Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “LAVA”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Igneous and tectonic evolution of Venusian and terrestrial coronae

A great variety of tectonic and volcanic features have been documented on Venus. It is widely appreciated that there are close spatial associations among certain types of tectonic structures and some classes of volcanic flows and constructs. Coronae are endowed with a particularly rich variety of volcanism. It is thought that coupled tectonic and volcanic aspects of coronae are cogenetic manifestations of mantle plumes. An outstanding feature of most venusian coronae is their circular or elliptical shape defined by peripheral zones of fracturing and/or folding. Some coronae are composite, consisting of two or more small coronae within a larger enclosing corona, suggesting complex histories of structured diapirism analogous in some ways to salt dome tectonics. Coronae range widely in size, from smaller than 100 km to over 1000 km in diameter. Volcanic features associated with venusian coronae include lunar-like sinuous rilles, thin lava flows, cinder cone-like constructs, shield volcanos, and pancake domes. Several types of volcanic features are often situated within or near a single corona, in many instances including land-forms indicating effusions of both low- and high-viscosity lavas. In some cases stratigraphic evidence brackets emplacement of pancake domes during the period of tectonic development of the corona, thus supporting a close link between the igneous and tectonic histories of coronae. These associations suggest emplacement of huge diapirs and massive magmatic intrusions, thus producing the tectonic deformations defining these structures. Igneous differentiation of the intrusion could yield a range of lava compositions. Head and Wilson suggested a mechanism that would cause development of neutral buoyancy zones in the shallow subsurface of Venus, thereby tending to promote development of massive igneous intrusions.

Kargel, J. S.↗
NASA NTRS1992

Small volcanic edifices and volcanism in the plains of Venus

The different types of eruption that have occurred over time in the Venusian plains are considered. The most extensive volcanic units consist of flood lavas, the largest of which have volumes of the order of thousands of cubic kilometers. They are inferred to have erupted at high effusion rates, and they exhibit a range of radar backscatter characteristics indicating different surface textures and ages. Small edifices on the plains occur mainly in clusters associated with fracture belts. The majority are shield volcanos that may be up to a few tens of kilometers across but are generally 10 km or less in diameter. Volcanic domes have diameters up to several tens of kilometers and volumes of the order of 100 cu cm. These are interpreted as being constructed of lava erupted with a relatively high effective viscosity and thus possibly composed of more silicic lava. For many domes, the flanks were unstable during and after eruption and experienced gravity sliding that produced steep scalloped outer margins.

Guest, John E.↗
NASA NTRS1993

Infrared image analysis of volcanic thermal features - Lascar Volcano, Chile, 1984-1992

Fifteen Landsat TM images of Lascar volcano (Chile), recorded between December 1984 and April 1992, document the evolution of a lava dome within the summit crater. In every image, the two short-wavelength infrared bands, 5 and 7, have detected thermal radiation from the volcano. As a consequence of the Planck distribution function, the relative response of these two channels depends on the proportions of very hot surfaces occupying tiny pixel areas and broader regions at moderate temperatures. Intercomparison of bands 5 and 7 thereby provides a means for interpreting TM thermal anomalies even in the absence of ground observations. Pronounced changes in the configuration and intensity of the Lascar anomaly suggest that the volcano has experienced at least two cycles of lava dome activity since 1984. The first of these progressed through a 'cooling' period, possibly reflecting a reduced flux of magmatic volatiles at the surface, and culminated in an explosive eruption on September 16, 1986, which appears to have completely destroyed the inferred lava dome.

Oppenheimer, Clive↗
NASA NTRS1993

Venusian channels and valleys - Distribution and volcanological implications

An updated map is presented which shows the distribution of more than 200 channels and valleys on Venus. A large number of channels are concentrated in equatorial regions characterized by highlands, rift and fracture zones, an associated volcanic features. Many channels associated with flow deposits are similar to typical terrestrial lava drainage channels. They are associated with a wide range of volcanic edifices. More than half of the sinuous rilles are associated with coronae, coronalike features, or arachnoids. Corona volcanism driven by mantle plume events may explain this association. Many valley network are observed in highlands and in association with coronae, coronalike features, or arachnoids. This indicates that highlands and coronae provided fractures and flow-viscosity lavas, both of which seem to be required for network formation by lava sapping processes. Canali-type channels have a unique distribution limited to some plains regions.

