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Showing papers on "Silicate minerals published in 1969"



Journal ArticleDOI
TL;DR: The properties of chondrites can be interpreted in terms of metamorphic equilibration and recrystallization of primary chondritic matter, although alternative hypotheses exist as mentioned in this paper.

101 citations


Journal ArticleDOI
TL;DR: In this paper, a detailed study of the strontium isotopic composition of closely associated alpine-type ultramafic intrusions in western North Carolina has revealed variable but high 87 Sr 86 Sr ratios, similar to those found in previous reconnaissance studies.

34 citations


Journal ArticleDOI
TL;DR: In this paper, a method for the accurate determination of the major and some minor elements in silicate minerals is presented, in which the elements are absorbed from an oxalic-hydrochloric-sulphuric acid mixture on a column of AGI-X8 anion-exchange resin in the oxalate-chloride-Sulphate form and a column in AG 50 W-X 8 cation exchange resins in the hydrogen form.

24 citations


Journal ArticleDOI
01 Jul 1969-Nature
TL;DR: Mackenzie and Garrels as discussed by the authors suggested that the amorphous aluminium silicate fraction of river sediment with dissolved bicarbonate, silica and cations in ocean water to form authigenic sedimentary silicate minerals.
Abstract: IN the search for a general theory to explain the chemical composition of ocean water, emphasis has been put on inorganic equilibrium models which are themselves based on the postulate of a steady state oceanic system1–3. The major cation content and pH of ocean water at present are very similar to the values predicted by equilibrium calculations, and one of the most important of these reactions is supposed to be that of the amorphous aluminium silicate fraction of river sediment with dissolved bicarbonate, silica and cations in ocean water to form authigenic sedimentary silicate minerals. Mackenzie and Garrels3 suggest that these reactions take place before deposition of the sediments and calculate that only 7 percent of the amount of suspended river sediment entering the ocean would have to form authigenic minerals if the composition of the oceans were to remain constant. Although there is no conclusive field evidence for the proposed mineral–water reactions and their effect on the major cation budgets in the oceanic system, there is field and laboratory evidence to show that boron is taken up by the fine-grained silicate material during the transfer from the fresh water to the marine environments4–10.

24 citations


01 Jul 1969
TL;DR: Titaniferous Ferruginous latosols are an important group of Hawaiian soils as discussed by the authors, which have a profile of very friable silt material with very little horizon differentiation, and when exposed to dehydration by removal of the protective canopy cover of the forest, as occurs after forest fires, a tremendous change occurs in the soil profile morphology.
Abstract: Titaniferous Ferruginous latosols are an important group of Hawaiian soils. They have developed by pedogenetic weathering of the volcanic materials of basic and ultrabasic lava flows and their associated pyroclastic materials, under climatic conditions having definite alternating dry and wet seasons. The annual rainfall range for these soils is 30 to 60 inches. Under the native and undisturbed vegetation, these soils have a profile of very friable silt material with very little horizon differentiation. When exposed to dehydration by removal of the protective canopy cover of the forest, as occurs after forest fires, a tremendous change occurs in the soil profile morphology. The change is greater than the morphological differences which normally occur between the profiles of the Great Soil groups. A surface indurated horizon develops in which the bulk density and particle density have an approximate two-fold increase. The mineralogical changes are substantial. The amorphous hydrated titanium and iron oxides are converted into good crystalline forms of anatase, rutile, pseudo-brookite, titanohematite and titanomaghemite. In some cases these minerals develop from the weathering of titanomagnetite-ilmenite mixed crystals. The unusual characteristic of these soils is the apparent movement of the colloidal material in a very short space of time, which results in an accumulation of titaniferous minerals in the indurated surface horizon and the accumulation of amorphous silica giving weak X-ray diffraction patterns of alpha quartz on the very surface of the soil. Rutile is also identified along with the silica at the surface. Aluminum oxides are removed to the lower horizons and in some cases accumulated as irregularly shaped gibbsite nodules in scattered pockets below the clay horizon. TITANIFEROUS FERRUGINOUS LATOSOLS include soils which have horizons rich in titanium and iron oxides. This group of soils has formed from the basic and ultrabasic lavas and pyroclastic materials of the post-erosional volcanic activity which has occurred on the geologically old islands of the Hawaiian group. There is strong evidence that the formation of these soils may be limited to the pyroclastic materials of post-erosional origin. The pedogenetic weathering of the original primary minerals evidently has been intense, as all of the silicate minerals have been completely decomposed. Leaching has been thorough and unimpeded, as the bases have 1 Published with the approval of the Director of the Hawaii Agricultural Experiment Station, Honolulu, as Technical Paper No. 559. Manuscript received February 20, 1969. 2 Hawaii Agricultural Experiment Station, University of Hawaii, Honolulu, Hawaii 96822. 3 Tokyo Institute of Technology, Tokyo, Japan. been removed to an extremely low level. These soils have attracted much attention because of the marked changes which occur in their chemical, physical, and mineralogical composition when they have become exposed and are dehydrated by the removal of their forest canopy and tall grass cover by fire, over-grazing, or other activities of man. The profile morphology of the soil changes from a friable silt profile having little horizonal differentiation and similar to Reddish Prairie profile to one having an indurated high bulk density surface horizon and a morphology similar to that described for the laterite profile formed ill situ. These soils have been studied and described by several workersFujimoto et al. (1948), Katsura et al. (1962), Sherman et al. (1948), Sherman et al. (1953), and Tamura et al. (1955). The purpose of this paper is to identify some of the mineralogical changes which result from

