scholarly journals Evolução do Manto de Intemperismo Laterítico Rico em Fosfatos na Ilha de Itacupim (PA) - Mineralogia, Micromorfologia e Geoquímica

2006 ◽  
Vol 33 (2) ◽  
pp. 109 ◽  
Author(s):  
MARIA CRISTINA MOTTA DE TOLEDO ◽  
SONIA BARROS DE OLIVEIRA ◽  
MARCONDES LIMA DA COSTA ◽  
CAMILA PASSOS ◽  
HENRIQUE DINIZ DE ALMEIDA
Keyword(s):  
Chemical Composition ◽  
Parent Rock ◽  
Ultramafic Rocks ◽  
Altered Rock ◽  
Island State ◽  
Northern Brazil ◽  
Bottom To Top

The lateritic mantle overlying ultramafic rocks at Itacupim Island (state of Pará, northern Brazil) comprises 5 horizons. From bottom to top they are: (1) altered rock (hornblende, phlogopite, apatite, magnetite, fissural wavellite, and smaller amounts of smectite or kaolinite), (2) a smectitic saprolite (smectite, wavellite, goethite, and traces of hornblende), a kaolinitic saprolite (kaolinite, wavellite, goethite, and traces of phlogopite), a phosphatic duricrust (crandallite, goethite and hematite), and a ferruginous duricrust (hematite, goethite and crandallite). The mineralogical and chemical composition of the saprolitic and duricrust horizons indicate a discontinuity in the weathering evolution: the P-rich crandallitic duricrusts cannot be derived from the P-poor wavellitic saprolites. Most probably, the duricrusts developed during an earlier stage of the weathering evolution, under a drier climate, when the hypogene phosphates (wavellite and apatite) transformed into crandallite. Under subsequent more humid conditions, the weathering alteration of the parent rock led to the dissolution of the hypogene phosphates, resulting in the P-depleted saprolites.

scholarly journals Tectonic control on the stratigraphic framework of Late Pleistocene and Holocene deposits in Marajó Island, State of Pará, eastern Amazonia

2010 ◽  
Vol 82 (2) ◽  
pp. 439-449 ◽  
Author(s):  
Dilce F. Rossetti
Keyword(s):  
Late Quaternary ◽  
Fault Reactivation ◽  
Passive Margin ◽  
Stratigraphic Correlation ◽  
Sedimentary Records ◽  
Stratigraphic Framework ◽  
Island State ◽  
Marajó Island ◽  
Northern Brazil

The traditional view that the Brazilian Amazonia is located in a tectonically stable area since the Cretaceous is changing in front of the increasing documentation of fault reactivations even during the Holocene. How the sedimentary record has responded to these events is an issue that remains to be approached with basis on field data. This work focuses on the stratigraphic correlation of late Quaternary deposits from eastern Marajó Island, with the goal of demonstrating the role of fault reactivation on the origin and preservation of these deposits. Despite the location in a stable platform of a continental passive margin, three studied stratigraphic units display significant vertical offsets that define two depocenters that are better explained through tectonic displacements. This interpretation is reinforced by several morphostructural features related to faults that occur between the studied drills. Without the influence of tectonics, sediment preservation in this characteristically low-lying terrain would have been negligible. The results of the present work motivate to look for other tectonically-influenced areas in Amazonia, which similarly might have acted as sites for sediment accommodation during the late Quaternary. These sedimentary records have great potential to be the source of valuable information for reconstructing Quaternary geological events in Northern Brazil.

scholarly journals PESTRÉ SEDIMENTY OTTNANGU V BRNĚ-KOHOUTOVICÍCH

2018 ◽  
Vol 25 (1-2) ◽  
Author(s):  
Pavla Tomanová Petrová ◽  
David Buriánek ◽  
Karel Kirchner ◽  
Oldřich Krejčí ◽  
František Laufek ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Clay Minerals ◽  
Heavy Fraction ◽  
Parent Rock ◽  
Fine Grained ◽  
Sediment Layers

The reddish coloured sediment layers (up to 5 m thick) were found within building pit in the Brno-Kohoutovice on the Libušina třída Avenue (NW part of Brno). These sediments were assigned to the Ottnangian based on characteristic pseudoassociation of microfossils. Smectite or illite/smectite dominates over kaolinite among the clay minerals. Minerals typomorphic for granitoids of the Brno Massif, i.e. epidote, amphibole and altered titanite, absolutely dominate (99 mod. %) within the assemblage of translucent heavy fraction. Minerals like garnet and staurolite which are typical for the Ottnangian sediments in this region, are presented only in accessoric amount. The chemical composition of the studied sediments is located between the chemical composition of granodiorites of the Brno Massif and Neogene clays. Relatively high content of Zr, Hf and HREE, which is interpreted as result of presence of very fine grained zircon in studied sediments, is characteristic. High content of SiO2 and comparatively low contents of Al2O3 and Fe2O3 indicates non-lateritic type of weathering. The chemical composition of studied sediments reflects semiarid to humid paleoclimate that the granitoids of the Brno Massif as parent rock have undergone.

