Streamflow generation in a headwater basin on the precambrian shield

Current conceptual runoff models hypothesize that stormflow generation on the Canadian Shield is a combination of subsurface stormflow and saturation overland flow. This concept was tested during spring runoff in a small (3.3 ha) headwater basin using: (1) isotopic and chemical hydrograph separation and (2) field mapping and direct tracing of saturated areas. Isotopic and chemical hydrograph separation indicated three runoff components: (1) pre-melt subsurface flow; (2) subsurface flow of new (event) water; and (3) direct precipitation on to saturated areas (DPS). During early thaw-freeze cycles, their relative contributions to total flow remained constant (65 per cent, 30 per cent, and 5 per cent respectively). It is hypothesized that lateral flow along the bedrock/mineral soil interface, possibly through macropores, supplied large volumes of subsurface flow (of both old and new water) rapidly to the stream channel. Much higher contributions of DPS were observed during an intensive rain-on-snow event (15 per cent of total flow). Mapping and direct tracing of saturated areas using lithium bromide, suggested that saturated area size was positively correlated to stream discharge but its response lagged behind that of discharge. These observations suggest that the runoff mechanisms, and hence the sources of stream flow, will vary depending on storm characteristics.     

Ballistic transport in Saturn's rings: An analytic theory

Ejecta from impacts of micrometeoroids on Saturn's ring particles will, in most cases, remain in orbit about Saturn and eventually be reaccreted by the rings, possibly at a different radial location. The resulting mass transport has been suggested as the cause of some of the features observed in Saturn's rings. Previous attempts to model this transport have used numerical simulations which have not included the effects of the angular momentum transport coincident with mass transport. An analytical model for ballistic mass transport in Saturn's rings is developed. The model includes the effects of angular momentum advection and shows that the net material movement due to angular momentum advection is comparable to that caused by direct ballistic mass transport.     

Monitoring of movement of potential earthquake areas with precise distance measuring and leveling systems

Whether monitoring crustal movements in localized volcanic areas along known fault lines, or over large crustal-movement areas, the geodesist has been restricted by the measurement accuracy of the instruments used, the accumulation of errors, the lack of reliable air refraction information and the problem of finding proper measurement procedures and mathematical solutions to assure that the inherent errors of the measurement-mathematical procedures do not exceed any conceivable ground movement.

Recent technological advances have placed new instruments and systems at the disposal of the geodesist, so that is now feasible to measure and analyze these micro and macro crustal movements within the accuracies required.

The paper describes three such systems:

1. (1) The Wild Electronic Theodolite T-2000 with a highly precise distance-measurement instrument, the DI-4S, together with a data collector, the GRE-3, which are connected to a computer and a plotter to measure and analyze both micro and macro crustal movements.

2. (2) The Wild NAK-2 level with an antimagnetic compensator which increases the accuracy in the height/velocity monitoring of vertical crustal movements by virtual elimination of the influence of natural or man-made magnetic fields on the automatic level.

3. (3) The use of analytical photogrammetry employing both terrestrial and aerial photography to monitor crustal movements.

By taking advantage of these new instruments and systems, the scientists capability to provide crustal movement data for use in the analysis and prediction of micro or macro crustal movement is greatly enhanced.     

Noble gas abundance patterns in deep-sea basalts — Primordial gases from the mantle

Rapidly cooled portions of eleven samples of mid-ocean ridge tholeiitic basalt pillows have noble gas abundance patterns which resemble the solar rare gas pattern rather than the noble gas pattern of the terrestrial atmosphere. We conclude that these samples contain primordial noble gases. In contrast, holocrystalline samples and a sample from the interior of a basalt pillow have noble gas abundance patterns which resemble the sea water pattern. Whereas the quenched glossy margins of basalt pillows record a non-atmospheric gas reservoir, these slowly cooled samples apparently have undergone exchange of their noble gases with those dissolved in sea water.     

Local volcanic activity and ice nuclei concentrations on Hawaii

Summary Ice nuclei counts made twice daily at Mauna Loa Observatory, Hawaii, throughout the Kilauea Iki and Puna eruptions of November 1959 to February 1960 did not show the increases reported elsewhere during periods of volcanic activity and were apparently not, affected by the visible presence of the volcanic effluent, even on days when this could be presumed to include enormous numbers of salt particles produced along the contact zone between hot lava flows and the sea. The observations suggest that not all active volcanos act as important sources of atmospheric ice nuclei, but that, in fact, other substances concurrently released may even inhibit nucleation.

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Zusammenfassung Während der Eruptionen des Kilauea Iki und des Puna von November 1959 bis Februar 1960 wurden am Mauna-Loa-Observatorium (Hawaii) täglich zweimal Zählungen der Eiskerne mit Hilfe einer Expansionskammer vorgenommen. Im Gegensatz zu den Beobachtungen an anderen Orten bei Vulkanausbrüchen konnte im vorliegenden Fall kein Anstieg der Eiskernzahlen festgestellt werden, obwohl der vulkanische Staub sichtbar war. Selbst an Tagen, an welchen von der Kontaktfläche zwischen Lavastrom und Meer große Mengen von Salzpartikeln in die Atmosphäre gelangt sein müssen, wurde kein Anstieg beobachtet. Die vorliegenden Ergebnisse deuten darauf hin, daß nicht alle aktiven Vulkane wesentliche Quellen von Eiskernen sind und daß möglicherweise andere Stoffe, die gleichzeitig ausgestoßen werden, die Eisbildung sogar hindern können.

