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NASA NTRS2021

Western Montana Ecological Forecasting: Modeling Habitat Suitability of Mustelid Species to Guide Detection Dog Surveys for Contaminants Monitoring, via Collected Scats in River Systems of Western Montana

Environmental contaminants are becoming increasingly prevalent in riverine ecosystems. The status of contaminants in western Montana’s relatively pristine river systems is largely unknown. Monitoring for heavy metals, brominated flame-retardants (BFRs), and pharmaceuticals is important due to their negative effects on ecosystems. Exposure to these contaminants can have significant endocrine, neurological, and reproductive effects. Contaminants easily travel up the food chain and bioaccumulate in apex predators. As predators with a largely aquatic diet, American mink (Mustela vison) and North American river otter (Lontra canadensis) serve as reliable indicator species of environmental health and the status of contaminants. Analysis of scat from these species is a noninvasive method to measure contaminant levels, and detection dogs from Working Dogs for Conservation (WD4C) have been used to locate these scat samples. To aid in the search of these samples, habitat suitability models were created for mink and otter for the years 2013-2020 and projected to 2040 using the random forest algorithm in the Software for Assisted Habitat Modeling (SAHM). Predictor variable data were acquired from Landsat 8 Operational Land Imager (OLI), Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Global Precipitation Measurement Integrated Multi-satellite Retrievals for GPM (GPM IMERG), Shuttle Radar Topography Mission (SRTM), and Soil Moisture Active Passive (SMAP). Within these models, the most important variable for mink and otter habitat was distance to river. Suitable habitat also corresponded with emergent herbaceous land cover and deeper river locations. These habitat suitability models will inform sampling site section for further contaminant analysis.

Anna Winter↗

NASA NTRS1972

The relative age of the transition zone between Hellas and the Martian cratered terrain.

Consideration of the relationships of craters to scarps and ridges and of the antiquity of Hellas relative to the cratered terrain. Scarps and ridges in the transition zone between Hellas and the cratered terrain both postdate and predate large craters. It appears that there are a number of craters which are older than the transition zone structures, which in turn are presumably related in some way to the formation of Hellas. Sharp et al. (1971) have suggested impact, large-scale volcanic explosion, or subsidence for the origin of Hellas. Volcanic explosion seems the least likely explanation, for the resulting deficiency of mass beneath Hellas should induce later isostatic rebound, contrary to observations of the transition zone which imply subsidence relatively late in the history of the Martian surface. An origin of Hellas by impact with later isostatic subsidence (because of a dense mass under its floor, as suggested by Sharp et al.) to account for the characteristics of the transition zone seems to be the best model, and may also account for the featureless floor of the basin.

Thorman, C. H.↗

NASA NTRS1973

Assessment of flood damage in Arizona by means of ERTS-1 imagery

ERTS-1 MSS images clearly show two important effects of a large flood in southeastern Arizona - the extent of inundation and the areas affected by servere sediment deposition and erosion - although the images were made a week and a half after the flood. On October 20 and 21, 1972, the upper Gila River had its third-largest flood on record. Peak flows attained about 42,000 and 82,000 cubic feet a second at Duncan and Safford, Arizona, respectively. The first ERTS-1 images after the flood were made on November 1 and 2. The inundated area is best displayed on the infrared bands, particularly on band 7, where it appears as a belt along the river that is distinctly darker than adjoining parts of the flood plain. This dark belt does not appear on ERTS images that predate the flood. Presumably the low infrared reflectance of this belt is caused by still-moist soil and by flood-stressed vegetation. Inundation limits mapped from ERTS imagery agree well with those obtained by aerial photography during the flood and by ground surveys.

Morrison, R. B.↗

NASA NTRS1974

Kansas environmental and resource study: A Great Plains model. Extraction of agricultural statistics from ERTS-1 data of Kansas

The author has identified the following significant results. Wheat area, yield, and production statistics as derived from satellite image analysis, combined with a weather model, are presented for a ten county area in southwest Kansas. The data (representing the 1972-73 crop year) are compared for accuracy against both the USDA August estimate and its final (official) tabulation. The area estimates from imagery for both dryland and irrigated winter wheat were within 5% of the official figures for the same area, and predated them by almost one year. Yield on dryland wheat was estimated by the Thompson weather model to within 0.1% of the observed yield. A combined irrigated and dryland wheat production estimate for the ten county area was completed in July, 1973 and was within 1% of the production reported by USDA in February, 1974.

Morain, S. A.↗

NASA NTRS1973

A component of primitive nuclear composition in carbonaceous meteorites

Oxygen isotope analysis of anhydrous high-temperature phases from carbonaceous meteorite chondrites indicates a high degree of O(17) and O(18) isotope depletion. The isotope decay is believed to be a result of nuclear rather than chemical processes caused by the admixture of a component consisting of almost pure O(16). It is theorized that this component may predate the solar system and may represent interstellar dust with a separate history of nucleosynthesis.

