Friday, August 9, 2019

Slide Complex at Mesa del Oro in the Rio Grande Rift

One of my ventures afforded a view of the Rio Grande Rift in New Mexico.

Rio Grande south of Albuquerque

 J Fleck writes about water in the southwest and the Rio Grande water flows. Viewed from above the contrast of the river and irrigated land is sharp.

Mesa del Oro with large landslide complexes on the west side of the mesa 

Mesa del Oro is a basalt mesa made up of lava flows that have come up along the Rio Grande Rift zone. The mesa also has a thick travertine deposit (Priewisch, Crossey and Karlstrom, 2013). The travertine was deposited from springs with volcanic field associated CO2-rich groundwater.   

Basalt lava flows can break into large landslides due to the weak zones of soil soil between the basalt flows and the vertical fractures that develop in the flows upon cooling. It is hard to have a good sense of scale from 30,000 feet. The mesa is a about 800 feet high. The slide complexes from the top edge of the mesa to outer edge of the slide complexes are nearly 2 miles. I suspect that the slide complex has slowly developed as the top edge of the mesa breaks and collapses onto the slide surface the failed basalt blocks have slid and spread towards the west away from the mesa behaving somewhat like a very slow glacier.      

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