Genesis of the Shear Zone-related Gold Vein Mineralization of the Lega Dembi Gold Deposit, Adola Gold Field, Southern Ethiopia

The Lega Dembi Primary Gold Deposit in southern Ethiopia is related to the shear zone-hosted vein in the Neoproterozoic metamorphosed volcano-sedimentary succession of greenschist- to amphibolite-facies metamorphism. The rocks consists of a sequence of biotite-feldspar-quartz schists, carbonaceous mica-schists, amphibolites and basic to ultrabasic rocks. This unit is separated from a foot wall biotite gneiss by a major shear zone. The ore bodies are hosted in the volcano-sedimentary sequence and consist of swarms of quartz veins, lenses, and stockworks that propagated along mesoscale ductile to brittle-ductile shear zones.The mineralization is defined by a complex paragenesis of gold in association with Cu-Pb-Zn-Fe sulphides, tellurides and sulphosalts. The presence of Ni-bearing minerals in amphibolites of the host sequence, together with the ore mineral association, suggests an origin related to mafic volcanism.     

喀拉通克铜镍矿床铂族元素地球化学特征及其成矿作用意义

喀拉通克铜镍矿床位于准噶尔板块北缘,矿区主要矿体赋存于Y1-Y3号岩体中。矿石构造类型为致密块状和浸染状两大类,其中前者与后者呈贯入接触,不同浸染状类型之间为过渡关系。岩石和矿石的PGE总量偏低,且以PPGE为主,IPGE含量较低。整体上岩石中的PGE含量显示随基性程度降低而变小。矿石中的PGE含量随硫化物含量增加增大,显示PGE主要分布于硫化物熔离形成的物相中。100%硫化物计算后,矿石PGE含量平均仅为573×10^-9。各岩体中浸染状矿石PGE组成并无明显差异;岩石和矿石具有相似的PGE分配模式,均属于Pt-Pd配分型。岩石Ni/Cu-Pd/Ir关系以及岩石地球化学资料显示,形成喀拉通克岩体的初始岩浆为MgO含量较高的玄武质岩浆,属于PGE不亏损的岩浆。基于PGE不亏损的大陆拉斑玄武岩初始岩浆推算,喀拉通克矿床母岩浆明显亏损PGE,而深部硫化物熔离可能是导致母岩浆PGE亏损的主要原因。岩石和矿石Pd/Pt比值总体特征,岩石Cr与Ni、Ir、Ru和Rh相关性,以及硫同位素和岩石学资料分析表明,初始岩浆在地壳深部发生的橄榄石、铬铁矿等矿物的分离结晶作用,可能是促使硫过饱和与深部熔离的主要因素。IPGE与PPGE分异特征及其相关分析,结合矿床宏观地质特征,推断该矿床浸染状矿的成矿作用经历了初始岩浆（PGE不亏损）→橄榄石等矿物分离结晶→硫化物深部熔离→成矿母岩浆（PGE亏损）→上侵并结晶分异的成矿过程。块状矿则可能是这一过程中PGE亏损的成矿母岩浆相对滞后熔离形成的硫化物熔体贯入的结果。     

赞皇变基性岩中锆石的U-Pb定年及其地质意义

赞皇变质杂岩区位于阜平杂岩南部,地处华北克拉通中部造山带的中段,和中部带北段杂岩一样,是洞悉华北克拉通前寒武纪基底构造演化历史的一个重要窗口.研究区变基性岩可分为斜长角闪岩和角闪斜长片麻岩两种,二者均以似层状方式产于黑云斜长片麻岩或长英质片麻岩中,斜长角闪岩亦可呈透镜状,二者后期与围岩一起共同经历了高角闪岩相变质作用....     

The Karchiga copper massive sulfide deposit in the high-grade metamorphosed rocks of the Kurchum block: geologic structure,formation, and metamorphism (Rudny Altai)

