Seems like removing the chain, putting it in a closed container of cleaner, shaking the daylights out of it, rinsing and drying, lubing and replacing would rid it of any particles. Not knowing what minerals comprise the silt it's hard to guess if it would cause accelerated wear.

But it's not as though you were swamping for hours, and mtn bikers deal with this routinely and probably don't do more than a scrub and hose-off. OTOH now that we're in an era of $80 chains and $400 clusters I'm less of a mind to "use it up and toss it" and intermittently give my chains a complete clean off the bike. I appreciate the silence of a clean, lubed chain.