[Mike]

Mike  asked the Naked Scientists:
   
Hi

This is a simple question.

I'd like to know which mountain was the tallest before Mt Everest and the himalayas were pushed up by the Indian sub-continent?

many thanks

Swampy

What do you think?

[RD]

You seem to ask about the tallest mountain outside the Himalayas.

Olympus Mons (Latin for "Mount Olympus") is the tallest known volcano and mountain in the Solar System and was formed during the Amazonian epoch. It is located on the planet Mars at approximately 18°24′N 226°00′E / 18.4°N 226°E / 18.4; 226.[1] It is a little under three times as tall as Mount Everest.

http://en.wikipedia.org/wiki/Olympus_mons

[LeeE]

On the Earth, if you rule out the Himalayas then you might look towards the Andes and the Cascades, but then I don't know, off-hand, if they formed before or after the Himalayas.

[JimBob]

The Rocky Mountains were twice the size they were now, much higher than the Himalayas. This can easily be calculated by putting the amount of eroded material found in basins, such as the Wind River Basin and in the piedmont to the east of the mountains.

[LeeE]

Hmm... that's interesting.  A bit of digging around on wikipedia suggests that the Himalayas, although regarded as one of the youngest mountain ranges, started forming around 70 million years ago, but the Rocky Mountains are described as having formed around 70 million years ago (the wording suggests that were already extant by the time that the Himalayas started forming).  The Andes is described as a Mesozoic-Tertiary orogenic belt of mountains, which suggests an origin sometime around the boundary between the two periods i.e. about 65 million years ago.

Looks like the Rockies were the highest mountains then, before Everest formed, and were higher than Everest is now (Everest is still growing though).

[LeeE]

Ah, but Olympus Mons is a volcano and not a mountain...

[LeeE]

Volcanoes, all of 'em.

[Geezer]

Is there any sense of how high the mountains in Scotland might have been at one time? I understand they are pretty ancient. They certainly have eroded a lot.

[LeeE]

The oldest rocks in Scotland date to about 3 billion years ago, and were volcanic in origin, but when you go that far back Scotland wasn't where it is now (it was hanging around the South Pole for a while), or joined to the rest of what is now the U.K. and Europe.  There're a lot of sedimentary deposits overlaying the oldest volcanic stuff too, which were laid down when northern Scotland was lying beneath a shallow sea.  Since then, Scotland has been in a pretty wide variety of environments, from deserts, to more volcanism and more seas.

Have a look at:

http://en.wikipedia.org/wiki/Geology_of_Scotland#Chronology

The last volcanic activity seems to have finished about 50-60 million years ago, during the Paleogene period, but it's only when you get down to the Miocene and Pliocene epochs, about 2 million years ago, that "...the landscape would have been broadly recognisable today, with Scotland lying in its present position on the globe."

[Geezer]

There is a castle that sits on black rock in Edinburgh, right?

Right. Edinburgh Castle is built on top of a volcanic plug. Edinburgh is a quite spectacular city.

[Madidus_Scientia]

I always thought Mt Mauna Kea was the tallest mountain.

[Mazurka]

The Rocky Mountains were twice the size they were now, much higher than the Himalayas. This can easily be calculated by putting the amount of eroded material found in basins, such as the Wind River Basin and in the piedmont to the east of the mountains.

Much as I fear disagreeing with the great JB, whilst it is possible to do a mass balence calculation to establish a "theoretical" maximum height for any particular moutain range (whether the Rockies, the Andes or the highlands of Scotland), it is not easy to do this as some erosion will be contemporaneous with the uplift.  In a simplistic way, the taller the mountain the more erosion (via freeze/thaw cycles, glacial action etc.)

This is illustrated by the Ganges(-Brahmaputra) river system that drains the Himialaya.  It is estimated to carry around a billion (10^9) tonnes of sediment per year down from the mountains...

There is also an issue of isostasy as well, bu thtere is no need to over complicate the point.  []