15 citations


Journal ArticleDOI
TL;DR: In this article, the ordering of iron in biotites is discussed, and the ferrous-ferric iron ratio in all the silicates is determined in all silicates.
Abstract: Biotites and Ca-amphiboles have been studied. Certain changes in composition of the Ca-amphiboles could be correlated to changes in the Mossbauer parameters. The ordering of iron in biotites is discussed. The ferrous-ferric iron ratio could be determined in all the silicates. Biotite und Ca-Amphibole wurden untersucht. Die Unterschiede in der chemischen Zusammensetzung konnten mit den Veranderungen der Mossbauer-Parameter korreliert werden. Die Anordnung des Eisens in den Biotiten wird diskutiert. Das Ferro-Ferri-Verhaltnis wurde in allen Silikaten bestimmt.

14 citations


Journal ArticleDOI
01 Jan 1969-Analyst
TL;DR: In this article, the same authors used glyoxal bis(2-hydroxy anil) to determine the amount of calcium in silicate minerals in the presence of mannitol and magnesium.
Abstract: Calcium in silicate minerals is determined in alkaline solution with glyoxal bis(2-hydroxy anil). At the pH of the reaction, aluminium, present as sodium aluminate, does not interfere, and co-precipitation of calcium with magnesium and iron is prevented by adding mannitol. Fifty micrograms of calcium can be determined in the presence of 3000 µg of magnesium and 2000 µg of iron, the calibration being linear between 0 and 80 µg of calcium.

5 citations


Journal ArticleDOI
TL;DR: In this article, a simple direct pelletization method for the analysis of SiO 2, TiO 2, Al 2 O 3, Fe 2 O3, MnO, CaO, MgO and K 2 O in silicate minerals is described.

2 citations


Journal ArticleDOI
TL;DR: A homologous series of nitro-alkylphenols has been isolated from the odoriferous oil extracted from rocks, clays, and silicate minerals, which have been exposed to the atmosphere.
Abstract: A homologous series of nitro-alkylphenols has been isolated from the odoriferous oil extracted from rocks, clays, and silicate minerals, which have been exposed to the atmosphere. A relatively large amount of another nitro-hydroxy compound, possibly a derivative of diphenyl, is also present in the oil. The most likely origin of these compounds, or their precursors, is alkylphenols liberated into the atmosphere from plant material.

1 citations