Log In
Hughes Mountain State Natural Area, Washington County, Missouri, USAi
| Regional Level Types | |
|---|---|
| Hughes Mountain State Natural Area | Nature Reserve |
| Washington County | County |
| Missouri | State |
| USA | Country |
This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84):
37° 48' 6'' North , 90° 42' 35'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
Local clubs are the best way to get access to collecting localities
| Club | Location | Distance |
|---|---|---|
| Mineral Area Gem & Mineral Society | Park Hills, Missouri | 18km |
The 1.5 billion year-old Precambrian rock outcrops on Hughes Mountain are among the oldest exposed rocks in the United States. A rhyolite formation, known locally as the Devil’s Honeycomb, is one of Missouri’s geologic wonders; it is the highest point on Hughes Mountain.
Hughes Mountain is mountain is primarily inter-layered volcanic ash and lava flows with a few features suggesting a nearby vent. Pratt et al mapped Hughes Mountain and the neighboring Round Mountain as unnamed quartz latites, with an adjoining southwest outcrop area mapped as Grassy Mountain Ignimbrite.
Sheet jointing can be noted along the trail on the way to the top of Hughes Mountain. Sheet joints are broadly spaced, undulating and roughly parallel to the ground surface. They divide the rock into flat sheets, or lenticular tabs that lie so that the thick part of one lens lies upon the thin ends of two underlying lenses. The thickness of the slabs tends to increase with depth. This type of fracturing is believed to be due to the release of pressure, and consequent vertical expansion through removal of the overlying rock by erosion.
The trail eventually comes to a large open area of outcrops. The best way to get to the next stop is to head toward the left (north) edge of the trees and travel upward to an open area between a grove of trees and the edge of the glade.
At the top of Hughes Mountain is a large area of columnar jointing approximately 10 acres in size (several thousand square meters give or take a few), locally known as the Devil’s Honeycomb. The columns tend to be square to rectangular in plan and are rarely more than 4 feet (1.2 m) high. This type of jointing is usually associated with a nearby eruptive vent, suggesting that the ash and lava vent for Hughes Mountain is nearby. Topographic relief of Hughes Mountain, Round Mountain and nearby hills also suggests that these features are erosional remnants of the edge of a volcanic crater or caldera.
Vertical non-columnar joints and fractures near the mountain top occasionally have a leached appearance and are probably most often the result of weathering. In a few cases leaching may be due to hydrothermal leaching or thermal alteration related to heat transfer from overlying lava or volcanic ash flow.
Sheet jointing can be noted along the trail on the way to the top of Hughes Mountain. Sheet joints are broadly spaced, undulating and roughly parallel to the ground surface. They divide the rock into flat sheets, or lenticular tabs that lie so that the thick part of one lens lies upon the thin ends of two underlying lenses. The thickness of the slabs tends to increase with depth. This type of fracturing is believed to be due to the release of pressure, and consequent vertical expansion through removal of the overlying rock by erosion.
The trail eventually comes to a large open area of outcrops. The best way to get to the next stop is to head toward the left (north) edge of the trees and travel upward to an open area between a grove of trees and the edge of the glade.
At the top of Hughes Mountain is a large area of columnar jointing approximately 10 acres in size (several thousand square meters give or take a few), locally known as the Devil’s Honeycomb. The columns tend to be square to rectangular in plan and are rarely more than 4 feet (1.2 m) high. This type of jointing is usually associated with a nearby eruptive vent, suggesting that the ash and lava vent for Hughes Mountain is nearby. Topographic relief of Hughes Mountain, Round Mountain and nearby hills also suggests that these features are erosional remnants of the edge of a volcanic crater or caldera.
Vertical non-columnar joints and fractures near the mountain top occasionally have a leached appearance and are probably most often the result of weathering. In a few cases leaching may be due to hydrothermal leaching or thermal alteration related to heat transfer from overlying lava or volcanic ash flow.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
1 valid mineral.
Rock Types Recorded
Note: data is currently VERY limited. Please bear with us while we work towards adding this information!
Select Rock List Type
Alphabetical List Tree DiagramGallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Quartz | 4.DA.05 | SiO2 |
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Granite-Rhyolite ProvinceMagmatic Province
- Shawnee DomainDomain
This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to
visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders
for access and that you are aware of all safety precautions necessary.
Hughes Mountain State Natural Area, Washington County, Missouri, USA