Hot Saline Water Research Articles

Magnetometer array studies, Earth structure, and tectonic processes

This review presents results from magnetovariation fields recorded by two‐dimensional arrays of magnetometers. The emphasis is on the conductive structures mapped and studied and their tectonic implications. Eleven arrays were operated in North America between 1967 and 1985. A region of highly conductive uppermost mantle and/or lower crust, extending at least from 33°N to 54°N, has been shown to extend beneath much of the continent west of the Rocky Mountains. Two recent investigations are discussed in more detail: those of conductive structures under the Canadian Rockies and EMSLAB (Electromagnetic Sounding of the Lithosphere and Beyond) array results for Washington and Oregon, including a conductive strip beneath the Cascades volcanoes. Correlations with high heat flow and seismic parameters make it reasonable to attribute these regional conductors to partial melting and/or hot saline water. Within the craton the North American Central Plains conductor is discussed; this narrow, crustal feature is associated with a major fracture zone and age boundary, which may be a plate boundary of Proterozoic time. An array beneath the auroral electrojet, for study of the external currents, is noted. Results from four array studies in southern Africa are considered. Two of these relate to the Southern Cape Conductive Belt, which correlates not with high heat flow but with a large static magnetic anomaly. The magnetovariation, magnetic and gravity anomalies, and geological data can be accounted for if an accumulation of ophiolitic rocks including serpentine is present in the lower crust. Such an accumulation may have formed at a subduction in Proterozoic time. Two other arrays delineated a conductive belt associated with the southwestern end of the African rift system, in Namibia. Subsequent resistivity soundings located a conductor of resistivity 10 ohm m at less than 4 km depth. Two array studies in India follow, one in the north and one in the south. The array in the Himalayan foothills and Indo‐Gangetic plain mapped a conductor transverse to the regional strike; this may be a fracture zone produced in the interplate collision, with a rise of asthenospheric material such as fluids into the fractures. The southern Indian array reveals crustal conductors under the Indo‐Sri Lankan graben and another under the Comorin Ridge southwest of the tip of the subcontinent. Array studies in central and southeastern Australia and in Fennoscandia, in regions without large local conductivity anomalies, have been used to study conductivity variation with depth. A note on the Carpathian crustal anomaly is included as an example of combination of response parameters secured at different times to form a “virtual” array.

Corrosion Test of Metallic Plate with Wick in the Simulated Hot Saline Water Evaporating Environment

Corrosion Test of Metallic Plate with Wick in the Simulated Hot Saline Water Evaporating Environment

工業用純チタンの隙間腐食に及ぼす隙間充填材の影響

In the crevice corrosion of commercially pure titanium in hot saline water, the effect of gasket materials and the coupling with dissimilar metals, e. g. with copper alloy or mild steel, has been studied and the mechanism of crevice corrosion was discussed. Titanium crevice specimen with the gasket of dimethacrylate resin was more susceptible to crevice corrosion compared with specimens with PTFE and rubber or without gasket. A role of dimethacrylate in crevice corrosion seems to be attributable to the formation of more tight crevice.The results of potentiostatic electrolysis for titanium crevice specimens revealed that the crevice corrosion occurred at potential more noble than about -0.4V (SCE). Therefore, titanium crevice specimen coupled with copper alloy and mild steel were immune to crevice corrosion because corrosion potentials of these couples are less noble than -0.4V.It was clarified that passive film thickness of titanium decreased markedly with lowering solution pH to the depassivation pH of titanium. On the other hand, pitting potential of titanium was about 5 volts (SCE), regardless of the solution pH and so titanium would be hardly subject to pitting corrosion even in low pH solution.These results suggest that crevice corrosion of titanium is caused by not pitting corrosion but by active corrosion in the crevice.

