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1.
四川力马河镁铁-超镁铁质岩体的地球化学特征及成岩成矿分析 总被引：4，自引：3，他引：4
四川会理力马河镍矿是峨眉山大火成岩省最重要的岩浆硫化物矿床之一,成矿岩体为一小型锾铁-超镁铁岩侵入体,由含斜长石的超镁铁岩(包括舍长辉石橄榄岩和斜长橄榄辉石岩)和辉长岩类的镬铁质岩组成.矿床富含硫化物,成矿元素组合为铜、镍,铂族元素含量很低,没有铂族元素的工业富集,是蛾眉山大火成岩省中富铜镍贫铂族元素的代表性岩浆硫化物矿床.本文对力马河镍矿成矿岩体的镁铁、超镁铁岩及矿床中各种硫化物矿石进行了主量元素、微量元素及铂族元素含量分析.分析结果表明,力马河岩体的镁铁、超镁铁岩属拉斑玄武岩成因系列,岩石特征微量元素比值大致与高钛的峨眉山玄武岩相当、与低钛的峨眉山玄武岩有明显区分,但估计原始岩浆强不相容微量元素绝对含量大大低于高钛玄武岩,因此,其成矿岩体不是与一般的低钛或高钛峨眉山玄武岩(不包括苦橄岩在内)直接对应的深成相.岩体超镁铁岩及矿石铂族元素组成特征表现为无钌亏损的型式,钯/铱比值较小、在5左右,也显著不同于一般的峨眉山玄武岩,而类似于峨眉山大火成岩省苦橄岩的铂族元素组成.运用岩石地球化学研究方法计算,原始岩浆为苦橄质成分:MgO含量约17%、SiO2含量约48%.估计原始岩浆形成于130公里左右的深度,由类似于洋岛玄武岩岩浆源区成分的地幔经19%左右的部分熔融形成.超镁铁岩及硫化物矿石铂族元素含量一般在10-9～10-8暑级,铂族元素相对铜镍强烈亏损,铜/钯比值高于原始地幔10～100倍,铜镍铂族元素组成的原始地幔标准化曲线呈铂族元素显著亏损的“U“型.模式分析说明,导致铂族元素亏损的原因是岩浆成矿演化过程中多阶段硫化物熔离作用造成的,早期熔离出来的硫化物被丢失并造成岩浆中铂族元素亏损,其铂族元素亏损后的岩浆(第)二次硫化物熔离富集形成铂族元素亏损的矿石. 相似文献
2.
新疆北山地区两个含铜镍镁铁—超镁铁质岩体铂族元素地球化学研究 总被引：2，自引：0，他引：2
对北山地区坡一和罗东含铜镍的镁铁-超镁铁质岩体铂族元素研究表明,两个岩体的铂族元素(PGE)总量较低,PPGE较IPGE富集,原始地幔标准化模式呈正斜率,均较原始地幔亏损,具Ir和Rh的弱负异常。较低的Pd/Ir比值表明岩石主要受岩浆作用控制,后期热液作用影响不明显。两个岩体的原生岩浆均为MgO 含量较高的PGE不亏损的拉斑玄武质岩浆,较高的Cu/Pd、Ti/Pd比值表明岩浆在演化过程中发生了硫化物的熔离。罗东岩体早期矿物相（橄榄石、铬铁矿）的分离结晶作用对岩浆中的硫达到饱和具有重要的贡献,而坡一岩体该作用对硫化物熔离的贡献不明显。坡一和罗东岩体的R值表明两岩体均具有达到中型Ni矿床的潜力。 相似文献
3.
金川超大型铜镍硫化物矿床的铂族元素地球化学特征 总被引：21，自引：2，他引：19
对金川超大型铜镍岩浆硫化物矿床岩石、矿石的铂族元素地球化学特征研究表明 ,金川岩体的平均Cu/Pd值远大于原生地幔岩浆的Cu/Pd值 ,说明其岩石为因硫化物析离而失去Pd的岩浆所结晶 ;且岩石的PGE具有部分熔融趋势 ,与地幔橄榄岩接近 ,这些均指示存在岩浆熔离作用。该矿床岩石、矿石的PGE球粒陨石标准化分布模式比较对应 ,均可分为两种类型 ,反映了岩浆多次侵入、熔离分异同时成岩成矿的特征。另外 ,PGE S关系分析表明其成岩成矿过程中有少量地壳物质混染。PGE地球化学特征参数还指示了其高镁拉斑玄武质母岩浆的性质。 相似文献
4.
