白云鄂博碳酸岩墙的稀土和微量元素地球化学及对其成因的启示

根据矿物组成白云鄂博矿区的碳酸岩岩墙可分为白云石型、白云石 -方解石共存型和方解石型三种类型。 REE和微量元素地球化学表明 ,这三类碳酸岩岩墙为碳酸岩浆演化不同阶段的产物 ,白云石型和白云石 -方解石共存型对应于早期岩浆阶段 ,其 (L a/ Nd) n、(L a/ Y) n 和 (L a/ Yb) n 比值随稀土总量的增加而增大 ;方解石型则对应于碳酸岩浆演化的晚期热液阶段 ,其稀土总量明显富集 ,但其 (L a/ Nd) n、(L a/ Y ) n 和 (L a/ Yb) n 比值随稀土总量的增加却有减小的趋势 。

Geochemistry of Trace and Rare Earth Elements in Red Soils from the Dongting Lake Area and Its Environmental Significance

Trace element(TE) and rare earth element(REE) contents in red soils from the Dongting Lake area of China were determined to understanding the provenance and weathering characteristics of the red soils.The results showed similar REE distribution patterns among red soils from the Dongting Lake area,Xiashu loess from Zhenjiang,loess and Pliocene red soil from the Loess Plateau.These patterns implied a similar provenance from dust-storms,except for red soil R5 which formed by bedrock weathering and had significant light REE(LREE) enrichment and heavy REE(HREE) depletion due to longer weathering periods and higher intensity of weathering.Trace element,especially the Rb/Sr and Li/Ba ratios,and REE,especially the LREE/HREE ratio and δEu could trace weathering intensity.Higher Rb/Sr,Li/Ba,and LREE/HREE ratios and negative Eu anomalies were present in the red soils from the Dongting Lake area.The weathering intensity was in the decreasing order of R5 in the Dongting Lake area > red soils from the Dongting Lake area(including reticulate red soil,weak reticulate red soil,and homogeneous red soil formed by dust storms) > Xiashu loess from Zhenjiang > loess-paleosol and Pliocene red soil from the Loess Plateau.Variations in the TE and REE contents of soil could be effectively used to study the provenance and the weathering intensity.

Synthesis and luminescent properties of ternary complexes of terbium with thenoyltrifluoroacetone and reactive ligand

Three new reactive ternary terbium complexes were synthesized with the first ligand of thenoyltri-(fluoroacetone) and the reactive secondary ligand such as maleic anhydride, undecenoic acid, oleic acid, and characterized by means of elemental analysis, ethylenediamine tetraacetic acid titrimetric method, Fourier transform infrared and ultraviolet spectroscopies. And the luminescent properties of the ternary terbium complexes were investigated. The results show that the ternary terbium complexes possess much higher luminescent intensity than the binary complex of terbium with thenoyltrifluoroacetone, and the synergy ability sequence of the three reactive ligands is as follows: undecenoic acid>oleic acid>maleic anhydride. Because the ternary terbium complexes contain reactive (ligands) that can be copolymerized with other monomers, a new way for the synthesis of the bonding-type rare earth polymer functional materials with excellent luminescent properties is provided.

Behavior of rare earth elements in granitic profiles, eastern Tibetan Plateau, China

Rare earth elements(REEs) can record geologic and geochemical processes. We studied two granitic regolith profiles from different climatic zones in eastern Tibetan Plateau and found that(1)∑ RREEs ranged from119.65 to 275.33 mg/kg in profile ND and5.11–474.55 mg/kg in profile GTC, with average values of205.79 and 161 mg/kg, respectively. ∑RREEs was higher in accumulation horizon and semi-regolith;(2) Influenced by climate, the fractionation of light and heavy REEs(LREEs and HREEs) varied during weathering. The ratio of LREEs/HREEs in pedosphere was higher than semi-regolith in tropical profile;(3) A negative Eu anomaly in both profiles was the result of bedrock weathering. A positive Ce anomaly was observed in all layers of profile ND, and only in the upper 100 cm of profile GTC. This indicates that redox conditions along the regolith profile varied considerably with climate.(4) Normalized by chondrite,LREEs accumulated much more than HREEs; REE distribution curves were right-leaning with a V-type Eu anomaly in both profiles.

