scholarly journals Distribution and Source Determination of Rare Earth Elements in Sediment Collected From The Continental Shelf Off Hainan Island, China

2021 ◽  
Author(s):  
Pengjie Cai ◽  
Guanqiang Cai ◽  
Xuejie Li ◽  
Xin Chen ◽  
Jie Lin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Continental Shelf ◽  
Hainan Island ◽  
Major Elements ◽  
The South ◽  
Factors Affecting ◽  
The North ◽  
Source Determination ◽  
The Pearl River

Abstract Contents of rare earth elements (REEs), major elements and the Total Organic Carbon (TOC) were determined for 152 surface sediment samples collected from the continental shelf off Hainan Island (CSHI). From high to low, the average contents of REEs were: Ce > La > Nd > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Tm. The concentrations of REEs in the north of the study area were higher than in the south. The LREE concentrations in the south were higher than in the north. This resulted higher values for the LREE/HREE ratio in the south than in the north. The mean EF could be arranged from highest to lowest as follows: Tm > Sm > Pr > Er > La > Lu > Ce > Tb > Eu > Nd > Yb > Gd > Ho > Dy. The enrichment factor (EF) indicates that pollution as a result of human activity was more serious in the southeast of the study area than in the north. The factors affecting the REE concentrations in this area include naturally occurring minerals and industrial pollution. Based on the spatial variation of upper continental crust (UCC)-normalized REE concentrations, the CSHI was classified into three geochemical provinces. The sediment of province I was controlled by the Red and Pearl rivers. The composition of the province II is mainly controlled by the Red River and the Pearl River, although some sediments have originated from the South China Sea Island. Province III sediments mainly originated from sources on Hainan Island.

scholarly journals HIGH PERCENTAGE OF RARE EARTH ELEMENT CONNECTION WITH THE ACCUMULATION SEDIMENT AS RESPONSE LONGSHORE CURRENTS IN THE BELITUNG WATERS

2016 ◽  
Vol 30 (2) ◽  
pp. 75
Author(s):  
Delyuzar Ilahude ◽  
Maman Surachman
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Wave Energy ◽  
Coastal Area ◽  
Sediment Accumulation ◽  
The South ◽  
The West ◽  
The North ◽  
Longshore Currents ◽  
Prediction Curve

The study area is geographically located in the West coast of Belitung island at coordinates 105o48'00" - 106o06' 00" E and 06o46'00" - 06o50' 00" S. The beach and coastal area is influenced by wave energy from the West and North directions The purpose of this study is to analyze the relationship between the zone of sediment accumulation of empirical approaches on oceanography parameter containing rare earth elements. The approach used is to predict the shore wave energy using wave prediction curve deep waters to obtain the energy flux of the wave at each point of reference. Sediments containing rare earth elements tend to lead to the south as a result of the movement of longshore currents. Regional coastal area of the western part of the island of Belitung, especially in the southern part of the estuary of the river Tanjung Pandan is estimated to be a zone of sediment accumulation. The movement of sediment caused by wave energy from the north led to sedimentation evolved significantly in the south which is thought to contain rare earths minerals derived from land. This sedimentation process takes place on a seasonal basis, which allegedly took place in the west. The movement of sediment to the south of the mouth of the Cerucuk River it is predicted that rare earth elements were supplied from these rivers tend to settle in the southern part of the estuary Cerucuk throughout the year.Keywords: accumulation of sediment, longshore currents, rare earth elements offshore Belitung Lokasi daerah penelitian secara geografis terletak di pesisir pantai barat Pulau Belitung pada koordinat 105o48'00" - 106o06'00" BT dan 06o46'00" - 06o50'00"LS. Pesisir pantai termasuk pantai terbuka terhadap pengaruh energi gelombang dari arah barat dan utara. Tujuan dari penelitian ini untuk melakukan analisis hubungan antara zona akumulasi sedimen dari pendekatan empirik parameter osenografi dan kandungan unsur tanah jarang. Pendekatan yang digunakan yaitu dengan memprediksi energi gelombang pantai menggunakan kurva prediksi gelombang perairan dalam untuk memperoleh energi fluks gelombang pada setiap titik referensi. Pengendapan sedimen bermuatan unsur tanah jarang cenderung mengarah ke selatan sebagai akibat dari pergerakan arus sejajar pantai. Daerah kawasan pesisir bagian barat Pulau Belitung terutama di bagian selatan muara sungai Tanjung Pandan diperkirakan menjadi zona akumulasi sedimen. Pergerakan sedimen akibat dari energi gelombang dari arah utara menyebabkan adanya sedimentasi berkembang cukup signifikan di bagian selatan yang diduga bermuatan mineral unsur tanah jarang asal dari darat. Proses sedimentasi ini berlangsung secara musiman, yang kemungkinan berlangsung pada musim barat. Adanya pergerakan sedimen ke arah selatan dari muara Sungai Cerucuk maka diperkirakan unsur tanah jarang yang dipasok dari sungai tersebut cenderung mengendap di bagian selatan dari muara Sungai Cerucuk sepanjang tahun. Kata kunci: akumulasi sedimen, arus sejajar pantai, unsur tanah jarang lepas pantai Belitung

scholarly journals Geochemistry of Surface Sediments From the Emperor Seamount Chain, North Pacific