新疆黄山铜镍硫化物矿床成矿岩浆作用过程 总被引：10，自引：0，他引：10
黄山铜镍硫化物矿床镁铁．超镁铁质岩体岩相发育良好,主要包括橄榄岩、辉石岩、辉长岩和闪长岩,橄榄岩中部分橄榄石包含有硫化物珠滴。对该岩体不同岩相进行了主元素、微量元素、铂族元素和单矿物的分析,结果表明,不同类型岩石的化学组成受橄榄石、辉石和斜长石结晶分异作用的控制。微量元素和稀土元素具有相似的分布模式,（La／Yb）N介于1．14—3．65之间,明显亏损Nb和Ta,富集Sr。含矿岩石Cu／Pd和Ti／Pd比值大于原生地幔岩浆。上述结果揭示黄山镁铁-超镁铁质岩体不同岩性的岩石具有不同的主元素和微量元素特征,但母岩浆来自同一源区。根据橄榄石的F0值和全岩的主要氧化物组成估算出母岩浆为高镁（MgO约为15％）玄武岩岩浆,在岩浆作用过程中地壳富硅组分的混染是导致硫化物熔离的主要机制。 相似文献
5.
云南朱布镁铁-超镁铁岩体赋存中型铜镍铂族元素矿床,侵位于元谋群片岩和花岗片麻岩中,岩体垂直分异明显,自下而上为橄榄岩、橄辉岩、辉石岩、辉长岩等相带.矿体以底部“边缘矿”为主,上部有呈透镜状产出的少量“上悬矿”.本文报道了朱布岩体主元素、微量元素、铂族元素(PGE)和 Sr-Nd 同位素组成新的测试结果.分析表明朱布岩体具有拉斑玄武质岩浆分异演化趋势,富集 LREE 的分布模式,弱的Nb 异常和较明显的 Sr 负异常,并与峨眉山大火成岩省(ELIP)苦橄岩相类似,暗示两者可能存在成因上的联系.朱布岩体的铂族元素相对分布模式为“Pt-Pd”富集型,原始地幔标准化曲线向左陡倾.较高的(87Sr/86Sr)i (0.7096~0.7107)和较低的εNd(t)(-3.1~-2.3),表明朱布岩浆受到了地壳物质不同程度的混染.通过岩浆演化过程反演,得出其母岩浆性质为苦橄质,并估算地壳混染程度在3%~20%之间,发现在 R (岩浆与熔离硫化物的比例)值为1000~5000时比较吻合朱布样品中硫化物的实际测定值,证实了朱布岩体可能为开放系统的岩浆房,经过多级富集过程,先熔出的硫化物从后续多期次岩浆中吸收了大量 PGE,岩浆房中同时存在堆晶和岩浆演化,分别形成了底层橄榄岩和上部的辉长岩,中间过渡为橄辉岩和辉石岩 相似文献
6.
红旗岭铜镍硫化物矿床位于兴-蒙造山带东部。矿区出露30多个镁铁-超镁铁质侵入体,主要由橄榄岩、辉石岩和辉(苏)长岩组成。本文通过对红旗岭含矿镁铁-超镁铁质岩体的主、微量及铂族元素(PGE)的研究,探讨了红旗岭岩体成矿母岩浆性质、PGE亏损的原因以及岩体形成的构造环境。全岩主、微量元素地球化学分析表明,红旗岭岩体具有高MgO(平均28.75%)、低TiO2(平均0.44%),富集轻稀土元素(LREE)、亏损高场强元素(HFSE),极低ΣPGE(平均2.08×10~(-9))和高Cu/Pd(平均2916×10~3)的特征。岩石样品显示相似的微量和PGE配分模式,表明其来源于相同的岩浆源区。根据橄榄石-熔体平衡及质量平衡原理估算出红旗岭母岩浆为高镁玄武质岩浆(MgO=10.74%、FeO=7.78%)。红旗岭母岩浆在早期演化过程中发生硫化物熔离作用导致了红旗岭含矿岩体PGE的极度亏损。结合中亚造山带东段构造演化历史,本文认为红旗岭岩体形成于晚三叠世碰撞后伸展环境,矿床的形成受到了古亚洲洋俯冲结束后板片断离的影响。 相似文献
7.
