Lightweight Alternative to Base Layer Pants?

I got to thinking the other day, that I have a pair of "leggings" that I use when mountain biking in the winter. They are basically long tubes that you slip over your legs, and compression keeps them in place. There is no crotch, backside, or anything else to connect the two pieces.

I plan on using them next week, as one of my geology classes is heading to the Four Corners for 4 days, 3 nights of field study. Temps should get down to the 20s at night.

I am not sure what they weigh, and when I get new batteries for my scale, I will post back with results.

I used to use leg and arm warmers while cycling. For hiking, I much prefer my Capilene top and bottoms. They are more comfortable and thinner than my warmers were and the bottoms don't slip down my legs, as my leg warmers tended to do after a while.