REE Characteristic of Hydrothermal Calcite in Langdu Skarn Copper Deposit

2012 ◽  
Vol 524-527 ◽  
pp. 184-189
Author(s):  
Tao Ren ◽  
Run Sheng Han ◽  
Yu Zhao Hu
Keyword(s):  
Hydrothermal Fluid ◽  
Yunnan Province ◽  
Copper Deposit ◽  
Magmatic Fluid ◽  
Substitutional Site ◽  
Complex Species ◽  
Ion Radius ◽  
The Stability ◽  
Ree Patterns ◽  
Distribution Behavior

Langdu is one of the highest grade, skarn copper deposits in Zhongdian area, Yunnan province. The chondrite-normalized REE patterns for syn-sulfide calcite from Langdu deposit are unique, being HREE-enriched, LREE-depleted and have significant positive Eu anomalies. REEs could derive from magmatic fluid exsolved from near melt. This distribution behavior is predominately constricted by REE patterns of hydrothermal fluid and the stability of complex in solutions than crystallographic factors. The DREE are increase with the decrease of ion radius. The optimum ion radius of substitutional site for REEs in the hydrothermal calcites is 0.1032nm. Eu occurs as Eu 2+ and complex species can explain the positive Eu anomalies

scholarly journals Petrogenesis and Metallogenic Implications of Neoproterozoic Granodiorite in the Super-Large Shimensi Tungsten-Copper Deposit in Northern Jiangxi, South China

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 429 ◽  
Author(s):  
Wenfeng Wei ◽  
Chunkit Lai ◽  
Bing Yan ◽  
Xiaoxi Zhu ◽  
Shengqiong Song ◽  
...  
Keyword(s):  
South China ◽  
Copper Deposit ◽  
High Background ◽  
Granite Emplacement ◽  
High K ◽  
P Content ◽  
Continental Arc ◽  
Type Granite ◽  
Ree Patterns ◽  
Type Classification

The newly discovered Shimensi deposit is a super-large tungsten-copper (W–Cu) deposit with a metal reserve of 742.55 thousand tonnes (kt) W and 403.6 kt Cu. The orebodies are hosted in Mesozoic granites, which intruded the poorly documented Shimensi granodiorite belonging to the Jiuling batholith, the largest intrusion (outcrop > 2500 km2) in South China. Our new SHRIMP (Sensitive High Resolution Ion MicroProbe) zircon dating revealed that the granodiorite at Shimensi (ca. 830–827 Ma) was formed coeval (within analytical uncertainty) or slightly earlier than those in many other places (ca. 819–807 Ma) of the Jiuling batholith. The Neoproterozoic Shimensi granodiorite is peraluminous and high-K calc-alkaline, and contains low P content with no S-type trend (positive P2O5 vs. SiO2 correlation) displayed, thus best classified as peraluminous I-type. The I-type classification is also supported by the zircon REE patterns, largely (93%) positive εHf(t) (−0.87 to 6.60) and relatively low δ18O (5.8–7.7‰). The Neoproterozoic Shimensi granodiorite was formed after the continental arc magmatism (ca. 845–835 Ma), but before the post-collisional S-type granite emplacement (ca. 825–815 Ma) in the Jiangnan Orogen. Therefore, we propose that the Shimensi granodiorite was formed in a collisional/early post-collisional setting. The δ18O increase from the Shimensi granodiorite to many younger (ca. 819–807 Ma) granodiorites (6.0–8.5‰) in the Jiuling batholith probably reflects an increase of supracrustal rock-derived melts with the progress of collision. The Shimensi granodiorite contains low zircon Ce4+/Ce3+ and Eu/Eu*, suggesting a relatively reducing magma that does not favor porphyry Cu–Au mineralization. This left a high background Cu concentration (avg. 196 ppm) in the Neoproterozoic granodiorite, which may have contributed to the Mesozoic W–Cu mineralization, when the granodiorite is intruded and assimilated by the Mesozoic granites.

The Pulang Porphyry Copper Deposit and Associated Felsic Intrusions in Yunnan Province, Southwest China

2011 ◽  
Vol 106 (1) ◽  
pp. 79-92 ◽  
Author(s):  
L. Wenchang ◽  
Z. Pusheng ◽  
H. Zengqian ◽  
N. C. White
Keyword(s):  
Yunnan Province ◽  
Southwest China ◽  
Porphyry Copper ◽  
Copper Deposit ◽  
Porphyry Copper Deposit

Sequence, Salt, Charge, and the Stability of DNA at High Pressure

1996 ◽  
Author(s):  
Robert B. Macgregor Jr ◽  
John Q. Wu
Keyword(s):  
Molar Volume ◽  
Volume Change ◽  
Salt Concentration ◽  
Electrostatic Interactions ◽  
Proposed Model ◽  
Dna Strands ◽  
Positive Volume ◽  
Ion Radius ◽  
The Stability ◽  
Kinetics Of

