Makin an Earthcache!

[+Puppy Dawg]

So here's a description of the area I found on a website:

Dry Lakes Ridge was created primarily during the orogeny (mountain building) of the western Transverse Ranges, likely during the middle Pliocene (1 to 5 million years ago), and major deformation as middle Pleistocene (20,000 to 1 million years ago). Geologically, Dry Lakes Ridge is composed of Oligocene nonmarine and Miocene and Eocene marine sedimentary formations. The ridge represents a large anticline trending east-west. The youngest rock, of the Coldwater and Cozy Dell Formations, only remain on the flanks of the ridge, mostly on the south side. The oldest rock, the Juncal Formation of Eocene Era, is exposed on the ridgetop, primarily on the northwest part. Most of the ridgetop finds exposed Matilija Formation of late-Miocene Era. The anticline is clearly exposed in the roadcut at Dry Lakes Ridge Summit on State Route 33, but is not marked on the road. A small spring surfaces here seasonally, and the Forest Service tried drilling for a reliable source of water here, but failed, as this spring is not supported by the deep aquifer like that supplying Bellyache Falls.

 

The ridgetop "lakes" have never held water. I have hiked up to the top many times, and specifically went up there the morning after a heavy rainstorm to see for myself; no standing water. I did find a flotsum and jetsum rack line along the southern edge of what I call Basin 3, the largest, nearly westernmost basin, pictured above; however, no standing water at all. The soil and bedrock are very pourous, Eocene Juncal Formation sandstone, which absorbs water very quickly. In addition, the sedimentary strata are nearly vertical at the ridgetop, as Dry Lakes Ridge is an anticline with the top eroded away.

I'm just stuck on how to make good questions to get it approved. If anyone has help with that, please either PM me or reply here. Thanks!

[+catsnfish]

take vertical and horizontal measurements of the fold feature if possible. Ask the number of visible layers in the anticline. If there is a suitable exposure, time how long it takes a pint/quart or other suitable amount of water to be absorbed by the Eocene Juncal Formation sandstone, that would probably vary depending on conditions but the visitors would be taking a measurement and making an observation.

[+Puppy Dawg]

take vertical and horizontal measurements of the fold feature if possible. Ask the number of visible layers in the anticline. If there is a suitable exposure, time how long it takes a pint/quart or other suitable amount of water to be absorbed by the Eocene Juncal Formation sandstone, that would probably vary depending on conditions but the visitors would be taking a measurement and making an observation.

The water part..this is a really tough hike, so I don't think many folks would be willing to do that! The fold feature...is it the "lake" he's talking about? (the part that's all sandstone) And for the other idea, I'll try to find Dry Lakes Ridge Summit. (There is no summit in the road near the ridge, the road just keeps going up) Thanks!

[+TerryDad2]

It soulds like you should be able to see a nice repeat in units due to the fold. You could have them measure the thickness of one of the units on either side of the fold to see if they are the same or if other deformation has occured on the fold.

 

If you can get angles of the units on either side of the fold, have them see if the two limbs of the fold are symetrical.

 

Having depressions on the ridge suggests that the Juncal is more easily eroded than the younger rock which would leave a little valley along the ridge with Coldwater and Cozy Dell rising up on either side. Have them investigate that.

 

As for the water test, if they know the requirement ahead of time, one would hope that they come prepared (though I have found that is not always the case). So you could have them guess why the 'lakes' dry up so quickly.

[+TerryDad2]

So when do we get to see it published?