Oldest-Known Terrestrial Rocks Unearthed

wdavies writes "There are various news reports (see this Google search) Oldest Rocks University Quebec that are reporting the discovery of the oldest sedimentary rocks ever found. There are older rocks, but they are extra-terrestrial, and apparently these Earth-local rocks will give a lot more information about the early stages of life on our planet. IANAG so I can't judge any more, but seems significant"

Comments

Re:not significant

[sc7007]

i quit geological engineering after three years. geology is not significant. despite what some geologist may say. by their own word "geology is not an exact science". and nothing could be more true, it's a collection of hikers looking for a reason to visit the latest 'geological' hot spot... like hawaii, or chile.

Well, I am a geologist and I can say that it is definately significant. Most every resource mined on this planet comes to you through the work, if not always discovery, of geologists. Not to mention all of the work done by other branches of geology such as geochemists and paleontologists to explain the origin and deveopement of life on earth. Now, as for geological engineering, that may be another story. They are usually, in my experience (with no offense meant to any engineer), engineers who took some geology classes because they figures two or three would teach them all the geology they would need to know. Nothing could be further from the truth. Engineers, also in my experience, have a very difficult time understanding geology. Has something to do with not being trained to look at the big picture, as well as the smallest possible detail.

Sedimentary rocks that old?

[mikerich]

Almost all rocks of similar ages have been through one or more periods of metamorphism and have undergone physical and chemical changes. Their age just makes it nearly inevitable that they will have been through a mountain-building phase or two. Those rocks that weren't just recycled get heated up, squeezed and exposed to hot reactive fluids. Naturally they don't come out that well.

The Isua Complex in Greenland which appears to be older than these new samples has undergone several metamorphic episodes during which igneous and sedimentary rocks have been converted into new rocks like gneiss.

Sadly that process tends to destroy all of the potential fossil evidence. There are blobs of carbonaceous material in the Isua rocks which some people have ascribed to early life.

If these new rocks really do contain sediments it could be a fascinating chance to see if life had been kick-started by this time.

Thanks for posting!

Best wishes,
Mike.