尕秀雅平东含铜镍硫化物镁铁-超镁铁质岩体位于柴达木地块北缘,主要由蛇纹石化纯橄岩、单辉橄榄岩、橄榄辉石岩、辉石岩、辉长岩及斜长岩组成,侵位于古元古代达肯大坂岩群。本文对组成岩体的4件橄榄辉石岩样品和3件含矿岩石样品进行铂族元素分析,其∑PGE=8.82×10-9~84.8×10-9,原始地幔标准化配分曲线均呈左倾型式。利用Ni/Cu、Pd/Ir等相关参数确定原生岩浆为高镁玄武质岩浆,而低程度的地幔部分熔融作用是导致PPGE与IPGE强烈分异及Ru亏损的主要原因。岩体在形成过程中有一定程度地壳物质的混染作用,但早期硫化物的熔离作用不明显。同时,PGE元素间的协变关系显示热液蚀变作用对全岩PGE丰度影响不大。 相似文献
8.
新疆哈密白石泉含铜镍镁铁-超镁铁质岩体铂族元素特征 总被引：7，自引：1，他引：7
新疆哈密白石泉镁铁-超镁铁质岩体的铂族元素研究表明,岩体的铂族元素总含量较低,原始地幔标准化模式具镁铁质岩石的特征,并具Pt 正异常,且铂族元素的分异主要受结晶分异作用的影响.岩体的Cu/Pd、Se/S、Ti/Pd值表明其发生过硫化物的熔离作用.Pd/Ir、Ni/Cu特征表明了岩体系高镁玄武岩岩浆的产物.铂族元素特征揭示了白石泉岩体硫化物的熔离作用是由原始岩浆结晶分异导致的,岩体的形成是原始岩浆发生橄榄石等的结晶,导致硫化物的熔离作用后,其残余岩浆演化的结果. 相似文献
9.
四川攀西地区几个小型镁铁-超镁铁岩体含矿性的铂族元素示踪 总被引：2，自引：0，他引：2
峨眉山大火成岩省内带,四川攀西地区的杨合伍、黄草坪和清水河等镁铁-超镁铁岩体分布在南北向的安宁河断裂和磨盘山-元谋断裂之间。分析表明,这些岩体无矿岩石与金宝山、杨柳坪、力马河等含矿岩体无矿岩石具有相似的铂族元素组成,普遍较高的Cu/Pd比值暗示这些岩体的母岩浆在侵入到目前层位前经历过硫化物熔离作用。定量模拟计算表明,原始岩浆经过大约0.01%的硫化物熔离作用形成了杨合伍岩体母岩浆,经过0.035%硫化物熔离形成了黄草坪和清水河岩体的母岩浆。根据硫化物熔离情况,认为杨合伍等岩体底部可能形成Ni-Cu-(PGE)硫化物矿床,而黄草坪和清水河岩体之下及附近可能存在Ni-Cu硫化物矿化的岩体。 相似文献
10.
地幔部分熔融程度对东天山镁铁质-超镁铁质岩铂族元素矿化的约束——以图拉尔根和香山铜镍矿为例 总被引：21，自引：12，他引：9
东天山二叠纪镁铁质-超镁铁质岩带发育一系列的Ni-Cu硫化物矿床,但铂族元素(PGE)在这些矿化的岩体中没有明显地富集,岩体中PGE含量普遍低于原始地幔标准值.岩体中PGE含量过低可能有两方面原因:(1)岩浆上升过程中硫化物过早熔离,带走了岩浆中的大部分PGE;(2)原始地幔部分熔融程度较低,大部分PGE仍然保存在残留原始地幔中,导致部分熔融岩浆中PGE元素含量很低.本文模拟计算了原始地幔发生5%～20%部分熔融时产生岩浆中的PGE含量,与香山、图拉尔根为例与现有岩体中的PGE含量进行对比,结果显示PGE含量过低的原因可能是由于地幔部分熔融程度较低造成的,并推测本区的原始岩浆来自上地幔10%～20%的部分熔融.在通道系统内硫化物富集的部位可形成较好的(Pt Pd)矿化.图拉尔根矿区Pd-Ni图显示在岩浆演化早期没有发生过硫化物的熔离作用,熔离的硫化物也没有经历结晶分异作用. 相似文献
11.