Komatsu, Goro↗
NASA NTRS1992

Multispectral thermal infrared mapping of the 1 October 1988 Kupaianaha flow field, Kilauea volcano, Hawaii

Multispectral thermal infrared radiance measurements of the Kupaianaha flow field were acquired with the NASA airborne Thermal Infrared Multispectral Scanner (TIMS) on the morning of 1 October 1988. The TIMS data were used to map both the temperature and emissivity of the surface of the flow field. The temperature map depicted the underground storage and transport of lava. The presence of molten lava in a tube or tumulus resulted in surface temperatures that were at least 10 C above ambient. The temperature map also clearly defined the boundaries of hydrothermal plumes which resulted from the entry of lava into the ocean. The emissivity map revealed the boundaries between individual flow units within the Kupaianaha field. Distinct spectral anomalies, indicative of silica-rich surface materials, were mapped near fumaroles and ocean entry sites. This apparent enrichment in silica may have resulted from an acid-induced leaching of cations from the surfaces of glassy flows.

Realmuto, Vincent J.↗
NASA NTRS1993

Changes in Hawaiian palagonite FE mineralogy associated with thermal alteration: Implications for Mars

We have studied six Hawaiian palagonitic tephra samples (PH-1 through PH-6) from a site where a Mauna Loa lava flow has partially embayed a Mauna Kea cinder cone Tephra samples that were not affected by the lava flow (PH-5, PH-6) consist of partially palagonitized coarse-grained glassy Hawaiitic particles whose iron mineralogy is dominated by nanophase ferric oxide (np-Ox) and olivine. Samples closest to the lava flow (PH-1 through PH-4) have been strongly altered and their iron mineralogy is dominated by np-Ox, magnetite, and hematite. This suite of samples has many spectral similarities to Martian bright regions; thus, this localized thermal alteration event may be an analog to similar processes on Mars that lead to the production of small amounts of crystalline ferric oxides within a poorly-crystalline or amorphous palagonitic matrix.

Bell, James F., III↗
NASA NTRS1993

A two-stage (turbulent-drainage) mechanism for the emplacement of impact crater outflows on Venus

Several emplacement mechanisms were proposed for the unique flow features associated with 402 of the 912 impact craters found on Venus to date. Studies based on rheological models and laboratory results have suggested two separate depositional flow mechanisms: a turbulent emplacement and a lava like emplacement. Schultz proposed a progressive transition from the turbulent to the lava like mechanism during deceleration of some turbulent flows. He suggested that these composite flows were emplaced prior to the deposition of the normal ejecta. After an examination of the geomorphologic, stratigraphic, and topographic relations of the flows associated with the 402 craters, it is suggested that most of the outflows result from a two-stage emplacement process. In the first stage, a turbulent, proximal part is usually emplaced downrange of the impact site after the other ejecta materials. In the second stage, a distal part, composed of low-viscosity melt, slowly drains via dendritic channels from the proximal deposit and flows like lava. A few flows were identified that appear to have been emplaced prior to the ejecta; these flows likely result from a different mechanism.

