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Biogeochemical Prospecting of Sulphide Minerals in Winder Valley, Balochistan, Pakistan 总被引：1，自引：0，他引：1
Abstract: The Mor Range is mountainous terrain in southern Balochistan dominantly occupied by exposures of rocks of the Ferozabad Group which is comprised of Lower‐Middle Jurassic carbonates and siliciclastics. This group contains syngenetic and epigenetic Zn–Pb–Ba mineralization classified as Stratiform Sediment‐Hosted (SSH) and Mississippi Valley Type (MVT) deposits. Three important flora of the Saharo–Sindian, phytogeographical region of Pakistan, namely Tamarix aphyl–la, Salvadora oleoides and Acacia arabica have been studied as a mineralization prospecting tool. Samples of these species were collected from Winder Valley adjoining the Mor Range to prospect for new areas of mineralization, besides the known sulphide deposits. This study revealed the Draber, Thorar, Raj, Mithi and Kanrach localities as new prospect. Quantitative estimation of biophile elements (Zn–Cu–Pb) from the three species was made. A number of new Zn, Cu and Pb anomalies were distinguished in the area. The variation in the constituents of these species from different localities possibly varies with nature and distance from bedrock, mobility, climate, average abundance in the plant ash and exclusion mechanism of the flora. Acacia arabica with deep penetrating roots shows the best results and could be used to delineate new horizons of mineralization. In these species Zn and Cu are relatively concentrated whereas Pb shows limited enrichment. Lead therefore is the element best suited for pinpointing the mineralization owing to its relatively less mobile character. Relationships among Zn–Cu–Pb have been established using scattergrams and triangular variation diagram, which also demonstrate their genetic affiliation. Statistical analyses, such as determination of mean, mode, median, standard deviation, and coefficient of correlation, were also made to improve the raw geochemical data. These biogeochemical methods appear to be suitable in arid climate of Balochistan, if proper attention is paid to species selection. 相似文献
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Mahtab DOUSTI MOHAJER Massih AFGHAH Mohammadsadegh DEHGHANIAN Seyed Jamal SHEIKH ZAKARIAII 《《地质学报》英文版》2021,95(5):1647-1667
The Sarvak Formation is a carbonate sequence of Late Albian–Early Turonian age in Zagros Basin in Iran. In this investigation, the Sarvak Formation at the Pyun Anticline section (Izeh Zone) has been studied. It consists of 797 m thick limestone which overlies the Kazhdumi Formation conformably and underlies the Gurpi Formation unconformably at the Pyun Anticline. A very rich fossil association (85 genera and 132 species) characterizes the Pyun section. Based on the stratigraphic distribution of diagnosed foraminifera, five biozones are established: 1, Muricohedbergella-Globigerinelloides sp. assemblage zone (Late Albian); 2, Praealveolina iberica-Chrysalidina gradata interval zone (Early Cenomanian); 3, Chrysalidina gradata-Cisalveolina fraasi (fallax) and C. lehneri interval zone (Middle Cenomanian); 4, C. fraasi (fallax) and C. lehneri-Praetaberina bingistani assemblage zone (Late Cenomanian); 5, Nezzazatinella picardi-Mangashtia- Dicyclina assemblage zone (Early Turonian). Based on the petrographic and sedimentological analyses, some 13 carbonate microfacies were identified. The investigated microfacies confirm a ramp-type paleoenvironment. These microfacies, from distal to proximal environments, consist of: MF1: planktonic foraminifera wackestone-packstone; MF2: Oligostegina planktonic foraminifera wackestone to packstone; MF3: planktonic-benthic foraminifers sponge spicules wackestone-packstone; MF4: rudist floatstone; MF5: rudist rudstone; MF6: bioclast intraclast grainstone; MF7: peloid intraclast grainstone; MF8: benthic foraminifers rudist grainstone-packstone; MF9: peloid bioclast grainstone-packstone; MF10: bioclast (benthic foraminifers) wackestone-packstone; MF11: peloid bioclast packstone; MF12: dacycladacea benthic foraminifera packstone-wackestone; MF13: miliolids wackestone-packstone. 相似文献
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近年来对青藏高原中拉萨地块西部中生代岩浆作用的源区、成因和演化等问题的研究较少。本文针对中拉萨地块西部噶尔县左左乡两个中酸性岩体进行了岩石学、锆石U-Pb年代学、微量元素和锆石Hf同位素,以及主量元素和微量元素地球化学研究。左左乡北侧岩体寄主花岗闪长岩和闪长质包体获得同期(163Ma和160Ma)的年龄,属于晚侏罗世;南侧岩体花岗岩年龄为142～147Ma,属于早白垩世。北侧与南侧的中酸性岩石均属于准铝质-弱过铝质高钾钙碱性I型花岗岩,富集大离子亲石元素和轻稀土元素,亏损高场强元素。晚侏罗世岩体寄主岩具有较为富集的锆石Hf同位素成分(ε_(Hf)(t)=-16.8～-13.6),可能来源于古老下地壳的部分熔融;包体具有相似的Hf同位素成分(ε_(Hf)(t)=-15.7～-13.6),结合晚侏罗世寄主岩与包体较高的MgO(4.13%～6.90%)、Cr(146×10~(-6)～370×10~(-6))和Ni(31×10~(-6)～113×10~(-6))含量,说明包体代表的中基性岩浆可能源于古老富集地幔的熔融,并且在晚侏罗世寄主花岗闪长岩与闪长质包体所代表的两种岩浆间发生过充分的岩浆混合作用。南侧早白垩世花岗岩具有较负且变化范围大的ε_(Hf)(t)值(-8.2～-4.8和-3.8～+0.2),指示早白垩世岩浆活动中有更多亏损地幔物质或新生地壳物质的加入,并且亏损地幔物质或新生地壳物质与拉萨地块古老地壳物质熔融形成的酸性岩浆发生了岩浆混合,经历岩浆混合后中酸性岩浆又发生了角闪石、长石的分离结晶,最终形成南侧早白垩世岩体的一系列中酸性岩石。研究区早白垩世亏损地幔物质或新生地壳物质的增多可能与南向俯冲的班公湖-怒江板片的回转有关。 相似文献
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