Geochemistry of manganese nodules from a British Columbia fjord

Concretions of iron and manganese oxides and hydrous oxidesóobjects commonly called manganese nodulesóare widely distributed not only on the deep-sea floor but also in shallow marine environments1. Such concretions were not known to occur north of Cape Mendocino in the shallow water zones bordering the North-East Pacific Ocean until the summer of 1966 when they were recovered by one of us (J. W. M.) in dredge samples from Jervis Inlet, a fjord approximately 50 miles north-west of Vancouver, British Columbia.

Analysis of Mn-nodules from the Indian Ocean

This report studies the principal paramters governing the distribution of iron-manganese concretions on the sea floor of the Indian Ocean, as well as their petrography and mineralogy. The results are mainly based on the recoveries made during voyages 31, 33 and 35 of the "Vityaz"' (1959-1962) and partly during voyages 36 and 41 (1964-1966). During these voyages samples of Mn concretions and Mn crust were collected (by bottom grabs, cores, trawlings, and dredgings) at 39 stations. The following account is devoted to the problems concerning the geochemistry of these concretions.

Chemical and isotopic compositions of rocks and minerals from the Palenyi Island, Por'ya Guba (Bay), White Sea

Hypersthene-garnet-sillimanite-quartz enclaves were studied in orthopyroxene-plagioclase and orthopyroxene-clinopyroxene crystalline schists and gneisses from shear zones exposed in the Palenyi Island within the Early Proterozoic Belomorian Mobile Belt. Qualitative analysis of mineral assemblages indicates that these rocks were metamorphosed to the granulite facies (approximately 900°C and 10-11 kbar). Oxygen isotopic composition was determined in rock-forming minerals composing zones of the enclaves of various mineral and chemical composition. Closure temperatures of the isotopic systems obtained by methods of oxygen isotopic thermometry are close to values obtained with mineralogical geothermometers (garnet-orthopyroxene and garnet-biotite) and correspond to the high-temperature granulite facies (860-900°C). Identified systematic variations in d18O values were determined in the same minerals from zones of different mineral composition. Inasmuch as these zones are practically in contact with one another, these variations in d18O cannot be explained by primary isotopic heterogeneity of the protolith. Model calculations of the extent and trend of d18O variations in minerals suggest that fluid-rock interaction at various integral fluid/rock ratios in discrete zones was the only mechanism that could generate the zoning. This demonstrates that focused fluid flux could occur in lower crustal shear zones. Preservation of high-temperature isotopic equilibria of minerals testifies that the episode of fluid activity at the peak of metamorphism was very brief.

Chemical composition of phosphorites from the Peru and Chile shelves

Recent and Late Quaternary shelf phosphorites have low Fe, Ti and Al contents. These elements enter the phosphorites with terrigenous impurities and organic detritus. Ti, Al, and some Fe are removed when the phosphorites are lithified, whereas remaining iron settles in the phosphorites as sulfides. Ti/Fe, Al/Fe and Ti/Al ratios are used as examples of difference between behavior of Fe and that of Ti and Al.

Description and chemical composition of manganese nodules sampled during the R/V "Vityaz" Expedition Vityaz-35

This paper presents data on the chemical composition of iron-manganese nodules and associated sediments collected during the 35th voyage of the R/V "Vityaz" in 1962. The samples were made available to the author by Prof, P. L. Bezrukov. Data on the general distribution of manganese nodules at the bottom of the Indian Ocean were already given by P. L. Bezrukov (1962, 1963). Here the author analyzed the geochemistry of nodules samples from seven stations and four samples from the associated sediments. The analysis separates the outer layer of nodules from their apparent internal core.

Chemistry on manganese nodules from the Pacific Ocean

Three manganese nodules from the Pacific Ocean have been analysed for 35 elements by using mainly spectrophotometric and spectrographic methods. Cu, Co, Ni, Zn, and Pb were found in amounts approaching 1 %, which far exceeds their average concentrations in igneous rocks. On the other hand, elements having readily hydrolysable ions, such as Ga, Sc, Zr, Y, La and Ti, are present only in amounts comparable with their concentrations in igneous rocks. Sb, Bit Be, and Cr were not detected. The hydrochloric acid-insoluble fraction of nodules is practically free of the heavy metals that are characteristic of the acid-soluble fraction; it consists principally of clay minerals, together with lesser amounts of quartz, apatite, biotite and sodium and potassium felspars.

Composition and crystal parameters of carbonate-apatites from animal teeth and bones and from phosphate rocks of the ocean bottom

Samples of recent to Miocene fish and marine mammal bones from the bottom of the Atlantic and Pacific Oceans and Miocene Maikop deposits (Transcaspian region) are studied by X-ray diffraction technique combined with chemical and energy-dispersive analyses. Changes of lattice parameters and chemical composition of bioapatite during fossilization and diagenesis suggest that development of skeletal apatite proceeds from dahllite-type hydroxyapatite to francolite-type carbonate-fluorapatite. It is assumed that jump-type transition from dahllite to francolite during initial fossilization reflects replacement of biogeochemical reactions in living organisms, which are subject to nonlinear laws of nonequilibrium thermodynamics, by physicochemical processes according to the linear equilibrium thermodynamics.

Composition of bottom sediments and rocks from the Philippine Trough

New data on bottom sediments and igneous rocks of the Philippine Trench are under consideration. They show differences in geological structures of the island slope and the ocean slope of the trench. The island slope is comparable to the accretionary prism formations on the Philippines; there processes of gravitational re-deposition of sediments occur. The ocean slope is an edge of the Philippine Plate sinking into the trough, where basalts of the oceanic crust are exposed.

Geochemical composition of bentonite layers and U-Pb ages of detrital zircons from the Paleogene Basilika Formation (Svalbard) and Mount Lawson Formation (Ellesmere Island)

Major and trace element composition as well as Sm-Nd isotopes of whole-rock samples and clay fractions (<2 µm) of bentonite layers and U-Pb ages of detrital zircons from the Paleogene Basilika Formation (Svalbard) and Mount Lawson Formation (Ellesmere Island).