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a nice line of geology. So many shapes and sizes.
Many of the rocks in Joshua Tree National Park have been subjected to chemical and physical weathering. Chemical weathering generally occurs inside the rock and includes chemical changes, such as those that happen as water interacts with the mineral grains. The water itself and anything that is dissolved in it can cause a chemical reaction that changes the minerals.
Physical weathering involves the mechanical breakdown of rock by wind, water, gravity, or other forces such as freeze-thaw cycles or displacement by roots. Frost-wedging occurs when water fills fractures or pore spaces in rock and freezes. Expansion of the water as it turns to ice can crack the nearby rock and continue to widen cracks over time during freeze-thaw cycles. Root-wedging occurs when the roots of plants infiltrate the rock, usually through pre-existing cracks, and cause these cracks to widen.
INTERESTING: Much of the large-scale erosion that shaped the Joshua Tree National Park’s rocks is no longer occurring. Instead, the weathered formations that we see today occurred long ago.
Many of the rocks in Joshua Tree National Park have been subjected to chemical and physical weathering. Chemical weathering generally occurs inside the rock and includes chemical changes, such as those that happen as water interacts with the mineral grains. The water itself and anything that is dissolved in it can cause a chemical reaction that changes the minerals.
Physical weathering involves the mechanical breakdown of rock by wind, water, gravity, or other forces such as freeze-thaw cycles or displacement by roots. Frost-wedging occurs when water fills fractures or pore spaces in rock and freezes. Expansion of the water as it turns to ice can crack the nearby rock and continue to widen cracks over time during freeze-thaw cycles. Root-wedging occurs when the roots of plants infiltrate the rock, usually through pre-existing cracks, and cause these cracks to widen.
INTERESTING: Much of the large-scale erosion that shaped the Joshua Tree National Park’s rocks is no longer occurring. Instead, the weathered formations that we see today occurred long ago.