Effect of solute dispersion on thermal convection in a porous medium layer

Thermal convection and overstable motions may sometimes play an important role in salt diffusion in an aquifer. In such cases hot saline water is in the deep layers of the aquifer, from which salt diffuses into the upper freshwater. Often the horizontal steady flow of the water in the aquifer increases the rate of diffusion of soluted materials. Salt diffusion is then characterized by the anisotropic dispersion tensor. The effects of salt dispersion by the steady state flow in the aquifer were examined in connection with the thermal stability of the flow field. It was found that dispersion of the soluted material reduces the stabilizing effect of the salinity profile but increases the stability of the flow field to pure overstable motions. Dispersion also changes the dimensions of Bénard cells in the porous medium. The dispersion tensor fluctuations hardly affect the stability criteria of the flow field but cause very small overstable motions that distort the shape of the convective current cells.

Observations of Hot Saline Water Corrosion of Aluminum Alloys

Abstract Corrosion films formed on aluminum in hot salt water (100 to 177 C) after short time tests of thirty seconds to one hour were studied by transmission electron microscopy and diffraction. It was concluded from observation of 6061, 5454, 2024, Al-1.52Mn and Al-1.66Ni alloys that one controlling factor in the initiation and growth of the outer film of the duplex oxide film is the alloy composition. The outer film formed earlier on alloys containing copper and the film growth was also more rapid on these alloys. Additions of magnesium, manganese and nickel retarded this outer film formation but with nickel additions, pitting attack was more severe and deposition of copper from solution was increased. The formation and growth of the outer film was slowest on the 5454 alloy which was also the most resistant alloy tested.

Observations of Titanium Alloy Corrosion in Hot Saline Water

This work was conducted as part of a program to study materials which have potential use in desalination plants. Titanium has shown excellent corrosion resistance in neutral saline waters and it is important to know more about the corrosion process and how it might be influenced by other variables of the corroding system. Transmission electron microscopy has been employed to study uncorroded and corroded thin foils. This investigation concentrated on studying the initial stages of saline water corrosion by determining the morphology and composition of the oxide films and by checking the effects of increased temperatures, increased pressures and alloy composition on the corrosion process.

VIOLENT MUD-VOLCANO ERUPTION OF LAKE CITY HOT SPRINGS, NORTHEASTERN CALIFORNIA

During the night of March 1 and 2, 1951, an inconspicuous group of hot springs and small mud volcanoes in northeastern California burst into spectacular eruption, unequalled by other known mud volcanoes. The eruption cloud of steam, gases, and mud particles rose several thousand feet in the air and distributed fine debris to the southeast for a distance of at least 4 miles. More than 20 acres of the hot-spring area was intensely disturbed and greatly modified by the eruption, estimated to involve at least 6 million cubic feet or 300,000 tons of mud. Several days after the eruption, the area was barely active. The eruption appears to be unique in the history of the springs. The hot-spring system is in deep fine-grained clastic sediments immediately east of the Surprise Valley fault bounding the Warner Range. The sediments of the spring area are saturated with near-neutral hot saline water. Previous temperatures and geothermal gradient of the area were probably high. Mud volcanoes exist in similar physical environment near Gerlach in Washoe County, Nevada, and on the southeast shore of Salton Sea, Imperial County, California. Other mud volcanoes occur in acid thermal areas and are characterized by abundant volcanic gases and near-surface alteration by sulfuric acid; their eruptions involve only surficial material and not underlying competent bedrock. Eruptions in deep fine-grained basin sediments are attribured to unstable or metastable temperature-depth relations existing in many high-energy thermal systems. Vapor pressure at depth may equalor exceed hydrostatic pressure. Great energy is stored in a thermal system of this type, but ordinarily is released slowly. A mud-volcano origin is possible for some eruption deposits classed as phreatic or cryptovolcanic. Although near-boiling hot springs are considered phases of volcanism, true volcanic eruptions are distinct from mud-volcano eruptions. The former derive their energy directly from new volcanic rocks or magma, but the latter are caused by sudden release of energy stored in near-surface hydrothermal systems and do not involve direct release of energy from new volcanic magma. The energy of true volcanic eruptions, however, may be increased by release of energy from previously existing hydrothermal systems, for example in the Rotomahana phase of the great Tarawera eruption of 1886 in New Zealand. Language: en