南京汤山膨润土矿地质特征,物化性质及矿床成因

通过对南京近郊汤山膨润土矿床的矿区地质、矿床地质特征的分析,阐明了该矿床的成因及其矿石的物化性能。综合研究表明,该矿床是以流纹岩及凝灰岩为成矿原岩,在特定的条件下,经热液蚀变改造而形成的矿床。此矿床之矿石属钙基膨润土,经适当选矿后可用于深加工。     

翡翠的成因及宝石学意义刍论

从地质学角度出发,对翡翠的成因作了初步研究。以此研究结果为基础,探讨了翡翠的矿床类型,翡翠矿床的找矿方向及翡翠“B”货的科学鉴定。     

Zircon U–Pb age and Hf isotope evidence for contrasting origin of bimodal protoliths for ultrahigh-pressure metamorphic rocks from the Chinese Continental Scientific Drilling project

A combined study of zircon morphology, U–Pb ages and Hf isotopes as well as whole‐rock major and trace elements was carried out for ultrahigh‐pressure (UHP) eclogite and felsic gneiss from the main hole (MH) of the Chinese Continental Scientific Drilling (CCSD) project in the Sulu orogen. The results show contrasting Hf isotope compositions for bimodal UHP metaigneous rocks, pointing to contrasting origins for their protoliths (thus dual‐bimodal compositions). The samples of interest were from two continuous core segments from CCSD MH at depths of 734.21–737.16 m (I) and 929.67–932.86 m (II) respectively. Zircon U–Pb dating for four samples from the two core segments yields two groups of ages at 784 ± 17 and 222 ± 3 Ma, respectively, corresponding to protolith formation during supercontinental rifting and metamorphic growth during continental collision. Although the Triassic UHP metamorphism significantly reset the zircon U–Pb system of UHP rocks, the Hf isotope compositions of igneous zircon can be used to trace their protolith origin. Contrasting types of initial Hf isotope ratios are, respectively, correlated with segments I and II, regardless of their lithochemistry. The first type shows positive ?_Hf(t) values of 7.8 ± 3.1 to 6.0 ± 3.0, with young Hf model age of 1.03 and 1.11 Ga. The second type exhibits negative ?_Hf(t) values of ?6.9 ± 1.6 to ?9.1 ± 1.1, with old Hf model ages of 2.11 and 2.25 Ga. It appears that the UHP rocks from the two segments have protoliths of contrasting origin. Consistent results are also obtained from their trace element compositions suggesting that mid‐Neoproterozoic protoliths of bimodal UHP metaigneous rocks formed during supercontinental rifting at the northern margin of the South China Block. Thus, the first type of bimodal magmatism formed by rapid reworking of juvenile crust, whereas the second type of bimodal magmatism was principally generated by rift anatexis of Paleoproterozoic crust. Melting of orogenic lithosphere has potential to bring about bimodal magmatism with contrasting origins. Because arc–continent collision zones are the best place to accumulate both juvenile and ancient crusts, the contrasting types of bimodal magmatism are proposed to occur in an arc–continent collision orogen during the supercontinental rifting, in response to the attempted breakup of the supercontinent Rodinia at c. 780 Ma.     

Nodes and Field of Tourist Origins to Ancient Village——A Case Study of Huangcheng Village in Shanxi Province of China

Based on Hagget's theory of spatial structure,researches on the nodes and field of tourist origins to Huang-cheng Village in Shanxi Province of China have been explored.Nodal hierarchy structure of tourist origins is analyzed with cluster analysis and the gravity model.And field of tourist origins is analyzed with attraction radius index(R)and geography concentration index(G).In the field analysis,R and G of Huangcheng Village are compared with Xidi Village that is a world heritage located in Huangshan City of Anhui Province in China.According to comparison of loca-tions of two areas,influential factors for field area of Huangcheng Village are identified.It is concluded that:1)cluster analysis and gravity model can be complementary methods to each other for nodal hierarchy structure analysis of tour-ist origins;and 2)as far as location is concerned,the weak intensity effect of tourism resources in the tourist region is a major cause for explaining why tourist origins to Huangcheng Village are mainly its neighboring areas.Moreover,it is suggested that the regional effect of tourist resources should be regarded as a component of destination attractiveness when applying gravity model.     

The origin,type and preservation of organic matter of the Barremian–Aptian organic-rich shales in the Muglad Basin,Southern Sudan,and their relation to paleoenvironmental and paleoclimate conditions

Barremian–Aptian organic-rich shales from Abu Gabra Formation in the Muglad Basin were analysed using geochemical and petrographic analyses. These analyses were used to define the origin, type of organic matters and the influencing factors of diagenesis, including organic matter input and preservation, and their relation to paleoenvironmental and paleoclimate conditions. The bulk geochemical characteristics indicated that the organic-rich shales were deposited in a lacustrine environment with seawater influence under suboxic conditions. Their pyrolysis hydrogen index (HI) data provide evidence for a major contribution by Type I/II kerogen with HI values of >400 mg HC/g TOC and a minor Type II/III contribution with HI values <400 mg HC/g TOC. This is confirmed by kerogen microscopy, whereby the kerogen is characterized by large amounts of structured algae (Botryococcus) and structureless (amorphous) with a minor terrigenous organic matter input. An enhanced biological productivity within the photic zone of the water columns is also detected. The increased biological productivity in the organic-rich shales may be related to enhanced semi-arid/humid to humid-warm climate conditions. Therefore, a high bio-productivity in combination with good organic matter preservation favoured by enhanced algae sizes are suggested as the OM enrichment mechanisms within the studied basin.     

