Eruptive styles and inferences about plumbing systems at Hidden Cone and Little Black Peak scoria cone volcanoes (Nevada, U.S.A.)

Abstract

We describe two small scoria cone volcanoes, Hidden Cone and Little Black Peak (ages between~320-390 ka), in the Southwestern Nevada Volcanic Field and discuss their eruption mechanisms and inferences about their plumbing systems. Cone-forming pyroclastic deposits are consistent with eruptive styles ranging from Strombolian to violent Strombolian, and lavas emanated from near the bases of the cones. The volcanoes are monogenetic (rather than polycyclic, as allowed by previous geomorphic interpretations). Vents at each volcano appear to coincide with pre-existing normal faults, consistent with observations at older, deeply eroded volcanoes in the region. The existence of these two volcanoes on a topographically high area (particularly Hidden Cone) provides evidence for short feeder dike lengths (~500 m at the surface). We infer that this short length reflects the small length scale of the mantle source region that was tapped to feed each volcano.

Spatial distribution and structural analysis of vents in the Lunar Crater Volcanic Field (Nevada, USA)

“…Valentine and Perry (2007) hypothesized that intraplate monogenetic volcanic fields form a spectrum between two basic end-member behaviors; in tectonically controlled volcanic fields, the long-term eruptive magma flux (measured over time frames of 10 4 -10 6 years) is extremely low, magmatism is a passive response to regional deformation, and behavior is likely to be time-predictable (duration of repose period is proportional to the volume of the preceding eruption), and in some cases, favorably oriented pre-existing joints and faults (Delaney et al 1986;Gudmundsson and Loetveit 2005;Gaffney et al 2007) in the crust might "capture" ascending dikes so that vents can be closely related to faults. This is consistent with field data in some volcanic fields (Conway et al 1997;Valentine and Krogh 2006;Valentine and Keating 2007;Valentine and Perry 2007;Keating et al 2008;Gazel et al 2012;Le Corvec et al 2013a). Conversely, in magmatically controlled fields, the long-term magma flux is high, frequent dike injection into the crust produces a local stress field whose orientation might be different with respect to the regional, tectonically imposed one, allowing two effects: (1) addition of material into the crust takes up much or all of the strain that would otherwise be taken up by faulting, thereby reducing the abundance of faults, and (2) regional stresses modified by frequent and abundant dike injection might promote magma ponding in the crust, after which feeder dike orientation may be guided by stresses associated with magma reservoirs rather than regional tectonic stresses.…”

Assessing tephra total grain-size distribution: Insights from field data analysis

“…For these reasons only a few TGSDs are available in the literature, and are often lacking of either or both the fine and the coarse fraction (e.g. Bonadonna and Houghton, 2005;Rose and Durant, 2009;Scollo et al, 2014). The large uncertainties associated with the determination of TGSD, limit our understanding of eruption dynamics and significantly affect the simulation of tephra dispersal necessary for hazard assessments and real-time forecasting.…”

“…Other key conduit properties, such as magma permeability, shear-rate, and crystallinity, can vary locally due to differential magma velocity, shear heating and crystal resorption, determining non-uniform fragmentation within the conduit or during the eruption (e.g. Costa et al, 2007;Mueller et al, 2008;Polacci et al, 2001).…”

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

“…In general, the cooling front is perpendicular to the column orientation [162][163][164][165]. Dikes associated with monogenetic alkalic volcanoes are commonly described from deeply eroded volcanic fields [38,103,166].…”