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Chen ◽  
Jianjun Zou ◽  
Aimei Zhu ◽  
Xuefa Shi ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Depth ◽  
Surface Sediment ◽  
North Pacific ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific ◽  
Emperor Seamount Chain

Investigating the composition and distribution of pelagic marine sediments is fundamental in the field of marine sedimentology. The spatial distributions of surface sediment are unclear due to limited investigation along the Emperor Seamount Chain of the North Pacific. In this study, a suite of sedimentological and geochemical proxies were analyzed, including the sediment grain size, organic carbon, CaCO3, major and rare earth elements of 50 surface sediment samples from the Emperor Seamount Chain, spanning from ∼33°N to ∼52°N. On the basis of sedimentary components, we divide them into three Zones (I, II, and III) spatially with distinct features. Sediments in Zone I (∼33°N–44°N) and Zone III (49.8°N–53°N) are dominated by clayey silt, and mainly consist of sand and silty sand in Zone II. The mean grain size of the sortable silt shows that the hydrodynamic condition in the study area is significantly stronger than that of the abyssal plain, especially at the water depth of 1,000–2,500 m. The CaCO3 contents in sediments above 4,000 m range from 20 to 84% but decrease sharply to less than 1.5% below 4,000 m, confirming that the water depth of 4,000 m is the carbonate compensation depth of the study area. Strong positive correlations between Al2O3 and Fe2O3, TiO2, MgO, and K2O (R > 0.9) in the bulk sediments indicate pronounced contributions of terrigenous materials from surrounding continent mass to the study area. Furthermore, the eolian dust makes contributions to the composition of bulk sediments as confirmed by rare earth elements. There is no significant correlation between grain size and major and minor elements, which indicates that the sedimentary grain size does not exert important effects on terrigenous components. There is significant negative δCe and positive δEu anomalies at all stations. The negative Ce anomaly mainly exists in carbonate-rich sediments, inheriting the signal of seawater. The positive Eu anomaly indicates widespread volcanism contributions to the study area from active volcanic islands arcs around the North Pacific. The relative contributions of terrestrial, volcanic, and biogenic materials vary with latitude and water depth in the study area.

scholarly journals Vulcânicas potássicas intemperizadas como protólitos dos filitos hematíticos da Serra do Espinhaço Meridional (Minas Gerais)

2020 ◽  
Vol 34 (2) ◽  
pp. 183-194
Author(s):  
Alexandre Chaves ◽  
Luiz Knauer
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Volcanic Rocks ◽  
Alkaline Rock ◽  
Major Elements ◽  
Volcanic Origin ◽  
Espinhaço Range ◽  
Weathering Processes ◽  
Igneous Layering ◽  
Hematitic Phyllite

The hematitic phyllite is a rock that occurs in the São João da Chapada and Sopa-Brumadinho formations of the southern Espinhaço range. Its origin is widely discussed in papers on Espinhaço, but there is no consensus on its protolith due to certain characteristics of the lithotype, such as its chemical composition and textural features. The pattern of rare earth elements strongly enriched [(La/Yb)N 6.80-17.68], with light rare earth elements [(La/Sm)N 2.54-4.83] richer than heavy ones [(Gd/Yb)N 1.28-3,32], suggests that the protolith was an alkaline volcanic rock formed during the rift that generated the Espinhaço basin. The major elements indicate that the alkaline rock met weathering processes, becoming a regolith. During the Brasiliano metamorphism, it finally became hematitic phyllite. Other characteristics of the lithotype, such as the presence of sericite-bearing rounded parts (possibly formed by alteration and deformation of leucite crystals) and the preservation of igneous layering, suggest a potassic volcanic origin for hematitic phyllite. In diagram that allows identifying altered and metamorphic volcanic rocks, the investigated samples have composition similar to a feldspathoid-rich alkali-basalt, probably a leucite tephrite, a leucitite or even a lamproite, rocks from mantle source.

