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Author Topic: Heat Bursts in the Highlands  (Read 4365 times)

Offline JimBob

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Heat Bursts in the Highlands
« on: 19/10/2007 03:17:40 »
GEOLOGY: Heat Bursts in the Highlands
Earth Planet. Sci. Lett. 261, 500 (2007).

Brooks Hanson

Because rocks are good insulators, it is generally thought that temperatures deep in the crust evolve slowly, rising and falling over millions to tens of millions of years. Rapid pulses of fluid or the intrusion of hot magmas can heat or cool rocks more quickly, as can rapid uplift along a fault (which juxtaposes hot and cold rocks at a rate faster than heat conduction). Thus metamorphic processes are also thought to act over these time scales. Ague and Baxter challenge some of these notions in well-studied metamorphic rocks in Scotland, known as the Barrovian metamorphic belt and thought to represent burial and heating of rocks during continental collision. They show that concentrations of a trace element, strontium, across the mineral apatite are surprisingly variable. Laboratory data imply that if the minerals were at the temperatures inferred for the host rocks for even 1 million years, diffusion should have homogenized any gradients. Thus the authors infer that the rocks were heated and cooled in less time. This would seem to require rapid heat input by fluids and rapid exhumation, but at scales and rates that start to challenge what have been thought to be geologic limits. Stay tuned. -- BH



 

Offline pete_inthehills

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Heat Bursts in the Highlands
« Reply #1 on: 19/10/2007 14:50:38 »
can someone get this heat burst sorted.  I had to defrost the car this morning!

pete
inthehills
in Northern Scotland
 

Offline Ophiolite

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Heat Bursts in the Highlands
« Reply #2 on: 19/10/2007 15:19:23 »
I look to percolating hydrothermal fluids as the means of heat transmission in that case. There is certainly plenty of evidence for metasomatism in the higher metamorphic grades.

(Pete, it was bloody cold this morning, wasn't it?)
 

Offline turnipsock

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Heat Bursts in the Highlands
« Reply #3 on: 09/12/2007 00:15:11 »
It's snowing here now.
 

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Heat Bursts in the Highlands
« Reply #3 on: 09/12/2007 00:15:11 »

 

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