scholarly journals First report of Anisakis sp. (Nematoda: Anisakidae) parasitizing Muscovy duck in Marajó Island, state of Pará, Brazil

2020 ◽  
Vol 29 (2) ◽  
Author(s):  
Elaine Lopes de Carvalho ◽  
Ricardo Luis Sousa Santana ◽  
Evonnildo Costa Gonçalves ◽  
Raul Henrique da Silva Pinheiro ◽  
Elane Guerreiro Giese
Keyword(s):  
Climatic Conditions ◽  
Human Consumption ◽  
Esophageal Mucosa ◽  
Muscovy Duck ◽  
Cairina Moschata ◽  
Island State ◽  
Third Stage ◽  
Marajó Island ◽  
Northern Brazil ◽  
Muscovy Ducks

Abstract Among the avian used for human consumption, the Muscovy duck is well adapted to various climatic conditions and its breeding is widespread due to its easy handling, and its meat is widely consumed and appreciated, especially in the cuisine of northern Brazil. The present study aimed to report and identify taxonomically the nematodes found in the esophagus of Muscovy ducks reared and marketed in the municipality of Soure, Marajó Island, state of Pará, Brazil, and discuss its zoonotic potential to human. The samples consisted of 30 specimens of Cairina moschata domestica analyzed. A total of 258 nematodes were recovered, which were strongly fixed in the esophageal mucosa of hosts. The morphological and morphometric characteristics were compatible with Anisakis third-stage larvae.

Al-rich warwickite from lnglefield Land, North-West Greenland

1997 ◽  
Vol 61 (408) ◽  
pp. 693-698
Author(s):  
Peter W. Uitterdijk Appel
Keyword(s):  
New York ◽  
Chemical Composition ◽  
Type Locality ◽  
Ultramafic Rocks ◽  
West Greenland ◽  
North West ◽  
Metamorphic Alteration

AbstractWarwickite constitutes about 5% of an outcrop of metamorphosed ultramafic rocks of Precambrian age in North-West Greenland. It occurs as slender grains, several millimetres long, and in anhedral grains up to 5 mm in size, together with forsterite, pleonaste, phlogopite, magnetite ± tourmaline. Post-metamorphic alteration of warwickite produced a network of boron-rich minerals and magnetite. The warwickite, containing up to 9.72% Al2O3, displays a significantly different chemical composition from warwickite elsewhere, such as that in recrystallized limestones from the type locality Warwick, New York, and in lamproitic and carbonatite-like rocks at Jumilla, Spain.

scholarly journals Petrographic and geochemical characteristics of the Nui Chua pegmatoid mafic-ultramafic series, Northern Vietnam: Significance in petrogenesis and Fe-Ti-V metallogenesis

2020 ◽  
Vol 43 (1) ◽  
pp. 80-94
Author(s):  
Pham Thi Dung ◽  
Tran Tuan Anh ◽  
Tran Quoc Hung ◽  
Tran Trong Hoa ◽  
R. A. Shelepaev ◽  
...  
Keyword(s):  
Rare Earth ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
Fractional Crystallization ◽  
Geochemical Characteristics ◽  
Ultramafic Rocks ◽  
Magma Source ◽  
Distribution Characteristics ◽  
Magmatic Origin ◽  
Northern Vietnam

The pegmatoid intrusions of the Nui Chua complex are one of the important mafic-ultramafic intrusive series associated with Fe-Ti-V ores in northern Vietnam. These intrusions consist of plagiowebsterite, clinopyroxenite, melanogabbronorite, mesogabbro, gabbronorite, and leucogabbronorite. The Fe-Ti oxide ores being massive or disseminated appear layered or veined in pegmatoid rocks. The geochemical characteristics of pegmatoid rocks are rich in Fe, Ti, V and poor Mg; their HREE are higher than LREE, with [La/Yb]N of 0.49 to 0.91 (average: 0.67), showing negative anomalies at Nb, Ta, Th, U, Sr, Zr and positive anomalies at Cs, Ti, and K. The chemical composition and distribution characteristics of trace and rare earth elements of mafic and ultramafic rocks show that they share the same magma source. Having the same geochemical tendency of intrusive formations, Fe-Ti oxide ores are magmatic origin associated with intrusive pegmatoid rocks. The pegmatoid rocks of the Nui Chua complex and Fe-Ti oxide ores are formed as a product of the fractional crystallization of Fe-Ti-rich residual melts after crystallization of the layered rocks.

