First-day road log: Las Vegas to Mineral Hill, Johnson Mesa, Gallinas Canyon, and Montezuma
— Jennifer Lindline, Barry Kues, Kenneth Bentson, and Jospeh Zebrowski
Day 1 of the field conference will take participants through the Proterozoic and Paleozoic-Mesozoic geologic history and structural development of the Las Vegas Range—the eastern salient of the southern Sangre de Cristo Mountains. The morning route transects Mesozoic-Paleozoic strata of the Las Vegas basin and visits a Paleoproterozoic foliated granite (Stop 1) to consider the timing of plutonism relative to deformation. Stop 2 provides an overview of major structures and crests of the southern Sangre de Cristo Mountains. The route then travels to Johnson Mesa (Stops 3 and 4) to examine the late Paleozoic stratigraphy of the southeastern Sangre de Cristo Mountains and discuss the structure and age of the Hermit Peak granite while enjoying a 360° view of New Mexico from above the treeline. The afternoon agenda visits Proterozoic rocks of Gallinas Canyon (Stops 5 and 6) to view Paleo- and Mesoproterozoic igne¬ous and metamorphic rocks, examine a variety of igneous intrusive relationships, discuss the timing of plutonism relative to deformation, and consider the tectonomagmatic history of the region. The day also includes laying hands on the 1.4 billion year time gap represented by the Great Unconformity, and enjoying a barbeque on the grounds of the Armand Hammer United World College (Stop 7) with an optional soak in the Montezuma hot springs.
Note: Full-text Fall Field Conference road logs for recent guidebooks are only available in print.
- Lindline, Jennifer; Kues, Barry; Bentson, Kenneth; Zebrowski, Jospeh, 2015, First-day road log: Las Vegas to Mineral Hill, Johnson Mesa, Gallinas Canyon, and Montezuma, in: Geology of the Las Vegas Region, Lindline, Jennifer; Petronis, Michael; Zebrowski, Joseph, New Mexico Geological Society, Guidebook, 66th Field Conference, pp. 1-53.