新疆萨吾尔地区二叠纪火山岩成岩机制:来自稀土元素的约束

新疆萨吾尔地区发育大量二叠纪火山岩。通过研究该火山岩的稀土元素特征，并利用稀土元素与常量元素相关关系以及稀土元素协变关系判别图解，结合其区域地质背景和岩石学、岩石化学特征，判断该地区二叠纪基性、中性火山岩成岩过程以平衡部分熔融作用为主，分离结晶作用不明显，而中酸性火山岩成岩过程则受到部分熔融作用和分离结晶作用的共同影响。稀土元素地球化学研究为新疆准噶尔地区二叠纪后碰撞阶段的岩浆作用机理及地球动力学演化过程提供了重要证据。     

江西武山块状硫化物矿石表生风化过程中稀土元素地球化学行为

The behavior of REE during the sulphide weathering is still poorly understood, although REE geochemistry during weathering of igneous rocks has been well documented, in this study, the REE contents of primary sulphide and their weathering products （gossan） of the Wushan copper mine were investigated. The mobility of REE in the weathering profile of sulphide is limited, with the majority of REE retained in the gossans. However, REE are fractionated in the weathering process, with HREE relatively enriched in the gossan samples. Ce is depleted in the gossan, whereas the difference of Eu anomaly of the gossan and primitive sulphide is neglectable.     

内蒙古准苏吉花铜钼矿床稀土元素特征及对成矿作用的约束

准苏吉花高-中温热液脉型铜钼矿床是近年来中蒙边境新发现的众多中型铜钼矿床之一,矿体主要赋存在二叠纪花岗闪长岩中,仅少量产于宝力高庙组变质粉砂岩中,多呈透镜状产出,具尖灭再现现象。矿床稀土元素组成特征表明:花岗闪长岩和闪长岩脉稀土配分模式相似,表现为强负Eu异常和极弱或无负Ce异常,为同源岩浆演化的产物。变质粉砂岩稀土组成与岩浆岩截然不同。辉钼矿矿石稀土元素组成大致可分为两组:一组矿石表现为明显的负Eu异常,Ce表现为由弱异常过渡为无异常的特征,与矿区花岗闪长岩稀土组成相似;另外一组矿石表现为弱负Eu异常和极弱负Ce异常,介于花岗闪长岩与变质粉砂岩稀土元素组成之间,暗示成矿过程中岩浆热液与地层之间发生了水/岩交换。说明区内成矿物质一部分来源于花岗闪长岩,另一部分来源于宝力高庙组变质粉砂岩。矿石δEu值指示矿石沉淀于高温、低氧的相对还原环境。     

贵州红枫湖溶解态稀土元素地球化学研究

以中国西南碳酸岩盐地区的红枫湖及环湖河流水体为研究对象,采用液-液萃取和ICP-MS测试方法,对水中溶解态稀土元素浓度进行了测定,借以探讨碳酸盐岩水体环境下稀土元素的地球化学行为和环境效应。研究结果表明,红枫湖湖水溶解态稀土含量相对较低,∑REE总浓度分布于14.3～27.2 ng.kg-1之间,平均含量为18.24 ng.kg-1,明显低于地表水体浓度平均值。环湖河水溶解态∑REE浓度分布于4.07～102.28 ng.kg-1,平均为24.12 ng.kg-1。湖水和河水的页岩(PAAS)标准化的溶解态稀土元素配分模式都显示了显著的重稀土富集特征以及Ce元素负异常,而水化学络合计算结果显示,水体中溶解态稀土几乎以占绝对优势的碳酸盐无机络合形态存在,其他络合方式所占比例非常微小。这些都显示与相对偏碱性的水化学环境有关。     

吉林夹皮沟金矿带的稀土元素地球化学研究

为了解吉林夹皮沟金矿带的成矿期次,利用稀土元素的示踪性,对夹皮沟金矿带含矿石英脉、花岗岩及变质地层斜长角闪岩等21个样品进行稀土元素含量测定。测定结果表明,石英脉ΣREE=19.12×10-6～147.57×10-6,δEu=0.61～1.22,平均值0.89,具弱的负Eu异常;太古代花岗岩ΣREE=121.40×10-6～157.32×10-6,δEu=0.87～1.09;中生代花岗岩ΣREE=69.78×10-6～90.95×10-6,δEu=0.94～1.02,LREE/HREE比值分别为11.51～14.12和14.16～16.73,后者轻重稀土分馏程度略高于前者;变质围岩ΣREE=22.40×10-6～275.86×10-6,δEu=0.75～5.79,平均值2.30,具明显的正Eu异常。三者都具有轻稀土富集的平滑稀土配分模型。结合其区域地质背景、流体包裹体和稀土元素特征,得出夹皮沟金矿存在两期成矿作用,分别对应于太古代成矿花岗岩岩浆作用及中生代燕山期花岗岩岩浆作用。太古代首次富集成矿,中生代燕山期叠加成矿并扩大成矿规模,成矿时代分别为2475～2469 Ma和170～160 Ma;结合稀土特征研究及包裹体研究,成矿流体以岩浆热液流体为主,遭受轻微地层变质热液混染,中生代成矿流体混染作用更强烈。     

Thermal Stability of 4-chloro-2-nitro- and 4-chloro-3-nitrobenzoates of Rare Earth Elements: Influence of substituent positions

The physico-chemical properties and thermal stability in air of rare earth element 4-chloro-2-nitro- and 4-chloro-3-nitrobenzoates of the general formulae Ln(C₇H₃NO₄Cl)₃2H₂O were compared and the influence of the position of the Cl and NO₂ substituents on their thermal stabilities was investigated. The complexes of both series are crystalline, hydrated salts with colours typical of Ln³⁺. The carboxylate group in these complexes is a bidentate, chelating ligand. The NO₂ group in the chloronitro complexes does not undergo isomerization. The thermal stabilities of the 4-chloro-3-nitrobenzoates of rare earth elements were studied in the temperature range 293–1173 K, but those of 4-chloro-2-nitrobenzoates of those elements were studied only at 293–523 K because they decompose explosively above 523 K. The positions of the Cl and NO₂ substituents on the benzene ring influence the thermal properties of the complexes and their decomposition mechanisms. The different thermal stabilities of the complexes are connected with various inductive and mesomeric effects of the Cl and NO₂ substituents on the electron density in benzene ring.This revised version was published online in November 2005 with corrections to the Cover Date.     