The contents of the platinum-group elements (PGEs: Os, Ir, Ru, Rh, Pt, Pd) in the Abulangdang ultramafic intrusion have been
determined using ICP-MS after nickel sulfide fire assay preconcentration. Different samples show significant differences in
absolute PGE abundance. They display a pronounced negative incline in mantle-normalized patterns which are characterized by
strong enrichment in IPGEs (Os, Ir, Ru) and depleting to slight enrichment in PPGEs (Rh, Pt, Pd). The characteristics of PGE
distribution in the Abulangdang rocks are due to the combined action of sulfide and non-sulfide (spinel/chromite or alloy
or micro-granular aggregation of metals). In comparison with the mafic-ultramafic rocks which host Ni-Cu-PGE deposits in the
Emeishan Large Igneous Province (ELIP), it is assumed that the Abulangdang ultramafic intrusion may be the product of early-stage
magma activity in the ELIP. 相似文献
12.
金宝山杂岩体位于扬子板块西缘,毗邻哀牢山造山带北段,岩体中蕴含丰富的铂钯资源,是峨眉山大火成岩省(ELIP)中大型岩浆型铂族元素矿床。岩体的主要组成为辉石橄榄岩,矿体以似层状、透镜状产出于辉石橄榄岩中。地幔是镍矿床和铂族元素矿床最重要的源区,因而对Ni、Cu及PGE等元素行为的研究,是剖析岩浆型Ni-Cu-PGE矿床源区特征的一个重要研究方向。该研究获得金宝山岩体中辉橄岩铂族元素及Sr-Nd同位素数据,结合前人对ELIP中不同类型岩石系列PGE成分研究及Ni、Cu、PGE等元素在岩浆和硫化物中的分配系数,半定量模拟得到金宝山原始岩浆的形成源于地幔中高度部分熔融(25%~40%)形成的富PGE岩浆(含12.8×10-9 Pd,9.8×10-9 Pt,0.6×10-9 Rh和0.7×10-9 Ir),其铂族元素成分与ELIP苦橄岩成分相当,并且岩浆在演化的过程中遭受了10%~20%地壳混染作用。利用批式部分熔融公式及各铂族元素在硅酸盐矿物和熔体之间的分配系数反演计算得到产生金宝山熔体的地幔约含有5.3×10-9 Pd,7.5×10-9 Pt,0.75×10-9 Rh和1.5×10-9 Ir,相比原始地幔而言并没有表现出明显富集PGE的特征。这表明地幔中高度部分熔融+大量岩浆与硫化物的充分反应是形成大型岩浆型铂族元素矿床的一种可具备的条件。 相似文献
13.
The Qingkuangshan Ni-Cu-PGE deposit, located in the Xiaoguanhe region of Huili County, Sichuan Province, is one of several Ni-Cu-PGE deposits in the Emeishan Large Igneous Province (ELIP). The ore-bearing intrusion is a mafic-ultramafic body. This paper reports major elements, trace elements and platinum-group elements in different types of rocks and sulfide-mineralized samples in the intrusion. These data are used to evaluate the source mantle characteristics, the degree of mantle partial melting, the composition of parental magma and the ore-forming processes. The results show that Qingkuangshan intrusion is part of the ELIP. The rocks have trace element ratios similar to the coeval Emeishan basalts. The primitive mantle-normalized patterns of Ni-Cu-PGE have positive slopes, and the ratios of Pd/Ir are lower than 22. The PGE compositions of sulfide ores and associated rocks are characterized by Ru depletion. The PGE contents in bulk sulfides are slightly depleted relative to Ni and Cu, which is similar to the Yangliuping Ni-Cu-PGE deposit. The composition of the parental magma for the intrusion is estimated to contain about 14.65 wt% MgO, 48.66 wt% SiO2 and 15.48 wt% FeOt, and the degree of mantle partial melting is estimated to be about 20%. In comparison with other typical Ni-Cu-PGE deposits in the ELIP, the Qingkuangshan Ni-Cu-PGE deposit has lower PGE contents than the Jinbaoshan PGE deposit, but has higher PGE contents than the Limahe and Baimazhai Ni-Cu deposit, and has similar PGE contents to the Yangliuping Ni-Cu-PGE deposit. The moderate PGE depletions in the bulk sulfide of the Qingkuanghan deposit suggest that the parental magma of the host intrusion may have undergone minor sulfide segregation at depth. The mixing calculations suggests that an average of 10% crustal contamination in the magma, which may have been the main cause of sulfide saturation in the magma. We propose that sulfide segregation from a moderately PGE depleted magma took place prior to magma emplacement at Qingkuangshan, that small amounts of immiscible sulfide droplets and olivine and chromite crystals were suspended in the ascending magma, and that the suspended materials settled down when the magma passed trough the Qingkuangshan conduit. The Qingkuangshan sulfide-bearing intrusion is interpreted to a feeder of Emeishan flood basalts in the region. 相似文献
14.
