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Greg A. Valentine - One of the best experts on this subject based on the ideXlab platform.
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compound maar Crater and co eruptive scoria cone in the Lunar Crater volcanic field nevada usa
Journal of Volcanology and Geothermal Research, 2017Co-Authors: Jamal Amin, Greg A. ValentineAbstract:Abstract Bea's Crater (Lunar Crater Volcanic Field, Nevada, USA) consists of two coalesced maar Craters with diameters of ~ 440 m and ~ 1050 m, combined with a co-eruptive scoria cone that straddles the northeast rim of the larger Crater. The two Craters and the cone form an alignment that parallels many local and regional structures such as normal faults, and is interpreted to represent the orientation of the feeder dyke near the surface. The maar formed among a dense cluster of scoria cones; the cone-cluster topography resulted in Crater rim that has a variable elevation. These older cones are composed of variably welded agglomerate and scoria with differing competence that subsequently affected the shape of Bea's Crater. Tephra ring deposits associated with phreatomagmatic maar-forming eruptions are rich in basaltic lithics derived from
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Lunar Crater volcanic field reveille and pancake ranges basin and range province nevada usa
Geosphere, 2017Co-Authors: Greg A. Valentine, Joaquín A. Cortés, Eugene I Smith, Racheal Johnsen, Christine Rasoazanamparany, Elisabeth Widom, Jason P Briner, Andrew Harp, Brent D TurrinAbstract:The Lunar Crater volcanic field (LCVF) in central Nevada (USA) is dominated by monogenetic mafic volcanoes spanning the late Miocene to Pleistocene. There are as many as 161 volcanoes (there is some uncertainty due to erosion and burial of older centers); the volumes of individual eruptions were typically ∼0.1 km 3 and smaller. The volcanic field is underlain by a seismically slow asthenospheric domain that likely reflects compositional variability relative to surrounding material, such as relatively higher abundances of hydrous phases. Although we do not speculate about why the domain is in its current location, its presence likely explains the unusual location of the LCVF within the interior of the Basin and Range Province. Volcanism in the LCVF occurred in 4 magmatic episodes, based upon geochemistry and ages of 35 eruptive units: episode 1 between ca. 6 and 5 Ma, episode 2 from ca. 4.7 to 3 Ma, episode 3 between ca. 1.1 and 0.4 Ma, and episode 4, ca. 300 to 35 ka. Each successive episode shifted northward but partly overlapped the area of its predecessor. Compositions of the eruptive products include basalts, tephrites, basanites, and trachybasalts, with very minor volumes of trachyandesite and trachyte (episode 2 only). Geochemical and petrologic data indicate that magmas originated in asthenospheric mantle throughout the lifetime of the volcanic field, but that the products of the episodes were derived from unique source types and therefore reflect upper mantle compositional variability on spatial scales of tens of kilometers. All analyzed products of the volcanic field have characteristics consistent with small degrees of partial melting of ocean island basalt sources, with additional variability related to subduction-related enrichment processes in the mantle, including contributions from recycled ocean crust (HIMU source; high-µ, where µ = 238 U/ 204 Pb) and from hydrous fluids derived from subducted oceanic crust (enriched mantle, EM source). Geochemical evidence indicates subtle source heterogeneity at scales of hundreds of meters to kilometers within each episode-scale area of activity, and temporary ponding of magmas near the crust-mantle boundary. Episode 1 magmas may have assimilated Paleozoic carbonate rocks, but the other episodes had little if any chemical interaction with the crust. Thermodynamic modeling and the presence of amphibole support dissolved water contents to ∼5–7 wt% in some of the erupted magmas. The LCVF exhibits clustering in the form of overlapping and colocated monogenetic volcanoes that were separated by variable amounts of time to as much as several hundred thousand years, but without sustained crustal reservoirs between the episodes. The persistence of clusters through different episodes and their association with fault zones are consistent with shear-assisted mobilization of magmas ponded near the crust-mantle boundary, as crustal faults and underlying ductile deformation persist for hundreds of thousands of years or more (longer than individual episodes). Volcanoes were fed at depth by dikes that occur in en echelon sets and that preserve evidence of multiple pulses of magma. The dikes locally flared in the upper ∼10 m of the crust to form shallow conduits that fed eruptions. The most common volcanic landforms are scoria cones, agglomerate ramparts, and ‘a‘ā lava fields. Eruptive styles were dominantly Strombolian to Hawaiian; the latter produced tephra fallout blankets, along with effusive activity, although many lavas were likely clastogenic and associated with lava fountains. Eroded scoria cones reveal complex plumbing structures, including radial dikes that fed magma to bocas and lava flows on the cone flanks. Phreatomagmatic maar volcanoes compose a small percentage of the landform types. We are unable to identify any clear hydrologic or climatic drivers for the phreatomagmatic activity; this suggests that intrinsic factors such as magma flux played an important role. Eruptive styles and volumes appear to have been similar throughout the 6 m.y. history of the volcanic field and across all 4 magmatic episodes. The total volume and time-volume behavior of the LCVF cannot be precisely determined by surface observations due to erosion and burial by basin-fill sediments and subsequent eruptive products. However, previous estimates of a total volume of 100 km 3 are likely too high by a factor of ∼5, suggesting an average long-term eruptive flux of ∼3–5 km 3 /m.y.