The Karchiga copper massive sulfide deposit is located in the Kurchum block of high-grade metamorphosed rocks. This block is part of the Irtysh shear zone, which belongs to the largest transregional fault in Central Asia. The deposit is associated with the gneiss–amphibolite middle unit of the metamorphic complex, which is distinct in the geochemical fields. The mineralization is spatially and paragenetically related to the amphibolite beds, which are ore-bearing together with terrigenous rocks.The deposit contains two spatially isolated lodes, in which all the discovered commercial reserves concentrate. They conformably overlie the host rocks and are tabular or ribbonlike. The mineralization has a close spatial relationship with Mg-rich anthophyllite-containing rocks. The sulfide ores are disseminated or massive and comprise pyrite, chalcopyrite, pyrrhotite, sphalerite, and magnetite. The ore is of Zn–Cu composition, in which Cu dominates considerably over Zn (average contents 2 and 0.4%, respectively; Cu/(Cu + Zn) = 0.83). The ores are rich in Co (up to 0.16%, averaging 0.02%), poor in Au and Ag (0.3 and 7.2 ppm, respectively), and almost free of Pb and Ba.All the rocks and ores experienced epidote–amphibolitic metamorphism. Meanwhile, the ores experienced a recrystallization and partial regeneration, but the initial shape of the lodes remained unchanged.The essentially chalcopyritic ores, the volcaniclastic ore-bearing rocks, and the spatial and genetic relationship of the mineralization with undifferentiated mafic and siliciclastic rocks suggest that this deposit belongs to the Besshi type, formed in a back-arc environment, near large rises.The studies show that Besshi-type Cu–Zn massive sulfide deposits differ from most of the polymetallic (Kuroko-type) deposits in Rudny Altai in the composition of volcanics and geodynamic settings, but belong to the same evolutionary series in this VMS province. Both types of deposits might have formed in the Paleozoic, during the main peak of VMS generation in the Earth's history.     

Physicochemical conditions of deposition and origin of carbonate-hosted base metal sulfide mineralization, Thermes ore-field, Rhodope Massif, northeastern Greece

Vein and stratabound base metal sulfide mineralization of the Thermes ore-field, Rhodope Massif, NE Greece, is hosted in marbles. The Thermes area is a structurally complex, E-W-trending zone consisting of felsic gneisses alternating with amphibolites, amphibole-biotite, and biotite gneisses, and marbles. These rocks have undergone amphibolite facies metamorphism (5–7 kbar, 580°–620°C), in Upper Cretaceous to Eocene times, and were subsequently retrograded to greenschist facies metamorphism of Miocene age. Granitoids of Oligocene age, and volcanic rocks of Eocene-Oligocene age, crosscut the metamorphic rocks. Two major base metal sulfide ore varieties occur in the Thermes ore-field. The first comprises brecciated vein Pb-Zn mineralization, related to NNWand NNE-trending faults. The second comprises stratabound (manto) polymetallic, and Pb-Zn replacement ores with associated veins. On the basis of ore geochemistry, as well as field and textural evidence, these two ore varieties form part of a vein associated skarnreplacement base metal sulfide ore system. Based on fluid inclusion data in quartz, together with the iron content of sphalerites and existing lead and sulfur isotope data, it is suggested that after the cessation of the regional amphibolite facies metamorphism circulating evolved meteoric waters, probably with magmatic fluid contributions, deposited sulfide ores at temperatures of 200°2-400°C, and pressures of less than 300 bar. Ore was deposited as a result of increase in pH of the mineralizing fluids due to fluid-rock interaction, and adiabatic cooling and/or simple cooling accompanying fluid boiling. Thermochemical considerations indicate a pH increase from about 4 to 7 and a decrease in and .     

内蒙古乌兰浩特古元古代变质岩系的发现及其地质意义

在乌兰浩特东白音乌苏一带新发现一套斜长角闪片岩、透辉透闪岩、斜长角闪片麻岩的岩石组合,岩石普遍经高绿片岩相-低角闪岩相变质,经受了后期多期构造改造。斜长角闪片岩经原岩恢复为基性火山岩,锆石晶形、阴极发光、背散射图像及高Th/U值等特征显示为岩浆锆石。采用LA-ICP-MS锆石U-Pb测年技术,在变质岩系中获得了1864.1±7.3Ma的同位素年龄,时代归属为古元古代,该年龄为岩浆形成年龄。此年龄限定了该套变质岩系的形成时代,证明乌兰浩特地区可能存在前寒武纪结晶基底。与区域上松嫩地块南部新发现的古元古元代岩浆锆石年龄进行对比发现,松嫩地块西缘可延伸至乌兰浩特一带。     

