Apatite helium dating

The wavy fabric indicates solid flow at mid-crustal temperatures of 400-500C.To recast barely conceivable geologic time intervals in a more familiar format, they'll also appear from time to time as military hours in a single 24-hour day (and all-nighter) of creation beginning at the planet's formation and ending with the here and now.My piano tuner's job security rests on the fact that properly tuned piano wire flows (stretches) at a similar rate and falls out of tune in a matter of months.Over a few Ma, fingernail speed is plenty fast enough to fold great thicknesses of sedimentary rock over the east edge of the relatively brittle Front Range basement block, as in the photo at right.The entire Mesozoic Era (295 Ma long) shot by in under an hour, the dinosaurs departed just 20 minutes ago (thank goodness), and we've been comfy and relatively ice-free for only a mere 0.2 seconds.

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This telling elevation distribution reflects a powerful synergy between truly ancient plate processes driven by the cooling of the earth in the presence of gravity and ongoing mantle processes driven by Lord knows what.

If you need more help with geologic time or terminology, check out these resources.

Colorado's geologic history is as complex as it is fascinating.

Over 50 Ma, an entire mountain range like the Ancestral Rockies can rise up and vanish.

The pink feldspar bands in the severely deformed metamorphic rock at right (a mylonite from the Homestake Shear Zone in the northern Sawatch Range) show the kind of internal folding you'd expect from warm taffy, but this rock didn't actually melt.

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