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Résumé A l'observatoire de Mauna Loa (Hawaï), on a dénombré les noyaux de congélation deux fois par jour au moyen d'une chambre d'expansion; ces mesures ont été effectuées de novembre 1959 à février 1960, c'est à dire durant la période d'éruption du Kilauea Iki et du Puna. Au contraire d'observations faites ailleurs lors d'éruptions volcaniques, il ne fut pas possible de déterminer ici une augmentation du nombre des noyaux de congélation bien que la poussière volcanique ait été visible à l'oeil nu. On n'a même pas constaté d'augmentation au cours des journées où le courant de lave entrait en contact avec la mer, c'est a dire durant les périodes où de grandes quantités de particules de sel étaient entraînées dans l'atmosphère. Ces résultats montrent que tous les volcans actifs ne doivent pas nécessairement être source de noyaux de congélation et qu'il est en outre possible que certaines substances émises en même temps que la poussière volcanique empêchent même la formation de glace.

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With 2 Figures     

A climate-related oxidizing event in deep-sea sediment from the Bering Sea

Many cores from the deep basins of the Bering Sea have a thin oxidized zone within otherwise reduced sediment. This oxidized zone began to form about 6000 yr ago and represents an interval of about 3200 yr. Mineralogically, the oxidized and reduced sediments are similar, but chemically they differ. Concentrations of Fe and C are lower, and concentrations of Mn, Ba, Co, Mo, and Ni are higher in the oxidized than in the reduced sediment. Mn is enriched about 10-fold in the oxidized zone relative to its concentration in the reduced sediment, Mo about threefold, and Ba, Co, and Ni about twofold. These data suggest that the oxidized zone developed diagenetically as the result of the balance between the flux of organic matter and the available dissolved oxygen in bottom and interstitial waters.We propose that the Bering Sea was substantially ice covered when global glacial conditions prevailed. during the transition to global interglacial conditions, seasonal meltwater from thawing sea ice formed a lens of fresh water that decreased organic productivity. During the winter seasons, however, sea ice reformed and caused downwelling of dense, oxygen-rich waters to recharge bottom waters. The combination of lower organic productivity and more oxygen-rich bottom water allowed oxidized sediment to accumulate. Once full interglacial conditions were established, the volume of sea ice produced was insufficient to affect either productivity or the supply of dissolved oxygen and so bottom conditions again became reducing.Similar events probably occurred during the onset of global glacial conditions, and similar oxidized layers probably formed at these times. Such oxidized zones are highly unstable, however, in a reducing environment and, once buried beyond the influence of bacterial and infaunal activities, are depleted of their available oxygen and converted to reduced sediment.     

Phase equilibria involving humite minerals in impure dolomitic limestones

The natural occurrence of critical assemblages among the phases clinohumite, chondrodite, norbergite, tremolite, forsterite, brucite, periclase, diopside, calcite and dolomite, together with experimental and thermochemical data, permits the calculation of phase equilibria governing the stability of the humite group minerals in impure dolomitic limestones. The phase relations are described by 29 divariant (OH-F) continuous reactions, and 11 univariant discontinuous reactions. The equilibrium conditions for these reactions have been calculated and plotted in isobaricT-X(OH-F) andT- phase diagrams. Continuous reactions govern the compositions of (OH-F) solid solutions and the consequent movement of three-phase triangles on the chemographic diagram. Discontinuous reactions result in the appearance or disappearance of a distinct phase assemblage. The pure OH-humite minerals are metastable relative to forsterite+brucite. With increasing fluorine content, clinohumite, followed in turn by chondrodite and norbergite, becomes stable. The stability fields for the individual humite minerals expand to more CO₂-rich fluid compositions with increasing fluorine content and decreasing total pressure. At 1,000 bars, clinohumite can contain a maximum of 58 mole percent fluorine before reacting discontinuously to form chondrodite (X _F=0.61) and forsterite. The stability field for clinohumite+calcite is restricted to fluids with <0.40. At temperatures less than 700°C, the minimum fluorine mole fractions required to stabilize chondrodite and norbergite are 0.31 and 0.62 respectively. At the same conditions, chondrodite can contain a maximum of approximately 85 mole % F. The calculated phase equilibrium boundaries, the range of stable humite compositions and the compositions of coexisting (OH-F) phases are in good overall agreement with natural assemblages. Owing to steepdT/d slopes for several of the humite continuous reactions, the F/(F+OH) ratio of a given humite mineral is a useful indicator of the CO₂/H₂O ratio of the fluid phase.