Tectonic Striae

[Rokcet Scientist]

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.

[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.

[Rokcet Scientist]

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.

[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.

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.

[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.

[dannan14]

Well, then, maybe you should read up on oceanic crust formation at mid ocean ridges.

[Rokcet Scientist]

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!

[Digit]

Where would you find rock of sufficient age?

Roy.

[Rokcet Scientist]

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.

[Digit]

Logic would suggest that any rock of that age has already been subducted.

Roy.

[Rokcet Scientist]

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.

[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.

[Rokcet Scientist]

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.

[Digit]

Why does pushing up mean expansion?

Roy.

[Rokcet Scientist]

Why does pushing up mean expansion?

I'll leave that to you to figure out.