Aeromagnetic and spectral expressions of rare earth element deposits in Gallinas Mountains area, Central New Mexico, USA

Abstract

KeywordNew Mexico, Gallinas Mountains, Aeromagnetic, Landsat, 2D magnetic modeling Interpretation 2 ABSTRACT The Gallinas Mountains located in the conjunction of Lincoln County and Torrance County, New Mexico, USA are a series of alkaline volcanic rocks intruded into Permian sedimentary rocks. The Gallinas Mountains area is known to host fluorite and copper as veins containing bastnasite while hydrothermally altered rocks associated with iron oxides have been found in the area as well. In this study, multispectral band ratio method was used for surface mineral interpretation by processing satellite image, while aeromagnetic inversion method was applied using aeromagnetic data, digital elevation model and physical properties for 2-D subsurface structure modeling. Bastnasite has higher magnetic susceptibility than the host rocks and surrounding sedimentary rock whereas magnetization of iron oxides (magnetite & hematite) is much stronger than bastnasite; both of them can contribute to a positive aeromagnetic anomaly. Results of this study hypothesize the possible presence of mineralogies and lithologies among the Gallinas Mountains area, indicating the presence of a positive magnetic anomaly that is possibly resultant from both bastnasite and iron oxides.

Geology and mineral deposits of the Gallinas Mountains, Lincoln and Torrance Counties, New Mexico

“…The regional aeromagnetic data indicates multiple magnetic anomalies in the subsurface of the Gallinas Mountains and surrounding areas (Fig. 56; Kucks et al, 2001;McLemore, 2010a;Li, 2017). Li (2017) modeled the data and the blue in the center of the Gallinas Mountains is a magnetic low anomaly.…”

“…111; Gagnon et al, 2003), geophysical anomalies (Fig. 8;McLemore, 2010a;Li, 2017), fluid inclusion and stable isotope studies (Vance, 2013), geochemistry of igneous rocks and hydrothermal breccia and fissure vein Campbell et al, 1995). Eudialyte is the predominant REE mineral in the Cornudas Mountains (McLemore et al, 1996).…”

“…56; Kucks et al, 2001;McLemore, 2010a;Li, 2017). Li (2017) modeled the data and the blue in the center of the Gallinas Mountains is a magnetic low anomaly. Li (2017) suggested that the magnetic low anomaly centered in the middle of Gallinas Mountain is a result of underlying body enriched in one of four mineralogical models including (1) bastnäsite, (2) mixture of bastnäsite and iron oxides, (3) iron oxides (magnetite and hematite), or (4) magnetite.…”

Nb and REE Distribution in the Monte Verde Carbonatite–Alkaline–Agpaitic Complex (Angola)

“…These include radioactive anomalies-due to the high contents in Th and U in pyrochlore and other minerals, magnetic anomalies-due to the high magnetite content, or gravimetric anomalies-since large volumes of magnetite can create a noticeable density contrast, or time-domain electromagnetic anomalies-when conductive sulphide deposits are present. These methods have been proven to be effective to determine the 3D structure of carbonatites and alkaline intrusions in several places, such as in Mt Weld, Australia [64]; El Morro, Brazil [65]; Elk Creek, USA [66]; Alnö, Sweden [67], Gallinas Mountains in USA [68]; and Beldih in India [69].…”