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origin of chemical and isotopic heterogeneity in a mafic monogenetic volcanic field a case study of the Lunar Crater volcanic field nevada
Chemical Geology, 2015Co-Authors: Christine Rasoazanamparany, Greg A. Valentine, Joaquín A. Cortés, Eugene I Smith, Elizabeth Widom, David Kuentz, Racheal JohnsenAbstract:Major and trace element geochemistry and Sr, Nd, Pb, Hf and Os isotope signatures of basaltic lavas and tephra from volcanic centers inthe northern Lunar Crater VolcanicField (LCVF), Nevada, provide insight into the nature of their mantle sources and the role of lithospheric contamination versus source-related enrichment in producing compositional variations in basaltic monogenetic volcanic fields. Three of the studied eruptive centers (Hi Desert and Mizpah, ~620–740 ka; and Giggle Springs, b80 ka) are located within ~500 m of each other; the Marcath volcano (~35–38 ka) and Easy Chair (140 ka), two of the youngest eruptive centers in the field, are located ~6 and 12 km southwest of these cones, respectively. Isotopic studies of the volcanic rocks show a limited range in 143 Nd/ 144 Nd and 176 Hf/ 177 Hf, but significant heterogeneity in 87 Sr/ 86 Sr, 206 Pb/ 204 Pb and 187 Os/ 188 Os. The older (N140 ka) Hi Desert, Mizpah, proto-Easy Chair and several unnamed flows exhibit Nb–Ta enrichment, Rb,Cs and K depletion, and high 206 Pb/ 204 Pb but low 87 Sr/ 86 Sr.Incontrast,theyounger(≤140ka) Giggle Springs, Easy Chair and Marcath lavas have high Ba, Rb and Cs and lower 206 Pb/ 204 Pb and higher 87 Sr/ 86 Sr. The lavas produce a well-defined negative correlation between Sr and Pb isotopes, attributed to mixing of heterogeneous mantle sources. The geochemical and isotopic signatures of the older Hi Desert, Mizpah, proto-Easy Chair and unnamed lavas are consistent with derivation from a mantle source with a component of ancient recycled oceanic crust. In contrast, the relatively high Ba, Rb and Cs coupled with lower 206 Pb/ 204 Pb and higher 87 Sr/ 86 Sr of the younger Giggle Springs, Easy Chair and Marcath lavas are consistent with derivation from a similar, but fluid-enriched, mantle source. Mixing calculations indicate that incorporation of ~18% of 0.8 Ga recycled oceanic crust into depleted mantle can explain the trace element and isotopic signatures of the older group end member. Subsequent addition to this source of minor (b1%) hydrous fluid derived from subducted oceanic crust could account for the chemical and isotopic compositions of the younger group end member. Variable degrees of mixing between these two mantle end members can generate the full range of isotopic compositions observed in the northern LCVF sample suite, as well as within single eruptions. Our data indicate that the mantle source region in the LCVF is characterized by chemical and isotopic heterogeneity that manifests itself over a very small spatial scale (<500 m) and within the time frame of a single monogenetic eruption. Similar processes may explain the geochemical and isotopic heterogeneities observed in other mafic monogenetic volcanic fields, the evidence for which may be preferentially preserved where small degrees of melting and rapid source to surface transport prevail.
