It is sort-of explained, yes. From your link:
Data then offers a partial explanation. The anomaly is a multiphasic
temporal convergence in the space-time continuum, an eruption of
anti-time. The relationship between time and anti-time is analogous to
the relationship between matter and anti-matter, and upon contact, the
two would annihilate each other, causing the rupture in space.
Q transfers them back to Earth, about 3.5 billion years in the past.
He shows Picard the sky, which is full of the anomaly. Picard then
realizes that the anomaly is expanding as it moves back in time. Q
then shows Picard a pool of green sludge, a pool of amino acids. They
are about to combine to form the first proteins, however, the
disturbance from the anomaly stops the combination as it happens. Life
on Earth doesn't start, and the anomaly stopped the creation of
The event isn't really explained:
They look into the water.
Q (continuing): Here they go... the amino acids are moving closer...
closer... closer... (reacts) Ohhhh! Nothing happened! (to Picard) You
see what you've done?
Picard thinks for a moment, then looks up at the sky.
PICARD: You mean I caused the anomaly... and the anomaly... in some
way... disrupted the beginning of life on Earth.
Q's eyes bore into Picard.
Earlier in the episode a pregnant crew member also lost her baby due to the effects of the anomaly, which Crusher explained like this:
I think it's the same thing that happened to Geordi. Somehow, the
temporal energy from the anomaly caused the fetal tissue to revert to
an earlier stage of development. It was as if the unborn child began
to... grow younger... until finally the DNA itself began to break