青岛榴辉岩相蛇绿混杂岩的岩石学证据及退变质P-T轨迹

青岛榴辉岩相蛇绿混杂岩发育在胶南隆起北缘地缝合线附近,构造侵位于胶南群云母斜长片麻岩中。它主要由斜方辉橄岩、玄武质和玄武安山质火山岩及少量杂砂岩和硅质岩组成。它与一般仰冲蛇绿岩的主要区别是:玄武质和玄武安山质岩石普遍遭受了榴辉岩相变质作用并发生强烈的糜棱岩化和退变质作用。强烈的退变质作用使大部分榴辉岩变为含石榴石石英斜长角闪岩,但仍保留有少量榴辉岩透镜体。它们可能是俯冲陆壳前缘岛弧地壳或岛弧型蛇绿岩残片的推覆体。它的退变质P-T轨迹表明,在其上升过程中热传导速率较高,这可能与该岩石强烈糜棱岩化和含水有关。     

吉林省延边卧龙地区青龙村群地球化学特征

青龙村群分布于华北板块北缘东段,岩石类型主要为片麻岩类,少量片岩类、斜长角闪岩类.变质作用由角闪岩相退变为绿片岩相.其原岩为钙碱性安山岩和流纹岩组合.岩石地球化学特征表明:青龙村群所属构造环境为岛弧区,岩浆同源,并经过岛弧区玄武质岩浆的分异作用,而玄武质岩浆产生与富集型MORB地幔经历中等程度部分熔融有关,Ti相对于Zr弱亏损可能与岛弧区俯冲深度有限有关.这表明青龙村群是华北板块北缘古亚洲洋俯冲消减的结果,并且与周围岩群没有可比性.     

Polymetamorphism of ores in Precambrian stratiform massive sulfide deposits at Ambaji-Deri,Western India

Massive stratiform zinc-lead-copper sulfide ores, in association with cordierite-anthophyllite rocks, occur in adjacent localities of Ambaji and Deri, in Western India. The metasedimentary country rocks, interlayered with amphibolites and intruded by acidic to intermediate plutonic rocks, belong to the Precambrian Delhi Supergroup. The ore minerals identified by detailed mineragraphic studies include: sphalerite, galena, chalcopyrite, pyrite, pyrrhotite (both monclinic and hexagonal phases), magnetite, ilmenite, rutile, arsenopyrite, molybdenite, cubanite, mackinawite, boulangerite, gudmundite, meneghinite, lautite, tenantite, native bismuth, native silver, chalcocite and covellite. The common sulfide-silicate schistosity in the ores, flowage of sulfide streaks and tails around rotated poikiloblasts and in their pressure shadow region developed during early folding (F₁) and regional metamorphism of the rocks under green schist facies condition. These were superimposed by a pervasive hornfelsic fabric involving sulfides and silicates and including microfabrics due to annealing and grain growth in sulfides, during a subsequent phase of low pressure thermal metamorphism and related tectonism (F₂). Finally certain deformation features and some uncommon fabrics like martensitic lamellae in galena and subgrains in sphalerite developed during a mild deformation episode (F₃) in the waning stages of tectonism in the area. Compositional change in the ores during thermal metamorphism was minimal.     

Volkovsky deposit of titanomagnetite and copper-titanomagnetite ores with accompanying noble-metal mineralization, the Central Urals, Russia

The geology of the Volkovsky deposit, the composition of its rocks, titanomagnetite and copper-titanomagnetite ores with accompanying noble-metal mineralization, and their formation conditions are considered. Special attention is paid to the recently revealed noble-metal mineralization and its attendant character in respect to titanomagnetite ore is shown. Ore minerals and their relationships are characterized. Initially immiscible sulfide segregations are described and their evolution is traced up to interrelations with oxide and silicate cumulates. The distribution of noble metals (NM) in titanomagnetite and copper-titanomagnetite ores is discussed. Throughout ore formation, NM gradually accumulated in silicates, oxides, and sulfides. The highest NM concentrations are related to the sulfide schlieren and veinlike segregations in gabbroic rocks. It is suggested that the deposit was formed as a product of fractionation of basaltic magma. The copper-iron ore was deposited from the residual melt enriched in Cu, Fe, Ti, V and volatile P and S in a wide temperature range of 800 to 570°C. Noble metals concentrated in parallel with their own minerals (largely tellurides and native gold) at the final stage of crystallization of gabbroic intrusion.     