峨眉火成岩省内带岩浆硫化物含矿岩体橄榄石的成因意义 总被引：4，自引：0，他引：4
峨眉火成岩省内带出露数十个含Ni-Cu-铂族元素(PGE)硫化物矿床(或矿化)的镁铁质-超镁铁质侵入岩体.根据铂族元素(PGE)含量的不同,这些岩浆硫化物矿床可分为Ni-Cu型(如力马河和清水河)、Ni-Cu-PGE型(如清矿山和黄草坪)和PGE型(如金宝山和杨合武).不同类型含矿岩体的橄榄石电子探针分析表明,除了清矿山岩体少数几个橄榄石晶体属于镁橄榄石外(Fo90.1～Fo93.1),其余均为贵橄榄石(Fo76.8～Fo89.6).不同矿化类型的岩体的橄榄石成分差异明显.Ni-Cu型硫化物含矿岩体的橄榄石Fo为77～87,Ni含量变化范围为(976～2176)×10-6.Ni-Cu-PGE型硫化物含矿岩体的橄榄石Fo为80～86,Ni含量范围为(1024～2543)×10-6.PGE型硫化物含矿岩体的橄榄石Fo为78～84,Ni含量在(776～1755)×10-6之间变化.清矿山Ni-Cu-PGE型硫化物含矿岩体橄榄石具有高Fo(最高达93.1)和CaO含量(0.245%～1.14%)、以及非常低的Ni(266×10-6)的特征,可能是同化混染作用的结果.利用力马河岩体最高Fo含量的橄榄石成分计算表明,母岩... 相似文献
15.
西南暗色岩铜镍硫化物矿化岩体与峨眉山玄武岩的关系--以云南金宝山岩体为例 总被引：23，自引：0，他引：23
内容提要本文以金宝山为典型实例,根据元素地球化学特征探讨了西南暗色岩铜镍硫化物矿化岩体与峨眉山玄武岩的关系。分析表明,金宝山超镁铁岩与低钛峨眉山玄武岩在元素地球化学特征上具有一致的岩浆成因属性,两者在成岩机制上互补,低钛峨眉山玄武岩普遍经历了橄榄石结晶分异和硫化物熔离亏损作用,金宝山成矿岩体则与低钛峨眉山玄武岩同源岩浆深部分异的堆晶相相对应,由堆晶橄榄石及熔离硫化物和部分残余熔体构成的“晶-糊”侵位形成,因此认为铜镍硫化物矿床成矿岩体与低钛峨眉山玄武岩为同源异相产物。 相似文献
16.
Yan Tao Chusi Li Ruizhong Hu Edward M. Ripley Andao Du Hong Zhong 《Contributions to Mineralogy and Petrology》2007,153(3):321-337
The Jinbaoshan ultramafic intrusion is a sheet-like body with a thick wehrlite unit in the center and thin pyroxenite units
at the margins. PGE are enriched in several disseminated sulfide zones in the intrusion. Olivine from the intrusion has low
Fo and depleted Ni contents compared to olivine from coeval Emeishan picrites. Whole rock major and trace element concentrations
suggest that the Jinbaoshan wehrlites originally contained <30% trapped liquid. The total amount of sulfide in the rocks exceeds
that which could have been dissolved in the trapped liquid. The Jinbaoshan wehrlites are interpreted to represent residual
assemblages formed by dissolution of plagioclase by passing magma. No clear evidence of crustal contamination is indicated
by S, Nd and Os isotopes. We envision that sulfide saturation occurred at depth due to olivine and chromite crystallization.
Immiscible sulfide droplets were transported to the Jinbaoshan conduit where they accumulated and reacted with magma successively
passing through the conduit to achieve high PGE concentrations. 相似文献
17.
