Run into/hack at the pillar from a certain direction until it falls down and creates a bridge for you to cross over to the other platform. Your reward is .....(sorry, won't spoil it for you).
(I haven't gotten to that point in the game yet. This is something I found in a walkthru)

run into? I tried action + forwarding it forever... I guess I'll try whacking and running into it more.... will update when i get home today

I had the same problem. Try as I might, I was unable to tip it over. Whenever I go into attack mode, it is no longer targeted. I guess I should try every conceivable angle until I get lucky.
I will revisit it at a later point.

well, I managed to knock it over, but it fell in the WRONG DIRECTION. ??????
So, after all that work, it didn't really help me. If anyone else wants to try to knock it over, the only angle that action + forward did anything was if you are facing the pillar with the chasm you are trying to cross ahead of you, go all the way to the left side of the pillar right on the edge of the chasm as close as you can with the highlighting still showing up and use the action forward button.... but this will knock it backwards, so go figure, maybe its a cruel joke.

I have also read that if you train in acrobatics, it is possible to jump the chasm.

yea i didn't do that... i wonder if its worthwhile

Could you post a link to that walk-through?? Normally, I don't use guides and cheats and stuff, but I've spent the better part of 3 hours just at this stupid monument, without getting any further into the game. So now I'm somewhat miffed, and am willing to "cheat" only because I want to know if it's for real or a "cruel joke". I too only managed to make it fall the wrong way. I too tried to jump it. I am trained in acrobatics. No good.
So please, post that walk-through. At this point I just want to know WTF is going on.
Thanks.

I would say training in acro is totally worth it. It lets you get into lots of areas, not just this one.
EDIT: wait how were you not able to jump this with acro? I was.

http://strategywiki.org/wiki/Gothic/Walkthrough
this is the link to walkthru. It just says to run into the pillar, doesn't give any info after that.

Here is an easy way to get to the other side without using the column.
Take a Bloodfly spell along with you and when you reach the top level (level of the column) turn into a Bloodfly and fly up along the mountain ridge to a flat area and then down to the chest.
Hit the enter key to break the spell and get the loot. It is not much but at least it is something for your troubles.
Also, you can jump back across with no spell (I did it first try) if you jump along the mountain back to the column side.
Hope this helps as hitting the column forever is not much fun.
EDIT: You can bring along a second Bloodfly spell to get down faster with no damage.

Some light on this topic is provided by NicoDE (http://forum.worldofplayers.de/forum/archive/index.php/t-186457.html).

In a previous version, the column could be pushed and felt in the right direction. But there was a bug with effect that the player was passing through the column when walking on it (= falling in the ravine). So they solved the bug ... by turning the column 180° => now it fells down the wrong side (= is useless). LOL.

i couldnt jump on the other platform even when using acrobatics. will have to use the bloodfly spell, i suppose. this patch is really one of the silliest, it doesnt fix anything, it just avoids the whole problem

You need to be right on the edge, to be able to jump with Acrobatics.
Turning into a bloodfly doesn't help, since they don't actually fly, they just hover above the ground.

For me personally it was always easier to jump to either side after drinking any type of potion of haste.