Rare Earth element patterns of the Central Indian Basin sediments related to their lithology (original) (raw)
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Geochemistry of Rare Earth Elements in Sediment of Central India
Journal of Environmental Protection, 2016
The rare earth elements (REE) are of great interests due to wide industrial applications. In the present work, geochemistry of REE in the contaminated pond sediment of Ambagarh Chowki, central India is described. The concentration (n = 24) of La,
Chinese Journal of Geochemistry, 2015
Siliciclastic sedimentary rocks, including sandstones and associated shales, from the Permo-Carboniferous Kanawar Group of NW Tethys Himalaya, Spiti Region, India were examined geochemically to monitor the evolutionary changes in the upper continental crust in the Himalaya. The rocks are characterized by consistent rare earth element (REE) patterns with light REE enrichment (La N /Yb N = 5.3-28.2) and flat heavy REE patterns. The P REE values are high (up to 281 ppm) with large negative Eu anomalies (avg. Eu/Eu* = 0.57). The REE characteristics of the sediments are similar to those of post-Archean Australian shales and North American shale composite. La/Th values (avg. 2.34) correspond to a relatively felsic composition of the terrestrial igneous rocks standard (La/Th of G-1 = 2.3). The evolved felsic composition of the sediments probably relates to widespread acidic activity in the source. The REE patterns and Th/U values seem to have been affected by the sedimentary environment as well as by the provenance. The presence of positive Ce anomalies in some sediments may be the result of post-depositional processes. Moreover, the Permo-Carboniferous sediments indicate that hydraulic sorting, even over short transport distances, is capable of concentrating enough accessory phases to influence REE composition and to develop negative Eu anomalies. High P REE, La/ Yb, and Th/U contents and large negative Eu anomalies reveal that the sediments were deposited in an oxidizing environment, suggesting the surficial environment became oxidizing around the Carboniferous-Permian boundary in the Indian craton.
GEOCHEMICAL JOURNAL, 2003
We have studied the REE distribution in shallow marine continental platform carbonates belonging to two late Neoproterozoic basins of India. Their REE abundance patterns normalized by chondrite display well defined W-type tetrad effect. Based on chondrite-normalized Gd/Ho, La/Nd ratios, the REE abundance patterns have been classified into three groups. (Y/Ho) and (Y/Dy) concentration ratios reflect a combined effect of Y fractionation relative to neighboring trivalent REEs during carbonate precipitation from seawater and influence of continental contributions with chondritic ratios. Negative Ce anomalies recorded in Krol and Bilara carbonates resembles the Ce anomaly reported from shallow marine waters. However, absence of Ce anomaly and distinct positive anomalies in some of our carbonate samples reflect post-depositional redox condition related to Ce mobilization and preferential enrichment during early diagenesis. Variations in the REE abundance patterns may be attributed to contamination with terrigenous particulates having shale like REE abundances and post-depositional early diagenetic processes. marine realm owing to differences in intrinsic quantum chemical properties (Racah parameters) of the REE complexes in the solution (Masuda and Ikeuchi, 1979; Masuda et al., 1987; Kawabe et al., 1998; Ohta and Kawabe, 2000). The tetrad effects are observed as concave curves consisting of LaCe -Pr-Nd, Pm-Sm-Eu-Gd, Gd-Tb-Dy-Ho and Er-Tm-Yb-Lu in chondrite-normalized REE abundance patterns. Tetrad effect has been documented from marine chemical sediments like limestone/ dolomite (Kawabe et al., 1991; Kawabe et al., 1998; Tanaka et al., 2002) and chert (Minami et al., 1998). On the other hand Minami and Masuda (1997) and Minami et al. (1998) suggested quadratic equations for each tetrad curve which enable quantification of the degree of lanthanide tetrad effect. REEs in marine carbonate rocks have been
Marine Geology, 1993
. Rare earth element distribution and behaviour in buried manganese nodules from the Central Indian Basin. Mar. Geol., 112: 303-312. Eight buried manganese nodules taken in the upper metre of a siliceous ooze sediment core in the Central Indian Basin at 14°S and 74°E were analysed for major, trace and rare earth (REE) elements. Interelemental correlation yields a strong positive association (r > 0.75) between Fe, P, Ti and REE suggesting a single carrier phase for REE in these nodules namely a titaniumrich ferriphosphate. This correlation significantly improved (r> +0.90) when the influence of detrital Fe is eliminated and only authigenic Fe is considered. The buried nodules appear to retain the mineralogical and geochemical characteristics (including positive Ce anomaly) acquired during the accretion at the sediment-water interface prior to their burial at ~225 kyr B.P. The effect of burial is observed only in the depletion of heavy REE (HREE) in a nodule buried at 23.5 cm depth where the environment is suboxic to anoxic. Middle REE (MREE) in the nodules exhibit enrichment over light REE (LREE) and HREE while LREE exhibit enrichment over HREE compared to the ratios in shale (NASC). This enrichment pattern suggests an uptake sequence of the REE as MREE > LREE> HREE in the manganese nodules.
