Lava Flow Leftovers
| Here is what the pamphlet has to say about lava: Magma is molten rock and gas confined within the earth, its temperature ranging between 1,500° and 2,700°F. Magma does not always surface. Often it will cool and crystallize within the earth creating coarse-grained rocks such as granite. When magma does surface, the result is an eruption of lava and gas. Most of the gas dissipates into the air while the lava remains on the surface. The basalt lava found here is fine grained because it cooled so quickly. It is believed that Sunset Crater began erupting some time around 1064. After most of the gasses had escaped from the magma during the crater’s eruption, lava began to flow between the spaces of the cinders. Basalt, the type of lava at Sunset Crater, tends to form either jagged blocks or a smooth, ropey surface as it cools and hardens. The jagged block version is call Aa (ah ah). When aa is forming, cooled, hardened blocks on the surface of hot, moving lava are rafted along, making clinking noises as they tumble into each other. Sometimes called “clinkers,” these hardened blocks would still make a clinking sound if you knocked them together. Sunset Crater flowed lava down two sides. There is the Bonito Flow on the west side (the one you can walk down into) and the Kana-a on the east side. I still say it looks like a giant rototiller came through here and ground up the rock to look like churned up asphalt. See for yourselves. The first picture is a view over the top of the flow, looking out over about a half a mile. The second is a close up of the Aa. |
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