龙湾套铜矿岩石学特征及矿床成因

泗水县龙湾套地区发育大面积新太古代角闪辉长岩,为在该区寻找赋存在角闪辉长岩中的岩浆熔离型铜矿床,曾开展过普查工作,最终发现了一小型铜矿床。探讨该区角闪辉长岩岩石学特征,对在该区进一步寻找同类型铜矿床有重要意义。     

鲁西南地区地下水锰的分布特征及其成因

为了解鲁西南地区地下水中锰的含量及其成因,采集并分析了276组地下水样和18组地表水样,结果表明,鲁西南平原区浅层地下水中锰含量在未检出至2.84mg/L之间,平均浓度为0.35mg/L,超标率达41%。鲁西南地区地下水中锰含量的分布与该区的工业化程度以及所处的补、径、排条件密切相关。影响地下水中锰含量分布的因素主要有表层土壤、地下水径流条件及含水层介质和地下水矿化度等。     

苏里格气田西区地层水成因、分布规律与控制因素

苏里格气田西区气井产水严重,地层水成因、分布规律及控制因素不明确,成为制约该区致密砂岩气开发的关键科学问题.在大量测井数据、生产动态数据收集的基础上,分析了苏里格气田西部地层水性质及地球化学特征,结果发现:地层水矿化度高,整体属于盐水;水型主要为CaCl2型;pH值范围为6～6.9,呈弱酸性.分析认为:1)地层水主要为...     

Early Evolution of Apocrita(Insecta,Hymenoptera)as Indicated by New Findings in the Middle Jurassic of Daohugou,Northeast China

<正>The classification and phytogeny of the basal Vespina(=Orussoidea+Apocrita)are reconsidered based primarily on rich and well preserved material from the Middle Jurassic of Daohugou in Inner Mongolia,China. Comparatively smooth morphological transitions are traced from a Xiphydriidae-like ancestor toward Orussoidea via the Jurassic family Karatavitidae,and through Karatavitidae and the Jurassic and Early Cretaceous family Ephialtitidae independently to Stephanidae,to Evanioidea,and,via the extinct Jurassic Kuafuidae fam.nov.to the remaining Apocrita.New hypothesis is proposed concerning development of the characteristic wasp-waist of Apocrita,which is supposed to appear independently and in different ways in Evanioidea and in the rest of Apocrita.As a result,six infraorders are proposed for the suborder Vespina with the following taxonomic structure:infraorder Orussomorpha including the only superfamily Orussoidea(Karatavitidae+Paroryssidae + Orussidae),infraorder Stephanomorpha with the only superfamily Stephanoidea(Ephialtitidae+Stephanidae), infraorder Evaniomorpha with the only superfamily Evanioidea of traditional composition,infraorder Ceraphronomorpha with the superfamilies Ceraphronoidea s.str.and monotypical Megalyroidea and Trigonaloidea,and the infraorders Proctotrupomorpha,Ichneumonomorpha,and Vespomorpha of traditional composition.The family Kuafuidae is unplaced to infraorder because it is putatively paraphyletic with respect to Ceraphronomorpha,Proctotrupomorpha,Ichneumonomorpha and Vespomorpha.Described as new are Karatavites junfengi sp.nov,Praeratavites wuhuaensis sp.nov.,P.perspicuus sp.nov.,Postxiphydria daohugouensis gen.et sp.nov.,P.ningchengensis gen.et sp.nov.,Postxiphydroides strenuus gen.et sp.nov.,Praeratavitoides amabilis gen.et sp.nov.,Proapocrtius densipediculus sp.nov.,P.sculptus sp.nov.,P.longantennatus sp.nov., P.formosus sp.nov.,P.atropus sp.nov.,P.elegans sp.nov.,Stephanogaster pristinus sp.nov.,Asiephialtites lini sp. nov.,Praeproapocritus vulgatus gen.et sp.nov.,Sinaulacogastrinus solidus gen.et sp.nov.,Sinevania speciosa gen. et sp.nov.,Eonevania robusta gen.et sp.nov.,Kuafua polyneura gen.et sp.nov.(all from the Middle Jurassic of Daohugou),as well as Kuafuidae fam.nov.including Kuafua gen.nov.as well as Arthrogaster Rasnitsyn,1975,and Leptogastrella Rasnitsyn,1975 from the Upper Jurassic of Karatau in Kazakhstan.     

甘新北山金窝子韧性剪切带型金矿床成因

金窝子金矿床位于中朝_塔里木板块与哈萨克斯坦板块俯冲碰撞带南缘的甘新北山中带东段,受矿源岩系和区域性韧性剪切带的形成和演化的双重控制。下二叠统金窝子组中金元素含量高,又普遍发生浅变质作用和较强烈的构造变形作用,所以金窝子组能够提供成矿物质。区域性构造变形过程中,大规模深层次的韧性剪切变形促使金窝子组中金元素活化迁移,连同SiO2、K、Na等活性组分和岩石中H2O一起,形成含金动力变质热液;当含金热液上升并进入到NEE向低角度逆冲韧脆性断裂中,则发生交代蚀变和矿化,形成蚀变糜棱岩型和网脉型金矿化;而含金热液上升进入到NNW向高角度张性_张扭性脆性断裂中,则发生充填型矿化,形成石英大脉型金矿化。所以金窝子金矿的最主要控矿因素是矿源岩系和韧性剪切带。因此,金窝子金矿床属于韧性剪切带型金矿床,其成矿作用与控矿因素都与韧性剪切带有关。