Lamprophyre (kersantite) Dike above Lake Mead

36.046741, -114.870982

https://en.wikipedia.org/wiki/Lamprophyre
Lamprophyres are rare and poorly understood ultrapotassic hypabissal rocks that occur only as dikes.
A lamprophyre with plagioclase > K-feldspar and biotite as the dominant mafic mineral; no feldspathoid. A lamprophyre containing biotite and plagioclase (usually oligoclase or andesine), with or without clinopyroxene and olivine.

Til Lamprophyre dikes (middle Miocene)—Dikes and flows(?) of highly alkalic biotite, pyroxene, and plagioclase-bearing lamprophyre (kersantite) exposed in River Mountains (unit Tdl of Smith, 1984). Dark-green to purplish-gray with biotite phenocrysts to 1.2 cm in diameter

Free USGS Geologic Map of Boulder Beach Area (actual dikes):
https://pubs.nbmg.unr.edu/Order-as-M81-p/um3hg.htm

Free USGS Geologic Map of Henderson Quad (getting there):
https://pubs.nbmg.unr.edu/Order-as-M67-p/um3gg.htm

Camera: $200 Sony CX405 9MP 40x optical zoom 1080p/60fps.

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