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At least 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

The glass-ceiling convective regime and the origin and diversity of coronae on Venus

Venus and Earth are rocky planets of roughly the same size and bulk density, yet their surface volcanic and tectonic features appear substantially different. On Venus, the coexistence of large volcanic highlands—interpreted as the surface expression of long-lived mantle plumes—alongside coronae, smaller features thought to be caused by transient thermal diapirs, remains enigmatic. Using two-dimensional numerical models of mantle convection with sharp and broad mineral phase transitions for pyrolite, we show that both scales of upwellings can be generated in a stagnant lid planet with an interior temperature 250 to 400 K warmer than Earth’s. The smaller plumes originate from a ~600 km deep internal layer that exists as a consequence of the different sequence of mineral phase transitions that occur in warmer mantles less processed and differentiated by partial melting and volcanism. Future models that include melting will provide further tests of our hypothesis.

Science & Technology - Other Topics↗
DOE OSTI2020

Geology and climate influence rhizobiome composition of the phenotypically diverse tropical tree Tabebuia heterophylla

Plant-associated microbial communities have diverse phenotypic effects on their hosts that are only beginning to be revealed. We hypothesized that morpho-physiological variations in the tropical tree Tabebuia heterophylla, observed on different geological substrates, arise in part due to microbial processes in the rhizosphere. We characterized the microbiota of the rhizosphere and soil communities associated with T. heterophylla trees in high and low altitude sites (with varying temperature and precipitation) of volcanic, karst and serpentine geologies across Puerto Rico. We sampled 6 areas across the island in three geological materials including volcanic, serpentine and karst soils. Collection was done in 2 elevations (>450m and 0-300m high), that included 3 trees for each site and 4 replicate soil samples per tree of both bulk and rhizosphere. Genomic DNA was extracted from 144 samples, and 16S rRNA V4 sequencing was performed on the Illumina MiSeq platform. Proteobacteria, Actinobacteria, and Verrucomicrobia were the most dominant phyla, and microbiomes clustered by geological substrate and elevation. Volcanic samples were enriched in Verrucomicrobia; karst was dominated by nitrogen-fixing Proteobacteria, and serpentine sites harbored the most diverse communities, with dominant Cyanobacteria. Sites with similar climates but differing geologies showed significant differences on rhizobiota diversity and composition demonstrating the importance of geology in shaping the rhizosphere microbiota, with implications for the plant's phenotype. Our study sheds light on the combined role of geology and climate in the rhizosphere microbial consortia, likely contributing to the phenotypic plasticity of the trees.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Fe 3+ /Fe T ratios of amphiboles determined by high spatial resolution single-crystal synchrotron Mössbauer spectroscopy

The Fe 3+ /Fe T ratios (Fe 3+ /[Fe 2+ +Fe 3+ ]) in minerals can be used to understand their crystallization and post-crystallization conditions. However, as natural minerals are often zoned and contain inclusions, bulk techniques, e.g., wet chemistry, may not provide accurate Fe 3+ /Fe T values for a single phase of interest. We determined Fe 3+ /Fe T ratios of amphiboles in different crystallographic orientations by single-crystal synchrotron Mössbauer spectroscopy (SMS) in energy and time domain modes from four volcanic localities (Long Valley Caldera, Mount St. Helens, Lassen Volcanic Center, U.S.A., and Mt. Pinatubo, Philippines). The high spatial resolution (as low as 12 × 12 μm spot size) and standard-free nature of SMS allow the detection of intra-grain compositional heterogeneities in Fe 3+ /Fe T with relatively low uncertainties. Here, we combine SMS with major element compositions, water contents, and hydrogen isotope compositions to document the Fe 3+ /Fe T ratios as a function of mineral composition and post-crystallization dehydrogenation. Spectra were fitted with up to five distinct sites: ferrous iron on M(1), M(2), M(3), and ferric iron on M(2) and M(3), consistent with X-ray diffraction studies on single crystals of amphibole. The Fe 3+ /Fe T ratios range from 0.14 ± 0.03 (Long Valley Caldera), 0.51 to 0.63 ± 0.02 (representing intra-grain heterogeneities, Mount St. Helens) to 0.86 ± 0.03 (Lassen Volcanic Center). The latter grain experienced post-crystallization dehydrogenation, shown by its low water content (0.6 ± 0.05 wt%) and its elevated hydrogen isotope composition (δD = +25 ± 3‰ relative to SMOW). The Fe 3+ /Fe T ratios of 0.62 ± 0.01 and 0.20 ± 0.01 of two Mt. Pinatubo grains correlate with high-Al 2 O 3 cores and low-Al 2 O 3 rims and smaller phenocrysts in the sample, respectively. This study shows that SMS is capable of distinguishing two different domains with dissimilar Fe 3+ /Fe T values formed under different crystallization conditions, demonstrating that SMS in combination with major element, water, and hydrogen isotope compositions allows the interpretation of amphibole Fe 3+ /Fe T ratios in the context of crystallization and post-crystallization processes.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