中太平洋M海山富钴结壳稀土元素地球化学

用ICP-AES和重量法测试了中太平洋M海山不同水深范围内(1300~3000 m)25个富钴结壳样品的稀土元素和常量元素。结果显示M海山富钴结壳为水成结壳,稀土元素总量平均为2084.69μg.g-1,LREE/HREE平均为4.84,具有正的Ce异常。ΣREE(不含Ce)随水深增加而增加,而Ce和LREE/HREE比值则以文石溶跃面为界(水深2000 m)呈现不同的变化,稀土元素这些变化除了与海洋背景颗粒的吸附清扫有关外,还与稀土元素在海水中的行为有关。富钴结壳Ce虽随水深变化,但与水深关系不明显,可能反映其通量恒定。富钴结壳中Ce基本全为Ce(Ⅳ),表明氧化富集过程,这一过程受动力学因素控制。     

轻稀土元素在大鼠组织器官中的分布特征

研究La,Ce,Pr,Nd,Sm,Eu,Gd在大鼠组织器官中的分布规律。以雄性SD大鼠为试验对象,适应性喂养一周后剃去大鼠被毛,随机分为对照组和柠檬酸稀土低、中、高剂量组,每组10只共4组,剂量分别为0,50,500,5000 mg.kg-1(体重)。灌胃4周后,采集大鼠被毛、肝脏、脾脏等脏器。用等离子体质谱(ICP-MS)法测定大鼠被毛、肝脏、脾脏、全血中La,Ce,Pr,Nd,Sm,Eu,Gd轻稀土元素含量。轻稀土元素在大鼠全血、毛发及脏器中的分布特征分别为:肝、脾脏中的分布与摄入量完全对应;全血中分布趋于自然分布特征;股骨中对照及低剂量组的分布与摄入量倒置;而毛发中则呈现与受试物一致的特征,在一定程度上反映机体的稀土环境暴露水平。     

北黄海中部晚第四纪沉积物来源的稀土元素示踪

对北黄海中部DLC70-2孔166个沉积物样品进行了稀土元素测定,结合粒度参数研究,以探讨北黄海中部DLC70-2孔稀土元素地球化学特征和物质来源。结果表明:DLC70-2孔岩心稀土元素分布特征分别反映了末次间冰期(暖期)晚期以来北黄海海面波动以及沉积物物源的变化。判别函数和稀土元素配分模式表明北黄海DLC70-2孔沉积物物源主要为黄河源和鸭绿江源。La/Yb判别图解揭示DLC70-2孔上部0~32.10 m和下部37.60~60.72 m沉积物以黄河源为主,中部32.10~37.60 m和底部60.72~70.45 m沉积物以鸭绿江源为主。研究表明晚更新世以来黄河对北黄海中部沉积起着重要作用,而鸭绿江物质对北黄海中部沉积作用也有明显影响。     

The Complexes of Rare Earth Elements with 2,5-Dihydroxybenzoic Acid Preparation, properties and thermal decomposition

The conditions of the formation of rare earth(III) 2,5-dihydroxybenzoates have been studied; their compositions and solubilities in water at 293 K have been determined. The IR spectra of the anhydrous complexes with the general formula Ln(C7H5O4)3 have been recorded and their thermal decompositions in static air determined. During heating the anhydrous complexes of Y, Pr-Lu decompose to the oxides Ln2O3, Pr6O11 and Tb4O7 with formation of the intermediate Ln2(C7H4O4)3. The lanthanum complex decomposes to the oxide in three steps forming La2(C7H4O4)3 and La2O2CO3 as intermediates and the Ce(III) complex decomposes directly to CeO2. The properties of rare earth 2,5- and 2,4-dihydroxybenzoates have been compared. This revised version was published online in July 2006 with corrections to the Cover Date.     

Studies on the Uptake of Rare Earth Elements on Polyacrylamidoxime Resins from Natural Concentrate Leachate Solutions

Synthesis of poly(acrylamidoxime) resin from polyacrylonitrile performed with different crosslinking ratios 2, 5, and 10 wt% of divinylbenzene as crosslinking agent, using methylbenzoate and dioctylphthalate as pore producing solvent, the reaction mixture occurred under nitrogen. Studies carried out on diluted solution from rare earth elements (REEs) concentrate contains impurities as Cu²⁺, Ni²⁺, Zn²⁺, Fe³⁺, Al³⁺, Si⁴⁺, Th⁴⁺, U⁶⁺, Ca²⁺, and K⁺. Changing some parameters as pH of the solution, time of feeding and type of acid as HCl, HNO₃, H₂SO₄. The adsorption efficiency of resin is in the order pH 6 > pH 5 > pH 4 > pH 2 with excluding pH 6 due to the precipitation of some of REEs with the impurities and complete precipitation of Dy ion during pH adjustment, the adsorption in HNO₃ > HCl > H₂SO₄ media.