Is there even small possibility that a small amount of?

Hypothetically speaking- yes.

However Africa does have plate tectonic rifts and valleys.

The Afar triangle is one example of where a rift that extends into open air.

There is no such thing as strangium. They probably just made that up for the movie. Black holes are just ordinary matter that has been compressed to infinitely high density.

Probably all the other ideas in that movie are bogus too. I am not sure what would happen is a black hole that size hit Earth. I am not even sure if theory admits the possibility of a black hole that size existing. Theory says that under the right conditions a large star can become a black hole under the force of its own gravity, and subatomic black holes can exist but would have no visible effect on matter around them, but medium size ones like you describe are just something made up for the movie as far as I know.

Were some small particle of Strangium to hit the Earth during the month of March, it would be blown away by the high winds we always encounter during that month of the year.

It depends on what "small possibility" means to you. There's a small possibility that there's a submicroscpic tyranosaurus living behind my eyes. It's too small to worry about.

I'd put your "strangium" theory in that category.

Here go the "submicroscopic tyrannosaurus" rumors again! Mine live in my navel, it's silly to think they would be anywhere else.