Chlorine in phosphorites and bone phosphate from oceanic and marine deposits

The content, distribution patterns, and occurrence forms of Cl in phosphorites and bone phosphate from the ocean bottom, as well as in a set of samples from the land, are studied. The total Cl content ranges from 0.05 to 4.25% in phosphorites and from 2.48 to 2.75% in recent phosphate-bearing sediments. Recent phosphorites are enriched in Cl relative to ancient ones. The bound Cl content (not extractable by washing), which increases with lithification, ranges from 0.17 to 0.60% in oceanic and land phosphorites and from 0.02% to 1.30% in the bone phosphate. The Na content in most samples is higher relative to NaCl due to its incorporation into the crystal lattice of apatite. However, the opposite relationship is observed in some samples, indicating a partial Cl incorporation into the anion complex of phosphate. The behavior of Cl in phosphorites from the present-day ocean bottom is controlled by early diagenetic processes, whereas the role of weathering, catagenesis, and hydrogeological factors may be crucial for phosphorites on continents.Translated from Litologiya i Poleznye Iskopaemye, No. 1, 2005, pp. 65–77.Original Russian Text Copyright © 2005 by Baturin.     

Sulfides in phosphorites of Africain Island: Morphological peculiarities and origin

The investigation of phosphorites from Africain Island situated in the Indian Ocean revealed that they contain iron sulfides in the form of framboids consisting of separate crystallites, as well as fine-dispersed colloidal particles of micrometer and submicrometer size. Crystallites consist of pyrite, whereas colloidal matter consists of troilite, which is initially formed as hydrogel inside voids. During the subsequent interaction of gelatinous troilite with sulfur, pyrite crystals are formed. The growth of crystals inside a 10987ted microvoid space in the rock leads to their dense hexagonal and tetragonal packing.     

Uranium and Thorium in Phosphatic Bone Debris from the Ocean Bottom

Uranium and thorium content, as well as their distribution patterns are studied in biogenic phosphates from the Atlantic and Indian oceans. The material studied is represented by differently lithified fish remains (bones, scales, teeth) and marine mammal bones (ribs, vertebras, earbones) collected from both reduced shelf sediments and oxidized pelagic ones. The U content in the material varies from 0.7 to 700 ppm, and the Th content ranges from less than 0.5 to 14 ppm. The U/Th ratio varies from 0.16 to 400. Contents of both elements increase with the lithification of biogenic phosphates. The U concentration is more intense on shelves, whereas the thorium concentration increases in pelagic areas. A partial positive correlation of U and Th with Fe but a negative correlation of U with organic carbon are noted. The latter corresponds to increasing lithification of biogenic phosphates. Calcium phosphate, which is transformed from hydroxyapatite to fluorcarbonate-apatite serves as the main carrier of U, while transformed organic matter is a minor agent. Thorium is mainly bound with Fe.     

Comparison of elemental composition of recent and ancient carbonaceous sediments

The concentrations of 13 macroelements and 36 microelements are determined in calcareous deposits from recent basins, namely, the Black Sea (coccolith and sapropel oozes), the Namibian shelf (diatomaceous oozes), and the Peruvian shelf (diatomaceous-terrigenous oozes). The essential similarity of the composition of the microelements is established for all three types of sediments, including calcareous, terrigenous, and siliceous sediments. The comparison of these data with the average composition of the world shales reveals similar trends of microelement distribution, which supports the former hypothesis about the comparable environment of formation of both ancient and some modern basins.     

Distribution of microelements in ferromanganese crusts of the sea of Okhotsk

The contents of 60 macro- and microelements were determined by inductively coupled plasma mass spectrometry in the samples of ferromanganese crusts collected on submarine slopes of the Kuril Islands. Along with a pronounced variability in the chemical composition of the crusts, the contents of several microelements vary according to the values of the europium anomaly. A positive value points to local volcanogenic hydrothermal activity, which provides for the accumulation of manganese and iron at the expense of the accumulation of some nonferrous and rare metals.     

Bubbled lava from the floor of the Sea of Okhotsk

A sample of bubbled lava raised from a submarine volcano in the Sea of Okhotsk was analyzed by means of electron microscopy and the ICP-MS technique. The outside of the sample is flecked with rounded micro- and macrocavities, and the inner part is characterized by a liquation structure. Along with this, the unstructured mass of the rock contains globular particles of nearly the same diameters as the cavities. The lava is close to andesites and volcanic ashes of Kamchatka Peninsula in the macro- and microelemental composition but different in the somewhat increased content of barium, strontium, lithium, niobium, tungsten, uranium, and thorium. It is suggested that the cavities were formed during the eruption of the submarine volcano owing to contact of the boiling gas-saturated lava with seawater accompanied by the ejection of ash, which was spread by marine currents over long distances.     

Solar convective zone and acoustic oscillations

The influence of the superadiabatic convection region and the hydrogen-helium ionization region on the spectrum of acoustic oscillations are considered. The spectrum peculiarities are studied by means of the phase-shift function which describes the reflection of the acoustic waves by the outermost layers of the Sun. This function permits us to investigate the influence of the envelope structure upon the oscillations without all the model data. It is shown that in spite of the strong influence of the superadiabatic convection upon acoustic oscillations, its structural changes cannot explain the discrepancy between observations and theory. It is emphasized that the explanation of the discrepancy between observations and standard model calculations requires taking into account the non-ideal nature of the plasma.