The latest meme to hit the geoblogosphere involves trees, of all things. Of course, vegetation changes can give important clues to changes in the underlying rock type (the acidity, mineral content and texture of soils will change significantly if you go from a shale to a granite, for example, and so will the sorts of things that like growing in it). But sometimes, they take a more active geological role. This fig tree is growing roots into the rock (2.5 billion year-old limestone, in this case), and breaking it apart:
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(why is the close-up is in black-and-white? I was obviously feeling arty that day)
However, it seems that most of the trees in my image collection are there for more traditional photographic reasons: intrinsic prettiness, or providing an interesting foreground for landscape photography. In Johnannesburg, the jacaranda trees are currently blossoming, meaning that one of the world’s largest man-made forests is looking distinctly purple in patches.
This tree is right at the end of my street, and is therefore on top of 2.9 billion year-old rocks of the Witwatersrand Supergroup. Meanwhile, over in the Barberton greenstone belt, some of the biggest things to sprout from the 3.2 billion year-old ground are aloes.
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