Clayton, R. N.↗

NASA NTRS1973

The Old Imbrium Hypothesis

It is proposed that the order of lunar events was such that the Imbrium event predates the formation of the lunar rock type called KREEP. This hypothesis is used to explain the distribution of KREEP in the regions of Imbrium ejecta and the location of KREEP within the Imbrium and Procellarum mare regions. Model ages of KREEP materials have been previously interpreted to mean that their 'formation' age (time of initial extrusion) is about 4.3 to 4.4 AE. Consequently it is suggested that the Imbrium impact was before 4.3 to 4.4 AE rather than at about 3.9 AE, as is currently believed. This Old Imbrium Hypothesis is not yet proven, but seems to be consistent with a large variety of basic lunar observations.

Schonfeld, E.↗

NASA NTRS1974

A refractory glass chondrule in the Vigarano chondrite

Vigarano, a type 3 carbonaceous chondrite, contains a chondrule composed of highly refractory Ca- and Al-rich glass with minor spinel. The chondrule formed from material similar to the Ca-, Al-, Ti-rich aggregates that are common in Vigarano and other type 3 chondrites and formation of these refractory aggregates must predate formation of some Vigarano chondrules. Experiments with synthetic analogs and a comparison with studies in the system CaO-MgO-Al2O3-SiO2 indicate a temperature for formation of the chondrule at or above 1700 C followed by very rapid cooling.

Reid, A. M.↗

NASA NTRS1975

Identification and interpretation of tectonic features from ERTS-1 imagery: Southwestern North America and the Red Sea area

The author has identified the following significant results. The ERTS-1 imagery was utilized to study major fault and tectonic lines and their intersections in southwestern North America. A system of transverse shear faults was recognized in the California Coast Ranges, the Sierra Nevada, the Great Basin, and Mexico. They are interpreted as expressions of a major left-lateral shear which predated the San Andreas system, the opening of the Gulf of California and Basin and Range rift development. Tectonic models for Basin and Range, Coast Ranges, and Texas-Parras shears were developed. Geological structures and Precambrian metamorphic trend lines of schistosity were studied across the Red Sea rift.

Abdel-Gawad, M.↗

NASA NTRS1975

Preliminary geologic terrain map of Mercury

A geologic terrain map of Mercury has been constructed by use of the photogeologic methods employed for the moon and Mars. The oldest and most widespread unit, intercrater plains, forms nearly level to rolling surfaces on which are superposed numerous secondary impact craters. This unit may represent a very old surface that predates the last heavy bombardment of the inner planets. The effects of this bombardment are recorded in a second widespread unit, heavily cratered terrain, consisting of closely spaced craters and basins from 30 km to several hundred kilometers in diameter. Units formed by excavation of the 1300-km-diameter Caloris basin are widespread on one hemisphere of the planet. The development of the Caloris basin was followed relatively quickly by emplacement of widespread plains materials, most of which are probably volcanic.

Trask, N. J.↗

NASA NTRS1976

Some aspects of core formation in Mercury

Some questions dealing with the nature and history of a large metallic core within Mercury are considered. These include the existence of a core, its size, whether it is fluid or solid, the timescale for core formation, the geological consequences of core formation, and whether such consequences are consistent with the surface geology. Several indirect lines of evidence are discussed which suggest the presence of a large iron-rich core. A core-formation model is examined in which core infall is accompanied by an increase of 17 km in planetary radius, an increase of 700 K in mean internal temperature, and substantial melting of the mantle. It is argued that if the core differentiated from an originally homogeneous planet, that event must have predated the oldest geological units comprising most of the planetary surface. A convective dynamo model for the source of Mercury's magnetic field is shown to conflict with cosmochemical models that do not predict a substantial radiogenic heat source in the core.

Solomon, S. C.↗

NASA NTRS1976

Thermal expansion and thermal stress in the moon and terrestrial planets - Clues to early thermal history

The paper discusses how features of the surface geology of the moon and also Mars and Mercury impose constraints on the volumetric expansion or contraction of a planet and consequently provide a test of thermal history models. The moon has changed very little in volume over the last 3.8 b.y. Thermal models satisfying this constraint involve early heating and perhaps melting of the outer 200 km of the moon and an initially cold interior. Mercury has contracted by about 2 km in radius since emplacement of its present surface, so core formation must predate that surface. A hot initial temperature distribution is implied.

Solomon, S. C.↗

NASA NTRS1977

Pre-mare cratering and early solar system history

An evaluation of the application of the high extralunar flux in pre-mare times to more general problems of early solar system history is attempted by combining the results of dynamic studies with lunar chronological data. There is a twofold to fourfold contrast in the integral impact flux between the Apollo 14 and 16 sites and the older mare surfaces. This is judged insufficient to account for the contrasting lithology between these two sites: basalts and soil breccias in the maria, annealed breccias and impact melts in the highlands. Therefore, these rocks and their ages (3.9-4.0 b.y.) are thought to predate the surfaces in which they are found. Estimation of the flux needed to produce these lithologies, and difficulties associated with extrapolating this further back in lunar history give support to the "cataclysm" hypothesis of Tera, Papanastassiou, and Wasserburg. Dynamical studies permit separate evaluation of the possible sources for both the "normal" flux during the first 600 million years of lunar history and the "peak" that apparently occurred 4.0 billion years ago. The most likely sources for the normal flux are comets from the vicinity of Uranus and Neptune. The most promising source for the peak is tidal disruption by Earth or Venus of a Ceres-size asteroid initially in a Mars-crossing orbit. Alternative possibilities are suggested.