Chadwick, D. J.↗
NASA NTRS1993

Relief of some small landforms on Venus

Three sets of radar images have been acquired under different viewing conditions by the Magellan synthetic aperture radar: (1) left-looking with varied incidence angles (cycle 1); (2) right-looking with nearly constant incidence angles (cycle 2); and (3) left-looking with varied incidence angles, most of which were smaller than those in (1) except for those acquired on passes across Maxwell Montes with incidence angles larger than those in (1) (cycle 3). Image displacements in the radar images that are caused by the relief of landforms provide several methods of estimating this relief: (1) monoscopic measurements of foreshortening of landforms that are symmetrical in the plane of the look-direction of the radar (includes radial symmetry); (2) stereoscopic measurements of parallax in same-side image pairs (cycles 1-2 and 3); and (3) measurements of parallax in opposite-side image pairs (cycles 1-2 and/or 2-3). Success in methods 2 and 3 (especially 3) depends on identifying conjugate image points in the two images. Here, we report our preliminary results for five impact craters, seven small volcanic edifices, and two lava flows. The three methods mentioned above lead to the interesting result that Venusian impact craters have depth-diameter ratios like those on Mars rather than those on Earth, but some appear partly filled. Our results for de Lalande and Melba also suggest filling, but there may be other causes for their relatively small depth-diameter ratios. A host of small volcanic edifices have relief that can be crudely estimated using the above methods. Relief/diameter ratios for our cratered cones are about the same as those of Icelandic lava shields; some Venusian cones resemble the Martian shields of Mareotis-Tempe and Ceraunius Fossae, but the Venusian relief diameter ratios are larger. The smallest cratered dome is similar in size and profile to a Martian dome north of Uranius Patera; the smallest cratered cone resembles one in Chryse Planitia. Lava flows on Venus that are thick enough to measure are rare, but we have applied methods 1 and 3 to the huge flow of Ovda Regio and flows of an unusual volcano, Mahuea Tholus.

Moore, H. J.↗
NASA NTRS1994

Volcano morphometry and volume scaling on Venus

A broad variety of volcanic edifices have been observed on Venus. They ranged in size from the limits of resolution of the Magellan SAR (i.e., hundreds of meters) to landforms over 500 km in basal diameter. One of the key questions pertaining to volcanism on Venus concerns the volume eruption rate or VER, which is linked to crustal productivity over time. While less than 3 percent of the surface area of Venus is manifested as discrete edifices larger than 50 km in diameter, a substantial component of the total crustal volume of the planet over the past 0.5 Ga is related to isolated volcanoes, which are certainly more easily studied than the relatively diffusely defined plains volcanic flow units. Thus, we have focused our efforts on constraining the volume productivity of major volcanic edifices larger than 100 km in basal diameter. Our approach takes advantage of the topographic data returned by Magellan, as well as our database of morphometric statistics for the 20 best known lava shields of Iceland, plus Mauna Loa of Hawaii. As part of this investigation, we have quantified the detailed morphometry of nearly 50 intermediate to large scale edifices, with particular attention to their shape systematics. We found that a set of venusian edifices which include Maat, Sapas, Tepev, Sif, Gula, a feature at 46 deg S, 215 deg E, as well as the shield-like structure at 10 deg N, 275 deg E are broadly representative of the approx. 400 volcanic landforms larger than 50 km. The cross-sectional shapes of these 7 representative edifices range from flattened cones (i.e., Sif) similar to classic terrestrial lava shields such as Mauna Loa and Skjaldbreidur, to rather dome-like structures which include Maat and Sapas. The majority of these larger volcanoes surveyed as part of our study displayed cross-sectional topographies with paraboloidal shaped, in sharp contrast with the cone-like appearance of most simple terrestrial lava shields. In order to more fully explore the differences between large venusian edifices and volcanoes on the Earth and Mars, we developed a volume scaling algorithm which relies on conservation of volcano morphometry as basal diameter is varied.

Garvin, J. B.↗
NASA NTRS1994

Recycling of volatiles at subduction zones: Noble gas evidence from the Tabar-Lihir-Tanga-Feni arc of papua New Guinea