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intrinsic conditions of magma genesis at the Lunar Crater volcanic field nevada and implications for internal plumbing and magma ascent
American Mineralogist, 2015Co-Authors: Greg A. Valentine, Joaquín A. Cortés, Eugene I Smith, Racheal Johnsen, Christine Rasoazanamparany, Elisabeth Widom, Mai Sas, Dawn C S RuthAbstract:The northern part of the Lunar Crater Volcanic Field (central Nevada, U.S.A.) contains more than 100 Quaternary basaltic cones and maars and related eruptive products. We focused on four informal units of different ages and locations in the field to test the compositional variability and magma ascent processes within the time span of an individual eruption and the variability between very closely spaced volcanoes with different ages. Based in whole-rock chemistry, mineral chemistry and the calculation of intrinsic properties (pressure, temperature, and oxygen fugacity) we found that individual magma batches were generated in the asthenospheric mantle from a heterogeneous garnet lherzolite/olivine websterite source by ~3–5% partial melting. Each magma batch and temporary deep reservoir was a separate entity rather than part of a continuous long-lived reservoir. Magmas ascended relatively fast, stalled and crystallized in the uppermost several kilometers of the mantle near the base of the crust and some also stalled at mid-crustal levels with minor or no geochemical interaction with surrounding rocks. Our data also suggest that volcanoes erupting within certain time windows had similar source characteristics and ascent processes whether they were located within a few hundred meters of each other or were separated by many kilometers.
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Spatial distribution and structural analysis of vents in the Lunar Crater Volcanic Field (Nevada, USA)
Bulletin of Volcanology, 2014Co-Authors: A. Tadini, F. L. Bonali, C. Corazzato, J. A. Cortés, A. Tibaldi, Greg A. ValentineAbstract:Volcanoes within monogenetic volcanic fields often are arranged in alignments and clusters, which are related to effects of magma source geometry in the upper mantle, principal stress orientations, and crustal structures on their magma feeding systems. We use cluster analysis with dendrogram, vent morphometric analysis, and field structural data to explore the relationships between volcanoes and tectonic features in the Plio-Pleistocene part of the Lunar Crater Volcanic Field (LCVF; Pancake Range, Nevada, USA), which includes 96 monogenetic volcanic edifices totaling 119 vents. Structural analysis identified three main sets of faults with dip-slip kinematics (mostly normal with a few examples of thrust faults), striking N-S, E-W, and NE-SW. The NE-SW set comprises dip-slip faults with a dominant normal component of movement which are consistent with the modern state of stress based upon the World Stress Map database. Spatial distribution pattern analysis suggests a clustered distribution of vents in the LCVF, and GIS-based spatial density analysis shows that these clusters trend mostly NE-SW. Morphometric study of the monogenetic cones, which provides information on feeder dike orientation where dikes are not directly exposed, suggests dominant NNE-SSW to NE-SW orientations of near-surface inferred dikes. An amount of 27 out of 31 inferred feeder dikes within the LCVF is parallel to the present orientation of the greatest principal horizontal stress ( σ _Hmax) as suggested by World Stress Map data derived from hydrofracturing and earthquake focal mechanisms. In some cases, dike strike is parallel with that of pre-existing Quaternary dip-slip faults. We suggest that the spatial distribution of vents is related to domains of different scales of partial melting and compositional heterogeneity in the upper mantle source, which is substantiated by geochemical data. The relationship of feeder dikes with respect to shallow tectonic structures, although somewhat ambiguous at LCVF, is consistent with behavior that is intermediate between volcanic fields with high- and low-long-term magma fluxes.
Joaquín A. Cortés - One of the best experts on this subject based on the ideXlab platform.
