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Re: Tectonic Striae
Posted: Mon Jan 10, 2011 10:56 am
by Rokcet Scientist
Digit wrote:We know how precise those are!
Better or worse than your own?
Neither.
But
I don't have the bald-faced gall to write it into a headline in New Scientist, etc., as if it's etched in stone.
Re: Tectonic Striae
Posted: Tue Jan 11, 2011 12:16 am
by dannan14
Hehe, did i say a page or two ago that the oldest parts of the ocean's crust were at most a few hundred million years old? Funny how that escaped ya RS.
Re: Tectonic Striae
Posted: Tue Jan 11, 2011 10:28 am
by Rokcet Scientist
dannan14 wrote:Hehe, did i say a page or two ago that the oldest parts of the ocean's crust were at most a few hundred million years old? Funny how that escaped ya RS.
No it didn't, my friend. I'm waiting for adequate support of your outspoken position. Until then it's just that:
your position, afaic.
Re: Tectonic Striae
Posted: Tue Jan 11, 2011 7:51 pm
by dannan14
Rokcet Scientist wrote:dannan14 wrote:Hehe, did i say a page or two ago that the oldest parts of the ocean's crust were at most a few hundred million years old? Funny how that escaped ya RS.
No it didn't, my friend. I'm waiting for adequate support of your outspoken position. Until then it's just that:
your position, afaic.
Yeah, i said it. It's on page 2.
http://topex.ucsd.edu/es10/lectures/lec ... agemap.gif
It also happens to be the position of Dietmar Muller and those other cool guys that drill holes in the rocks to see what's there.
Re: Tectonic Striae
Posted: Tue Jan 11, 2011 10:45 pm
by Rokcet Scientist
Pretty map.
Unfortunately lo-res and specifically uninformative where it matters.
Let's see those cool guys drill near a couple subduction zones.
In drill cores, age is a function of depth.
Just because they couldn't get any deeper doesn't mean there's nothing older beyond. To the contrary. It virtually guarantees that what's beyond is older.
Re: Tectonic Striae
Posted: Tue Jan 11, 2011 11:10 pm
by dannan14
Well, then, maybe you should read up on oceanic crust formation at mid ocean ridges.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 3:20 am
by Rokcet Scientist
dannan14 wrote:Well, then, maybe you should read up on oceanic crust formation at mid ocean ridges.
If I were looking for rocks of "at most a few hundred million years old", I should. But it so happens we're discussing much older rock here that you specifically
won't find around mid ocean ridges!
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 4:05 am
by Digit
Where would you find rock of sufficient age?
Roy.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 5:16 am
by Rokcet Scientist
Digit wrote:Where would you find rock of sufficient age?
I wouldn't
know until we find it, of course. But I would go looking near subduction zones.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 6:04 am
by Digit
Logic would suggest that any rock of that age has already been subducted.
Roy.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 7:00 am
by Rokcet Scientist
Digit wrote:Logic would suggest that any rock of that age has already been subducted.
But if it hasn't yet,
that's the place I would expect to find it. Not in/on/under a mid-ocean ridge. That's where 'new' rock emerges from the mantle.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 8:44 am
by Digit
Well just to clarify a point, striae are not the result simply of expansion, they are the result of friction between two moving faces, that all. Grooves, in other words.
Roy.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 2:14 pm
by Rokcet Scientist
Digit wrote:Well just to clarify a point, striae are not the result simply of expansion, they are the result of friction between two moving faces, that all. Grooves, in other words.
No, they are the result of being pushed up, expanded.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 3:30 pm
by Digit
Why does pushing up mean expansion?
Roy.
Re: Tectonic Striae
Posted: Wed Jan 12, 2011 4:50 pm
by Rokcet Scientist
Digit wrote:Why does pushing up mean expansion?
I'll leave that to you to figure out.