Grandmother Mountain
2023-12-18に共有
Grandmother Mountain.
Immediately north of Gage (and are visible from i10), New Mexico, Grandmother Mountain(s) represents a cluster of conical peaks that rise up from the surrounding flat desert terrain within the western edge of the Mimbres Basin. The highest point bears a massive exposure of igneous rock that cliffs out along its south, which gives it a slightly unique appearance. All the peaks of Grandmother Mountain are in close proximity to one another.
Very little literature is available that pertains to the geologic background of these peaks. However, it is believed that the Grandmother Mountains represent the remains of what was likely a volcanic site where eruption(s) occurred (Darton, 1916). The volcanic rock extruded from the vent(s) is a latite(?) lava that varies in shades of grays (medium-light) that can also vary with hints of light yellow and light browns (Thorman and Drewes, 1979). The latite(?) is estimated to have been extruded sometime during the Eocene or Oligocene epoch; around the 30 million year range, give or take (Thorman and Drewes, 1979). Personal inspection of the volcanic rocks on and around the Grandmother Mountains appears to be mostly fine-grain and with sparse vesicles, and most of any crystals seen were extremely small (smaller than grains of sand). This rock makes up most of what is seen at Grandmother Mountain and also those found at Clabber Top Hill.
While driving throughout the areas north and northeast of the Grandmother Mountains, I noticed uneven exposures and small outcrops of igneous rocks of very similar descriptions. I visually compared a sample from one I gathered at Clabber Top Hill and noticed numerous similarities. However, with no way to test them (yet), I can only propose conjecture based on the limited evidence I have observed. Is it possible, that provided the Grandmother Mountains were in fact an eruptive center, the volcanic rock it produced may have flowed as far as 6 miles from its source layering the regions immediately to its north and northeast? Are there more flows to the west and south that are sourced at the Grandmother Mountains? I would like to investigate this one day.
References:
Darton, N. H., 1916, Geology and underground water in Luna County, New Mexico: U.S. Geological Survey, Bulletin 618, 188 pp.
Julyan, Robert. The Mountains of New Mexico. Albuquerque: University of New Mexico Press, 2006.
Thorman, C. H. and Drewes, H., 1979, Geologic Map of parts of the Grandmother Mountain East and Grandmother Mountain West Quadrangles, Luna County, New Mexico: US Geological Survey, Miscellaneous Field Studies Map MF-1088, scale 1:24,000.
All photos and videos were taken by Alexander F. O'Connor.
Soundtrack by Alexander F. O'Connor.
Video produced using Movie Maker (Version 2012) by Microsoft Corporation.
Music production, mixing, and editing made possible using Music Maker (64-bit) Version 32.0.2.11 by MAGIX Software GmbH.
Full trip report:
peakbagger.com/climber/ascent.aspx?aid=2400486
This series is dedicated to the loving memory of my grandmother, Paula M. O'Connor.
Thank you for watching.