We report instrumental neutron activation analysis results for 15 elements (K, Fe, Sc, Cr, Co, Zn, As, Rb, Sb, Cs, Ba, Hf, Ta, Th, and U) in 16 geochemical reference samples, namely SDC-1, SCo-1, SGR-1, STM-1, RGM-1, BIR-1, MAG-1 and BHVO-1 from USGS (United States Geological Survey, Reston), Soil-5, Soil-7 and SL-1 from IAEA (International Atomic Energy Agency, Vienna), and GSS-1, GSS-4, GSS-7, GSR-2 and GSR-3 from IGGE Institute of Geophysical and Geochemical Prospecting, People's Republic of China), The results are compared with literature values. In general our results agree well with recommended or proposed values.
Three Canadian reference rocks, syenites SY-2 and SY-3, and gabbro MRG-1 have been analysed for Na, K, Sc, Cr, Fe, Co, Zn, As, Rb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta and Th, by instrumental neutron activation analysis. The results are reported and compared with usable values. In general the agreement is good.
The temporal and spatial distribution of the REEs was determined, by INAA, in sediment cores collected at Northern Iberian
shelf along the area between the Finisterra Cape and the mouth of Minho river, to contribute to the understanding of the origin
and sedimentation processes of sediments deposited at the Continental Shelf. The distribution pattern of the REEs were flat
and similar to the shales. A negative Eu anomaly was found for all the sections of the analyzed cores. Significant positive
correlations between the REE and Zr and Hf contents suggest that zircon is responsible for hosting both light and heavy REEs.
Authors:M. Gouveia, M. Prudencio, M. Freitas, E. Martinho and J. Cabral
A numerical procedure is given to correct for the interference of U in the determination of the light rare earths, Zr, and Ru. The corresponding interference factors were calculated and their values compared with experimental results. The agreement is favourable in most cases.
Authors:M. Gouveia, M. Prudencio, I. Morgado, M. Magalhaes and J. Cabral
Trace element data (Sc, Cr, Co, Hf, Ta and Th) are reported for a weathering profile of gabbroic rocks located near Serpa, Portugal. The results obtained for the whole rock samples showed that: (i) Co and Sc contents decrease upwards the profile. Co appears to be mobilized in the soil probably as soluble cation; (ii) Cr tends to remain in the profile; and (iii) Hf and Th concentrate in the upper horizons. Trace element distribution in different size fractions of the upper horizons revealed: (i) Sc, Cr and Co have a more uniform distribution than Hf, Ta and Th; (ii) Hf and Ta are concentrated in the intermediate fractions; and (iii) Th is concentrated in the finer fractions, probably due to incorporation in weathering resistant minerals, specially in the initial stages of weathering.
Authors:M. Gouveia, J. Seabra e Barros, M. Tavares and M. Freitas
Instrumental neutron activation, atomic absorption spectroscopy and conventional methods of analysis were used on eight different silicate rocks and two minerals. Trace elements and major constituents were determined. It was considered that the methods should be regarded as complementary analytical techniques.
Authors:M. Gouveia, M. Prudêncio, I. Morgado and J. Cabral
Two reference rocks of the Geological Survey of Japan have been analyzed for Na, K, Sc, Cr, Fe, Co, Zn, Rb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Th and U, using instrumental neutron activation analysis. The results are reported and compared with consensus values proposed in the literature. In general, the agreement is good except for Cs.
Authors:M. Gouveia, M. Prudêncio, J. Barros, L. Morgado and J. Cabral
Instrumental neutron activation analysis, atomic absorption spectrometry and conventional methods were used on five USGS Geochemical Exploration Reference Materials: GXR-1, 2, 3, 4 and 6. The concentrations of 35 elements are reported and compared with available literature values. In general the agreement is good.
Authors:C. Corredeira, M. Araújo, A. Gouveia and J.-M. Jouanneau
A geochemical study was carried out in sediment cores along the Galician Continental Shelf and at the mouth of the Vigo and
Pontevedra Rias. Multielemental analysis was performed by Instrumental Neutron Activation Analysis and Energy Dispersive X-ray
Fluorescence Spectrometry. Sedimentological and geochemical characterisation (lithogenic, biogenic and anthropogenic elements)
indicates different supplies for the fine-grained, deposited sediments. No significant heavy metal enrichment could be detected
in coastal sediments despite the current sediment contamination in adjacent Rias. Variations in the accumulation rates suggest
different factors controlling the sedimentation processes including sediment sources and geomorphology.
Authors:P. Álvarez-Iglesias, M. Araújo, A. Gouveia and T. Drago
Two sediment cores (~30 m long) were retrieved at the mouth of the Minho Estuary to assess its palaeoenvironmental evolution
for the last millennia. Samples were characterized by Energy-Dispersive X-Ray Fluorescence Spectrometry and Instrumental Neutron
Activation Analysis, complemented by sedimentological analyses. Provenance of major and trace element contents (lithogenic
or biogenic, continental or marine) is assessed. The influence of grain size effect on total element concentration is discussed.
Most of the samples present a negative Eu anomaly. Sedimentological and geochemical parameters allow differentiating four
geological units––fluvial, marine, estuarine and sand barrier––which reflects the temporal evolution of the Minho Estuary.