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Lunar Crater volcanic field reveille and pancake ranges basin and range province nevada usa
Geosphere, 2017Co-Authors: Greg A. Valentine, Joaquín A. Cortés, Eugene I Smith, Racheal Johnsen, Christine Rasoazanamparany, Elisabeth Widom, Jason P Briner, Andrew Harp, Brent D TurrinAbstract:The Lunar Crater volcanic field (LCVF) in central Nevada (USA) is dominated by monogenetic mafic volcanoes spanning the late Miocene to Pleistocene. There are as many as 161 volcanoes (there is some uncertainty due to erosion and burial of older centers); the volumes of individual eruptions were typically ∼0.1 km 3 and smaller. The volcanic field is underlain by a seismically slow asthenospheric domain that likely reflects compositional variability relative to surrounding material, such as relatively higher abundances of hydrous phases. Although we do not speculate about why the domain is in its current location, its presence likely explains the unusual location of the LCVF within the interior of the Basin and Range Province. Volcanism in the LCVF occurred in 4 magmatic episodes, based upon geochemistry and ages of 35 eruptive units: episode 1 between ca. 6 and 5 Ma, episode 2 from ca. 4.7 to 3 Ma, episode 3 between ca. 1.1 and 0.4 Ma, and episode 4, ca. 300 to 35 ka. Each successive episode shifted northward but partly overlapped the area of its predecessor. Compositions of the eruptive products include basalts, tephrites, basanites, and trachybasalts, with very minor volumes of trachyandesite and trachyte (episode 2 only). Geochemical and petrologic data indicate that magmas originated in asthenospheric mantle throughout the lifetime of the volcanic field, but that the products of the episodes were derived from unique source types and therefore reflect upper mantle compositional variability on spatial scales of tens of kilometers. All analyzed products of the volcanic field have characteristics consistent with small degrees of partial melting of ocean island basalt sources, with additional variability related to subduction-related enrichment processes in the mantle, including contributions from recycled ocean crust (HIMU source; high-µ, where µ = 238 U/ 204 Pb) and from hydrous fluids derived from subducted oceanic crust (enriched mantle, EM source). Geochemical evidence indicates subtle source heterogeneity at scales of hundreds of meters to kilometers within each episode-scale area of activity, and temporary ponding of magmas near the crust-mantle boundary. Episode 1 magmas may have assimilated Paleozoic carbonate rocks, but the other episodes had little if any chemical interaction with the crust. Thermodynamic modeling and the presence of amphibole support dissolved water contents to ∼5–7 wt% in some of the erupted magmas. The LCVF exhibits clustering in the form of overlapping and colocated monogenetic volcanoes that were separated by variable amounts of time to as much as several hundred thousand years, but without sustained crustal reservoirs between the episodes. The persistence of clusters through different episodes and their association with fault zones are consistent with shear-assisted mobilization of magmas ponded near the crust-mantle boundary, as crustal faults and underlying ductile deformation persist for hundreds of thousands of years or more (longer than individual episodes). Volcanoes were fed at depth by dikes that occur in en echelon sets and that preserve evidence of multiple pulses of magma. The dikes locally flared in the upper ∼10 m of the crust to form shallow conduits that fed eruptions. The most common volcanic landforms are scoria cones, agglomerate ramparts, and ‘a‘ā lava fields. Eruptive styles were dominantly Strombolian to Hawaiian; the latter produced tephra fallout blankets, along with effusive activity, although many lavas were likely clastogenic and associated with lava fountains. Eroded scoria cones reveal complex plumbing structures, including radial dikes that fed magma to bocas and lava flows on the cone flanks. Phreatomagmatic maar volcanoes compose a small percentage of the landform types. We are unable to identify any clear hydrologic or climatic drivers for the phreatomagmatic activity; this suggests that intrinsic factors such as magma flux played an important role. Eruptive styles and volumes appear to have been similar throughout the 6 m.y. history of the volcanic field and across all 4 magmatic episodes. The total volume and time-volume behavior of the LCVF cannot be precisely determined by surface observations due to erosion and burial by basin-fill sediments and subsequent eruptive products. However, previous estimates of a total volume of 100 km 3 are likely too high by a factor of ∼5, suggesting an average long-term eruptive flux of ∼3–5 km 3 /m.y.
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origin of chemical and isotopic heterogeneity in a mafic monogenetic volcanic field a case study of the Lunar Crater volcanic field nevada
