River Mountains Loop Trail

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You are here: Home / Geology of the River Mountains

Geology of the River Mountains

River Mountain Loop Trail

Volcanoes?

This phrase will certainly get the attention of many, particularly those who are not familiar with the geology of the River Mountains. This certainly explains why they are so rugged!

The River Mountains are composed of tilted and faulted mid-Miocene (15 to 12 million years old) andesite and dacite lava flows. Two volcanoes, the source of most of the lava, have been identified in the River Mountains. *

Strato Volcano

Volcano cross-section

Stratovolcano cross section – USGS file photo

The first, located just north of Boulder city, is a stratovolcano surrounded by numerous domes. Stratovolcanoes are cone-shaped features composed of lava flows interbedded with abundant agglomerate and breccia that formed from explosive eruptions. The surrounding domes formed by the eruption of very sticky lava such as dacite, which erupted to the surface but did not flow. Lava formed a low spine or a dome that quickly crumbled to a ring of debris about the dome.

Volcano with lava flow.

This could have been River Mountains 14-million years ago. The birth of a mountain range.

Shield Volcano

The second volcano, located in the northern part of the River Mountains, is a shield volcano – a broad volcano composed of basaltic and andesitic lavas similar to those erupting today on the island of Hawaii.

Both volcanos have been tilted, cut by numerous faults, and broken into numerous parts producing a jigsaw pattern of rocks that is now very difficult to recognize.

The photo below is of a cinder cone just a mile north and east of the River Mountains and can be seen from the trail between mile-marker 12 and mile-marker 14. Locally it is called “Lava Butte.”

Volcanic cinder cone, Henderson, NV.

Lave Butte, a volcanic cinder cone just north of the River Mountain Loop Trail.

* Reference material from Nevada Bureau of Mines and Geology Special Publication #16, “Geologic tours in the Las Vegas area.”

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River Mountains Loop Trail
2 months ago
River Mountains Loop Trail

Anyone know what all the helicopter activity is off McCullough Hill Trail on back side of Black Mountain??? ... See MoreSee Less

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They're doing water main construction. I live near there and was notified about the project.

Probably dropping construction materials to one of those mega mansions in the hill

Looks like a recovery or a rescue. Its been happening for a couple of hours.

River Mountains Loop Trail
2 months ago
River Mountains Loop Trail
Big thanks to all the volunteers who came out to clean up the trail on Saturday at Railroad Pass! Lots of trash was removed and the trail looks much better!

Big thanks to all the volunteers who came out to clean up the trail on Saturday at Railroad Pass! Lots of trash was removed and the trail looks much better! ... See MoreSee Less

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i didnt get the f.b notice..

I'd like more info for when you guys do a cleanup.

Thanks everyone. I’ve been on the trail many times and it always looks so clean. What kind of trash do you find? Is the trash coming from the casino?

Thanks Thanks Thanks. As a cyclist I occasional stop and kick large rocks off the pavement but i don’t pick up trash. Too bad the “walkers” can’t help keep the rocks off when they come across them.

Thank you all volunteers. That area gets alot of trash blown in from freeway etc.

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River Mountains Loop Trail
2 months ago
River Mountains Loop Trail
Get Outdoors Nevada
River Mountains Loop Trail Clean Up 
Saturday, December 3rd from 9am-11am.

Meet at the trail entrance on Railroad Pass Rd located at 1500 Railroad Pass Casino Rd, Henderson, NV 89002. 

Tools and supplies will be provided  such as gloves and trash grabbers. Volunteers can expect to travel approximately 1 mile on both paved trails and uneven terrain, without shade. 
Please wear closed-toed shoes, and bring water.

Thanks for helping beautify our community spaces!

Get Outdoors Nevada
River Mountains Loop Trail Clean Up
Saturday, December 3rd from 9am-11am.

Meet at the trail entrance on Railroad Pass Rd located at 1500 Railroad Pass Casino Rd, Henderson, NV 89002.

Tools and supplies will be provided such as gloves and trash grabbers. Volunteers can expect to travel approximately 1 mile on both paved trails and uneven terrain, without shade.
Please wear closed-toed shoes, and bring water.

Thanks for helping beautify our community spaces!
... See MoreSee Less

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How about a RMLT pee gravel and liquid rubber to fix the gaps in the trail event.

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