Convergent margin processes play an important but poorly understood role in the distribution of terrestrial volatile species. For example, subduction processes filter volatiles from the subducting package, thereby restricting their return to the mantle. In addition, once extracted from the downgoing slab, volatiles become an essential component in the petrogenesis of island arc magmas. The noble gases, with their systematic variation in physical properties and diversity of radiogenic isotopes, should carry a uniquely valuable record of these processes. However, thus far studies of noble gases in arc volcanics have achieved only limited success in this regard. Subduction-related lavas and geothermal fluids carry (3)He/(4)He ratios equal to or slightly lower than those found in the depleted upper mantle source of mid-ocean ridge basalts. Apparently slab-derived helium (which should have (3)He/(4)He much less than MORB) is extensively diluted by MORB-like helium from the mantle wedge, making it difficult to use helium as a tracer of convergent margin processes. Interpretation of the heavier noble gases (Ne-Ar-Kr-Xe) in arc lavas has also proven difficult, because the lavas carry low noble gas concentrations and hence are subject to pervasive atmospheric contamination. The low noble gas concentrations may be a consequence of degassing in the high level magma chambers characteristic of arc stratovolcanos. We have recently initiated a project to better constrain the behavior of volatiles in subduction zones through geochemical studies of the tectonically unusual volcanoes of the Tabar-Lihir-Tanga-Feni (TLTF) arc in the Bismarck Archipelago, Papua New Guinea.

Farley, Kenneth↗
NASA NTRS1994

Geology of the small Tharsis volcanoes: Jovis Tholus, Ulysses Patera, Biblis Patera, Mars

Jovis Tholus, Ulysses Patera, and Biblis Patera, three small volcanoes in the Tharsis area of Mars, provide important insight into the evolution of volcanism on Mars. All three are interpreted to be shield volcanoes, indicating that shield volcansim was present from the outset in Tharsis. Jovis Tholus is the least complex with simple repeated outpouring of lavas and caldera-forming events. Ulysses Patera is dominated by a giant caldera within which is a line of cinder cones or domes suggesting terminal stages of volcanism in which the magma had either significant volatiles or increased viscosity. Biblis Patera is characterized by nested calderas which have expanded by block faulting of the flank; it also exhibits lava flows erupted onto the flanks from events along concentric fractures. These shields are different from the younger Tharsis Montes shields only in terms of the volume of erupted material. The limited shield volume suggests that the magma source which fed the shields was rapidly depleted. The relatively large size ofthe calderas probably results from relatively large, shallow magma bodies rather than significant burial of the flanks by younger lavas. Eruption rates consistent with typical terrestrial basaltic eruptiuon rates suggest that these volcanoes were probably built over time spans of 10(exp 4) to 10(exp 5) years. Stratigraphic ages range from Early to Upper Hesperian; absolute ages range from 1.9 to 3.4 Ga.

Plescia, J. B.↗
NASA NTRS1996

Sulfur, Chlorine and Fluorine Degassing and Atmospheric Loading by the Roza eruption, Columbia River Basalt Group, Washington

In this study we attempt to quantify the amount of S, Cl and F released by the 1300 cu km Roza member (approximately 14.7 Ma) of the Columbia River Basalt Group, which was produced by a moderate-size flood basalt eruption in the mid-Miocene. Our results are the first indication of the potential atmospheric SO2 yield from a flood basalt eruption, and indicate the mechanism by which flood basalt eruptions may have seriously affected the environment. Glass inclusions in phenocrysts and quenched glass in products from various stages of the eruption were analyzed for concentrations of S, Cl and F and major elements. Glass inclusions contain 1965 +/- 110 ppm S, 295 +/- 65 ppm Cl and 1310 +/- 110 ppm F. Groundmass glass of Roza dike selvages contains considerably lower concentrations: 1110 +/- 90 ppm S, 245 +/- 30 ppm Cl and 1020 +/- 25 ppm F. Scoria clasts from near vent deposits contain 665 +/- 75 ppm S, 175 +/- 5 ppm Cl and 950 +/- 20 ppm F, and the groundmass glass of lava selvages contains 520 +/- 30 ppm S, 190 +/- 30 ppm Cl and 890 +/- 55 ppm F. In crystalline lava, the concentrations are 195 ppm S, 100 ppm Cl and 830 ppm F. Volatile element concentrations in these samples represent the progress of degassing through the eruption and can be used to estimate the potential amount of the volatiles S, Cl and F released by the magma into the atmosphere, as well as to evaluate the amount liberated by various phases of the eruption. The total amount of volatiles released by the Roza eruption is estimated to have been approximately 12,420 MtSO2, approximately 710 MtHCI and approximately 1780 MtHF. The Roza magma liberated approximately 9620 MtSO, (77% of the total volatile mass released), approximately 400 MtHCI (56%) and approximately 1450 MtHF (81%) at the vents and lofted by the eruption columns to altitudes of 7-13 km. Degassing of the lava is estimated to have released an additional approximately 2810 MtSO2, approximately 310 MtHCI and approximately 330 MtHF. The Roza eruption is likely to have lasted for approximately 10 years, indicating an annual H2SO4-mass loading of approximately 1800 Mt. Thus, the atmospheric perturbations associated with the Roza eruption may have been of the magnitude predicted for a severe "nuclear" or "volcanic" winter, but lasting up to a decade or more.

