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Devonian Extinction / Volcanic Action / Mercury


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#1 hazelm

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Posted 02 May 2018 - 08:37 AM

https://www.scienced...80501161805.htm

 

Geologists have discovered the likely cause of the Devonian extinction:  major volcanism  as revealed by a giant peak in the presence of mercury in the environment at that time.

 

The article does not say specifically that most of our mercury comes from volcanic activity.   It is only a conclusion that I have drawn.  I would like to find a good book about other results of volcanic activity.  I understand what causes a volcano to erupt but what happens afterward?  What does the eruption contribute to the environment?  I think there was much more volcanic action in the planet's ancient history than there is today.  How did that help form the planet?

 

Does anyone know of such a book?  Thank you.



#2 exchemist

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Posted 02 May 2018 - 10:51 AM

https://www.scienced...80501161805.htm

 

Geologists have discovered the likely cause of the Devonian extinction:  major volcanism  as revealed by a giant peak in the presence of mercury in the environment at that time.

 

The article does not say specifically that most of our mercury comes from volcanic activity.   It is only a conclusion that I have drawn.  I would like to find a good book about other results of volcanic activity.  I understand what causes a volcano to erupt but what happens afterward?  What does the eruption contribute to the environment?  I think there was much more volcanic action in the planet's ancient history than there is today.  How did that help form the planet?

 

Does anyone know of such a book?  Thank you.

Good question and I can't offhand think of one to recommend. I think most of what I have picked about that has been from odd articles and bits of books on other subjects. One effect I do recall is that volcanism may have contributed to fractionation of the Earth's rocks, because the process of melting that leads to volcanism causes the light fractions to rise to the surface. This has led, so I understand,  to the growth over geological time, of the continents, as these are masses of lighter rock floating on denser ones beneath. 

 

There ought to be a book on it, certainly.........but what I do not know....



#3 hazelm

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Posted 02 May 2018 - 11:12 AM

Good question and I can't offhand think of one to recommend. I think most of what I have picked about that has been from odd articles and bits of books on other subjects. One effect I do recall is that volcanism may have contributed to fractionation of the Earth's rocks, because the process of melting that leads to volcanism causes the light fractions to rise to the surface. This has led, so I understand,  to the growth over geological time, of the continents, as these are masses of lighter rock floating on denser ones beneath. 

 

There ought to be a book on it, certainly.........but what I do not know....

"Fractionation"?  Is this the separation of elements/molecules into new rocks of a different compositions?  I'll check Wiki.  Thank you, Exchemist.  I did know heavier rocks were below but never wondered why.  And, if I am not mistaken,, the lighter rocks eventually break down into soil or sand.  It would have been fun to hang around and watch all that.  Such an interesting topic. Maybe a good book will show up.  I'll keep looking.



#4 exchemist

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Posted 02 May 2018 - 03:03 PM

"Fractionation"?  Is this the separation of elements/molecules into new rocks of a different compositions?  I'll check Wiki.  Thank you, Exchemist.  I did know heavier rocks were below but never wondered why.  And, if I am not mistaken,, the lighter rocks eventually break down into soil or sand.  It would have been fun to hang around and watch all that.  Such an interesting topic. Maybe a good book will show up.  I'll keep looking.

Yes exactly, separation,  by density in this case. As I recall the argument, it is that originally the crust of the Earth might have been homogeneous and rather flat, but, by dint of these tectonic processes involving volcanism, the lighter fraction was gradually separated and built up into islands of lighter rock, standing proud of the rest, due to their buoyancy.  The area of the continents has not been stable over geological time, but has progressively increased!