The Fingerprints of Stratospheric Aerosol Injection in E3SM

The June 15, 1991 Mt. Pinatubo eruption is simulated in E3SM by injecting 10 Tg of SO 2 gas in the stratosphere, turning off prescribed volcanic aerosols, and enabling E3SM to treat stratospheric volcanic aerosols prognostically. This experimental prognostic treatment of volcanic aerosols in the stratosphere results in some realistic behaviors (SO 2 evolves into H 2 SO 4 which heats the lower stratosphere), and some expected biases (H 2 SO 4 aerosols sediment out of the stratosphere too quickly). Climate fingerprinting techniques are used to establish a Mt. Pinatubo fingerprint based on the vertical profile of temperature from the E3SMv1 DECK ensemble. By projecting reanalysis data and preindustrial simulations onto the fingerprint, the Mt. Pinatubo stratospheric heating anomaly is detected. Projecting the experimental prognostic aerosol simulation onto the fingerprint also results in a detectable heating anomaly, but, as expected, the duration is too short relative to reanalysis data.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Play Fairway Analysis of the Snake River Plain, Idaho (Final Report)

The Snake River Plain (SRP) volcanic province overlies a thermal anomaly that extends deep into the mantle; it represents one of the highest heat flow provinces in North America. The Yellowstone hotspot continues to feed a magma system that underlies much of southern Idaho and has produced basaltic volcanism as young as 2000 years old. It has been estimated to host up to 855 MW of potential geothermal power production, most of which is associated with the Snake River Plain volcanic province in Idaho, which lies outside the area of Yellowstone National Park (Neely, K.W. and Galinato, G., 2007, Geothermal power generation in Idaho: an overview of current developments and future potential, Open File Report, Idaho Office of Energy Resources).

15 GEOTHERMAL ENERGY↗
DOE OSTI2024

Validating a microphysical prognostic stratospheric aerosol implementation in E3SMv2 using observations after the Mount Pinatubo eruption