Constraints of REE and trace elements of high-pressure-veins and host rocks in western Tianshan on origin of deep fluids in paleosubduction zones

The western Tianshan high-pressure(HP) metamorphic belt represents the paleosubduction mélange of paleozoic south Tianshan ocean between the Yili-central Tianshan and Tarim plates. High-pressure veins are extensively developed in this HP belt. Compared with normal mid-ocean ridge basalt(N-MORB), the high-pressure veins and host rocks are enriched in light rare earth elements(LREE) and incompatible elements. But high-pressure veins show a larger variation than host rocks in total REE abundance. On the trace element spidergram, all the samples are enriched in incompatible elements and show strong positive Pb anomaly relative to N-MORB. The array tendency lines of plots of the HP rocks have apparent slopes on diagram of m(Sr) vs m(Sr)/m(Zr), m(Li) vs m(Li)/m(Y) and (m(Ce)) vs m(Ce)/m(Pb), which indicates that the enrichment in LREE and incompatible elements relative to N-MORB of the HP-metamorphic rocks from western Tianshan is not attributed to magma evolution process of the protolith. High field strength elements, such as Nb, Ta, Ti, Zr and Hf, do not show negative anomaly relative to N-MORB, which is dissimilar to that of island arc basalts. Therefore, the enrichment in LREE and incompatible elements of the HP rocks is not attributed to the enrichment of the source of the protolith. The mass ratios of Rb to Ba, Ce to Pb, Nb to U and Ta to U of high-pressure veins and host rocks are intermediate of mid-ocean ridge basalt or oceanic island basalt and continental crust. The fluids in western Tianshan paleosubduction zones are mixtures of two sources, dehydration or devolatilization of host rocks and of subducted sediments.

Influence on lacustrine source rock by hydrothermal fluid： a case study of the Chang 7 oil shale, southern Ordos Basin

Hydrothermal fluid activity during sedimenta- tion of the Triassic Yanchang Formation in the Ordos Basin and the impact of said activity on formation and preservation conditions of source rocks have received little attention. Oil yield, major element, trace element, rare earth element, and total sulfur （TS） data from the oil shale within the Yanchang are here presented and discussed in the context of hydrothermal influence. Oil shale samples returned relatively high total organic carbon （TOC）, in the range of 4.69%-25.48%. A high correlation between TS and TOC suggests TS in the oil shale is dominated by organic sulfur and affected by organic matter. The low Al/ Si ratio of oil shale samples implies quartz is a major mineralogical component. Si/（Si ＋ Al ＋ Fe） values suggest close proximity of the oil shale to a terrigenous source. δEu; Fe versus Mn versus （Cu ＋ Co ＋ Ni）× 10; and SiO2/（K2O ＋ Na2O） versus MnO/TiO2, Fe/Ti, and （Fe ＋ Mn）/Ti are evidence of hydrothermal fluid activity during oil shale sedimentation, and δU and U/Th of the oil shale indicate reducing conditions. The Sr/Ba of oil shale samples suggests fresh-water deposition. The high correlations of Fe/Ti and （Fe ＋ Mn）/Ti with δU, U/Th, and TS demonstrate that hydrothermal fluid activity promotes reducing conditions. Sr/Ba ratios had low correlation with Fe/Ti and （Fe ＋ Mn）/Ti, implying that hydrothermal fluid activity had little impact （Fe ＋ Mn）/Ti, δU, U/Th, and on paleosalinity. Fe/Ti, Cu ＋ Pb ＋ Zn all exhibited high positive correlation coefficients with TOC in oil shale samples, suggesting that more intense hydrothermal fluid activity improves conditions in favor of formation and preservation of organic matter.

Chracteristics and formation setting of granodiorite in Zhalute County,Inner Mongolia

Based on field investigation and study of petrology, mineralogy, geochemistry and isotopic geochronology for the granodiorite, the authors discussed the formation setting of the granodiorite. The pluton is calci alkalic and peraluminous granite in which light rare earth elements (LREE) are intensively enriched, heavy rare earth elements are relatively poor, the ratio of LREE to heavy rare earth elements (HREE) is 7.12, and the fractionation of REE is good. The pluton formed in late orogenic setting which is relatively steady.