Thordarson, Th.↗
NASA NTRS1995

Submarine Analogs to Venusian Pancake Domes

The morphology and dimensions of the large diameter, steep-sided, flat-topped "pancake domes" on Venus make them unlike any type of terrestrial subaerial volcano. Comparisons between images of Hawaiian seamounts and pancake domes show similarities in shapes and secondary features. The morphometry of pancake domes is closer to that of Pacific seamounts than subaerial lava domes. Considering both morphology and morphometry, seamounts seem a better analog to the pancake domes. The control of volatile exsolution by pressure on Venus and the seafloor can cause lavas to have similar viscosities and densities, although the latter will be counteracted by high buoyancy underwater. However, analogous effects of the Venusian and seafloor alone are probably not sufficient to produce similar volcanoes. Rather, Venusian lavas of various compositions may behave like basalt on the seafloor if appropriate rates and modes of extrusion and planetary thermal structure are also considered.

Bridges, Nathan T.↗
NASA NTRS1996

Sulfur, Chlorine, and Flourine Degassing and Atmospheric Loading by the 1783 - 1784 AD Laki (Skaftar Fires) Eruption in Iceland

The 1783-1784 Laki tholeiitic basalt fissure eruption in Iceland was one of the greatest atmospheric pollution events of the past 250 years, with widespread effects in the northern hemisphere. The degassing history and volatile budget of this event are determined by measurements of pre-eruption and residual contents of sulfur, chlorine, and fluorine in the products of all phases of the eruption. In fissure eruptions such as Laki, degassing occurs in two stages: by explosive activity or lava fountaining at the vents, and from the lava as it flows away from the vents. Using the measured sulfur concentrations in glass inclusions in phenocrysts and in groundmass glasses of quenched eruption products, we calculate that the total accumulative atmospheric mass loading of sulfur dioxide was 122 Mt over a period of 8 months. This volatile release is sufficient to have generated approximately 250 Mt of H2SO4 aerosols, an amount which agrees with an independent estimate of the Laki aerosol yield based on atmospheric turbidity measurements. Most of this volatile mass (approximately 60 wt.%) was released during the first 1.5 months of activity. The measured chlorine and fluorine concentrations in the samples indicate that the atmospheric loading of hydrochloric acid and hydrofluoric acid was approximately 7.0 and 15.0 Mt, respectively. Furthermore, approximately 75% of the volatile mass dissolved by the Laki magma was released at the vents and carried by eruption columns to altitudes between 6 and 13 km. The high degree of degassing at the vents is attributed to development of a separated two-phase flow in the upper magma conduit, and implies that high-discharge basaltic eruptions such as Laki are able to loft huge quantities of gas to altitudes where the resulting aerosols can reside for months, or even 1-2 years. The atmospheric volatile contribution due to subsequent degassing of the Laki lava flow is only 18 wt.% of the total dissolved in the magma, and these emissions were confined to the lowest regions of the troposhere and therefore important only over Iceland. This study indicates that determination of the amount of sulfur degassed from the Laki magma batch by measurements of sulfur in the volcanic products (the petrologic method) yields a result which is sufficient to account for the mass of aerosols estimated by other methods.