Petrogenesis of Eclogites in the Light of Punctuated Metamorphic Evolution in Dabie Terrane，China

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云南白马寨铜镍硫化物矿床形成过程的定量模拟

岩浆的分离结晶作用和地壳同化混染作用是造成硫饱和的重要因素。本文以金平-Song Da地区二叠纪低钛苦橄岩为原生岩浆,使用MELTS程序模拟了岩浆在分离结晶和围岩同化混染作用的控制下达到硫饱和,发生硫化物熔体的熔离。模拟结果表明,低钛苦橄质岩浆从源区上升到浅部岩浆房的过程中发生了约10%的橄榄石的分离结晶,形成高镁的玄武质岩浆。高镁玄武质岩浆在浅部岩浆房内同化混染>18%的围岩,并经历约27%硅酸盐矿物的分离结晶后达到硫饱和。熔离的硫化物熔体在岩浆通道内聚集形成了白马寨铜镍硫化物矿。经历硫化物熔体熔离后的残余岩浆喷出地表形成了金平地区亏损Ni和Cu并具有强烈地壳混染特征的低钛玄武岩。     

The Sin Quyen Cu–Fe–Au–REE deposit (northern Vietnam): composition and formation conditions

The Sin Quyen Cu–Fe–Au–REE deposit is localized in the Proterozoic deposits of the Phan Xi Pang zone, northern Vietnam. The mineralization is formed by lenticular and sheet-like bodies occurring concordantly with the host rocks. Seventeen orebodies have been recognized in the deposit, which form an ore horizon up to 140 m in total thickness, about 2 km in strike, and up to 350 m in dip. The ores are of simple mineral composition: Au-rich copper and iron sulfides (chalcopyrite, pyrite, pyrrhotite) and iron oxides (magnetite, hematite). Gold and silver are distributed unevenly in the ores: Their contents vary from hundredths and tenths of ppm to 1.8 ppm. Copper sulfide ores are the main concentrator of gold and silver. All ores are characterized by high REE contents, tens and hundreds of times exceeding the element clarkes. The highest contents have been revealed for Ce and La. Orthite is the main carrier of REE. No correlation between REE and ore elements of sulfide-oxide ores has been revealed, which points to the independent formation of the mineralization. Orebodies together with the host rocks underwent metamorphism at 500–600 to 630–685 °C and 3–7 kbar. The spatial association of the mineralization with amphibolites (metamorphosed basites) and the mineral composition of ores suggest that the Sin Quyen deposit is of Cyprian volcanogenic type.     

西藏谢通门县斯弄多大型叠加改造型铅锌矿床特征及找矿方向

斯弄多铅锌矿区位于冈底斯斑岩型矿床成矿带中。矿区花岗斑岩和闪长玢岩的地球化学特征表明,斯弄多铅锌矿与冈底斯斑岩型矿床为同一成矿体系,均形成于印—亚大陆主碰撞期和碰撞期后的构造体制转化阶段;岩浆来源于原岩以杂砂岩和泥质岩为主的前寒武纪念青唐古拉群变质结晶基底和下地壳基性岩类的部分熔融。成矿物质主要来源于雅鲁藏布江新特提斯洋对冈底斯弧俯冲板片的部分熔融并交代岛弧带上的基底岩系。矿床的形成分为3期:第一期为中石炭世,与碳酸盐岩沉积同时期的海底热水喷流沉积作用形成初始矿源层;第二期为构造活动成矿期,分2个成矿阶段:第一阶段为晚白垩世—始新世,即印-亚大陆主碰撞形成的早期与斑岩有关的岩浆热液型铅锌矿;第二阶段的铅锌矿化发生在主碰撞期后的伸展拉张阶段,由于花岗斑岩的侵位,使铅锌矿化进一步活化迁移、叠加、富集,与围岩接触部位形成夕卡岩型铅锌矿体,矿体的形成多受矿区内复杂的断裂构造控制,矿床类型主要为构造破碎带热液充填型和夕卡岩型;第三期为表生期,主要为原生硫化矿体的氧化流失和贫化。在I号矿带的深部、南部和北部异常区具有扩大矿床规模的远景。     

Ocean floor basalt, not continental gabbro: a reinterpretation of the Hoher Bogen amphibolites, Teplá-Barrandian, Bohemian massif