Synthesis and characterization of Nd doped M-type hexagonal barium ferrite ultrafine powders

The hexagonal BaNd x Fe12?x O19(x=0.1?1.0) fine powders with M-type structure were synthesized by sol-gel auto-combustion high-temperature synthesis method. The structure of powders, gels’ combustion and magnetic properties of powders were respectively studied by means of X-ray diffractometer (XRD), differential thermal analysis-thermogravimetric analysis (DTA-TG) and vibrating sample magnetometer (VSM). The powders before and after combustion and calcination at 450–850 °C with different mole ratio of Nd to Ba (0.1–1.0) were compared in terms of XRD. In addition, the effects of different synthesis conditions on magnetic properties of powders were also discussed. The results show that at pH 7.0 or so, mole ratio of citrate to nitrate (1–3) and calcination temperature of 850 °C for 1 h, M-type BaNd x Fe12?x O19(x=0.1?1.0) fine powders can be obtained, and the coercive force reaches 436880 A·m?1 at x=1, which is far greater than that of barium permanent ferrite (BaFe12O19).

Preparation and Structural Analysis of Lanthanide Complexes with α-Hydroxyl-phenyl-acetic Acid and 1,10-Phenanthroline as Ligands

A series of ternary lanthanide complexes Ln （C6H5CHOHCOO）3（phen） （H2O） （Ln= La, Ce, Pr, Nd, Sm, Eu） were synthesized with α-hydroxyl-phenyl-acetic acid and 1, 10-phenanthroline （phen） as ligands. The sturcture and property of complexes were characterized by elemental analysis, IR, 1^H-NMR, UV and TGA, and the coordinate mede of both ligands was discussed. It was shown that the co-ordinate mode of 1, 10-phenanthroline was chelated, while α-hydraxyl-phenyl-acetate ion was monedentate or bridging. The mechanism of thermal determinde by thermogravimetry was indicated that the degree of co-ordinate ability of ligand was： α-hydroxyl-phenyl-acetate ion 〉 1, 10- phenanthroline（phen）.

Sedimentary environment of Late Carboniferous Tangjiatun Formation in Acheng of Heilongjiang

According to the lithological assemblages and elemental geochemistry of the measured profile,the authors studied the sedimentary and tectonic environment of the Late Carboniferous Tangjiatun Formation in Acheng. The results show that the trace elements of mudstone samples from Tangjiatun Formation have the characteristics of high Th,V and Cu,but low Ba,Nb and Sr. The rare earth elements are characterized by significantly light and heavy rare earth elements differentiation,relative enrichment of light rare earth elements,and a negative anomaly of δEu. The Tangjiatun Formation belongs to a marine and delta sedimentary environment,and its tectonic setting is considered as a continental island arc environment.

Sedimentary environment of Middle Permian Zhesi Formation in Solon area of Inner Mongolia

Through a sampling analysis of trace elements and REE in the section of Middle Permian Zhesi Formation in Solon area of Inner Mongolia,it is found that the overall sandstone and mudstone samples are characterized by LREE-enrichment. By analysis of the discriminant index of the sedimentary environment,the tectonic setting of Zhesi Formation is determined to be a continental island arc environment. Meanwhile,according to the sedimentary structure and lithology combination,Zhesi Formation is divided into the neritic-bathyal retention-reduction environment as well as the delta front and prodelta sedimentary systems.

Geochemical evidence of paleogeography and paleoclimate during deposition of the 2nd Member of Kongdian Formation in Kongnan area

The 2nd Member of Kongdian Formation has been made up of a large number of oil shale and mudstone in the Kongnan aera of Huanghua depression around the Bohai Bay.In the Kongnan area,the lake basins were very large and deep during the deposition of the 2nd Member of Kongdian Formation.During that period,the lakes were sealed,uncommunicated with the sea water and the paleoclimate was very warm and wet in Kongnan area.Analyzing the content of the trace element and the rare earth element,carbon and oxygen isotope in the disquisition,The authors prove the two views correct.

Progress in the extraction and separation of rare earths and related metals with novel extractants: A review

Rare earths(REs) play a key role in high-tech fields and the associated thorium is a vital element for nuclear energy. However, to be used in high-tech industry or nuclear energy, these elements must first be recovered from the deposits and purified. As solvent extraction is the main technology for the recovery and purification of the metals, the review mainly presents our recent works on the extraction and separation of tetravalent cerium cation by neutral α-aminophosphonates, the individual rare earth separation by α-aminophosphonic acids, and the continuous preparation of high-purity thorium. The extraction and separation of some other metals are also discussed.

