composition map, in combination with one sensitive to water content, enables the discrimination of illite from montmorillonite clays that typically develop in large depositional environments over thin sinking continental crust such as the Lake Eyre Basin. The accuracy and information content of these satellite mineral maps are validated using published data. Parent rock, tectonics, climate, landform, groundwater, vegetative groundcover and time all contribute to the composition and architecture of the regolith 3. Progressive weathering is generally associated with increased development of volatiles yielding minerals like hydroxyl-bearing clays for example, illite, montmorillonite and kaolinite as well as decreased levels of mobile cations e. Ca, Mg, K and Na as a consequence of hydrological leaching 3 , 4 , 5 , 6.

A drought or drouth is an event of prolonged shortages in the water supply, whether atmospheric below-average precipitation , surface water or ground water. A drought can last for months or years, or may be declared after as few as 15 days. Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour. Many plant species, such as those in the family Cactaceae or cacti , have drought tolerance adaptations like reduced leaf area and waxy cuticles to enhance their ability to tolerate drought. Some others survive dry periods as buried seeds. Semi-permanent drought produces arid biomes such as deserts and grasslands.

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