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Stop 13
The Jornada Basin
The view from Vista Bench at the
Nature Park gives you a panoramic view of the (from left to right) San Andres
Mountains, San Augustine Mountains, and the Organ Mountains with the Jornada
Basin below. |
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The Jornada (pronounced hoor-nah-duh) Basin is a closed system.
All the precipitation that falls into the basin stays in the basin.
Geologic events spanning 280 million years produced
the Jornada Basin. The first event was the deposition of sediments
on the floor of a shallow ocean that covered the continent until
about 70 million years ago. The resulting sedimentary rocks (sandstone,
limestone) were then deformed, tilted, and uplifted to form hills
that were the precursors to the Doña Ana and San Andres Mountains.
The mountain-building
events ended about 33 million years ago. Since that time, erosive
forces of water and wind have worn down the lofty mountains, forming the
much lower skyline visible today. The rocks eroded from the mountains
were deposited in the valley, essentially burying the base of the mountains
in their own debris. The deposits in the basin are more than 5,000
feet thick. |
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