Why Would Every Rainstorm Have Caused Flooding 540 Million Years Ago?

[DonRocks]

A tired, hungry nucleus floated up to a group of cyanobacteria, and wearily asked:

"You carry oats?"

The leader of the gang moved forward, and replied, haughtily:

"We're pros."

(*)

I'm reviewing a book ("Life" by Richard Fortey) that's discussing the time in our Earth's history when there was abundant life in the seas, but virtually none on land. The exact eon, era, period, epoch, or age isn't important, and you don't need to know anything about paleontology to answer; the basis for my question consists of two things: 1) nothing had yet crawled out of the seas, and 2) the greening of the earth had not yet occurred, so there was essentially no plant life on land.

Okay, so picture the author going back in time, and standing on the seashore, where vast numbers of little squiggly things are swimming around, but behind him is a lifeless, barren, reddish-brown, mass of land with no sounds coming from it whatsoever - no birds chirping, no grass growing - just rock and soil that is completely devoid of life - for all practical purposes, not even bacteria was there, except incidental deposits from rainwater.

This passage, on page 138, is what I have a question about (only the Bold part; the rest is there for context):

"During the Cambrian, one-third of the world was devoid of life. The barren area was the land surface away from the sea. There may well have been bright stains of bacteria around springs, and covering such rocks as were washed regularly by showers. But the landscape would have been devoid of any softening tones of green. It would have seemed, to our eyes, naked and harsh. Nothing would have been there to consolidate loose soils, to absorb the worst of the weather, so that every rainstorm would have prompted a small flood, and stones and pebbles cascaded down slopes and tumbled freely into the choked beds of rivers."

Why would there have been floods every time it rained? I understand that trees and grass and plants absorb rainwater, but why couldn't the rains just drop down to the water table? I don't think the Earth was a solid slab of stone; there must have been plenty of loose soil which is extremely permeable. That having been said, this author is very smart and detail-oriented (he's former President of the Geological Society of London!), so I doubt he's wrong: What am I missing?

I wrote Professor Fortey and asked him, and with his permission, I'll pass along his response - in the meantime, if anyone could help, I'd appreciate it.

Cheers,

Rocks

(*) As for McGuffins, you'll just have to read one of the Alfred Hitchcock threads.

[Al Dente]

I don't think the Earth was a solid slab of stone; there must have been plenty of loose soil which is extremely permeable.

Would it have been "soil"? I would think it'd just be sand and pebbles. Sand doesn't absorb water like soil does.

[DonRocks]

Would it have been "soil"? I would think it'd just be sand and pebbles. Sand doesn't absorb water like soil does.

Yes, I misspoke - sand and pebbles. But why wouldn't the rainwater simply drop through it?

I guess the answer is here:

"Dangers of the Desert: Flash Floods and Sandstorms" by adventure.howstuffworks.com

Amazingly, this article says that more people drown in the desert than die of thirst!

Now that I think about it, molten lava would harden into solid rock, and "sand and pebbles" would only form by erosion - the wind and rain and oceans battering against the solid rock - which would take a very long time to form. I was having trouble visualizing this.