Figure 2 - available via license: Creative Commons Attribution 4.0 International
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Schematic map showing the spatial and temporal migration of volcanic sources within the eastern source area (indicated by the dashed line) of the Mount Belknap Volcanics in the Marysvale volcanic field. Figure after Cunningham et al. [14] (see also Cunningham et al. [16] for detail of the Central intrusion). See Figure 1 for location.
Source publication
Porphyry and epithermal deposits are important sources of base and precious metals. Most actively mined deposits have been exhumed such that ore bodies are relatively close to the surface and are therefore locatable and economic to extract. Identifying and characterizing concealed deposits, particularly more deeply buried porphyry deposits, represe...
Contexts in source publication
Context 1
... activity in the eastern source area began ca. 21-19 Ma northeast of Marysvale with shallow intrusions and the eruption of rhyolite tuffs, then migrated to the southwest over several Ma and culminated in the formation of the Deer Trail Ag-Aubase metal mantos and alunite veins at Alunite Ridge and Deer Trail Mountain, likely associated with the intrusion of two concealed stocks (Figure 2) [13,14,16,18]. However, no bimodal volcanic or intrusive rocks are exposed at Alunite Ridge or Deer Trail Mountain. ...
Context 2
... replacement alunite is fine-grained, and formed in near-surface, highly oxidizing conditions during hydrothermal alteration of volcanic rocks associated with intrusions of quartz monzonite stocks with published K/Ar and 40 Ar/ 39 Ar ages of 23-21 Ma [13,15,20]. These replacement deposits are mostly located near the periphery of the Central intrusion (Figure 2) [16], though several smaller deposits are associated with the intrusive core of the Monroe Peak caldera [13]. ...
Context 3
... for SGTF analyses were pooled for each sample to compute an inverse variance-weighted mean (hereafter simply a "weighted mean"; Table 2, Figures S30-S32). Where the í µí±í µí±í µí±í µí°· fell outside of the 95% CI of the í µí±í µí±í µí±í µí°· distribution, we performed outlier detection using an algorithm based on the Hampel identifier, which is based on deviations from the median rather than the mean (e.g., for more commonly applied Extreme Studentized Deviation or "2-sigma exclusion" identifiers) [39] (pp. . ...
Context 4
... timing of Miocene intrusive and hydrothermal activity at Deer Trail Mountain and Alunite Ridge is consistent with the migration of bimodal basalt-rhyolite magmatism across the Marysvale volcanic field (Figure 2) [18], and with broader patterns of Miocene bimodal igneous activity in southwestern Utah (e.g., [54]). Furthermore, the change around 22 Ma from calc-alkaline to bimodal basalt-rhyolite magmatic activity in the Marysvale volcanic field is consistent with the more regional compositional shifts within the Basin and Range Province that occurred during the late Oligocene to Miocene [55][56][57][58][59]. ...
Context 5
... this tectonic context, the last calc-alkaline events to occur in the MarysvaleDeer Trail area were the eruption of the Monroe Peak caldera and emplacement of the Central intrusion at ca. 23 Ma (Figure 2), and the eruption of the Delano Peak Tuff Member of the Bullion Canyon Volcanics ca. 22 Ma [15,16]. ...
Context 6
... Ma [15,16]. Bimodal igneous activity then promptly followed as asthenospheric mantle drove melting in the hydrated and thinned continental lithosphere, migrating from the northeast towards the southwest in the Marysvale area ( Figure 2). As this activity terminated near present day Alunite Ridge, felsic magmas were generated in part through partial melting associated with intrusion of subcontinental lithospheric mantle-derived basalts into the crust. ...