Wetherill, G. W.↗

NASA NTRS1977

Geological Observations in the Cydonia Region of Mars from Viking

During the Viking mission, three broad areas of the northern plains were investigated as possible landing sites for Viking lander 2. We present a geological map of the area designated the B1 landing site in Cydonia centered on 45 deg N latitude, 4 deg W longitude. Viking imagery of this area has given detailed coverage, allowing the northern plains to be examined in more detail over wider areas than was possible from Mariner 9. Some plains areas with polygonal fracture patterns are considered to be pediments in ancient southern hemisphere rocks. The fracture patterns predate at least some of the younger northern plains material. Several northern plains units are distinguished as well as surface textures of unknown origin. Viking pictures provide good data for future studies of stratigraphy and surface process in this region and others like it in northern latitudes.

Guest, J. E.↗

NASA NTRS1977

Global tectonics of Mercury and the moon

Lobate scarps on Mercury have been studied to determine the nature of the surface stress history and implications for the planet's early tectonic history. Morphologic and transection relations indicate that most Mercurian scarps are tectonic in nature and are due to compressive stresses in the surface layer. The azimuthal distribution of lobate-scarp trends is compatible with an early predominantly compressive global stress field due to thermal shrinkage of the planet. Superposition relations indicate that the contractive phase was largely a pre-Caloris process. The effects of stresses due to planetary despinning were either negligible, predate the scarps, or were largely obscured by cratering or volcanism. The tectonic history of Mercury as recorded in the lobate scarps is different from that which caused the system of lineaments on the moon.

Cordell, B. M.↗

NASA NTRS1978

Relative timing of rifting and volcanism on earth and its tectonic implications

It is suggested that two basic types of rifting-volcanism relative timing might be related to two basic modes of rifting. In one sequence, volcanism and, usually, local doming predate major rift formation, while in the other type, rifts form first and volcanism follows. In the first mode of rifting, the mantle plays an active role and convection 'plumes' dome up and crack the lithosphere, while in the second case, the horizontal movements of plates give rise to extension of the lithosphere and induce rifting, and the mantle is passive. Since numerous local conditions complicate this simple pattern, detailed stratigraphic/structural analysis of individual rifts is recommended.

Sengor, A. M. C.↗

NASA NTRS1978

Mercurian global tectonics - A consequence of tidal despinning

The surface of Mercury exhibits a global tectonic system consisting of an ancient set of NE and NW tending lineaments and a younger set of planimetrically arcuate escarpments interpreted as thrust of high-angle reverse faults. The trends, distribution, and age relations of these tectonic features can be explained by a combination of tidal despinning and global contraction of the planet. In our model, early tidal despinning resulted in conjugate shear fractures trending roughly N60 deg E and N60 deg W which were subsequently modified by a variety of surface processes to produce the presently visible set of lineaments. Continued despinning plus global contraction produced thrust faults with roughly north-south trends. Final contraction may have postdated despinning and produced randomly oriented thrust faults. All of these events predated the formation of Caloris basin, because basin-associated deposits blanket both lineaments and arcuate thrust faults.

Melosh, H. J.↗

NASA NTRS1979

Evidence for large-scale velocity features on the sun

Giant velocity features on the solar surface are seen in line-of-sight velocity data from the Mount Wilson magnetograph. Velocity amplitudes around 40 m/s are seen in features with dimensions about 15 deg in latitude and 30-60 deg in longitude. These features are associated with solar activity. The largest such feature accompanied the largest complex of activity in this interval, lived for about 16 rotations, and predated the first magnetic fields in the area by about two rotations. A general pattern of upward motion at the equator is seen, and motions away from the earth at higher latitudes could represent a meridional flow toward the poles of the order of 20 m/s.

Howard, R.↗

NASA NTRS1979

I-Xe dating of silicate and troilite from IAB iron meteorites

Silicate and troilite inclusions from IAB iron meteorites were dated by the I-Xe technique. Silicate samples from inclusions in the Copiapo, Landes, Woodbine, Pitts and Mundrabilla meteorites and troilite samples from Pitts and Mundrabilla were subjected to neutron irradiation and the xenon isotope ratios produced were determined. Well-defined I-Xe ages were obtained for Woodbine, Copiapo, Landes and Mundrabilla and are found to be within 3.7 million years of the Bjurbole meteorite, suggesting a close relationship to the stone chondrites. The analysis of troilite from Pitts suggests an age of 17 million years older than Bjurbole, while Mundrabilla troilite is observed to predate Mundrabilla silicate. The abundances of Ga, Ge and Ni are found to be correlated with I-Xe ages, supporting the validity of the I-Xe dating method. The results are considered to favor a nebular model of meteorite formation.

Niemeyer, S.↗