At its southern margin along the Hoher Bogen mountain, the Teplá-Barrandian (Bohemian massif, Central Europe) is made up of a 1- to 4-km wide belt of amphibolites. An upper amphibolite/lower granulite facies Variscan metamorphism has brought forth coarse-grained, weakly foliated rocks with hbl+pl±cpx±opx±grt parageneses. Since the beginning of this century, these rocks, together with fine-grained or mylonitized amphibolites, have been regarded as metamorphic gabbros (gabbro amphibolites) of the Neukirchen-Kdyne igneous complex. Relics of magmatic textures, however, cannot be found anywhere. The amphibolites are therefore reinterpreted as metamorphic basalts. The Hoher Bogen amphibolites (HBA) derive from N-type MORB. The most primitive samples have Mg#s between 60 and 65. Locally occurring (garnet-)hornblendites and leucodioritic mobilisates are the products of partial melting of amphibolites during the Variscan metamorphism and do not belong to the primary magmatic rock association. Ultramafic rocks are tectonically emplaced between the HBA belt and the metapelitic rocks of the Moldanubian. At the very least, the metapyroxenites among them seem to have a cumulus origin. Together with the ultramafic rocks, the HBA belt may be regarded as a metaophiolite, comparable to the Mariánské Lazne complex. The reinterpretation of the former "gabbro amphibolites" as a metaophiolite has consequences for the geology of the Teplá-Barrandian: the size of the Neukirchen-Kdyne igneous complex is reduced. The HBA belt is a piece of oceanic crust which is possibly younger than the Precambrian metasedimentary/metavolcanic country rock of the Neukirchen-Kdyne igneous complex.     

Acebuches amphibolites in the Aracena hercynian metamorphic belt (southwest Spain): Geochemical variations and basaltic affinities

A 1500–2000 m sequence of amphibolites exhibits progressively increasing metamorphic grade from greenschist to the amphibolite/granulite facies transition. The chemical variations are considered to be principally inherited from the basaltic parent. The appearance of clinopyroxene is related to P,T and to bulk-rock composition during metamorphism. Excluding some basal rocks in the orthopyroxene zone, chemical variations related to metamorphism are minor. The small decrease in the K₂O content from 0.3% to 0.1% with increasing grade suggests that the low K content was a characteristic of the basaltic precursor. These amphibolites have affinities with abyssal tholeiites.     

吉林省和龙地区鸡南BIF型铁矿床含矿建造地球化学特征及形成时代

鸡南铁矿床位于吉林省和龙地区,地处华北克拉通北缘与兴蒙造山带接壤的龙岗地块北部,是东北地区发现较早的BIF型铁矿床之一。该矿床铁矿体主要呈层状、似层状、扁豆状赋存于鞍山群鸡南组上段中部层位,含矿岩石以黑云斜长片麻岩、角闪黑云斜长片麻岩、黑云角闪斜长片麻岩及斜长角闪岩为主,为角闪岩相的中低级区域变质岩系;主要矿石类型为条带状磁铁石英岩型和块状磁铁角闪岩型。为确定该矿床含矿建造的原岩、变质时代及构造背景,重点对含矿岩系中的斜长角闪岩进行了岩石地球化学和锆石U-Pb年代学研究。结果表明：斜长角闪岩的地球化学特征表现为富集大离子亲石元素、轻微富集重稀土元素;主量元素质量分数与中性-基性岩类基本相似,结合原岩恢复图解,判断其原岩类型为亚碱性玄武岩（拉斑玄武岩）,形成于弧后盆地背景;LA-ICP-MS锆石U-Pb年代学研究中,2个较老的锆石测点年龄分别为（2 468±15）和（2 469±9）Ma,代表区内峰期变质年龄（约2 460 Ma）,26个锆石测点的测年数据较为集中,加权平均年龄为（2 275±25）Ma,代表区内退变质年龄。通过与国内外典型BIF型铁矿床的对比研究认为,区内的鸡南铁矿与官地铁矿同属Algoma型铁矿床。     

新疆北山红石山含铜镍镁铁-超镁铁质岩体PGE和Re-Os同位素地球化学特征及成矿意义

对新疆北山地区红石山镁铁-超镁铁质岩体中含铜镍的硫化物矿石和岩石进行了铂族元素和Re-Os同位素地球化学特征研究,结果表明,矿石及岩石的铂族元素(PGE)总量较低,变化于0.54×10-9~15.84×10-9之间。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。较高的Cu/Pd和Ti/Pd比值表明岩浆在演化过程中发生了硫化物的熔离。岩体的母岩浆为有早期结晶橄榄石加入的高镁的玄武质岩浆。γOs(t)的变化较大,变化于-282~+282之间,表明有较多的地壳物质混入。地壳物质混染和橄榄石等矿物的分离结晶可能是引起岩浆中的S达到饱和进而熔离的重要因素。红石山岩体是经历了结晶分异和硫化物熔离后橄榄石的堆积体与残余岩浆演化的混合体。     