Abstract. This paper describes the addition of a stratospheric prognostic aerosol (SPA) capability – developed with the goal of accurately simulating sulfate aerosol formation and evolution in the stratosphere – in the Department of Energy (DOE) Energy Exascale Earth System Model, version 2 (E3SMv2). The implementation includes changes to the four-mode Modal Aerosol Module microphysics in the stratosphere to allow for larger particle growth and more accurate stratospheric aerosol lifetime following the Pinatubo eruption. E3SMv2-SPA reasonably reproduces stratospheric aerosol lifetime, burden, aerosol optical depth, and top-of-atmosphere flux when compared to remote sensing observations. E3SMv2-SPA also has close agreement with the interactive chemistry–climate model CESM2-WACCM (Community Earth System Model version 2–Whole Atmosphere Community Climate Model) – which has a more complete chemical treatment – and the observationally constrained, prescribed volcanic aerosol treatment in E3SMv2. Global stratospheric aerosol size distributions identify the nucleation and growth of sulfate aerosol from volcanically injected SO2 from both major and minor volcanic eruptions from 1991 to 1993. The modeled aerosol effective radius is consistently lower than satellite and in situ measurements (max differences of ∼ 30 %). Comparisons with in situ size distribution samples indicate that this simulated underestimation in both E3SMv2-SPA and CESM2-WACCM is due to overly small accumulation and coarse-mode aerosols 6–18 months post-eruption, with E3SMv2-SPA simulating ∼ 50 % of the coarse-mode geometric mean diameters of observations 11 months post-eruption. Effective radii from the models and observations are used to calculate offline scattering and absorption efficiencies to explore the implications of smaller simulated aerosol size for the Pinatubo climate impacts. Scattering efficiencies at wavelengths of peak solar irradiance (∼ 0.5 µm) are 10 %–80 % higher for daily samples in models relative to observations through 1993, suggesting higher diffuse radiation at the surface and a larger cooling effect in the models due to the smaller simulated aerosol; absorption efficiencies at the peak wavelengths of outgoing terrestrial radiation (∼ 10 µm) are 15 %–40 % lower for daily samples in models relative to observations, suggesting an underestimation in stratospheric heating in the models due to the smaller simulated aerosol. These potential biases are based on aerosol size alone and do not take into account differences in the aerosol number. The overall agreement of E3SMv2-SPA with observations and its similar performance to the well-validated CESM2-WACCM makes E3SMv2-SPA a viable alternative to simulating climate impacts from stratospheric sulfate aerosols.

Brown, Hunter York (ORCID:0000000218147874)↗
NASA NTRS1971

Evidence for vulcanism on the moon.

Discussion of various kinds of lunar features generally agreed to be of entirely volcanic origin. Possible mechanisms of formation of lunar domes, crater chains (especially those that lie along a rill), craters surrounded by dark halos, sinuous rills, mare ?wrinkle' ridges, dark smooth level material, and ring dike-like structures through volcanic activity are suggested. The examples considered are believed to provide strong evidence and implications that considerable volcanism has occurred on the moon, has played a large part in modifying and shaping the visible surface features, and may still be mildly active at present.

Cameron, W. S.↗
NASA NTRS1973

Thermal surveillance of volcanoes of the Cascade Range and Iceland utilizing ERTS DCP systems and imagery

The author has identified the following significant results. Significant results of the thermal surveillance of volcanoes experiment during 1972 included the design, construction, emplacement, and successful operation at volcanic sites in the Cascade Range, North America and on Surtsey, Iceland, of automated thermistor arrays which transmit ground and fumarole temperatures via the ERTS-1 data communication system to Goddard Space Flight Center. Temperature, radiance, and anomalous heat flow variations are being plotted by a U.S. Geological Survey IBM 360/65 computer program to show daily fluctuations at each of the sites. Results are being compiled in conjunction with NASA and USGS aircraft infrared survey data to provide thermal energy yield estimates during the current repose period of several Cascade Range volcanic systems. ERTS-1 MSS images have provided new information on the extent of structural elements controlling thermal emission at Lassen Volcanic National Park.

Friedman, J. D.↗
NASA NTRS1973

Iron-absorption band analysis for the discrimination of iron-rich zones

The author has identified the following significant results. Lineament analysis of the area was initiated on individual images and then expanded areally by the use of mosaics at the 1:1,000,000 scale. Principal trends are NE, NW, NNE-NNW, and ENE. Several previously unrecognized lineaments are mapped which may be the surface manifestations of major fault or fracture zones. Three lineaments are especially noteworthy. Two of these, the Walker Lane and the Midas Trench lineament system, transect the prediominantly NNE-NNW trending mountain ranges for more than 500 km. A third major lineament, formed by the alinement of several topographic escarpments 10-20 km long, is orthogonal to the Midas Trench lineament. This lineament is marked by a distinct positive magnetic anomaly for approximately 200 km. Further visual analysis of ERTS-1 images has resulted in the delineation of 50 circular or elliptical features which are presumed to be volcanic or intrusive centers. A comparison with the 78 Tertiary volcanic centers mapped in the study area in 1970 indicates some good agreement between the proposed and known volcanic centers. The coincidence of some major lineaments and productive ore bodies implies a genetic relationship.