Thordarson, T.↗
NASA NTRS2003

Gish Bar Patera, Io: Geology and Volcanic Activity, 1996-2001

Since the two Voyagers passed by Jupiter in 1979, it has been known that volcanic activity is ubiquitous on the surface of Io. With over 400 volcanic centers, Io is even more volcanically active than the earth with massive flood basalt-style eruptions and komatitite lavas a common occurrence. Additionally, some volcanoes appear to be giant lava lakes, with violent activity churning the crust of the lake for periods of 20 years or more. Finally, sulfur is believed to play a large role in Io's volcanism, be it as a primary lava or as a secondary product of large, high-temperature eruptions. By studying one volcano in particular, Gish Bar Patera, one can observe many of these characteristics in one volcanic center.

Perry, Jason↗
NASA NTRS2003

Jupiter's Hot, Mushy Moon

Jupiter's moon Io is the most volcanically active body in the Solar System. Observations by instruments on the Galileo spacecraft and on telescopes atop Mauna Kea in Hawai'i indicate that lava flows on Io are surprisingly hot, over 1200 oC and possibly as much as 1300 oC; a few areas might have lava flows as hot as 1500 oC. Such high temperatures imply that the lava flows are composed of rock that formed by a very large amount of melting of Io's mantle. This has led Laszlo Keszthelyi and Alfred S. McEwen of the University of Arizona and me to reawaken an old hypothesis that suggests that the interior of Io is a partially-molten mush of crystals and magma. The idea, which had fallen out of favor for a decade or two, explains high-temperature hot spots, mountains, calderas, and volcanic plains on Io. If correct, Io gives us an opportunity to study processes that operate in huge, global magma systems, which scientists believe were important during the early history of the Moon and Earth, and possibly other planetary bodies as well. Though far from proven, the idea that Io has a ocean of mushy magma beneath its crust can be tested with measurements by future spacecraft.

Taylor, G. Jeffrey↗
NASA NTRS2004

Lunar and Planetary Science XXXV: Io, with a Dash of Titan

The session "Io, with a Dash of Titan" contained the following reports:A Deep Lava Channel on Io ; Volcanic Activity at Tvashtar Catena, Io; Characterization of Activity at Loki from Galileo and Ground-based Observations; Active and Passive Lava Resurfacing Processes on Io: A Comparative Study of Loki Patera and Prometheus; Loki Patera as the Surface of a Magma Sea; Lava Lakes on Io: New Perspectives from Modeling; Global Distribution of Active Volcanism on Io as Known at the End of the Galileo Mission Relationships Between Paterae, Mountains, and Hotspots on Io from a Global Database; Lithospheric Recycling on Io: The Role of Delamination; Building Mountains on Io: Implications for Io s Lithosphere ; The Effect of Large Melt Fraction on the Deformation Behavior of Peridotite: Implications for the Rheology of Io s Mantle; Matching Various Observations of Io with DSMC Modeling: Plume, Plume Shadow, Sodium Field Around Pele; and How Does Titan Retain a Finite Orbital Eccentricity?

Source record↗
NASA NTRS2004

Characterization of Activity at Loki from Galileo and Ground-based Observations

While Loki is the most active volcanic center on Io, major questions remain concerning the nature of that activity. Rathbun et al. showed that the activity was semi-periodic, and suggested it was due to a resurfacing wave which swept across a lava lake as the crust cooled and become unstable. However in 2001 new observations showed that an intermediate level, less periodic mode of activity had apparently begun. Galileo-NIMS observations of Loki clearly show that the highest temperatures are found near the edge of the patera, consistent with disruption of a lava lake at the margins. NIMS observations also show gradients in temperature across the patera which, when modeled in terms of lava cooling models, are generally consistent with ages expected for the resurfacing wave but may also be consistent with spreading flows. We present a further analysis of NIMS data from I24 and I32 which help define the nature of the temperature variations present in Loki patera, along with Galileo-SSI images from the G1-I32 flybys which show albedo changes apparently correlated with the "periodic" activity measured from ground-based observations.

Howell, R. R.↗