Distribution of rare earth elements in the Yamuna and the Chambal rivers, India
GEOCHEMICAL JOURNAL, 2004
We report here the first measurements of dissolved rare earth elements (REE) in the headwaters of the Yamuna river draining through the southern slopes of Himalaya. Due to intense weathering of the surface rocks of different lithologies and influence of tributaries, Yamuna river waters have variable dissolved REE contents (87 < ÂREE < 1374 ng L -1 , mean = 288.6 ng L -1 ) and exhibit negative Eu anomaly (0.49 < Eu/Eu* < 0.73, mean = 0.63). While most of the samples do not show discernable Ce anomalies; a negative Ce anomaly, however, found in a few of them, which can be explained by the colloidal pool preferentially enriched in Ce. A comparison among the river waters and bed sediments suggests that dissolved composition of REE is strongly fractionated and is enriched in MREE (Nd-Gd) with respect to sediments; presumably due to preferential dissolution of phosphate minerals such as apatite during weathering processes.
Journal of Asian Earth Sciences, 2017
The Paleoproterozoic era is marked by significant changes in the level of oxygen in the atmosphere and chemistry of the ocean, and the presence of world-wide glaciation. Geochemistry of chemogenic sediments provide clues to these changes. The Sausar Group (2478-2250 Ma) of Central India is one of the few places in the world where Paleoproterozoic glacial unit overlained by a cap carbonate horizon has been identified. Major, trace and rare earth element (REE) contents of Paleoproterozoic cap carbonates of the Sausar Group, have been analysed for their implications for ocean redox conditions during interglacial periods of the Huronian glaciation. The La/La*, Gd/Gd*, Lusn/Lasn and Y/Ho ratios of the cap carbonate reflect their pristine marine nature. Conspicuous Ce anomaly (Ce/Ce* up to 1.75), accompanied by the enrichment of Fe, Mn, Zn and U, provides insight into the redox state of the ocean at the time of deposition of the cap carbonate succession. Based on these observations, we infer anoxic depositional conditions in the basin during the interglacial period of the Paleoproterozoic glaciation before the Great Oxidation Event (GOE), and the level of oxygen in the atmosphere fluctuating between 10-5 and 10-2 of the present atmospheric level (PAL).
Quaternary International, 2009
The Yarlung Tsangbo (YT) is the Tibetan portion of the Brahmaputra River. It transports a large amount of sediment annually to the Indo-Gangetic Plain and thus contributes significantly to the Quaternary evolution of the Plain. Eighteen surface sediment samples were collected from the YT, and the compositions of rare earth elements (REEs) were analyzed for the bulk sediments, <63 mm and <20 mm fractions. Results show that the YT sediments originated mainly from the Lhasa Terrane. The REE compositions in the YT sediments are similar along the river, with the light and middle REEs enriched relative to the upper continental crust, but the REE concentrations are higher than its lower reaches -the Brahmaputra River. The average grain size of the sediments is in the coarse range (123.8 mm). Grain size influences the REE concentrations of the YT sediment significantly. The <63 mm fraction of the sediment has higher REE concentrations and different REE patterns when compared with those in the bulk sample and <20 mm fraction, due to the presence of REE-enriched heavy minerals of zircon, monazite and allanite in this fraction. The relatively low REE concentrations in acid-leachable fractions of the sediments suggest most REEs in the sediments occur in the stable minerals due to the dominance of physical weathering in this region.
Downcore variation of rare earth elements (REEs) in the authigenic Fe-Mn oxides of a sediment core (covering a record of last ∼ 40 kyr) from the Andaman Sea, a part of the Indian Ocean shows distinctive positive Ce and Eu anomalies. These positive Ce anomalies (Ce* = 1.1 ∼ 1.8) are ascribed to be due to oxidation of deep sea sediments. The large positive Eu anomalies (i.e., Eu* >1.8 to 3.2) occur within a time span near the glacial/interglacial transition (∼ 7000-14,000 yr BP) which could be due to the past hydrothermal activity or to the effects arising from sea level changes. During glacial times, the Andaman Sea was almost completely isolated due to low sea level, leading to a reduction in sediment supply from the Ayeyarwady River. The variations of metal abundances (i.e., Ca, Al, Mn, and Fe) in the authigenic fraction provided independent information to evaluate the water column physicochemical changes during the glacial/interglacial transition period. The studied sediment core records changes in riverine inputs and reflects depositional changes related to sea level fluctuations and climatic events over the past 40 kyr in the Andaman Sea.
GEOCHEMICAL JOURNAL, 2000
Rare earth elements (REEs) are considered as useful tracers of various surface geological processes in the river system. REEs and heavy metals (V, Pb, Cr, Co, Ag, Zn, Cd, Ni) were analyzed from the suspended sediments of Ganges and surficial sediments of Yamuna, Brahmaputra, Jamuna, Padma and Meghna, using VG Thermal Ionization Mass Spectrometer. Physical weathering process seems to be a major controlling factor for the distribution of REE and trace metals in the sediments of the Himalayan rivers. Weathering of the surface crustal area in the drainage basin shows significant variations due to changes in lithology and influence of tributaries. The distribution of REE shows an almost uniform pattern due to factors such as river transportation processes and high level of terrigenous mixing in the bed sediments. The results show that finer grain size and high content of clay mineral (illite) in these sediments are possible traps for the accumulation of metals. Anthropogenic activities seem to have very little influence in controlling the elemental distribution in the Himalayan rivers.