Post #2330542

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• @natcbr@mountains.social 2026-05-07 04:33

  You can see how Sydney has sprawled out east across sandstone (pastel green) and shale (emerald green) to Camden and Penrith, and onto an alluvial floodplain (brown) to Richmond. Sandstone-derived soils are typically nutrient-poor, while soils derived from shale are generally more fertile. This difference comes down primarily to mineralogy: sandstone is composed mostly of quartz, a chemically inert mineral that releases virtually no nutrients as it weathers. Shale, by contrast, is rich in clay minerals and often contains organic matter, releasing a much broader range of plant-available nutrients as it breaks down. Additionally, the coarser, sandier texture of sandstone-derived soils creates larger pore spaces, which allows water to drain rapidly and leach whatever nutrients are present deeper into the profile and out of reach of plant roots. #geology #ecohydrology

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