The effect of pressure on the helix-coil transition temperature (Tm) is reported for the double-stranded polymers poly(dA)poly(dT), poly[d(A-T)], poly[d(l-C], and poly[d(G-C] and triple-stranded poly(dA)2poly(dT). The Tm increases as a function of pressure, implying a positive volume change for the transition and leading to the conclusion that the molar volume of the coil form is larger than the molar volume of the helix. From the change in Tm as a function of pressure, molar volume changes of the transition (ΔVt) are calculated using the Clapeyron equation and calorimetrically determined enthalpies. For the doublestranded polymers, ΔVt, increases in the order poly[d(l-C] < polyt[d(A-T)] < poly(dA)-poly(dT) < polylcl(G-C)]. The value of ΔVt, for the triple-stranded to single-stranded transition of poly(dA) 2poly(dT) is larger than that of poly[d(G-C)I. The magnitude of ΔVt increases with salt concentration in all cases studied; however, the change of ΔVt with salt concentration depends on the sequence of the DNA and the number of strands involved in the transition. In the model proposed to explain the results, the overall molar volume change of the transition is a function of a negative volume change arising from changes in the electrostatic interactions of the DNA strands, and a positive volume change due to unstacking the bases. The model predicted the direction of the change in the ΔVt for several experiments. The magnitude of AVJ increases with counter ion radius, thus for polyld(A-T)], ΔVt, increases in the series Na+ , K+, Cs+, The ΔVt also increases if the charge on the phosphodiester groups is removed. The kinetics of the formation of double-stranded (dA)19(dT)19 in 50 mM NaCI are slowed approximately 14-fold at 200 MPa relative to atmospheric pressure. The implied volume of activation of +37 ml mol−l in the direction of this change is also in agreement with the proposed model. The stability of double- and triple-stranded DNA helices in water around neutral pH depends on the base composition and sequence, as well as on the ionic strength of the solution. Each of these dependencies also defines how DNA interacts with water.

The affinity of aldehydic compounds to complex formation. Nickel(II) and cobalt(II) complexes with 2-pyridinecarboxaldehyde

1977 ◽  
Vol 55 (14) ◽  
pp. 2613-2619 ◽  
Author(s):  
M. S. El-Ezaby ◽  
M. A. El-Dessouky ◽  
N. M. Shuaib
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Metal Ion ◽  
Experimental Conditions ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Complex Equilibria ◽  
The Stability ◽  
Hydroxy Groups

The interactions of Ni(II) and Co(II) with 2-pyridinecarboxaldehyde have been investigated in aqueous solutions at μ = 0.10 M (KNO3) at 30 °C. The stability constants of different complex equilibria have been determined using potentiometric methods. Spectrophotometric methods were also used in the case of the nickel(II) – 2-pyridinecarboxaldehyde system. It was concluded that nickel(II) and cobalt(II), analogous to copper(II), enhance hyrdation of 2-pyridinecarboxaldehyde prior to deprotonation of one of the geminal hydroxy groups. Complex species of 1:1 as well as 1:2 metal ion to ligand composition exist under the experimental conditions used.

The determination of the stoichiometry and stability constant of weak complexes in solution: a restatement of the "straight-line" method

1983 ◽  
Vol 61 (6) ◽  
pp. 1100-1102 ◽  
Author(s):  
Aurelio Beltrán-Porter ◽  
José A. Ramírez
Keyword(s):  
Stability Constant ◽  
Stoichiometric Ratio ◽  
Complex Species ◽  
Line Method ◽  
Straight Line ◽  
Weak Complexes ◽  
The Stability ◽  
Degree Of Condensation ◽  
Straight Line Method

Usually, to establish the degree of condensation of a complex species in solution, primarily when it is a weak complex, is more cumbersome than to determine the stoichiometric ratio itself. The present work describes a modification of the Asmus method in order to render it suitable for the determination of the actual stoichiometric coefficients and the stability constant of weak complexes whatever the degree of condensation may be.

Aqueous Reactions of Sparingly Soluble Tellurites I. Silver Tellurite

1972 ◽  
Vol 50 (11) ◽  
pp. 1788-1791 ◽  
Author(s):  
M. C. Mehra ◽  
S. M. Kahn
Keyword(s):  
Experimental Data ◽  
Stability Constant ◽  
Constant Temperature ◽  
Solubility Product ◽  
Complex Species ◽  
Ionic Medium ◽  
The Stability ◽  
Aqueous Reactions

The aqueous interactions of the sparingly soluble silver tellurite show that in a controlled ionic medium and at a constant temperature, an aqueous complex,[Formula: see text] is formed in presence of free tellurite ions. The solubility product of silver tellurite and the stability constant of the complex species have been evaluated from the experimental data.

Seepage-Stability Analysis of a Mine Tailings Dam in Yunnan Province Based on ANSYS

2012 ◽  
Vol 226-228 ◽  
pp. 1406-1410
Author(s):  
Shu Qi Ma ◽  
Si Jing Cai ◽  
Miao Guo
Keyword(s):  
Stability Analysis ◽  
Mine Tailings ◽  
Yunnan Province ◽  
Reduction Method ◽  
Field Analysis ◽  
Dam Safety ◽  
Tailings Dam ◽  
Ansys Software ◽  
Safety Coefficient ◽  
The Stability

As a major hazard installation in mine the safe and effective running of a tailings dam is very important, therefore the stability analysis of tailings dam is necessary. In order to evaluate the effect of seepage on stability of mine tailings dam, in this paper, a numerical model of a tailings dam in Yunnan province was established by using ANSYS software. It was focused on the dam seepage field analysis and the seepage-stability analysis, and on using the strength reduction method to derive the safety coefficient of the tailings dam. The results were proved reasonable and could be used to provide helpful guidance of dam safety.

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