We spent a couple of nights near Alamosa, Colorado, so that we could revisit the Great Sand Dunes National Park.
The Sangre de Cristo Mountains present a barrier that entraps sand grains blown across the San Luis Valley by the prevailing winds, building the tallest sand dunes in the USA.
We were curious about what causes these black patches on the some of the dunes.
Plants had taken hold on a few areas on the dunes.
A dirt 4x4 road leads from the dunes into the Sangre de Cristo Mountains. We saw a variety of wildflowers while driving a portion of the road.
Rocky Mountain Bee Plant
Penstemon
Cactus blossoms
Some colorful fungi
Thunderheads started building as the day progressed.
We wondered if lightning had taken out this tree's top.
We liked this interplay of sunlight and shadows on the dunes.
Re: Black patches on sand dunes from Wikipedia:
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"The dunes contain dark areas which are deposits of magnetite, a mineral that has eroded out of the Sangre de Cristo Range. Magnetite is both attracted to a magnet and can be magnetized to become a magnet itself; it is the most magnetic mineral in nature.[19] Magnetite is an oxide of iron which is heavier than the surrounding particles of sand. When overlying sand is removed by wind, magnetite deposits stay in place and are visible as dark patches in the dunefield."
I bet you looked that up, too, Art! :)