Oro Grande Geology and Rock Hounding

Only an hour away from El Paso, the Oro Grande mining district lies within the Jarilla Mountains just north of the community of Oro Grande NM off Hwy 54. The district was, in the past, the location of significant mining interest with quantities of gold, silver, copper, iron, and lead extracted. Although some mining interest still remains, the area is largely inactive and offers an excellent place to study the relationship between igneous intrusions and occurrence of mineral resources.

Geologist Lance Robert will be leading the trip, with geologist James Lyons who has previously completed detailed geologic mapping of the area. In this trip we will be talking about the interesting history of the area and geologic setting, then observe the contact of igneous intrusions with mineralized country rock. Where permissible, we will aim to collect samples of the various minerals that host the metals of interest. Potential minerals we will see include pyrite, hematite, magnetite (iron), various colored garnets, and turquoise, malachite, chalcopyrite (copper)… and fossils in limestone.

We will meet at Circle K on NE corner of 54 and Transmountain Rd (address: 4501 Woodrow Bean) leaving there at 08:30 sharp, so please arrive by 08:15. We will caravan up Hwy 54 to the area which is about 45 minutes drive. The field trip involves moderate walking and hill climbing plus driving on several miles of moderately rough gravel roads. 4WD cars with high clearance are recommended. Please also note that water, sunscreen, and hats are important as there is no shade. It is also a good idea to bring lunch, rock hammers and other usual rock-collecting kit.

The expected duration is from 8:30 am to 2:30 pm. Additionally, since there is a solar eclipse on this day we encourage anyone educated in astronomy to join and help us enjoy this experience.

Contact info for Lance Robert is 409-554-1961