Geology and Geochemistry of Highly Metamorphosed Footwall Alteration Zones in the Hongtoushan Volcanogenic Massive Sulfide Deposit,Liaoning Province,China

The Hongtoushan Archean Cu–Zn volcanogenic massive sulfide (VMS) deposit, which was metamorphosed (3.0–2.8 Ga) to upper amphibolite facies at temperatures between 600 and 650°C, occurs in the Hunbei granite–greenstone terrane, Liaoning Province of NE China. Stratiform cordierite–anthophyllite gneiss (CAG) that occurs hundreds of meters below the ore horizon in the Hongtoushan district corresponds to the metamorphosed semi‐conformable alteration zone of the VMS hydrothermal system, whereas the CAG that contains abundant deformed sulfide‐bearing quartz veins immediately below the main ore layer represents the metamorphosed discordant alteration zone. Whole‐rock geochemistry indicates that stratiform CAG was derived ultimately from five lithologies (basalt, basaltic andesite, andesite, dacite, and rhyolite), while discordant CAG derived from a single lithology (rhyolite). Amphibolite and biotite‐rich gneiss are identified as a metamorphosed least‐altered precursor for these CAGs. Mass change calculation indicates that, compared to the least‐altered rocks, stratiform CAG is enriched in Fe and Mg, and depleted in Na, K, Ca, Cu, Pb and Zn, while discordant CAG is enriched in Fe, Mg, Si, Na, Pb, Cu and Zn, and depleted in K. HREE and HFSE (Zr, Ti, Nb and Ta) behaved inertly during submarine alteration, whereas Rb, Sr, Ba and LREE (especially Eu) were leached off. Both stratiform and discordant CAGs are depleted in ¹⁸O, with values up to 7‰ lower than their corresponding least‐altered precursors. Addition of Fe, Mg, and depletion of Ca, K, Sr, and ¹⁸O, indicate that hydrothermal alteration for both types of CAGs was characterized by chloritization prior to metamorphism. Stratiform CAG could be used to evaluate the mineralization potential of VMS in metamorphic terranes, while discordant CAG containing sulfide‐bearing quartz veins could be a good indication for overlying stratiform massive sulfide ores as well as an exploration target itself.     

阿拉善地区前寒武纪斜长角闪岩的岩石学、地球化学、形成环境和年代学

阿拉善地区前寒武纪不同岩群、岩组和杂岩中的斜长角闪岩均呈层状产出 ,其原岩多为高铁拉斑玄武岩 ,普遍具有高钾高钛、稀土元素含量高、轻稀土元素富集的地球化学特征 ,与典型的大洋拉斑玄武岩、太古宙的TH1型和TH2 型拉斑玄武岩有较明显的区别。岩石组合特征和多种地球化学判别图解均表明 ,该区的斜长角闪岩主要形成于板内环境 ,属于板内裂陷或大陆边缘裂陷的大地构造环境。初步的同位素年代学研究表明 ,叠布斯格岩群中斜长角闪岩的原岩形成于新太古代 ,含黑云斜长角闪岩中的角闪石3 9Ar_40 Ar坪年龄和等时线年龄分别为 1918Ma和1919Ma ,说明其曾经历了古元古代角闪岩相变质作用的叠加。巴彦乌拉山岩组中斜长角闪岩形成于 2 2 71Ma～2 2 6 4Ma。波罗斯坦庙片麻杂岩中的斜长角闪岩已被 1818Ma和 1839Ma花岗片麻岩侵入 ,根据该杂岩体中斜长角闪岩与巴彦乌拉山岩组中同类岩石的地球化学特征 ,推断其形成于古元古代早期。阿拉善群德尔和通特组中的斜长角闪岩目前尚无确切的同位素年代学数据 ,但相同层位的石榴石二云母石英片岩中锆石离子探针定年已获得平均同位素年龄值为 136 3Ma ,推测它有可能形成于中元古代