Life off Interstate 84 - Idaho

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(19 April 2014)  My name is Tim Bondy and the owner of this website.  As of Jan 1st, 2014 we moved to a different domain.  Please head over to the Bondy Blogs Website at  Different address, different system but same type of great articles, photos, stories and information. 

You are here: Mtn Home Outdoor Local Outdoor News Oolite Interpretive Site near Grand View Idaho

Oolite Interpretive Site near Grand View Idaho

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Oolite? What the heck is that? It's not a new beer or some kind of new fad diet food. Read on to find out.

Owyhee Oolite Formation Site

The BLM has a “new” interpretive site south of Grand View on Mud Flat Road. This geologic information site is pretty cool and there is a walking trail on site also.

While hiking and enjoying the great Idaho outdoors, sometimes it's nice to actually understand the area to gain a better appreciation of what I'm seeing.

1. The Big Picture
How Idaho Oolite formed

What it says:
  • Extending across southwest Idaho between the Owyhee Mountains and Boise Front is the broad valley of the western Snake River Plain. Evidence indicates that the Plain began as a continental rift about 12 million years ago. Here, the earth's crust was pulled apart, northeast to southwest, and was stretched thin like taffy.
  • As crustal extension progressed between 11 and 9 million years ago, the Owyhee Mountains and the Boise Front responded by rising to their present height along faults bordering the rift. Now a valley, the Plain became a basin for Lake Idaho. Some 200 miles long and 35 miles wide, Lake Idaho drained south into Nevada.
  • Thousands of feet of sediment were deposited on the Lake's bottom over its 6.5 million years of existence, interrupted at times with layers of basalt and volcanic ash (tuff) from eruptions of adjacent volcanoes.
  • Geologist think that 2 to 4 million years ago, water from melting glaciers caused Lake Idaho to overflow to the west.. Captured by the Snake River, the waters drained out in a massive flood that gouged Hell's Canyon. The sediments left behind from Lake Idaho are known as the Chalk Hills and Glenns Ferry Formation.

2. Shoofly Oolite
Shoofly Oolite near Grand View Idaho

What it says:
  • The natural sculpture garden is a section of the Glenns Ferry Formation called the Shoofly Oolite. Oolite is sedimentary limestone composed of tiny ooids, which form when calcium carbonate precipitates in concentric layers around individual grains of sand. The Shoofly Oolite is one of the largest freshwater lakebed oolites known in the world.
  • Most other examples of ooid formation and deposition are found in wave-agitated sea waters or on the beds of much saltier lakes. Wave action that varied with the seasons, the weather, and the types of sediment in the water washed the ooids back and forth in the shallows on the southwestern side of Lake Idaho, depositing them from 2 to 40 feet thick on steeper benches near the shore.
  • Erosion carried away softer siltstone and volcanic tuffs but left the more resistant oolite to weather above the mudflats. Small, isolated deposits are exposed discontinuously across the 40 miles between this spot and Murphy. In some places, the upper surface of the oolite has been sculpted into hummocks, small arches, and intriguing shapes.
  • Beach sands of varying thickness underlie the oolite. Siltstone, deposited by lake waters, forms the stratum above it. Rivers and fans at the base of the adjacent mountain slopes later deposited a veneer of alluvium over the lake deposits.
  • The physical and chemical properties of the Shoofly Oolite provide the foundation for the unique set of plants and fossils found here. Few other lands in Idaho support such a rich suite of rare species in such a small area.

3. Vegetation of the Shoofly Oolite
Plants that grow in Idaho Oolite

The 5 Rare Plants in the Shoofly Oolite Formation

  • Mulford’s Vilkvetch (Astragalus mulfordiae)
  • Snake River Milkvetch (Astragalus purshii var. ophiogenes)
  • Packard’s Cowpie Buckwheat (Eriogonum shockleyi var. packardiae)
  • White-margined Wax Plant (Glyptopleura marginata)
  • White Eatonella (Eatonella nivea)

While the information on the sign indicated these plants are rare, in my experience only the White Eatonella seems to be the only “rare plant” in the Owyhee's. Your mileage may vary.

Coordinates for the BLM Oolite Interpretive Site on Mud Flat Road: 42.837189, -116.122149



Comments (2)
  • AacquelineX  - Thanks Bondyweb

    Thanks you for the time you put into this websight. Idaho is lucky to have someone who is willing to write about places in our area. I see you are looking for a job. Noone in the Mountain Home area will ever hire you or ant outsider. Ive been here for 27 years and know many of the business owners. They brag about keeping our town clean of outsiders. Think they have done a good job in that respect. Keep trying as this inbred town will have to change. A few new faces in the stores in town might actually bring in new customers.

  • Jay Hauser

    :D Thank you! My wife and I spent a wonderful Idaho Fall Day at the Oolitic formation on Veterans Day. I work as an interpretive ranger at the Hagerman Fossil Beds. Lake Idaho is the reason that we have the marvelous fossil beds that are preserved by the National Monument. Your website helps put one more piece of the puzzle together. Thanks again! Jay

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