Understanding Societies in War

2018 ◽  
Author(s):  
Paul D. Escott
Keyword(s):  
Ethnic Groups ◽  
Irregular Warfare ◽  
The South ◽  
Factors Affecting ◽  
The North ◽  
Role Of Women ◽  
Democratic Parties ◽  
The Impact

This chapter emphasizes the analysis of the wartime forces in both sections that affected unity or division. It raises questions about the roots of the large amount of internal violence or irregular warfare in the South. For the North, it probes the nature of nationalism and asks about that section’s social, political, and religious divisions. Factors affecting both the Republican and the Democratic Parties of the North deserve new attention, as do the role of women in both sections, ethnic groups in the North especially, and the impact of emancipation and racism.

Zircon U–Pb and molybdenite Re–Os dating and geological implications of the Shimadong porphyry molybdenum deposit in eastern Yanbian, northeastern China

2020 ◽  
Vol 57 (5) ◽  
pp. 630-646
Author(s):  
Xi-Tao Nie ◽  
Jing-Gui Sun ◽  
Feng-Yue Sun ◽  
Bi-Le Li ◽  
Ya-Jing Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Lower Crust ◽  
Active Continental Margin ◽  
Major And Trace Elements ◽  
Northeastern China ◽  
Heavy Rare Earth ◽  
The North ◽  
Heavy Rare Earth Elements ◽  
Porphyry Mo Deposit

The Shimadong porphyry Mo deposit is located in eastern Yanbian, in the eastern part of the north margin of the North China craton, northeastern China. Here, we present the whole-rock major and trace elements, zircon U–Pb and Hf isotope data, and molybdenite Re–Os data for the Shimadong deposit. The porphyry was emplaced at 163.7 ± 0.9 Ma and the mineralization at 163.1 ± 0.9 Ma, suggesting that the mineralization was associated with the emplacement of the Shimadong porphyritic monzogranite. The porphyritic monzogranite had high SiO2 (70.09–70.55 wt%) and K2O + Na2O (7.98–8.27 wt%) contents and low MgO (0.51–0.53 wt%), TFeO (2.4–2.47 wt%), CaO (2.19–2.26 wt%), and K2O/Na2O (0.8–0.82) contents. The porphyry was rich in large ion lithophile elements Rb, Ba, K, and Sr, depleted in high-field-strength elements Y, Nb, Ta, P, and Ti, without significant Eu anomaly (δEu = 0.86–1.00), and depleted in heavy rare earth elements with light rare earth elements/heavy rare earth elements = 18.25–20.72 and (La/Yb)N = 27.10–34.67. These features are similar to those of adakitic rocks derived from a thickened lower crust. Zircon εHf(t) values for the porphyritic monzogranite ranged from –19.2 to 6.3, and the two-stage Hf model ages (TDM2) were 2421–811 Ma. These data indicate that the primary magma of the Shimadong porphyritic monzogranite was mainly derived from partial melting of the thickened lower crust consisting of juvenile crust and pre-existing crust. Combined with the results of previous studies, our data suggest that the Shimadong porphyry Mo deposit was emplaced along an active continental margin related to the westward subduction of the paleo-Pacific Plate.

Deformation-driven emplacement-differentiation in the Closepet pluton, Dharwar Craton, South India: an alternate view

2019 ◽  
Vol 489 (1) ◽  
pp. 261-274 ◽  
Author(s):  
Abhijit Bhattacharya
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
South India ◽  
Major Element ◽  
Volume Fraction ◽  
Dharwar Craton ◽  
The North ◽  
Magmatic Fabric ◽  
Melt Composition ◽  
Crystal Content

AbstractIn the Late Archean north-trending Closepet pluton, trains of euhedral K-feldspar phenocrysts and matrix-supported idiomorphic K-feldspar crystals in the central part of the pluton define oblique-to-pluton margin steep-dipping east/ENE-trending magmatic fabrics. The magmatic fabric is defined by phenocryst-rich and phenocryst-poor layers, with the euhedral porphyries continuous across the layers. The fabrics are near-orthogonal to the gently-dipping gneissic layers in the host gneisses. The fabrics curve adjacent to locally-developed north/NNE-trending melt-hosted dislocations parallel to the axial planes of horizontal/gently-plunging north-trending upright folds in the host gneisses. In the pluton interior, both fabrics in the intrusives formed at supra-solidus conditions, although the volume fraction of melts diminished drastically due to cooling/melt expulsion. At the pluton margin, the north-trending fabric is penetrative and post-dates magma solidification. Within the pluton, the major element oxides, rare earth elements, anorthite contents in plagioclase, and (Mg/Fe + Mg) ratios in biotite decrease with increasing SiO2 from phenocryst-rich (up to 75% by volume) granodiorite to phenocryst-poor (<15 vol%) granite that broadly correspond to minimum melt composition. The chemical-mineralogical variations in the pluton is attributed to deformation-driven ascent of magma with heterogeneous crystal content, ascending at variable velocities (highest in crystal-poor magma) along oblique-to-pluton margin east/ENE-trending extensional fractures induced by dextral shearing.

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