Chemical Geology, 2015Co-Authors: Christine Rasoazanamparany, Greg A. Valentine, Joaquín A. Cortés, Eugene I Smith, Elizabeth Widom, David Kuentz, Racheal JohnsenAbstract:Major and trace element geochemistry and Sr, Nd, Pb, Hf and Os isotope signatures of basaltic lavas and tephra from volcanic centers inthe northern Lunar Crater VolcanicField (LCVF), Nevada, provide insight into the nature of their mantle sources and the role of lithospheric contamination versus source-related enrichment in producing compositional variations in basaltic monogenetic volcanic fields. Three of the studied eruptive centers (Hi Desert and Mizpah, ~620–740 ka; and Giggle Springs, b80 ka) are located within ~500 m of each other; the Marcath volcano (~35–38 ka) and Easy Chair (140 ka), two of the youngest eruptive centers in the field, are located ~6 and 12 km southwest of these cones, respectively. Isotopic studies of the volcanic rocks show a limited range in 143 Nd/ 144 Nd and 176 Hf/ 177 Hf, but significant heterogeneity in 87 Sr/ 86 Sr, 206 Pb/ 204 Pb and 187 Os/ 188 Os. The older (N140 ka) Hi Desert, Mizpah, proto-Easy Chair and several unnamed flows exhibit Nb–Ta enrichment, Rb,Cs and K depletion, and high 206 Pb/ 204 Pb but low 87 Sr/ 86 Sr.Incontrast,theyounger(≤140ka) Giggle Springs, Easy Chair and Marcath lavas have high Ba, Rb and Cs and lower 206 Pb/ 204 Pb and higher 87 Sr/ 86 Sr. The lavas produce a well-defined negative correlation between Sr and Pb isotopes, attributed to mixing of heterogeneous mantle sources. The geochemical and isotopic signatures of the older Hi Desert, Mizpah, proto-Easy Chair and unnamed lavas are consistent with derivation from a mantle source with a component of ancient recycled oceanic crust. In contrast, the relatively high Ba, Rb and Cs coupled with lower 206 Pb/ 204 Pb and higher 87 Sr/ 86 Sr of the younger Giggle Springs, Easy Chair and Marcath lavas are consistent with derivation from a similar, but fluid-enriched, mantle source. Mixing calculations indicate that incorporation of ~18% of 0.8 Ga recycled oceanic crust into depleted mantle can explain the trace element and isotopic signatures of the older group end member. Subsequent addition to this source of minor (b1%) hydrous fluid derived from subducted oceanic crust could account for the chemical and isotopic compositions of the younger group end member. Variable degrees of mixing between these two mantle end members can generate the full range of isotopic compositions observed in the northern LCVF sample suite, as well as within single eruptions. Our data indicate that the mantle source region in the LCVF is characterized by chemical and isotopic heterogeneity that manifests itself over a very small spatial scale (<500 m) and within the time frame of a single monogenetic eruption. Similar processes may explain the geochemical and isotopic heterogeneities observed in other mafic monogenetic volcanic fields, the evidence for which may be preferentially preserved where small degrees of melting and rapid source to surface transport prevail.
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intrinsic conditions of magma genesis at the Lunar Crater volcanic field nevada and implications for internal plumbing and magma ascent
American Mineralogist, 2015Co-Authors: Greg A. Valentine, Joaquín A. Cortés, Eugene I Smith, Racheal Johnsen, Christine Rasoazanamparany, Elisabeth Widom, Mai Sas, Dawn C S RuthAbstract:The northern part of the Lunar Crater Volcanic Field (central Nevada, U.S.A.) contains more than 100 Quaternary basaltic cones and maars and related eruptive products. We focused on four informal units of different ages and locations in the field to test the compositional variability and magma ascent processes within the time span of an individual eruption and the variability between very closely spaced volcanoes with different ages. Based in whole-rock chemistry, mineral chemistry and the calculation of intrinsic properties (pressure, temperature, and oxygen fugacity) we found that individual magma batches were generated in the asthenospheric mantle from a heterogeneous garnet lherzolite/olivine websterite source by ~3–5% partial melting. Each magma batch and temporary deep reservoir was a separate entity rather than part of a continuous long-lived reservoir. Magmas ascended relatively fast, stalled and crystallized in the uppermost several kilometers of the mantle near the base of the crust and some also stalled at mid-crustal levels with minor or no geochemical interaction with surrounding rocks. Our data also suggest that volcanoes erupting within certain time windows had similar source characteristics and ascent processes whether they were located within a few hundred meters of each other or were separated by many kilometers.
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Time and space variations in magmatic and phreatomagmatic eruptive processes at Easy Chair (Lunar Crater Volcanic Field, Nevada, USA)
Bulletin of Volcanology, 2013Co-Authors: Greg A. Valentine, Joaquín A. CortésAbstract:The products of monogenetic volcanoes often record complex sequences of eruptive processes. Easy Chair volcano (Lunar Crater Volcanic Field, Nevada, USA) was formed by a monogenetic eruption along a ∼2.5-km-long series of en echelon fissure vents. Hawaiian to Strombolian fountains along the fissures dominated initial activity, producing a series of agglomerate ramparts. Focusing of eruptive activity to two central vents and the formation of two overlapping scoria cones followed the early phase. Fountain-fed lavas from those cones merged to form a channel that fed lava onto a flow field at the foot of the cones. Focusing of subsurface magma flow toward the central conduits may have reduced magma flux in the remaining fissures, and the southern segment(s) entered a phase of phreatomagmatic explosions that destroyed the early agglomerate rampart and formed a maar and tephra ring composed of lapilli tuff rich in clasts derived from pre-Easy Chair lavas and early agglomerates. The eruption closed with a minor phase of magmatic activity that deposited scoria lapilli and bombs on top of the phreatomagmatic deposits. The eruptive sequence indicates that relatively low hazard Strombolian to Hawaiian activity can be replaced by more hazardous phreatomagmatic explosions well into a monogenetic eruption.