New occurrence and characterization of Ni-serpentines in the Kwangcheon area, Korea

Clay Minerals ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 211-224 ◽  
Author(s):  
Y. Song ◽  
H-S. Moon ◽  
H-T. Chon
Keyword(s):  
Large Degree ◽  
Phase Relations ◽  
Parent Rock ◽  
Ultramafic Rocks ◽  
Isomorphous Substitution ◽  
Concentrated Solutions ◽  
Ni Content ◽  
Fe Content ◽  
The Difference

AbstractPecoraite and nepouite, Ni-serpentines, occur in the serpentinized ultramafic rocks in the Kwangcheon area, Korea, where the parent rock is classified as harzburgite and/or lherzolite. Pecoraite was precipitated twice from the solution; the early-formed pecoraite coexists with magnetite, millerite, and polydymite both in the Buk- and Nam-sites, while the late-formed pecoraite appears as well-grown colloform and opaque-free phase only in the Buk-site. The typical colloform texture of the late-formed pecoraite strongly indicates that it was precipitated from the solution in supergene conditions. Pecoraite is characterized by its extremely high Ni content and the difference in Fe content between the early- and late-formed pecoraite. Nepouite is distinguished from pecoraite by its prismatic morphology and the large degree of isomorphous substitution between Ni and Mg. The phase relations among coexisting magnetite-millerite-polydymite assemblage with the early-formed pecoraite suggest that the pecoraite might have precipitated in the extremely limited fO2 and fs2 environment from the highly Ni-concentrated solutions and is stable at 25°C and 1 bar.

The geochemistry of soils on a catena on sedimentary rock at Nam Phong, north-east Thailand

Soil Research ◽  
2006 ◽  
Vol 44 (2) ◽  
pp. 143 ◽  
Author(s):  
Suphicha Thanachit ◽  
Anchalee Suddhiprakarn ◽  
Irb Kheoruenromne ◽  
Robert J. Gilkes
Keyword(s):  
Factor Analysis ◽  
Chemical Composition ◽  
Elemental Composition ◽  
Clay Fraction ◽  
Fine Sand ◽  
Parent Rock ◽  
Chemical Compositions ◽  
Large Dataset ◽  
North East ◽  
Affinity Group

The elemental composition of size fractions of soils on the Nam Phong catena, north-east Thailand, has been determined. The catena can be divided into 6 geomorphic positions: summit, shoulder, upper midslope, lower midslope, footslope and toeslope positions where soils have developed on sedimentary rocks under a tropical savannah climate. Factor analysis was used to interpret the large dataset and to determine profile and spatial trends in geochemistry. Silica is the major component of the soils on this catena, reflecting the presence of much quartz in the silt and sand fractions in soils at all landscape positions. Smaller amount of Al and Fe are also present; these elements are associated with the presence of kaolin and iron oxides. Factor analysis shows systematic differences in chemical composition between soils on higher positions and the soil on the lowest position in the landscape. Small variations in the chemical compositions of the whole soil, fine sand and silt between upslope soils are recognised. Soils on the summit, shoulder, midslope, and footslope exhibit little within-profile variation in chemical composition and the compositions of the profiles overlap closely. The Al affinity group (Al, Co, Ca, Mg, K, Sr, Cs, Rb, Ga, Zn, Ni, Li, Mn, Ti) increases in abundance in the toeslope soil, which is clearly different in chemical composition from the soils on higher positions. For the clay fraction, the differences in concentration of both the Si group (Si, Ni, Mn, Co, Mg, K, Ba, Pb) and Ca group (Ca, Zn, Cu, Sr, Cr, P) result in soils on toeslope and footslope positions being distinctly different from upslope soils, which have similar compositions. Soils at all positions show moderate variation in chemical composition of the clay with depth. The small variations in the chemical compositions of upslope soils on the Nam Phong catena are due to different degrees of weathering of the same parent rock, whereas soil on the toeslope position has a quite different elemental composition, possibly due to a different parent rock and the authigenesis of minerals in this landscape position where leached ions accumulate.

Variations in chemical composition of volcanic ultramafic rocks

1982 ◽  
Vol 24 (10) ◽  
pp. 1133-1147
Author(s):  
L. N. Dudenko ◽  
B. A. Markovskiy
Keyword(s):  
Chemical Composition ◽  
Ultramafic Rocks

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

On the Inhomogeneity of Chemical Composition over the Surface of 21 Per

1976 ◽  
Vol 32 ◽  
pp. 343-349
Author(s):  
Yu.V. Glagolevsky ◽  
K.I. Kozlova ◽  
V.S. Lebedev ◽  
N.S. Polosukhina
Keyword(s):  
Chemical Composition ◽  
Spectral Line ◽  
Variable Star ◽  
Radial Velocities ◽  
Crimean Astrophysical Observatory ◽  
Line Intensities ◽  
Magnetic Variable

SummaryThe magnetic variable star 21 Per has been studied from 4 and 8 Å/mm spectra obtained with the 2.6 - meter reflector of the Crimean Astrophysical Observatory. Spectral line intensities (Wλ) and radial velocities (Vr) have been measured.

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