The Earth's Best Dandruff

Every backcountry traveler or camper has had a nightmarish experience with wet clay roads. But do you know about "anti-clay", that is, a surface that is as miraculous on the positive side as wet clay is on the negative?

It is easy to be ignorant of what causes wet clay's amazing properties. It would be so nice to learn about things when they make huge impressions on you -- that is the very time when you are motivated to learn. 

There might be a really good source of popular science out there, but I haven't found it yet. (And extra credit to any reader who has any ideas on this.) I am familiar with Wikipedia and "How Things Work". They both help. But the Wikipedia articles on a scientific topic quickly degenerate into the algebraic patois of the specialist, which makes for excruciating reading.

What I need to find is popular science, written by an educated layman or generalist, with a minimum of info-mercial intrusions.

But let's get back to "anti-clay," that is, the most wonderful surface in the world to be traveling on, especially in wet weather. That surface is decomposed granite, the ground that I am camping on, now.

It is miraculously well-behaved. If it appears loess loose, you can still mountain bike or drive right over it. In size, it is 2--6 mm. It is rather sharp at the corners, that is, block-shaped rather than oval and rounded like the gravel in streams. Therefore it interlocks when under the pressure of feet or tires.

Decomposed granite, my favorite surface for mountain biking, camping, or driving on. Ordinary "dirt" at the top of the photo.

Among its miraculous properties, the parent rock or its dandruff is easily worn into smooth troughs by the tires of mountain bikes and other vehicles. This makes for glorious mountain biking. The ultimate miracle is not turning into soup or sticky muck when it is wet, as anyone who drives a rear-wheel-drive vehicle can attest.

The opening paragraphs of Wikipedia's article on "Soil Mechanics" are pretty good. 

Soils that are not transported are called residual soils—they exist at the same location as the rock from which they were generated. Decomposed granite is a common example of a residual soil. 

But I am not really complaining about how hard it is to find popular science articles about topics that interest me. It causes an intense interest to pop up in my fevered brain. It is fun to obsess over traction-enhancing technologies, such as the locking differential.