110 Linking Mineral Resources and the Geologic Framework of North America: The USGS Earth Mapping Resources Initiative (Earth MRI) and Related Activities (Posters)

Knowledge of the geologic framework and mineral resources is improving through new geologic mapping, airborne geophysics, geochemistry, and lidar acquisition, especially through Earth MRI. We welcome submissions of Earth MRI research and similar studies linking framework geology and mineral resources.

Monday, 20 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Preliminary Geologic Mapping and Assessment of Lithium in the Barstow Formation at Daggett Ridge, California, USA

Paper number: 110-1
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Volcano-sedimentary deposits have recently gained attention as significant hosts for potentially economic lithium (Li) resources. In the Mojave Desert, Li enrichment has been identified in smectite clays within Miocene lacustrine and tuffaceous sediments of the Barstow Formation. The Barstow Formation spans a broad region; however, previous research has mainly focused on a few specific sites, leading to a limited understanding of the tectonostratigraphic framework and pervasiveness of Li enrichment. To address this knowledge gap, we are conducting new 1 to 24,000 scale geologic mapping of the Daggett 7.5-minute quadrangle with accompanying cross section and stratigraphic analyses, and sample collection for geochronology, geochemistry, and petrography. Interpretations are further supplemented by lidar, airborne electromagnetic surveys, and previous mapping. Our initial assessments of Li concentrations of Barstow Formation sediments are semi-quantitatively generated using a handheld Laser Induced Breakdown Spectroscopy (LIBS) analyzer.

 

Preliminary observations suggest that the geology of Daggett Ridge is structurally and stratigraphically analogous to neighboring Miocene localities (e.g., Lead Mountain, Calico Mountains). The Barstow Formation at Daggett Ridge overlies resistant Mesozoic basement and late Oligocene to early Miocene strata of faulted and tilted coarse volcaniclastics, basaltic to andesitic flows, and rock avalanche deposits, likely correlative to the syn-extensional Pickhandle Formation. The Barstow Formation is shallow to moderately dipping with localized folding and faulting due to displacement and transpressional deformation along the active Lenwood and Camp Rock right-lateral strike-slip faults. Exposure thicknesses of the Barstow Formation north of Daggett Ridge range between 200-400 m and consist of sand-, silt-, and mudstones with several <1-3 m thick reworked tuff beds. The presence of marls, root casts, pedogenic features, algal mats, and occasional vertebrate fossils indicate deposition within and near a shallow lake environment. Several carbonate horizons with varying degrees of silica mineralization and porous textures also suggest possible influence of mineral springs. Pending geochronology (40Ar/39Ar, U-Pb) and geochemistry (ICP-OES-MS) sample results from Daggett Ridge will assist in the construction of a robust geologic timeline and test potential relationships between Li concentrations, rock compositions, and mappable features that may further inform genetic models of volcano-sedimentary Li resources.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-411953

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