K Ennico - One of the best experts on this subject based on the ideXlab platform.
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An Overview of the Lunar Crater Observation and Sensing Satellite (LCROSS)
Space Science Reviews, 2012Co-Authors: Anthony Colaprete, Richard C. Elphic, Jennifer Heldmann, K EnnicoAbstract:The Lunar Crater Observation Sensing Satellite (LCROSS), an accompanying payload to the Lunar Reconnaissance Orbiter (LRO) mission (Vondrak et al. 2010 ), was launched with LRO on 18 June 2009. The principle goal of the LCROSS mission was to shed light on the nature of the materials contained within permanently shadowed Lunar Craters. These Permanently Shadowed Regions (PSRs) are of considerable interest due to the very low temperatures,
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The Lunar Crater Observation and Sensing Satellite (LCROSS) Payload Development and Performance in Flight
Space Science Reviews, 2012Co-Authors: K Ennico, Anthony Colaprete, Mark Shirley, Leonid OsetinskyAbstract:The primary objective of the Lunar Crater Observation and Sensing Satellite (LCROSS) was to confirm the presence or absence of water ice in a permanently shadowed region (PSR) at a Lunar pole. LCROSS was classified as a NASA Class D mission. Its payload, the subject of this article, was designed, built, tested and operated to support a condensed schedule, risk tolerant mission approach, a new paradigm for NASA science missions. All nine science instruments, most of them ruggedized commercial-off-the-shelf (COTS), successfully collected data during all in-flight calibration campaigns, and most importantly, during the final descent to the Lunar surface on October 9, 2009, after 112 days in space. LCROSS demonstrated that COTS instruments and designs with simple interfaces, can provide high-quality science at low-cost and in short development time frames. Building upfront into the payload design, flexibility, redundancy where possible even with the science measurement approach, and large margins, played important roles for this new type of payload. The environmental and calibration approach adopted by the LCROSS team, compared to existing standard programs, is discussed. The description, capabilities, calibration and in-flight performance of each instrument are summarized. Finally, this paper goes into depth about specific areas where the instruments worked differently than expected and how the flexibility of the payload team, the knowledge of instrument priority and science trades, and proactive margin maintenance, led to a successful science measurement by the LCROSS payload’s instrument complement.
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an overview of the Lunar Crater observation and sensing satellite lcross
Space Science Reviews, 2012Co-Authors: Anthony Colaprete, Richard C. Elphic, Jennifer Heldmann, K EnnicoAbstract:The Lunar Crater Observation Sensing Satellite (LCROSS), an accompanying payload to the Lunar Reconnaissance Orbiter (LRO) mission (Vondrak et al. 2010), was launched with LRO on 18 June 2009. The principle goal of the LCROSS mission was to shed light on the nature of the materials contained within permanently shadowed Lunar Craters. These Permanently Shadowed Regions (PSRs) are of considerable interest due to the very low temperatures, <120 K, found within the shadowed regions (Paige et al. 2010a, 2010b) and the possibility of accumulated, cold-trapped volatiles contained therein. Two previous Lunar missions, Clementine and Lunar Prospector, have made measurements that indicate the possibility of water ice associated with these PSRs. LCROSS used the spent LRO Earth-Lunar transfer rocket stage, an Atlas V Centaur upper stage, as a kinetic impactor, impacting a PSR on 9 October 2009 and throwing ejecta up into sunlight where it was observed. This impactor was guided to its target by a Shepherding Spacecraft (SSC) which also contained a number of instruments that observed the Lunar impact. A campaign of terrestrial ground, Earth orbital and Lunar orbital assets were also coordinated to observe the impact and subsequent Crater and ejecta blanket. After observing the Centaur impact, the SSC became an impactor itself. The principal measurement goals of the LCROSS mission were to establish the form and concentration of the hydrogen-bearing material observed by Lunar Prospector, characterization of regolith within a PSR (including composition and physical properties), and the characterization of the perturbation to the Lunar exosphere caused by the impact itself.
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the lcross Cratering experiment
Science, 2010Co-Authors: P.h. Schultz, B Hermalyn, Anthony Colaprete, K Ennico, Mark D F Shirley, William S MarshallAbstract:As its detached upper-stage launch vehicle collided with the surface, instruments on the trailing Lunar Crater Observation and Sensing Satellite (LCROSS) Shepherding Spacecraft monitored the impact and ejecta. The faint impact flash in visible wavelengths and thermal signature imaged in the mid-infrared together indicate a low-density surface layer. The evolving spectra reveal not only OH within sunlit ejecta but also other volatile species. As the Shepherding Spacecraft approached the surface, it imaged a 25- to-30-meter-diameter Crater and evidence of a high-angle ballistic ejecta plume still in the process of returning to the surface--an evolution attributed to the nature of the impactor.
