Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Quote:
Abstract
‘Mineral evolution’ has attracted much attention in the last decade as a counterpart of the long-established biological concept, but is there a corresponding ‘mineral extinction’? We present new geochronological data from uranium-bearing secondary minerals and show that they are relatively recent, irrespective of the age of their primary uranium sources. The secondary species that make up much of the diversity of minerals appear to be ephemeral, and many may have vanished from the geological record without trace. Nevertheless, an ‘extinct’ mineral species can recur when physiochemical conditions are appropriate. This reversibility of ‘extinction’ highlights the limitations of the ‘evolution’ analogy. Mineral occurrence may be time-dependent but does not show the unique contingency between precursor and successor species that is characteristic of biological evolution.
Alfredo Petrov wrote:
Minerals requiring cold environments to survive, like ikaite, could become endangered if the climate heats up enough.
Photosynthesis may well have "killed" a lot of minerals unstable in the presence of oxygen, although of course the planet still has plenty of little anaerobic niche environments.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Another post from the MSA thread
Marty Rutstein wrote:
so true- look at loss of exposures of ophiolte suite and serpentinized rocks in the Thetford Mines region- see the now "remediated" and closed Black Lake asbestos "mine" (quarry). Now, the best place to study asbestos may well be in buildings undergoing asbestos abatement,
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Clearly, this topic is interesting to ME....cough cough
Richard Maxwell Thompson wrote:
A mineral could be defined extinct if it is no longer forming. Non-avian dinosaurs are no longer forming, but their fossilized remains still exist. Under that analogy, a specimen of mineral that is no longer forming anywhere on the planet would be considered a “fossil” and the mineral would be considered “extinct”. To me, it seems the more important distinction in terms of mineral evolution is whether or not a mineral can still be created, not whether every trace of it has been eradicated from Earth.
It is a bit of a silly concept I suppose but kind of a fun thought exercise.
(I'll be honest, much as I love the associated minerals I 1000% don't mind burying asbestos deposits under tons of water. One can find something else to study).
Well, 'silly' definitely isn't the right word--I guess I mean more that it's an odd metaphor. I guess part of what makes it strange to think about is that most of the rocks and minerals we see are already so temporally removed from their original formation. Most gems and minerals beginning to form today will likely never be seen by human eyes, outside of a few niche cases. I think the related topic which captures my imagination more is more what's exhausted. Like cryolite, which we found one big chunk of and mined down to nothing for aluminum. I found a chunk of that in an old collection I was sorting and identifying with beautiful crystals of brown siderite in it (mislabeled 'siderite in quartz'), and outside of reading the name once or twice in a mineralogy book I had never seen or heard of it before. And of course humanity has worked out many gem deposits throughout history, to the point we may never an example of the stones people had in mind when they were inventing names like 'emerald' and 'sardonyx'. But that's a lot less profound on a geological scale.
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