Rowan, L. C.↗
NASA NTRS1973

Fracture trends identified by ERTS-1 imagery in Utah and Nevada

The author has identified the following significant results. In the Utah-Nevada area, linear structural trends recorded on ERTS-1 imagery conform in part to previously recognized structures. In addition, the ERTS-1 imagery reveals cryptic structures not previously identified and not readily apparent in other imagery. These structures are illustrated by prominent east-west trending structures which appear to be concentrated in pre-volcanic rocks. This suggests that the structures are older than many of those with other trends which are equally prominent in volcanic and non-volcanic terrain. Since the older east-west structures may have controlled early Tertiary emplacement of magma or the ascent of mineralizing fluids, their recognition is important in minerial exploration. Soil-gas sampling and analysis for mercury content is being continued over structures, and projected trends of buried structures which appear, from studies of ERTS-1 imagery, to be favorable to mineralization. Comparison of ERTS-1 and Skylab imagery indicated that ERTS-1 imagery records more previously unrecognized linear structures than the Skylab imagery. In differentiating and identifying different rock types, the Skylab imagery appears to be more effective.

Jensen, M. L.↗
NASA NTRS1972

Significant results from Apollo 14 lunar orbital photography.

Apollo 14 obtained 950 photographs from lunar orbit using the Hasselblad and Hycon cameras. The photographs reveal a number of new geologic features as well as previously unrecognized details of the morphology, structure, and stratigraphy of lunar surface units. The primary result is the verification of the extensive role of volcanism in the formation and modification of the lunar highlands, especially on the far side. Terra volcanism appears to be manifest in the formation of (1) constructional units of hilly and furrowed materials of regional extent as in the Kant Plateau in the central near-side highlands and northwest of the crater Pasteur near the eastern limb of the moon; (2) somewhat viscous lava flows and pools associated with fracture systems and/or what appear to be volcanic craters; (3) craters, crater chains, and irregular depressions, particularly on the lunar far side. The first photographs of a flow channel, a leveed sinuous rille that apparently originated by lava flowage on the surface, were obtained by Apollo 14. Another first is a high-resolution photograph of the interior of what appears to be the youngest lunar crater yet photographed in the 20- 40-km size range.

El-Baz, F.↗
NASA NTRS1973

A generalized geologic map of Mars.

A geologic map of Mars has been constructed largely on the basis of photographic evidence. Four classes of units are recognized: (1) primitive cratered terrain, (2) sparsely cratered volcanic eolian plains, (3) circular radially symmetric volcanic constructs such as shield volcanoes, domes, and craters, and (4) tectonic erosional units such as chaotic and channel deposits. Grabens are the main structural features; compressional and strike slip features are almost completely absent. Most grabens are part of a set radial to the main volcanic area, Tharsis.

Carr, M. H.↗
NASA NTRS1975

Surface history of Mercury - Implications for terrestrial planets

A plausible surface history of Mercury is presented which is suggested by Mariner 10 television pictures. Five periods are postulated which are delineated by successive variations in the modification of the surface by external and internal processes: accretion and differentiation, terminal heavy bombardment, formation of the Caloris basin, flooding of that basin and other areas, and light cratering accumulated on the smooth plains. Each period is described in detail; the overall history is compared with the surface histories of Venus, Mars, and the moon; and the implications of this history for earth are discussed. It is tentatively concluded that: Mercury is a differentiated planet most likely composed of a large iron core enclosed by a relatively thin silicate layer; heavy surface bombardment occurred about four billion years ago, which probably affected all the inner planets, and was followed by a period of volcanic activity; no surface modifications caused by tectonic, volcanic, or atmospheric processes took place after the volcanic period.

