× Figure 1: Geologist inspecting a sill crosscut by a dike intruded fault with a low amount of offset.
2024 Photo by Jon Krupnick
Figure 2: Up close view of the sill (drab green) overlooking the Tularosa Basin including the outskirts of Alamogordo with White Sands National Park and the San Andres Mountains on the horizon.
× Figure 2: Up close view of the sill (drab green) overlooking the Tularosa Basin including the outskirts of Alamogordo with White Sands National Park and the San Andres Mountains on the horizon.
2024 Photo by Jon Krupnick
Figure 3: Geologist inspecting float from an outcrop to the north where magnitude of offset on the fault displacing the sill increases.
× Figure 4: Crinoids and other fossils in a Mississippian limestone intruded by the igneous rocks.
2024 Photo by Jon Krupnick
October 11, 2024
Postcard from the field —Jon Krupnick, Field Geologist, NMBGMR Two field geologists from the New Mexico Bureau of Geology and Mineral Resources ventured to the Sacramento Mountains east of the Tularosa Basin to map thrust faults, measure a fracture dataset, and collect samples for 40 Ar/ 39 Ar geochronology. At this location, Mississippian (~323-358 million years old) limestone is intruded by younger igneous rocks. The intrusive rock is suspected to be as young as 36 million years old and has been deformed and faulted by compressive tectonics after being emplaced. This could signify a very young example of Laramide tectonics in New Mexico if analysis of fractures and faults does not indicate an alternate origin for these features.
