Compton–Belkovich Volcanic Complex (CBVC): An ash flow caldera on the Moon

Chauhan, M.; Bhattacharya, S.; Saran, S.; Chauhan, Prakash; Dagar, A.

doi:10.1016/j.icarus.2015.02.024

Cited by 20 publications

(23 citation statements)

References 82 publications

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“…The very rare occurrence on the Moon of the morphologically and spectroscopically distinctive Gruithuisen (Figure 32a) and Mairan domes in northeast Oceanus Procellarum (Head and McCord, 1978;Glotch et al, 2011;Kusuma et al, 2012;Ivanov et al, 2015) and the farside domes between the craters Belkovich and Compton Chauhan et al, 2015) (Figure 32b) implies the localized eruption of unusually viscous,…”

Section: G Non-mare Volcanic Domes and Complexes: Relation To Basaltmentioning

confidence: 99%

Generation, ascent and eruption of magma on the Moon: New insights into source depths, magma supply, intrusions and effusive/explosive eruptions (Part 2: Predicted emplacement processes and observations)

Head

Wilson

2017

Icarus

173

197

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1 Highlights  Mare basalt eruption process predictions are compared to observed features/deposits.  Single dike event magma volume predicted to be 10 2 -10 3 km 3 ; dikes 40-100 m by 60-100 km. Shallower-source dikes continuous from source to surface; deeper dikes detach from source. Dikes reaching surface form wide range of predicted/observed effusive/explosive eruption types. Intrusion is favored in thicker farside crust; extrusion is favored on thin nearside crust. AbstractWe utilize a theoretical analysis of the generation, ascent, intrusion and eruption of basaltic magma on the Moon to develop new insights into magma source depths, supply processes, transport and emplacement mechanisms via dike intrusions, and effusive and explosive eruptions. We make predictions about the intrusion and eruption processes and compare these with the range of observed styles of mare volcanism, and related features and deposits. Density contrasts between the bulk mantle and regions with a greater abundance of heat sources will cause larger heated regions to rise as buoyant melt-rich diapirs that generate partial melts that can undergo collection into magma source regions; diapirs rise to the base of the anorthositic crustal density trap (when the crust is thicker than the elastic lithosphere) or, later in history, to the base of the lithospheric rheological trap (when the thickening lithosphere exceeds the thickness of the crust). Residual diapiric buoyancy, and continued production and arrival of diapiric material, enhances melt volume and overpressurizes the source regions, producing sufficient stress to cause brittle deformation of the elastic part of the overlying lithosphere; a magma-filled crack initiates and propagates toward the surface as a convex upward, blade-shaped dike. The volume of magma released in a single event is likely to lie in the range 10 2 km 3 to 10 3 km 3 , corresponding to dikes with widths of 40-100 m and both vertical and horizontal extents of 60-100 km, favoring eruption on the lunar nearside. Shallower magma sources produce dikes that are continuous from the source region to the surface, but deeper sources will propagate dikes that detach from the source region and ascend as discrete penny-shaped structures. As the Moon cools with time, the lithosphere thickens, source regions become less abundant, and rheological traps become increasingly deep; the state of stress in the lithosphere becomes increasingly contractional, inhibiting dike emplacement and surface eruptions.In contrast to small dike volumes and low propagation velocities in terrestrial environments, lunar dike propagation velocities are typically sufficiently high that shallow sill formation is not favored; local low-density breccia zones beneath impact crater floors, however, may cause lateral magma migration to form laccoliths (e.g., Vitello Crater) and sills (e.g., Humboldt Crater) in floor-fractured craters. Dikes emplaced into the shallow crust may stall and produce crater chains due to active andpassive gas venting (e.g., Men...

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Section: G Non-mare Volcanic Domes and Complexes: Relation To Basaltmentioning

confidence: 99%

Generation, ascent and eruption of magma on the Moon: New insights into source depths, magma supply, intrusions and effusive/explosive eruptions (Part 2: Predicted emplacement processes and observations)

Head

Wilson

2017

Icarus

173

197

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“…However, there are considerable differences between typical DMD compositions (mafic) and the bulk of the Lassell massif 'red spot' (which is predominantly silicic, Fe-poor, and enriched in Th). Recent work on the Compton-Belkovich Volcanic Complex proposed a highly silicic form of pyroclastic eruption possible for the Moon ( Jolliff et al, 2011;Chauhan et al, 2015 ), although this material is characterized by high reflectance. We suggest that the occurrence of low-reflectance materials at Lassell is consistent with a pyroclastic origin, but sample collection and analysis will be required to make definitive determinations of these and other materials across the massif as their compositions are not resolved by current instruments.…”

Section: Low-reflectance Depositsmentioning

confidence: 99%

“…The massif lowreflectance materials could represent emplacement of late-stage, minor iron-bearing effusive basalts or pyroclastics resulting from magma chamber stratification (e.g., Blake, 1981 ). The Lassell massif exhibits several similarities with the Compton-Belkovich silicicvolcanic complex ( Jolliff et al, 2011;Chauhan et al, 2015 ) and the Mairan domes ( Glotch et al, 2010 ), including elevated Th concentrations ( Hagerty et al, 2006 ), pits with irregular to arcuate margins, candidate volcanic cones (e.g., Fig. 10 ), lobate flows, and Sirich materials.…”

Section: Low-reflectance Depositsmentioning

confidence: 99%

The Lassell massif—A silicic lunar volcano

Ashley

Robinson

Stopar

et al. 2016

Icarus

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“…This region is located within the lunar highlands, which are heavily cratered, and generally anorthositic in composition. The CBVC is characterized by high surface reflectance ( Clegg et al, 2014( Clegg et al, , 2015, isolated high thorium and silica contents ( Jolliff et al, 2011 ), and volcanic morphologies, such as cones, domes, and irregular depressions ( Jolliff et al, 2011;Chauhan et al, 2015 ). The volcanism is of particular interest because it is not basaltic, but instead represents an evolved composition with high silica content ( Glotch et al, 2010 ;Jolliff et al, 2011 ).…”

Section: The Compton-belkovich Volcanic Complexmentioning

confidence: 99%

“…Subdued morphologies and high reflectance, coupled with the extended area of high reflectance to the southeast ( Jolliff et al, 2011 ), may indicate that silicic pyroclastic activity occurred at the CBVC. Chauhan et al (2015) interpreted the caldera subsidence features as a source of volcanic ash, and Wilson et al (2015) interpreted the extended thorium signature in Lunar Prospector Gamma Ray Spectrometer results as caused by pyroclastic dispersal of Th-rich rhyolitic material from the CBVC. A high pyroclastic glass component in the regolith would provide a low-density, high porosity target and may have affected the size of craters < 300 m, making them larger relative to nominal production and therefore skewing AMA results toward older ages ( van der Bogert et al, 2010( van der Bogert et al, , 2013.…”

Section: Target Property Influencementioning

confidence: 99%