Murray, B. C.↗
NASA NTRS1975

The geology of Mars - A brief review of some recent results

Some Mariner 9 data on geologic provinces, volcanic processes, geophysical models, Eolian activity, surface water, and atmospheric composition on Mars are presented. Ways in which this data is expected to be augmented by the Viking mission are briefly reviewed. Information given in map form includes permanent ice, layered deposits, etched plains, volcanic constructs (shields, domes, or cones), volcanic plains, moderately cratered plains, cratered plains, hummocky terrain, channel deposit, undivided plains, and grooved terrain.

Mutch, T. A.↗
NASA NTRS1976

Volcanology and morphology

Apollo 15 photographs of the southern parts of Serenitatis and Imbrium were used for a study of the morphology and distribution of wrinkle ridges. Volcanic and structural features along the south margin of Serenitatis were also studied, including the Dawes basalt cinder cones. Volcanic and structural features in crater Aitken were investigated as well. Study of crater Goclenius showed a close relationship between morphology of the impact crater and grabens which tend to parallel directions of the lunar grid. Similar trends were observed in the walls of crater Tsiolkovsky and other linear structures. Small craters of possible volcanic origin were also studied. Possible cinder cones were found associated with the Dawes basalt and in the floor of craters Aitken and Goclenius. Small pit craters were observed in the floors of these craters. Attempts were made to obtain contour maps of specific small features and to compare Orbiter and Apollo photographs to determine short term changes associated with other processes.

Bryan, W. B.↗
NASA NTRS1976

Acoustic noise from volcanoes - Theory and experiment

The paper discusses some theoretical aspects of acoustic investigation of volcanoes and describes a field experiment involving the recording, analysis, and interpretation of acoustic radiation from energetic fumaroles at Volcan Acatenango, Guatemala, during mid-January 1973. Particular attention is given to deriving information about the flow velocity of the erupting medium from acoustics as a means to study eruption dynamics. Theoretical considerations suggest that acoustic power radiated during gaseous volcanic eruptions may be related to gas exit velocity according to appropriate power laws. Eruption acoustics proves useful as a means of quantitative monitoring of volcanic activity.

Woulff, G.↗
NASA NTRS1976

Ground water recharge to the aquifers of northern San Luis Valley, Colorado: A remote sensing investigation

The author has identified the following significant results. Ground water recharge to the aquifers of San Luis Valley west of San Luis Creek was primarily from ground water flow in the volcanic aquifers of the San Juan Mountains. The high permeability and anisotropic nature of the volcanic rocks resulted in very little contrast in flow conditions between the San Juan Mountains and San Luis Valley. Ground water recharge to aquifers of eastern San Luis Valley was primarily from stream seepage into the upper reaches of the alluvial fans at the base of the Sangre de Cristo Mountains. The use of photography and thermal infrared imagery resulted in a savings of time and increase in accuracy in regional hydrogeologic studies. Volcanic rocks exhibited the same spectral reflectance curve as sedimentary rocks, with only the absolute magnitude of reflectance varying. Both saline soils and vegetation were used to estimate general ground water depths.

Lee, K.↗
NASA NTRS1977

The relationship between crustal tectonics and internal evolution in the moon and Mercury

The relationship between crustal tectonics and thermal evolution is discussed in terms of the moon and Mercury. Finite strain theory and depth and temperature-dependent thermal expansion are used to evaluate previous conclusions about early lunar history. Factors bringing about core differentiation in the first 0.6 b.y. of Mercurian evolution are described. The influence of concentrating radioactive heat sources located in Mercury's crust on the predicted contraction is outlined. The predicted planetary volume change is explored with regard to quantitative limits on the extent of Mercurian core solidification. Lunar and Mercurian thermal stresses involved in thermal evolution are reviewed, noting the history of surface volcanism. It is concluded that surface faulting and volcanism are closely associated with the thermal evolution of the whole planetary volume. As the planet cools or is heated, several types of tectonic and volcanic effects may be produced by thermal stress occurring in the lithosphere.

Solomon, S. C.↗