This story is at http://phys.org/print273420123.html … and is largely based around a new dating process associated with a phosphate mineral known as apatite. The research claims the Grand Canyon was directly carved within a few hundred metres of its current depth by about 70 million years ago. This is before the asteroid strike that brought an end to the dinosaurs – see the journal Science, Nov 29th 2012. This sound a lot like very rapid formation – but don't be fooled. Different dating techniques mean that different sections of the Grand Canyon are thought to have formed at different times – and not altogether as one might logically assume. Some bits are thought to have formed at 55 million years ago, for example, quite a while after the new dates. We are informed it was carved in large part by an ancestral waterway of the Colorado River – flowing in the opposite direction. The most popular date for the formation, however, is just 6 or 7 million years ago, based on the gae of the gravel washed downstream by the Colorado River. Another study, in 2008, also published in Science, estimated its age at 17million years ago after dating mineral deposits inside caves in the canyon walls. Scientists have in fact been arguing about its age for 150 years – which puts it all into perspectivbe. We don't know.