The first thing to get out of the way is the matter of my blog’s title, which has garnered accolades ranging from ‘more difficult to pronounce than Pharyngula’ to ‘awesome geo-nerd term’.
An allochthon is a sequence of rocks which has been superimposed by faulting on top of another sequence which it was originally a large distance away from; for example, a sequence of sediments which were originally deposited in the deep sea, and have then been thrust over shallow marine or continental deposits of a similar age.
Therefore, a ‘highly allochthonous’ sequence is one that has been transported a large distance from its original position (or, more accurately, relative to the fixed ‘autochthon’).
Of course, that doesn’t explain why I chose the term as to appear at the top of my homepage. The pretentious answer would be that the name ‘poetically reflects my aspirations to cover the vast diaspora of disciplines which make up Earth Sciences’. But that would also be a complete lie: the embarrassing, nerdy truth is that it’s just a phrase which formed part of the banter when I was a geology undergrad, and I just thought that it sounded cool. Yes, I am that sad. On balance, though, I think the geeky true answer is preferable to the poncy false answer. Probably.