Anthony Colaprete - One of the best experts on this subject based on the ideXlab platform.
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An Overview of the Lunar Crater Observation and Sensing Satellite (LCROSS)
Space Science Reviews, 2012Co-Authors: Anthony Colaprete, Richard C. Elphic, Jennifer Heldmann, K EnnicoAbstract:The Lunar Crater Observation Sensing Satellite (LCROSS), an accompanying payload to the Lunar Reconnaissance Orbiter (LRO) mission (Vondrak et al. 2010 ), was launched with LRO on 18 June 2009. The principle goal of the LCROSS mission was to shed light on the nature of the materials contained within permanently shadowed Lunar Craters. These Permanently Shadowed Regions (PSRs) are of considerable interest due to the very low temperatures,
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The Lunar Crater Observation and Sensing Satellite (LCROSS) Payload Development and Performance in Flight
Space Science Reviews, 2012Co-Authors: K Ennico, Anthony Colaprete, Mark Shirley, Leonid OsetinskyAbstract:The primary objective of the Lunar Crater Observation and Sensing Satellite (LCROSS) was to confirm the presence or absence of water ice in a permanently shadowed region (PSR) at a Lunar pole. LCROSS was classified as a NASA Class D mission. Its payload, the subject of this article, was designed, built, tested and operated to support a condensed schedule, risk tolerant mission approach, a new paradigm for NASA science missions. All nine science instruments, most of them ruggedized commercial-off-the-shelf (COTS), successfully collected data during all in-flight calibration campaigns, and most importantly, during the final descent to the Lunar surface on October 9, 2009, after 112 days in space. LCROSS demonstrated that COTS instruments and designs with simple interfaces, can provide high-quality science at low-cost and in short development time frames. Building upfront into the payload design, flexibility, redundancy where possible even with the science measurement approach, and large margins, played important roles for this new type of payload. The environmental and calibration approach adopted by the LCROSS team, compared to existing standard programs, is discussed. The description, capabilities, calibration and in-flight performance of each instrument are summarized. Finally, this paper goes into depth about specific areas where the instruments worked differently than expected and how the flexibility of the payload team, the knowledge of instrument priority and science trades, and proactive margin maintenance, led to a successful science measurement by the LCROSS payload’s instrument complement.
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an overview of the Lunar Crater observation and sensing satellite lcross
Space Science Reviews, 2012Co-Authors: Anthony Colaprete, Richard C. Elphic, Jennifer Heldmann, K EnnicoAbstract:The Lunar Crater Observation Sensing Satellite (LCROSS), an accompanying payload to the Lunar Reconnaissance Orbiter (LRO) mission (Vondrak et al. 2010), was launched with LRO on 18 June 2009. The principle goal of the LCROSS mission was to shed light on the nature of the materials contained within permanently shadowed Lunar Craters. These Permanently Shadowed Regions (PSRs) are of considerable interest due to the very low temperatures, <120 K, found within the shadowed regions (Paige et al. 2010a, 2010b) and the possibility of accumulated, cold-trapped volatiles contained therein. Two previous Lunar missions, Clementine and Lunar Prospector, have made measurements that indicate the possibility of water ice associated with these PSRs. LCROSS used the spent LRO Earth-Lunar transfer rocket stage, an Atlas V Centaur upper stage, as a kinetic impactor, impacting a PSR on 9 October 2009 and throwing ejecta up into sunlight where it was observed. This impactor was guided to its target by a Shepherding Spacecraft (SSC) which also contained a number of instruments that observed the Lunar impact. A campaign of terrestrial ground, Earth orbital and Lunar orbital assets were also coordinated to observe the impact and subsequent Crater and ejecta blanket. After observing the Centaur impact, the SSC became an impactor itself. The principal measurement goals of the LCROSS mission were to establish the form and concentration of the hydrogen-bearing material observed by Lunar Prospector, characterization of regolith within a PSR (including composition and physical properties), and the characterization of the perturbation to the Lunar exosphere caused by the impact itself.
