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Kick back for a thread about Robert Smithson's #SpiralJetty
It was commissioned by Robert in 1970 and it is 1500ft long from the shore. What isn't talked about, is the rocks he used to construct it, which I will discuss here.
It was commissioned by Robert in 1970 and it is 1500ft long from the shore. What isn't talked about, is the rocks he used to construct it, which I will discuss here.
Let's begin with the sand. It's difficult to see from the photo but this sand is special. The grains at the Great Salt Lake are ooilitic, meaning they are well rounded grains. This leads to a slippery walk where they are dry and you sink into the sand further than "normal" sand
As you walk further away from shore you notice several things. 1- the ground is "crunchy" 2- it's white 3- there are masses on the ground (not rocks). This perhaps is the most wide known fact, that the lake is high in saline. You can pick up the masses and taste them to confirm.
The water receeds and with high salt content, the pools left behind are so high in saline that the ground forms a crust of salt as the water evaporates.
If you look closely you can find #stromatolites in some places. These are algal communities that build up and grow toward the surface of the water to remain where they can receive the sun's rays.
Next up is the jetty itself. It is composed of black #basalts brought from the small mountain in the background and at the beach. The jetty itself is only basalt however there are other rocks nearby.
First up is brecciated basalts in (not confirmed but believed) to be white limestone. These are quite interesting to find here and there but I found none in situ so I cannot say if they were moved here or not.
And some of these basalts also included some clasts in the matrix of unknown origin.
Also around you, is Lake Bonnevilles' shoreline(s) where they are extremely well preserved. Above the grey marker you will see at least 3 shorelines. The top I believe is the highstand and the lowest is the Provo level which was cut into limestone beds at this location.
So next time you head out there, appreciate much more than the jetty itself because Robert chose an amazing place for this piece of art. – bei Robert Smithson's Spiral Jetty