Enrichment mechanisms of rare earth elements in marine hydrogenic ferromanganese crusts

A series of selective extraction experiments were conducted on marine hydrogenic ferromanganese crusts from the seamount near the Line Island to investigate the distribution of rare earth elements （REEs） and the mechanisms of combination between REEs and the hydrogenic ferromanganese crusts. The enrichment of REEs in hydrogenic ferromanganese crusts is attributed mainly to the mineral or oxide/hydroxide of the crust rather than the growth environment. The REEs are present mainly in amorphous ferric oxide/hydroxide rather than in 6-MnO2. Amorphous ferric oxide/hydroxide preferentially combines free REE3＋, while 6-MnO2 combines the REE-carbonate complexes in modern seawater. The REEs in seawater are combined more strongly with amorphous ferric oxide/hydroxides than with 6-MnO2. The positive Ce anomaly in hydrogenic ferromanganese crusts results from the oxidation of soluble Ce3＋ to insoluble Ce4＋ by the actively soluble oxygen of the bottom current rather than by the oxidation of δ-MnO2.

Rare earth element and yttrium compositions of the Paleoproterozoic Yuanjiacun BIF in the Lüliang area and their implications for the Great Oxidation Event(GOE)

In China, most Precambrian banded iron formations （BIFs） are situated in the North China Craton. The Yuanjiacun iron depos- it, located in the Ltlliang area, is arguably the most representative Superior-type BIF. This iron deposit is coherent with the sedimentary rock succession of the Yuanjiacun Formation in the lower Lliliang Group, and was interpreted to be deposited at 2.3-2.1 Ga, based on ages of overlying and underlying volcanic strata. This age overlaps with the time range of the Great Oxidation Event （GOE, 2.4-2.2 Ga）. The Yuanjiacun BIF consists mainly of subhedral-xenomorphic magnetite and quartz and rarely other minerals with a lower degree of metamorphism, from greenschist to lower amphibolite facies. The geochemical characteristics of this BIF are similar to those of Superior-type BIFs. Prominent positive La, Y, and Eu anomalies normalized by the Post Archean Australian Shale （PAAS） indicate that the primary chemical precipitate is a result of solutions that repre- sent mixtures of seawater and high-T hydrothermal fluids. The contamination from crustal detritus found is negligible based on low abundances of Al2O3 and TiO2 （〈0.5%） and of trace elements such as Th, Hf, Zr, and Sc （〈1.5 ppm）, as well as the lack of co-variations between Al2O3 and TiO2. In particular, the Yuanjiacun BIF samples do not display significant negative Ce anom- alies like those of the Archean iron formations, but rather, the Yuanjiacun BIF samples exhibit prominent positive Ce anoma- lies, low Y/Ho ratios, and high light to heavy REE （（Pr/Yb）sN） ratios, which are essentially consistent with the late Paleoprote- rozoic （〈2.0 Ga） BIFs around the world. These characteristics of the Yuanjiacun BIF samples imply that the ancient ocean （2.3-2.1 Ga） was redox-stratified from oxic shallow water to deeper anoxic water. The specific redox conditions of the ancient ocean may be related to the GOE, which gave rise to the oxidation of Ce and Mn in the upper water, and to the presence of a Mn oxide shuttle in the ocean, resulting in varying REE patterns due to the precipitation and dissolution of this Mn oxide shut tle under different redox states. Therefore, the Yuanjiacun BIF appears to have formed near the redoxcline and lower-level reduced marine water.

Geochemical characteristics and geological significance of Cretaceous phonotephrite from the Mid-Pacific Mountains

Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic rocks are mainly phonotephrite with a porphyritic texture. Phenocrysts are mainly composed of Ca-rich plagioclase, clinopyroxene and nepheline.These volcanic rocks are significantly rich in large-ion lithophile and light rare earth elements, without obvious Eu anomalies(δEu=0.99–1.03), and with relatively enriched^(87) Sr/^(86) Sr(0.703829–0.704313) and^(143) Nd/^(144) Nd isotopic ratios(0.512857–0.512871), suggesting that they have similar but more enriched features than the OIB magmatic source. These volcanic rocks may originate from relatively deep magma source with the existence of spinel-garnet Iherzolites, and have undergone partial melting at a low degree of 1–3%. In addition, The residual Nb-Ta minerals(such as sphene, rutile, perovskite) may remain in the mantle source, and the magma components have undergone metasomatism by carbonate melt/fluid or alkali-rich fluid, causing high contents of incompatible elements and significant loss of Nb, Ta and Ti in these volcanic rocks. There are many similarities between the phonotephrites in the Mid-Pacific Mountain and the volcanic rocks in the Line Islands based on the tectonic settings and the geochemical characteristics. We thus speculate that Site 313 volcanic rocks in the Mid-Pacific Mountain is most likely to be a continuation of the Line Islands.