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LCROSS (Lunar Crater Observation and Sensing Satellite) Observation Campaign: Strategies, Implementation, and Lessons Learned
Space Science Reviews, 2011Co-Authors: Jennifer Heldmann, Anthony Colaprete, Diane H. Wooden, R. F. Ackermann, David Acton, Peter Backus, Vanessa P. Bailey, Jesse G. Ball, William C. Barott, Samantha BlairAbstract:NASA’s LCROSS (Lunar Crater Observation and Sensing Satellite) mission was designed to explore the nature of previously detected enhanced levels of hydrogen near the Lunar poles. The LCROSS mission impacted the spent upper stage of the launch vehicle into a permanently shadowed region of the Lunar surface to create an ejecta plume. The resultant impact Crater and plume were then observed by the LCROSS Shepherding Spacecraft as well as a cadre of telescopes on the Earth and in space to determine the nature of the materials contained within the permanently shadowed region. The Shepherding Spacecraft then became a second impactor which was also observed by multiple assets.
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the lcross Cratering experiment
Science, 2010Co-Authors: P.h. Schultz, B Hermalyn, Anthony Colaprete, K Ennico, Mark D F Shirley, William S MarshallAbstract:As its detached upper-stage launch vehicle collided with the surface, instruments on the trailing Lunar Crater Observation and Sensing Satellite (LCROSS) Shepherding Spacecraft monitored the impact and ejecta. The faint impact flash in visible wavelengths and thermal signature imaged in the mid-infrared together indicate a low-density surface layer. The evolving spectra reveal not only OH within sunlit ejecta but also other volatile species. As the Shepherding Spacecraft approached the surface, it imaged a 25- to-30-meter-diameter Crater and evidence of a high-angle ballistic ejecta plume still in the process of returning to the surface--an evolution attributed to the nature of the impactor.
Amanda Rachel Hintz - One of the best experts on this subject based on the ideXlab platform.
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complex plumbing of monogenetic scoria cones new insights from the Lunar Crater volcanic field nevada usa
Journal of Volcanology and Geothermal Research, 2012Co-Authors: Amanda Rachel Hintz, Greg A. ValentineAbstract:Abstract The complexity of monogenetic basaltic eruptions is largely governed by the shallow plumbing of the volcanoes that develop in the upper hundreds of meters of the crust, as well as within the growing edifice during the eruption. We present data pertaining to geometry and dynamics of plumbing features associated with two monogenetic volcanoes observed within in the Lunar Crater Volcanic Field (Nevada; USA) that have been eroded to varying degrees, exposing numerous intrusive bodies. The majority of the intrusive bodies observed within the eroded scoria cone and cone remnant are radial dikes and dike sets, many of which have irregular shapes. We infer that the radial patterns of the dikes resulted from magma overpressure in central conduits and from the stresses induced by the topographic load of the cones, with the regional tectonic stresses playing a negligible role. Internally, the dikes display textural features such as multiple chilled margins and/or distinct bandings of vesicle populations, suggesting multiple injections or pulses of magma originating from the vent/conduit area were incrementally added to the dikes. Pressure fluctuations within the magma columns capable of producing such features can be associated with a variety of dynamic processes including; the ascent of slugs of gas through the magma column, variations in the source pressure of the ascending magma, as well as the weight of relatively degassed magma and temporary blockages of the conduit. Irregular shapes of some dikes are likely related to the interaction between viscous intruding magma and weakly consolidated scoria cone deposits. The geometry of the dikes and the relationship to a central magma column have important implications for eruption processes, degassing patterns, and gas–melt coupling associated with monogenetic eruptions.
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Models of maar volcanoes, Lunar Crater (Nevada, USA)
Bulletin of Volcanology, 2011Co-Authors: Greg A. Valentine, Nicole L. Shufelt, Amanda Rachel HintzAbstract:Maar volcanoes are generally understood to be the result of highly energetic, explosive interaction between magma and water (groundwater or surface water). Two end-member conceptual models have been proposed to explain the dimensions (diameter, depth) of maar Craters: (1) an incremental growth model, where a Crater grows due to subsidence and ejection of debris over the course of many explosions, and the final size is an integrated result of multiple explosive events; (2) a model in which the dimensions of a maar Crater are the result of the largest single explosion during the lifetime of the maar (major-explosion dominated model). In the latter case, the maar size can be used to estimate the energy and depth of the largest explosion, which in turn allows estimation of the magma mass involved. This paper describes Lunar Crater maar (Nevada, USA) and tests the two models as explanations for the characteristics of the volcano, in particular the major-explosion dominated model. This model implies magma mass and supply rates that are unrealistic, and the tephra at the maar do not contain key features observed in the ejecta at large single-explosion Craters. The incremental growth model seems most suitable based upon geological evidence.