Christina Yan Wang Mei-Fu Zhou Yali Sun Nicholas T. Arndt 《Contributions to Mineralogy and Petrology》2012,164(2):281-301
The Nantianwan mafic intrusion in the Panxi region, SW China, part of the ~260?Ma Emeishan large igneous province, consists of the olivine gabbro and gabbronorite units, separated by a transitional zone. Olivine gabbros contain olivine with Fo values ranging from 83 to 87, indicating crystallization from a moderately evolved magma. They have 0.2 to 0.9?wt?% sulfide with highly variable PGE (17?C151?ppb) and variable Cu/Pd ratios (1,500?C32,500). Modeling results indicate that they were derived from picritic magmas with high initial PGE concentrations. Olivine gabbros have negative ??Nd(t) values (?1.3 to ?0.1) and positive ??Os(t) values (5?C15), consistent with low degrees of crustal contamination. Gabbronorites include sulfide-bearing and sulfide-poor varieties, and both have olivine with Fo values ranging from 74 to 79, indicating crystallization from a more evolved magma than that for olivine gabbros. Sulfide-bearing gabbronorites contain 1.9?C4.1?wt?% sulfide and 37?C160?ppb PGE and high Cu/Pd ratios (54,000?C624,000). Sulfide-poor gabbronorites have 0.1?C0.6?wt?% sulfide and 0.2?C15?ppb PGE and very high Cu/Pd ratios (16,900?C2,370,000). Both sulfide-bearing and sulfide-poor gabbronorites have ??Nd(t) values (?0.9 to ?2.1) similar to those for olivine gabbros, but their ??Os(t) values (17?C262) are much higher and more variable than those of the olivine gabbros. Selective assimilation of crustal sulfides from the country rocks is thus considered to have resulted in more radiogenic 187Os of the gabbronorites. Processes such as magma differentiation, crustal contamination and sulfide saturation at different stages in magma chambers may have intervened during formation of the intrusion. Parental magmas were derived from picritic magmas that had fractionated olivine under S-undersaturated conditions before entering a deep-seated staging magma chamber, where the parental magmas crystallized olivine, assimilated minor crustal rocks and reached sulfide saturation, forming an olivine- and sulfide-laden crystal mush in the lower part and evolved magmas in the upper part of the chamber. The evolved magmas were forced out of the staging chamber and became S-undersaturated due to a pressure drop during ascent to a shallow magma chamber. The magmas re-attained sulfide saturation by assimilating external S from S-rich country rocks. They may have entered the shallow magma chamber as several pulses so that several gabbronorite layers each with sulfide segregated to the base and a sulfide-poor upper part. The olivine gabbro unit formed from a new and more primitive magma that entrained olivine crystals and sulfide droplets from the lower part of the staging chamber. A transitional zone formed along the boundary with the gabbronorite unit due to chemical interaction between the two rock units. 相似文献
18.
The Binchuan area of Yunnan is located in the western part of the Emeishan large igneous province in the western margin of the Yangtze Block.In the present study,the Wuguiqing profile in thickness of about 1440 m is mainly composed of high-Ti basalts,with minor picrites in the lower part and andesites,trachytes,and rhyolites in the upper part.The picrites have relatively higher platinum-group element（PGE） contents（ΣPGE=16.3-28.2 ppb）,with high Cu/Zr and Pd/Zr ratios,and low S contents（5.03-16.9 ppm）,indicating the parental magma is S-unsaturated and generated by high degree of partial melting of the Emeishan large igneous province（ELIP） mantle source.The slightly high Cu/Pd ratios（11 000-24 000） relative to that of the primitive mantle suggest that 0.007%sulfides have been retained in the mantle source.The PGE contents of the high-Ti basalts exhibit a wider range（ΣPGE=0.517-30.8 ppb）.The samples in the middle and upper parts are depleted in PGE and haveεNd（260 Ma） ratios ranging from -2.8 to -2.2,suggesting that crustal contamination of the parental magma during ascent triggered sulfur saturation and segregation of about 0.446%-0.554% sulfides,and the sulfide segregation process may also provide the ore-forming material for the magmatic Cu-Ni-PGE sulfide deposits close to the studied basalts.The samples in this area show Pt-Pd type primitive mantle-normalized PGE patterns,and the Pd/Ir ratios are higher than that of the primitive mantle（Pd/Ir=1）,indicating that the obvious differentiation between Ir-group platinum-group elements（IPGE） and Pd-group platinum-group elements（PPGE） are mainly controlled by olivine or chromites fractionation during magma evolution.The Pd/Pt ratios of most samples are higher than the average ratio of mantle（Pd/Pt=0.55）,showing that the differentiation happened between Pt and Pd.The differentiation in picrites may be relevant to Pt hosted in discrete refractory Pt-alloy phase in the mantle;whereas the differentiation in the high-Ti basalts is probably associated with the fractionation of Fe-Pt alloys,coprecipitating with Ir-Ru-Os alloys.Some high-Ti basalt samples exhibit negative Ru anomalies,possibly due to removal of laurite collected by the early crystallized chromites. 相似文献