Subject: Can a beam of focused sunlight melt a small iceberg?

I work in policy initiatives for an Arctic research think-tank.  I am not a
scientist, but a policy analyst.  Icebergs and pack ice are a big problem for
commercially viable arctic shipping.
I have an idea for a simple, economical reflecting/focusing orbiting sunbeam
'laser'.  It must not vaporize or fry the berg, just gracefully melt it, say 120
faranheit -- creating a localized sunny day on the area where the iceberg is.
Would a focused solar beam have enough power to create a 30-50' spotlight of 120
degrees faranheit, sufficient to melt a berg over a few days time?  Would cloud
cover, etc remove its efficiency entirely?  Can aerogel be bulletproofed, to
make a super-lightweight focusing lens?

Re: Can a beam of focused sunlight melt a small iceberg?